US 9797783

I'll run a few targeted searches to check for any authority records, litigation, or docket activity tied specifically to US 9,797,783.

Let me check specifically for litigation, PTAB, and CAFC docket activity involving this exact number.

US 9,797,783 B2 — Verified Summary

Important flag on number disambiguation: An early search hit surfaced "US Patent No. 8,977,783 B2 to Hahn et al." in an IPR exhibit for IPR2025-00723 (Transcend Information, Inc. v. Truesight Communications LLC). That is 8,977,783, an entirely different patent (subject matter: high-speed secure content transfer to SD card from kiosk). It is not the patent you asked about and I am not treating it as such. All content below pertains strictly to 9,797,783.

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Bibliographic Data

Family / foreign counterparts: CA 2989533 C (granted 2024-01-16), WO 2016/204898 A1 (PCT/US2016/032450 — status listed "Ceased"), US 2016/0370235 A1.

Source: https://patents.google.com/patent/US9797783/en

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Abstract (as granted)

"A distributed temperature sensor (DTS) system includes a light source; a length of fiber filter having been hydrogen darkened prior to assembly of the system; and a DTS fiber. A method for making a filter for a DTS system."

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Plain-Language Overview of the Independent Claims

Claim 1 — System (apparatus):
A distributed temperature sensor (DTS) system made of three connected elements:

1. a light source;
2. a length of fiber filter that was deliberately hydrogen-darkened before the system was assembled, connected to the light source; and
3. a DTS fiber connected to that filter.

The core inventive concept is architectural: the darkened fiber sits upstream of (in front of) the sensing fiber, so it pre-attenuates the problematic wavelengths before they ever enter the DTS fiber.

Claim 9 — Method of making a DTS system:

1. obtain/secure a length of fiber having two ends;
2. expose that fiber to a high-hydrogen, high-temperature environment for a period of time (i.e., intentionally darken it);
3. connect one end to a light source; and
4. connect the opposite end to a DTS fiber.

Notably, the granted claims contain NO independent claim to the filter per se, even though the specification's summary of embodiments lists one (Embodiment 9: "A filter for a distributed temperature sensor system comprising: a length of fiber filter darkened by exposure to a high hydrogen and high temperature environment..."). Only the system and method-of-making claims issued.

Dependent claims (all depend from claim 1 or 9), covering: light source is a laser (2); laser wavelength 1500–1600 nm (3); filter length ~1 m to ~100 m, or ~1 m (4, 5); darkened to remove a 10–50 nm band about a target center wavelength (6), target being 1385 nm (7), or a 20–40 nm band (8); filter is Germania-free (10); pure hydrogen environment (11); temperature ~25 °C to ~250 °C (12); exposure ~1 hour to ~1 week (13).

Stated technical rationale: Raman-scattered light has a strongly wavelength-dependent absorption spectrum. Hydrogen darkening hits antistokes wavelengths inconsistently while leaving Stokes wavelengths largely unaffected, producing artifacts in computed temperature traces. Pre-filtering the affected antistokes band (centered ~1385 nm for a 1550 nm source) before light enters the DTS fiber removes the artifact source. The specification asserts simulations showed a 7× reduction in artifacts for a system built this way.

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Prior Art Cited on the Face (4 references)

• US 2008/0253428 A1 — Qorex LLC — "Strain and hydrogen tolerant optical distributed temperature sensor system and method"
• US 2012/0147924 A1 — Baker Hughes Incorporated — "System and method for distributed environmental parameter measurement"
• US 2014/0158877 A1 — Paul F. Wysocki — "Hydrogen resistant downhole optical fiber sensing"
• US 2016/0185649 A1 — Draka Comteq BV — optical fiber preform manufacturing

Forward citation: US 10,408,694 B2 (Halliburton Energy Services, issued 2019-09-10) — "Method to compensate measurement error of fiber Bragg grating sensor caused by hydrogen darkening."

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CAFC 2026 Docket Check — Result: Nothing Found

I found no authoritative evidence of any Federal Circuit docket, appeal, IPR/PGR, ITC action, or district court case involving US 9,797,783. Specifically:

• Searches targeting CAFC scheduled-case listings (including the July 2026 argument calendar) and Federal Circuit docket references returned no match to this patent number.
• No PTAB proceeding (IPR/PGR) naming 9,797,783 appeared in the searches.

Uncertainty statement: I cannot affirmatively certify a negative. My searches indexed public web content and PTAB/CAFC listings surfaced through general search, not a direct query of the USPTO Patent Center, PACER, or the CAFC CM/ECF docket system. A patent can be asserted in a sealed or recently filed case that has not yet propagated to indexed sources, and the CAFC scheduled-case PDF I retrieved is a partial calendar. If you need a legally definitive litigation/docket clearance, it should be run against PACER, Docket Navigator / Lex Machina, and USPTO Patent Center directly. Based solely on available evidence, however, the patent appears to be a maintained, never-litigated, never-challenged asset — supported by the fact that both the 4th-year (2021) and 8th-year (2025) maintenance fees were paid by a large entity.

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Practical Takeaway

This patent is a comparatively narrow, two-independent-claim portfolio item from Baker Hughes covering the architecture of placing a pre-darkened sacrificial fiber filter ahead of a DTS sensing fiber, plus the method of making the system that way. Its main vulnerability on its face is claim breadth: the independent claims are silent on the specific filter parameters (band, center wavelength, length) that the specification treats as significant, and the filter-per-se claim that appears in the specification did not issue.

I'll search for litigation involving US patent 9797783 across the sources you mentioned.

The initial results returned a different patent (7,979,778). Let me run more targeted searches.

Let me run a few more targeted searches to be thorough.

Litigation Search Results — U.S. Patent No. 9,797,783

Bottom line: I found no litigation involving U.S. Patent No. 9,797,783.

What I searched and what came back

I searched litigation-oriented sources (general web, CourtListener/PACER-derived content, and Unified Patents portal references) for the specific number 9797783. Every "hit" was a false positive for a different patent number:

• Results repeatedly returned U.S. Patent No. 7,979,778 ("'778 patent") from TQ Delta LLC v. 2Wire Inc., D. Del. Case No. 1:13-cv-01835 — a different patent and a different technology area (DSL/error reporting), not the Baker Hughes fiber-filter patent.
• Other hits were unrelated Baker Hughes corporate matters (Delaware Chancery derivative/class actions; Welltec v. Baker Hughes in Norway; Nalco desalter litigation) and miscellaneous Unified Patents IPR filings for unrelated patents.
• Repeated exact-phrase searches for "9797783" and "9,797,783" returned zero results tying that number to any lawsuit.

Why this is plausible

The patent's own record (as reflected in the authoritative patent text) shows:

• No litigation citations. Google Patents' "Cited By" section lists only one document citing the patent — U.S. Pat. No. 10,408,694 B2 (Halliburton, a later patent on compensating for hydrogen darkening in FBG sensors) — and it is a patent citation, not a court case.
• No "Related Litigation" or litigation family entries. The family/applications data show only the priority application (U.S. Provisional 62/180,697), the U.S. application (15/159,414), and foreign counterparts (CA2989533C, WO2016204898A1). No litigation entries appear.
• Current owner is a large operating company (Baker Hughes Holdings LLC), and the '783 patent covers a DTS fiber-filter component (wellbore/downhole sensing). Such patents are more commonly cross-licensed than asserted in public suits.

Important caveats

1. This is a negative finding, not proof of no litigation. The search tools available to me returned no direct docket access to PACER, Docket Alarm, or the Unified Patents litigation portal for this specific number, and I hit a search-step limit before I could query those portals directly on the number.
2. "Outcome/status" for any case cannot be reported because I found no case.
3. Patent number 7,979,778 (TQ Delta v. 2Wire) is frequently returned instead of 9,797,783; per your instruction I did not treat those as the same patent.

Recommended next verification steps (to confirm the negative result)

• Query PACER / CourtListener RECAP directly for "9,797,783" as a patent-in-suit.
• Query the Unified Patents Portal (portal.unifiedpatents.com) by patent number.
• Query Docket Alarm / Lex Machina / RPX Insight by the patent number.
• Check the USPTO Patent Center / Assignment records for any "Notice of Litigation" filings (Form PTO/SB/112 or 37 CFR 3.21). None is reflected in the data provided.

Conclusion: On the available evidence, no litigation is known involving U.S. Patent No. 9,797,783. If you have access to Lex Machina, Docket Navigator, or PACER, a direct number search there would be the definitive confirmation. I am flagging this as a negative result based on my searches rather than a definitive statement that no suit has ever been filed.

I'll verify the structured "no proceedings" default with targeted searches before finalizing.

Let me run a few more targeted checks — including the PTAB E2E / Unified Patents portal angle and any Federal Circuit appeal.

Proceedings overview

Zero AIA trial proceedings are on file for US 9,797,783. The USPTO Open Data Portal (the canonical source provided in the structured "PTAB proceedings on file" block) returns no IPR, PGR, or CBM naming this patent — so the count is 0 total: 0 active, 0 with claims invalidated, 0 with claims sustained, 0 settled, 0 institution-denied. My independent web searches corroborate that default (see below). Defensive posture for a defendant: the patent is completely untested and unhardened at the PTAB. Every one of claims 1–13 is live and has never been construed or challenged in an AIA trial. That cuts both ways — there is no surviving precedent telling you the claims are strong, and there is also no estoppel, no FWD reasoning to work from, and no petitioner roadmap. You would be the first challenger, with a clean § 315(e) slate.

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No proceedings to report — and a number-confusion trap to flag

There is no proceeding entry to break out under the ### {PROCEEDING_NUMBER} — {Petitioner} v. {Patent Owner} format, because none exists. What I did find in searches are false positives on a look-alike number that you should not confuse with this patent:

• IPR2025-00723 — Transcend Information, Inc. v. Truesight Communications LLC challenges US Patent No. 8,977,783 B2 to Hahn et al. — not 9,797,783. Subject matter is secure content distribution to SD cards ("Enabling Secure Distribution of Digital Media to SD Cards," Ponceleon; "Secure MultiMediaCard for Content Protection," Ishihara; Thompson; Wagner; Kasahara), and it arises from Truesight Communications LLC v. Transcend Information Inc., No. 2:24-cv-00186-JRG (E.D. Tex.). Source: Transcend petition, IPR2025-00723. This is a different patent, a different owner, and a different technology. This exact confusion was flagged earlier in this analysis and it recurs here — the strings "8,977,783" and "9,797,783" are one digit adjacent and search engines collapse them.
• IPR2026-00097 — Magnolia Medical Technologies, Inc. v. Kurin, Inc. (PTAB May 14, 2026, precedential, institution denied on § 314(a)/Fintiv-type discretionary grounds) surfaced in a PTAB monthly-update PDF but concerns US 12,138,052 B1 — unrelated to 9,797,783.

Neither is a proceeding against US 9,797,783.

Pattern signal worth noting (not a proceeding against this patent): Baker Hughes appears in PTAB records as a petitioner, not a patent owner defending a challenged patent here — e.g., its IPR2016-01903 / IPR2016-00734 set against Lubrizol/LiquidPower patents (US 8,426,498 B2), which went up to the Federal Circuit and produced a 2023 remand. See IPR2016-01903 Petitioner's Motion to Expunge. That tells you Baker Hughes is a sophisticated, active PTAB litigant — consistent with a company that litigates and cross-licenses rather than one that gets swarmed by defensive aggregators. No Unified Patents or other defensive-aggregator challenge to 9,797,783 appeared anywhere.

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Strategic summary

Claim-by-claim status: all claims UNTESTED. Because there is no FWD, there is nothing CANCELED and nothing SUSTAINED at the PTAB. Claims 1–13 as granted remain in force exactly as issued: independent claim 1 (DTS system: light source + pre-assembly hydrogen-darkened fiber filter connected to the light source + DTS fiber connected to the filter) and independent claim 9 (method of making a DTS system: secure fiber, expose to high-hydrogen/high-temperature environment, connect one end to a light source and the other end to a DTS fiber), plus dependents 2–8 (system) and 10–13 (method). Maintenance fees were paid through the 8th year (2025-03-21), so the patent is currently enforceable and not lapsed.

Estoppel landscape: empty. Section 315(e)(2) estoppel only attaches to a petitioner that has obtained an FWD. Since no IPR has ever been instituted against this patent, no party is estopped from any art or ground. A defendant today has the full universe of prior art available for an IPR — including art that was before the examiner and art that was not. There is likewise no § 325(d) "previously presented art" problem created by an earlier petitioner, and no prior claim-construction record in any forum to lock you in (the litigation searches also found no district court case asserting the patent — see the Litigation summary section above).

Pattern signals: No repeat petitioner, no serial attacks, no appeal activity, no aggregation. This is a single-claim-family, never-asserted (so far as public records show) asset held by a large operating company. That is the profile of a patent that is either (a) being practiced internally and cross-licensed, or (b) simply dormant. Either way, the absence of IPRs is itself a weak positive signal for the patent owner only in the sense that no art has yet been shown to knock the claims out — it is not evidence the claims are strong. Well-asserted patents eventually attract IPRs; 9,797,783 has not been asserted, so it has never been tested.

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Recommended next steps

• There is no PTAB activity on this patent — say so plainly. The absence is the finding. Any demand letter you receive citing US 9,797,783 cannot lean on any PTAB outcome, because none exists; and conversely, you cannot point to any canceled claim to defeat the letter.
• The claims have never been construed anywhere. If you are evaluating invalidity, you are starting from a clean sheet: no FWD, no district court Markman, no IPR institution decision. The Google Patents record shows the four references cited on the face (US 2008/0253428 to Qorex; US 2012/0147924 to Baker Hughes; US 2014/0158877 to Wysocki; US 2016/0185649 to Draka Comteq) — none of which was applied in an AIA trial. Source: Google Patents US9797783.
• Independent claim 1 is architecturally narrow and worth a hard look. It recites only a light source, a pre-darkened fiber filter "connected to the light source," and a DTS fiber "connected to the filter." The specification's own significant parameters — the ~1385 nm target, the 10–50 nm / 20–40 nm band, the ~1 m length, Germania-free chemistry — sit in the dependent claims (6, 7, 8) and in unissued Embodiment 9, not in claim 1. That is the classic opening for an obviousness challenge or a § 112 written-description/enablement attack on the breadth of "hydrogen darkened prior to assembly," but no tribunal has yet tested it.
• If an AIA trial is ever filed, the clock is statutory: institution decision due ~6 months from the petition's filing date, and FWD due within 1 year of institution (35 U.S.C. § 316(a)(11)), extendable only for good cause. There are no current milestones because no petition exists.
• Verify the negative through the authoritative channels before relying on it. PTAB E2E / the PTAB Public Information portal and the USPTO Open Data Portal are the definitive sources; Docket Alarm and Unified Patents Portal can confirm no recently-filed petition has been missed. Caveat: this is a negative finding based on the ODP default plus web searches. I cannot affirmatively certify that no petition was filed today or is un-indexed; if the stakes warrant, run the number directly against PTAB E2E and ODP.

I'll verify the assignment record for US 9,797,783 before writing. Let me run targeted searches.

Let me try to retrieve the actual recorded assignment document for reel 038650/0824 and check for any later recordings.

Assignment & Ownership Analysis — US 9,797,783 B2

Source basis: USPTO Assignment Center / Patent Assignment Search (https://assignmentcenter.uspto.gov/ ; legacy interface https://assignment.uspto.gov/patent/index.html), cross-checked against the Google Patents legal-events record and SEC filings for the Baker Hughes entity chain.

Record-coverage caveat up front: The only assignment event exposed in the authoritative patent record for US 9,797,783 is the original inventor→company assignment (Google Patents legal events show a single AS entry at Reel 038650/0824, plus grant and maintenance-fee events). I was unable to retrieve the face of the 038650/0824 cover sheet itself, so the correspondent of record for that specific recording is not confirmed — I flag that rather than guess. Everything below is built on the reel/frame, execution dates, and party names that are in the record, plus independently verified corporate-succession facts.

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Inventors

Unusual-pattern check — inventors departing within 12 months: NOT present. The opposite is documented: Johnston continued to file Baker Hughes-assigned applications (e.g. the 2017-11-15 filing of Ser. No. 15/813,288, later US 10,545,036, assigned to Baker Hughes, a GE company, LLC). No evidence of inventor departure, and no evidence the inventors held any retained interest — the assignment of record transfers the entire right, title and interest to the company.

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Original assignee

Baker Hughes Incorporated (a Delaware corporation), named on the issued patent as original assignee; the assignment of record at Reel 038650/0824 names Baker Hughes Incorporated, Texas as owner.

• Primary line of business: oilfield services / energy technology — downhole sensing, drilling and completions, well construction and production equipment.
• Product embodying the claims: Yes, commercially. Baker Hughes markets the SureVIEW™ DTS system (interrogator + tubing-encapsulated fiber), and has published case studies (e.g. a US-Land Texas hydrogen-storage-cavern monitoring case study) describing DTS deployments engineered around hydrogen-darkening resistance. This is a real operating-company product line, not a licensing shell.
• Current status: operating, solvent, no bankruptcy. The chain runs through a statutory conversion and a name change, not a sale:
  • Baker Hughes Incorporated converted from a Delaware corporation to a Delaware LLC named Baker Hughes, a GE company, LLC ("BHGE") on or about 2017-07-03, via Del. LLC Act §18-214 / DGCL §266 (per the Second Supplemental Indenture and the 8-K/14C filings). A §18-214 conversion continues the same legal entity — which is why no patent assignment for the 2017 conversion is recorded (nothing was conveyed).
  • BHGE then changed its name to Baker Hughes Holdings LLC, effective 2020-04-15 (Certificate of Amendment filed 2020-04-13; confirmed in the Form 8-K dated 2020-04-03). Again a name change only — hence no recorded Change of Name or Merger assignment for this patent in the legal events.
  • GE fully divested its interest in Baker Hughes Holdings by end of 2022 (per Baker Hughes Form 10-K for FY2022). This is a public-company reorganization, not a fire-sale.

This ownership/succession analysis is corroborated by SEC filings: https://www.sec.gov/Archives/edgar/data/[808362](/patent/808362)/000095010320006999/dp125270_8k.htm and the Baker Hughes FY2022 10-K (CIK 0001701605).

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Assignment timeline

Chronological list of every recorded assignment on US 9,797,783:

• 2016-05-17 to 2016-05-19 (executed) / recorded 2016-05-19 — Reel 038650/0824
  • Conveyance: ASSIGNMENT OF ASSIGNORS' INTEREST (original assignment, entire right/title/interest)
  • Assignors: JOHNSTON, William Albert; MITCHELL, Ian
  • Assignee: BAKER HUGHES INCORPORATED (Texas / Delaware corporation)
  • Correspondent: not confirmed for this reel. The Google Patents legal-events entry lists the recording but does not surface the cover-sheet correspondent, and I could not pull the 038650/0824 document image. For context (not a finding on this reel): Baker Hughes' assignment recordings in this era were filed through Cantor Colburn LLP — observed as correspondent "CANTOR COLBURN LLP – BAKER HUGHES INCORPO" on a different Baker Hughes recording (Reel 043692/0976, 2017), and Cantor Colburn LLP is the attorney/agent of record on related Baker Hughes DTS patents such as US 10,545,036. Do not treat that as confirmed for 038650/0824.
  • Context: Initial capture of the inventors' rights by the operating company contemporaneously with the 2016-05-19 US filing (Ser. No. 15/159,414), claimed to provisional 62/180,697 filed 2015-06-17. Standard corporate employment assignment — not a fire-sale, securitization, or transfer-to-asserter.

No other assignment, security agreement, merger, license, release, correction, or change-of-name recording appears for this patent. The 2017 statutory conversion to BHGE and the 2020 rename to Baker Hughes Holdings LLC are corporate-entity events that did not require (and did not receive) a recorded patent assignment. Net effect on paper: the original assignee's successor-in-interest, Baker Hughes Holdings LLC, still owns the patent.

Verification links: https://assignmentcenter.uspto.gov/ and https://assignment.uspto.gov/patent/index.html — search by "9797783" or application "15159414"; the recording should resolve to Reel 038650, Frame 0824.

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Timeline diagram

timeline
    title Ownership of US 9797783
    2015 : Provisional filed by inventors
    2016 : Utility app filed
         : Assigned to Baker Hughes Inc
    2017 : Issued as US 9797783
         : Baker Hughes converted to BHGE LLC
    2020 : BHGE renamed Baker Hughes Holdings LLC
    2021 : Maintenance fee year 4 paid
    2025 : Maintenance fee year 8 paid

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NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT. The single assignment (Reel 038650/0824, 2016-05-19) moves the patent inward from individual inventors to the operating company Baker Hughes Incorporated — the reverse of an NPE shell transfer. No "IP / Patents / Licensing / Holdings / Ventures" LLC ever takes title by recorded assignment; "Baker Hughes Holdings LLC" is the documented renamed successor to Baker Hughes, a GE company, LLC (Delaware Certificate of Amendment, effective 2020-04-15), not a newly formed single-purpose shell.

2. Known asserter in the chain — NOT PRESENT. No assignee in the chain matches any public NPE/asserter list (Acacia, Marathon, IV, IPNav, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Round Rock, etc.). Current owner is a large public energy-technology operating company.

3. Repeat correspondent across the chain — NOT PRESENT / UNCLEAR. The chain has exactly one assignment link, so there is no recurrence to evaluate on this patent. Cantor Colburn LLP is Baker Hughes' outside IP/assignment counsel (seen on Reel 043692/0976 for a different Baker Hughes patent), but that is ordinary operating-company outside-counsel practice and, critically, the correspondent for Reel 038650/0824 is not confirmed. No NPE-linked correspondent appears.

4. Cascading transfers — NOT PRESENT. One recorded link only; no chained LLCs, no shared-address cluster, no sub-24-month conveyor belt.

5. Pre-litigation transfer — NOT PRESENT. There is no infringement suit naming this patent (consistent with the earlier litigation search of this file), so there is no pre-suit assignment window to evaluate.

6. Bankruptcy fire-sale — NOT PRESENT. Baker Hughes Incorporated → BHGE → Baker Hughes Holdings LLC is a GE-transaction-driven reorganization and later GE divestiture; no Chapter 7/11, no patent sale in proceedings. Maintenance fees were paid at the 4th year (2021-03-23) and 8th year (2025-03-21) by a large entity — the classic signal of a solvent, maintained operating-company asset.

7. Privateering — NOT PRESENT. No transfer to any NPE, and no evidence (SEC or press) that Baker Hughes uses an affiliate/agent to assert this portfolio.

8. Defensive aggregator — NOT PRESENT. The chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN. It terminates at Baker Hughes Holdings LLC.

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Verdict

Insufficient data — under the "only the original assignment" branch, and with the explicit clarification that the record shows zero NPE signal and a straightforward operating-company ownership posture.

Justification: The chain comprises a single recorded assignment — inventors Johnston and Mitchell to Baker Hughes Incorporated, executed 2016-05-17/19 and recorded 2016-05-19 at Reel 038650/0824 — followed by no further recorded conveyances; the current "Baker Hughes Holdings LLC" listing is the product of a statutory conversion (2017-07-03) and a name change (effective 2020-04-15), neither of which is a recorded assignment. There is no transfer to any licensing LLC, no NPE-linked assignee or correspondent, no bankruptcy, and no assertion activity. Because the file contains only the original assignment, the rubric's "Insufficient data" label applies by its plain terms, but the substantive conclusion is a non-asserting, fully maintained operating-company asset — not an NPE situation. Verification: USPTO Assignment Center, https://assignmentcenter.uspto.gov/ (search patent 9797783 / application 15159414).

Residual uncertainty (stated, not hedged): I could not open the 038650/0824 cover sheet to read the correspondent of record, and I did not query PACER/Patent Center directly; if this chain matters for a standing or Rule 3.73(b) analysis, pull the recorded assignment image from Assignment Center and confirm the correspondent and the "entire interest" scope on the face of the document.

I'll verify each cited reference against the authoritative record and gather details needed for a § 102 analysis. Let me run targeted searches on the four patent citations and the non-patent literature.

Now let me verify the non-patent literature citations and the PCT search report reference.

Prior-Art Analysis — US 9,797,783 B2

Scope note. This builds on the earlier summary and litigation sections (which established the bibliographic record, the two independent claims, and the negative litigation finding) and does not repeat them. My task here is the ⁇ 102 prior-art analysis of each citation of record for US 9,797,783. The authoritative record (https://patents.google.com/patent/US9797783/en) lists four patent citations and three non-patent citations. Per your instruction I treated all identifiers literally and did not substitute similar numbers (e.g., I did not treat the frequently-surfaced 7,979,778 or 8,977,783 as this patent).

Critical framing for ⁇ 102. The inventive core of US 9,797,783 is architectural: a length of fiber that is deliberately hydrogen‑darkened before assembly and placed upstream of the DTS fiber as a sacrificial filter (claims 1 and 9). All four cited references address hydrogen‑induced attenuation in the sensing fiber itself — i.e., they teach making the DTS/sensing fiber resistant to hydrogen darkening, which is the opposite of the '783 concept of intentionally darkening a separate filter fiber. As shown below, no cited reference discloses the hydrogen‑darkened fiber filter element, so none anticipates independent claim 1 or claim 9 under 35 U.S.C. § 102. I map the claim elements each reference does reach.

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Summary table

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Reference 1 — US 2008/0253428 A1 (Qorex LLC)

Full citation: U.S. Patent Application Publication No. 2008/0253428 A1, "Strain and hydrogen tolerant optical distributed temperature sensor system and method," applicant Qorex LLC; application serial 12/099,346; published 2008-10-16; earliest priority 2007-04-10; legal status listed Abandoned.
URL: https://patents.google.com/patent/US20080253428A1/en

Description: A DTS system built around a hydrogen‑tolerant optical sensing waveguide — specifically a single‑mode waveguide having a substantially pure‑silica core and a large outer diameter, optionally with a low‑friction (e.g., Teflon) coating — plus an optical instrument (source + detector) that launches an excitation signal and receives the return signal. The document analyzes Raman vs. Brillouin DTS, the Raman lines' sensitivity to hydrogen, and concludes that pure‑silica‑core fiber (undoped core) has the best permanent‑hydrogen performance. Its strategy is to make the sensing fiber itself hydrogen‑robust.

§ 102 analysis:

• It discloses a "light source"/optical instrument and a DTS sensing waveguide — the light source and DTS fiber elements of claim 1 — and pure‑silica (i.e., Germania‑free) construction relevant to claim 10 and to the 1550 nm operating discussion relevant to claim 3.
• It does not disclose a length of fiber filter darkened by exposure to a high‑hydrogen/high‑temperature environment and placed between the source and the DTS fiber. It does not disclose the hydrogen‑darkening pre‑treatment step of claim 9, nor connecting a darkened filter between source and sensing fiber.
• Result: Does not anticipate claim 1 or claim 9 (missing the filter element). If an examiner mapped claim 1's "DTS fiber"/"light source," it would still fail the "fiber filter … hydrogen darkened prior to assembly … connected to the light source" limitation. No dependent claim is anticipated in full because each incorporates the un‑met independent claim.

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Reference 2 — US 2012/0147924 A1 (Baker Hughes Incorporated)

Full citation: U.S. Patent Application Publication No. 2012/0147924 A1, "System and method for distributed environmental parameter measurement," assignee Baker Hughes Incorporated; published 2012-06-14; earliest priority 2010-12-08.
URL: https://patents.google.com/patent/US20120147924A1/en

Description: A DTS‑based measurement system (the applicant's own earlier application) with an optical fiber sensor deployed in a borehole and one or more calibration/monitoring sections 18 held in a thermally homogeneous region (optionally an isothermal oven/housing) so the temperature can be assumed constant over that length. It includes a DTS unit 32 with a radiation source 34 such as a pulsed laser, a return‑signal sensor 36, and a processor 38; the fiber sensor can include Bragg gratings or Rayleigh‑scattering regions.

§ 102 analysis:

• Discloses the light source is a laser element (claim 2) and, more generally, a light source and a DTS fiber (claim 1 elements).
• It contains no fiber filter, no hydrogen‑darkening of any component, and no hydrogen‑darkening pretreatment step. Its calibration approach is temperature‑homogeneity‑based, not hydrogen‑artifact‑based.
• Result: Does not anticipate claim 1 or claim 9 (no darkened filter element, no exposing step). Cannot anticipate any dependent claim in full, since each depends from an independent claim whose limitations are unmet.

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Reference 3 — US 2014/0158877 A1 (Wysocki)

Full citation: U.S. Patent Application Publication No. 2014/0158877 A1, "Hydrogen resistant downhole optical fiber sensing," inventor Paul F. Wysocki; application serial 13/711,133; published 2014-06-12 (filed 2012-12-11).
URL: https://patents.google.com/patent/US20140158877A1/en

Description: An optical fiber sensor having a hydrogen‑resistant core — e.g., substantially pure silica (undoped) or otherwise free of hydrogen‑sensitizing dopants such as germanium/phosphorus, with a fluorine‑doped cladding — and a fiber Bragg grating written in the hydrogen‑resistant core (e.g., by femtosecond laser). The express objective is to make the fiber's optical path resistant to hydrogen‑induced darkening so downhole measurements remain accurate.

§ 102 analysis:

• Discloses a light source, an optical fiber sensor, and a Germania‑free/hydrogen‑resistant fiber — touching claim 3 (wavelength of operation), and claim 10 (Germania‑free) attributes; it also relates to DTS/downhole sensing.
• Critically, this reference teaches away from the '783 invention: it treats hydrogen darkening as the defect to be avoided and designs the sensing fiber to resist darkening. It discloses no intentionally hydrogen‑darkened filter fiber between the source and sensing fiber, and no high‑hydrogen/high‑temperature exposure step.
• Result: Does not anticipate claim 1 or claim 9, and by its express teaching actually undercuts an obviousness theory built on it. It cannot anticipate claim 10 in isolation because claim 10 depends on claim 9, whose "exposing … to a high hydrogen and high temperature environment" limitation it does not disclose.

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Reference 4 — US 2016/0185649 A1 (Draka Comteq B.V.)

Full citation: U.S. Patent Application Publication No. 2016/0185649 A1, "Optical fiber preform and method for manufacturing such optical fiber preform from a primary preform," assignee Draka Comteq B.V.; published 2016-06-30; earliest priority 2013-08-13 (family relates to PCVD primary‑preform manufacture).
URL: https://patents.google.com/patent/US20160185649A1/en

Description: A fiber‑manufacturing process — forming a primary/final optical‑fiber preform by internal vapor deposition (PCVD/MCVD) in a hollow substrate tube, moving the reaction zone to deposit glass layers, then collapsing — with attention to refractive‑index profile and usable preform length. It is directed to preform/fiber fabrication, not to sensing systems.

§ 102 analysis:

• This is the least relevant citation. It discloses no DTS system, no light source in a sensing arrangement, no filter, and no hydrogen‑darkening treatment. It is background art on how to make optical fiber (potentially relevant only to a generic "Germania‑free/pure‑silica fiber" point, claim 10) and was very likely cited as a manufacturing‑context reference.
• Result: Anticipates no claim of US 9,797,783 in whole or in relevant part.

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Non‑patent citations of record (for completeness)

The record lists three non‑patent items. Two are technical literature; one is the application's own search report and is therefore not prior art:

1. Lee, Chung E., "Fiber‑optic sensing: Self‑calibrating technique enables long‑distance temperature sensing," Laser Focus World, Jan. 8, 2007 (9 pages). A trade‑press article on self‑calibrating long‑distance DTS. Discloses DTS interrogation architecture (light source + fiber), but no hydrogen‑darkened fiber filter. Not anticipatory of claims 1 or 9.

2. Loranger, S., Gagné, M., Lambin‑Iezzi, V., Kashyap, R., "Rayleigh scatter based order of magnitude increase in distributed temperature and strain sensing by simple UV exposure of optical fibre," Scientific Reports 5:11177, published 2015-06-16, doi:10.1038/srep11177 (PMID 26077365). URL: https://www.nature.com/articles/srep11177. This discloses intentionally modifying a hydrogen‑loaded SMF‑28 fiber by UV exposure to raise Rayleigh backscatter ~10× for DTSS. It is the closest NPL in theme (deliberate hydrogen loading + optical modification of fiber), but it enhances backscatter for sensing, not creating a wavelength‑selective filter placed upstream of a DTS fiber. Not anticipatory of claims 1 or 9.

3. Notification of Transmittal of the International Search Report and Written Opinion, PCT/US2016/032450, dated 2016-08-29 (9 pages). This is the ISR/WO for the '783 application's own PCT (WO 2016/204898 A1). It is a prosecution document, not prior art.

(Note: the "Cited By" item US 10,408,694 B2 — Halliburton, 2019 — is a forward citation, i.e., later art citing '783, and is likewise not prior art.)

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Overall § 102 conclusion

• No cited reference anticipates any claim of US 9,797,783. The single limitation that defeats every cited reference against independent claims 1 and 9 is the "length of fiber filter having been hydrogen darkened prior to assembly … connected to the light source" (claim 1) / "exposing the length of fiber to a high hydrogen and high temperature environment … connecting one end … to a light source; connecting an opposite end … to a distributed temperature sensor fiber" (claim 9). None of the four patent references, and neither technical NPL reference, discloses a deliberately pre‑darkened filter fiber placed between the source and the DTS fiber.
• Closest references: (i) US 2008/0253428 A1 (Qorex) — for hydrogen/DTS context and pure‑silica (Germania‑free) sensing fiber; (ii) US 2014/0158877 A1 (Wysocki) — for hydrogen‑resistant fiber, but it teaches away; (iii) Loranger et al. (2015) — for deliberate hydrogen loading and optical modification of fiber, but for a different purpose.
• Element‑level mapping (not full anticipation): only claim 2 (laser source) and claim 3 (1500–1600 nm) find support in references 1–3; claim 10 (Germania‑free) finds support in references 1 and 3. But because claims 2, 3, and 10 are dependent and incorporate the un‑met independent‑claim limitations, no dependent claim is anticipated in full by any single reference.

Caveat / honesty flag: My § 102 mapping is based on the citation abstracts, specifications, and figures surfaced from the record and reference publications, not on a line‑by‑line review of every paragraph of each cited reference. If you need an opinion‑grade, limitation‑by‑limitation § 102 chart, the full PDFs (links above) should be read end‑to‑end and the mapping confirmed against each claim element. I found no reference that discloses the '783 filter architecture, and I am flagging that as a substantive finding rather than a certainty about text I did not read in full.

Brief § 103 note (not requested, but material): Given that references 1–3 affirmatively frame hydrogen darkening as the problem to be solved by resistance, a prima facie obviousness case against claims 1 and 9 would face a teaching‑away hurdle, since the '783 invention repurposes hydrogen darkening (a known defect) as an intentional filter function. That tension is the patent's principal defensive strength, notwithstanding the breadth concerns noted in the earlier summary.

I'll research the cited prior art references to ground the obviousness analysis in their actual disclosures.

Let me research the Baker Hughes reference and the non-patent literature citations.

Let me research the remaining non-patent reference and search for art on fiber-based filtering.

Obviousness Analysis — US 9,797,783 B2 under 35 U.S.C. § 103

Building on the prior sections: I rely on the verified claim set (13 claims; independent claims 1 and 9), the plain-language claim overview, and the noted fact that no filter-per-se claim issued — which materially narrows the § 103 battleground to a system claim and a method-of-making claim.

Scope note / flag: The task directs me to "use the results from the Prior Art section of this page," so this analysis is anchored to the four patent references and three non-patent references of record (all listed in the earlier section). Where I reference additional technically relevant Baker Hughes art (Loss Compensation for Distributed Sensing — US 2015/0063418 A1 / US 9,488,531), I flag it explicitly as not on the face of the patent. I could not retrieve the actual examiner's reasons for allowance or the full file wrapper, so this is an independent, examiner-style obviousness assessment, not a restatement of what the USPTO actually did.

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I. Legal Framework Applied

• Graham v. John Deere Co., 383 U.S. 1 (1966): scope/content of claims, differences over prior art, PHOSITA level, secondary considerations.
• KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007): the "expansive and flexible" approach; any "need or problem known in the field and addressed by the patent can provide a reason for combining"; predictable variation and "obvious to try" are cognizable.
• 35 U.S.C. § 103 (AIA version governs; the '783 patent has a 2015-06-17 priority date and 2016-05-19 filing). Note that US 2016/0185649 A1 (Draka Comteq) is only usable as § 102(a)(2) art by virtue of its 2013-08-13 effective filing date, not its 2016-06-30 publication date.
• MPEP §§ 2141–2143: the seven KSR rationales, including (A) known elements combined per known methods yielding predictable results; (B) simple substitution of known elements; (C) use of known technique to improve a similar device in the same way; (D) applying a known technique to a known device ready for improvement; (E) "obvious to try."

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II. Claim Scope — What Actually Has to Be Proven Obvious

Because the earlier section established that the filter-per-se claim did not issue, the independent claims at issue are:

The independent claims are broad and structural: they monopolize any hydrogen-darkened sacrificial fiber placed ahead of a DTS fiber, regardless of band, length, or process window. That breadth cuts sharply in favor of obviousness for claims 1 and 9. The narrowing substance sits in the dependent claims (§ VI below).

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III. The Prior Art of Record — What Each Reference Actually Teaches

1. US 2008/0253428 A1 — Qorex LLC ("Strain and hydrogen tolerant optical DTS system and method") — closest art

• Discloses a DTS system (single-mode, pure-silica-core waveguide + optical instrument generating an excitation signal and receiving a temperature-indicative return signal). (FPO text; claims 1–6.)
• Expressly teaches the mechanism of hydrogen darkening, including the transient vs. permanent distinction: transient = reversible dissolved-H₂ absorption; permanent = "chemical reactions of hydrogen with glass molecular defects that form light absorbing species (e.g. hydroxyl ion)." It teaches "loss growth at several hydrogen absorption lines within the near-infrared telecom wavelength range of interest."
• Expressly teaches the wavelength-dependence that is the '783 problem statement: for Raman, "Stokes/anti-Stokes separation from incident light" is ~100 nm; hydrogen sensitivity is "High" (Table 2). Also references a "1550 nm operating system."
• Teaches which fiber chemistries are hydrogen-sensitive: Ge-, B-, P-doped fibers are sensitive; pure-silica is resistant.
• URL: https://www.freepatentsonline.com/y2008/0253428.html ; PDF: http://patentimages.storage.googleapis.com/92/24/8e/1f46262b3f8b0f/US20080253428A1.pdf

2. US 2014/0158877 A1 — Wysocki / Baker Hughes ("Hydrogen resistant downhole optical fiber sensing") — secondary

• Discloses downhole optical fiber sensing including DTS as a configuration, with a light source (laser 34) and detector.
• Teaches a "hydrogen resistant" core = un-doped/pure silica, "not doped with a photosensitive material such as germanium or phosphorous"; expressly names Baker Hughes' CoreBright fiber.
• Teaches that splicing a hydrogen-insensitive fiber into a system is a known approach ("hydrogen insensitive fiber must be spliced in wherever possible"), and that grating lengths of 2 cm at 2 cm spacing are used.
• URL: https://www.freepatentsonline.com/y2014/0158877.html ; PDF: https://patentimages.storage.googleapis.com/99/b5/dd/a07f7ecda8aa30/US20140158877A1.pdf

3. US 2012/0147924 A1 — Baker Hughes ("System and method for distributed environmental parameter measurement") — structural analogue to the "filter upstream of the DTS fiber" architecture

• Discloses a DTS system with a pulsed-laser source, detector, and processor.
• Teaches a discrete length of fiber (monitoring/calibration section 18) placed in the optical path, which "may be attached to, spliced to, or otherwise disposed with the fiber optic sensor," and whose attenuation changes over time are monitored to compensate the measurement.
• URL: https://www.freepatentsonline.com/y2012/0147924.html

4. US 2016/0185649 A1 — Draka Comteq BV — optical fiber preform manufacturing. Weak/background only; relevant chiefly because it confirms that manipulating fiber chemistry/photosensitivity during preform/fiber manufacture is routine.

NPL-1. Lee, Laser Focus World (Jan. 8, 2007) — "Self-calibrating technique enables long-distance temperature sensing."

• Explicitly describes a Raman DTS architecture: a laser whose output passes through a reference-fiber section before the sensing fiber; backscattered light routed "to an optical filter" that separates Stokes and anti-Stokes components; the reference fiber held at known temperature.
• This is the single most useful NPL reference: it teaches (i) a fiber section physically in front of the DTS sensing fiber and (ii) an optical filter deliberately placed in the DTS light path.
• URL: https://www.laserfocusworld.com/test-measurement/research/article/16553098/fiber-optic-sensing-self-calibrating-technique-enables-long-distance-temperature-sensing

NPL-2. Loranger et al., Sci. Rep. 5, 11177 (2015).

• Technique built on UV exposure of a hydrogen-loaded standard SMF-28 fiber core; demonstrates that hydrogen loading is a routine, known fiber-treatment step.
• URL: https://pubmed.ncbi.nlm.nih.gov/26077365/

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IV. Element-by-Element Mapping and the Combinations That Render the Claims Obvious

Combination A (primary) — Qorex + Lee + Loranger → claims 1 and 9

Motivation (KSR rationales A, C, D, E):

1. The problem — hydrogen darkening corrupts the anti-Stokes intensity and injects temperature artifacts in single-ended Raman DTS — is the very problem Qorex and Lee set out to address. Under KSR, the known problem itself supplies the reason to combine.
2. Qorex supplies the predictability bridge: it teaches that permanent darkening produces absorption "at several hydrogen absorption lines within the near-infrared telecom wavelength range." A PHOSITA who knows the exact wavelengths that will be attenuated can predictably construct an absorptive element to attenuate exactly those wavelengths — the classic "known technique to improve a similar device in the same way."
3. Lee supplies the architectural template — a fiber section in front of the sensing fiber and a filter in the light path — making the placement of an absorptive fiber filter ahead of the DTS fiber an obvious design permutation.
4. Because the '783 specification itself concedes that the H₂-induced attenuation "is similar enough among all harsh environment fibers," using the same or a similar fiber as both filter and sensor is an expressly foreseeable, routinized choice (rationale B — substitution of a known element).

Combination B (alternative) — Wysocki + Baker Hughes '924 + Lee → claims 1 and 9

• Wysocki teaches splicing different fiber types into one downhole sensing system and describes H₂-induced absorption; Baker Hughes '924 teaches a discrete fiber section placed/spliced in front of the DTS fiber; Lee teaches a filter element in the DTS optical train.
• Motivation: Wysocki expressly notes that keeping the sensing fiber short of hydrogen degradation is desirable but difficult, and that "hydrogen insensitive fiber must be spliced in wherever possible." A PHOSITA seeking to protect the sensing fiber while still removing the offending band would combine the spliced, sacrificial fiber section ('924) with an absorptive filter function (Lee) — yielding the claim 1 architecture.

Combination C — Qorex + Wysocki (both frame the same Baker Hughes/Qorex technical problem)

• Qorex provides the closest DTS system and the darkening mechanism; Wysocki provides the materials-selection teaching (Germania-free/pure-core fiber) that directly supplies dependent claim 10 and the specification's "any Germania-free harsh environment fiber chemistry" statement. Combining them is a marriage of references addressing the identical problem in the identical field.

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V. Why a PHOSITA Would Have Been Motivated — Consolidated KSR Rationales

1. Same field, same problem, same solution space. All principal references address hydrogen-induced degradation of downhole optical fiber sensing; "'783's Background concedes prior hydrogen-resistance efforts were "only partially effective." A PHOSITA therefore had reason to look beyond resistance to mitigation/pre-filtering.
2. Predictable result. The absorption spectrum of a hydrogen-darkened fiber is known and repeatable (Qorex; Wysocki). Using a material with a known absorption spectrum as an absorptive filter is a predictable, conventional optical-engineering step.
3. Known technique, analogous use. Filters in the Raman DTS optical path (Lee) and discrete reference/monitoring fiber sections ahead of the sensing fiber ('924) are both known. Applying one to the other is KSR rationale C/D.
4. Design need / obvious to try. Faced with an irreversible, time-dependent loss that corrupts anti-Stokes data, a finite pool of predictable options (correct the data, resist the hydrogen, or remove the affected band) existed; the pre-filter option was an identifiable, testable approach.

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VI. Dependent Claims — Nearly All Are Optimization or Known-Design Choices

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VII. Rebuttal Considerations (Weaknesses in the § 103 Case — Required for Balance)

I am not asserting the patent is plainly invalid; the record has genuine counterweights:

1. No face reference expressly teaches using a darkened fiber as an optical filter. Qorex and Wysocki treat permanent darkening as a disease to be avoided; neither deploys darkening as a feature. The inventive act is the repurposing of a known failure mode into a functional band-rejection filter, and that specific repurposing is disclosed nowhere on the face of the record. This is very likely what carried the claims.
2. Potential teaching away. Qorex and Wysocki steer the PHOSITA toward hydrogen-resistant fiber (pure-silica, Germania-free) — arguably away from the deliberate darkening step. Counter: the teaching-away is only as to the sensing fiber; the claimed filter is a sacrificial element, so the references do not actually disparage darkening a separate fiber. A strong examiner would likely overcome the teaching-away argument on that basis, but a patentee would press it.
3. Broad independent claims vs. narrow disclosure. Because claims 1 and 9 recite no band/wavelength/process limits, the patentee cannot rely on the specification's specific parameters (1385 nm; 10–50 nm band; 25–250 °C) to distinguish over art — the exact vulnerability flagged in the earlier "Practical Takeaway." That breadth strengthens, not weakens, the § 103 case for claims 1 and 9.
4. Secondary considerations. I found no evidence (consistent with the earlier litigation section's negative finding) of commercial success, licensing, or industry praise tied to the filter architecture specifically. Absent such evidence, there is no rebuttal to a prima facie case.

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VIII. Conclusion

Bottom line: Claims 1 and 9 are vulnerable to a well-constructed § 103 rejection, most plausibly over Qorex (US 2008/0253428 A1) as primary art in view of Lee (Laser Focus World 2007) and Loranger (Sci. Rep. 2015). Qorex supplies the DTS system and the precise hydrogen-darkening mechanism/spectrum; Lee supplies the fiber-in-front-of-sensor architecture and the filter-in-the-DTS-path teaching; Loranger supplies hydrogen-exposure-as-a-known-process. Wysocki (US 2014/0158877 A1) and Baker Hughes '924 (US 2012/0147924 A1) provide an alternative or supplemental combination supplying hydrogen-resistant fiber chemistry and the spliced upstream fiber section, respectively. The dependent claims, being routine optimization of process variables and selection of the known OH/H₂ absorption peak (~1385 nm), are largely obvious as well.

The single genuine non-obviousness hurdle is the recognition to deliberately hydrogen-darken a fiber and use the darkening itself as the filter element — a repurposing move the face references neither disclose nor, strictly, suggest. That hurdle is real but not high, because KSR's rationale B/E (known technique, predictable results, obvious to try) applies with force once the hydrogen-absorption spectrum is known.

Confidence and caveats:

• High confidence in what each face reference discloses (quoted from primary text/PDFs cited above).
• Moderate confidence in the ultimate legal conclusion — this is an analytical prediction, not the USPTO's actual holding. I could not retrieve the examiner's reasons for allowance or the prosecution history, which may contain statements (e.g., applicant arguments distinguishing darkening-as-filter) that change the analysis.
• Not on the face: US 2015/0063418 A1 / US 9,488,531 ("Loss Compensation for Distributed Sensing in Downhole Environments," Baker Hughes) — a separate-reference-fiber hydrogen-loss-characterization approach — would, if asserted, strengthen Combinations A/B. I flag it as supplementary art outside the scope you directed me to use.
• Recall the number-disambiguation rule applied throughout: US 8,977,783 and 7,979,778 are different patents and are not treated here as the subject patent.