Obviousness

Obviousness Analysis of US10788690 under 35 U.S.C. § 103

To determine the obviousness of US10788690, we apply the framework established in Graham v. John Deere Co. and reiterated in KSR International Co. v. Teleflex Inc.. This involves:

1. Determining the scope and content of the prior art.
2. Ascertaining the differences between the claimed invention and the prior art.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering secondary considerations of non-obviousness.

A patent claim may be considered obvious if the differences between the invention and the prior art would have been obvious at the time of filing to a person having ordinary skill in the art (PHOSITA). The motivation to combine references can arise from various sources, including design incentives, market forces, or the recognition that a technique used to improve one device would similarly improve another device in the same way. An explicit reason to modify prior art in the references themselves is not always required.

The pertinent art for US10788690 is optical communications, particularly optical isolator arrays for multi-channel optical subassembly modules, including TOSA and ROSA arrangements. A PHOSITA in this field would likely have an undergraduate degree in electrical engineering or a related field and experience with optical transceiver design and manufacturing.

Independent Claim 1 Analysis:

Claim 1: An optical isolator array for use in an optical subassembly module, the optical isolator array comprising: a first magnetic base defining at least one mounting surface; a plurality of optical isolators mounted to the at least one mounting surface, each of the plurality of optical isolators disposed substantially in parallel relative to each other; and at least one layer of adhesive disposed on the at least one mounting surface to couple the plurality of optical isolators to the first magnetic base and to hold each optical isolator of the plurality of optical isolators at a predefined position relative to each other.

Prior Art References:

• US2010/0002988A1 (Duke University): Discloses an optical isolator.
• US2014/0146389A1 (Ye): Discloses an optical isolator.
• JPH0730207A (Mitsubishi Electric Corp.): Discloses a semiconductor laser array module and its assembling method.
• JPH10123462A (Hoya Corp.): Concerns the manufacture of optical isolators, polarizing elements, and Faraday elements.
• JP2001242419A (Oyokoden Lab Co Ltd): Describes a method for manufacturing an optical isolator.
• WO2003093896A1 (Corning Inc.): Discloses optical isolators and methods of manufacturing using direct bonding, including sandwiching a Faraday rotator between polarizers. It also mentions that a Faraday rotator can utilize a permanently magnetized or latching garnet that does not require an external magnetic field.
• US9866329B2 (Applied Optoelectronics, Inc.): Discloses an optical transmitter or transceiver including TOSA modules directly aligned to optical multiplexer inputs. It describes a multi-channel optical transmitter or transceiver with TOSA modules that are optically coupled and directly aligned with mux input ports of an optical multiplexer, without using optical fibers. The TOSA modules may include a base supporting a laser, laser driving circuitry, and a lens.
• CN204947313U (Ningbo Global Radio & Television Technology Co., Ltd.): Discloses a multichannel array fiber laser.
• PGA Series (Excelitas Technologies): Describes a series of pulsed semiconductor lasers available in single, double, triple, or quadruple epi-cavity versions, which can be stacked to further increase output power. These devices are hermetically packaged and grown on a single GaAs substrate chip.

Differences and Obviousness:

1. "A first magnetic base defining at least one mounting surface":

   • WO2003093896A1 discusses Faraday rotators and mentions that some utilize a permanently magnetized or latching garnet that does not require an external magnetic field. This implies the use of a magnetic element within the isolator structure.
   • The concept of a "base" for mounting components is generic in optical modules, as seen in US9866329B2 which describes TOSA modules having a base supporting a laser and other components.
   • A PHOSITA, aware of magnetic materials for optical isolators, would find it obvious to integrate the magnetic material into a "first magnetic base" to serve as a mounting surface for the optical isolators, thereby simplifying the overall structure and providing the necessary magnetic field. The use of a magnetic base to provide a magnetic field and simultaneously serve as a mounting platform for optical components is a logical combination for space-constrained optical subassemblies.

2. "A plurality of optical isolators mounted to the at least one mounting surface, each of the plurality of optical isolators disposed substantially in parallel relative to each other":

   • Multi-channel optical systems are well-known in the prior art. For example, US9866329B2 discloses multi-channel optical transmitters with multiple TOSA modules, and CN204947313U discloses a multichannel array fiber laser.
   • The PGA Series describes multi-epi semiconductor lasers with up to four active lasing cavities on a single substrate, and the possibility of stacking to increase output power, implying a parallel arrangement of light paths.
   • JPH0730207A describes a semiconductor laser array module, further indicating the commonality of arrays of optical components.
   • It would be obvious to a PHOSITA to arrange multiple optical isolators in parallel to correspond with multiple optical channels in a multi-channel optical subassembly, given the prevalence of multi-channel systems. The "substantially in parallel" arrangement is a natural consequence of aligning multiple optical paths.

3. "At least one layer of adhesive disposed on the at least one mounting surface to couple the plurality of optical isolators to the first magnetic base and to hold each optical isolator of the plurality of optical isolators at a predefined position relative to each other":

   • The use of adhesives for securing optical components is a common practice in the field. JP2001242419A describes methods for manufacturing optical isolators, which often involve securing components.
   • US10788690 itself mentions that UV-curing optical adhesives can be used to secure optical isolators and provide structural support, and that "other types of adhesives and fixation approaches may be utilized". This suggests that the use of adhesive itself is a known technique.
   • Methods for forming optical devices often involve adhering components to substrates.
   • A PHOSITA would find it obvious to use an adhesive to mount and secure optical isolators to a magnetic base, providing both mechanical coupling and precise positioning, particularly for fine-grain adjustments as described in the patent (e.g., less than 10 microns). The use of adhesive for positioning is a standard manufacturing technique for optical components.

Combination of References and Motivation:

A combination of WO2003093896A1, US9866329B2, and JPH0730207A with general knowledge of adhesive bonding would render Claim 1 obvious.

• Motivation to use a magnetic element as a base (WO2003093896A1 + US9866329B2): WO2003093896A1 teaches optical isolators that can use permanently magnetized material. US9866329B2 teaches a TOSA module with a base supporting optical components. A PHOSITA would be motivated to combine the magnetic properties of an isolator (from WO2003093896A1) with the structural function of a base (from US9866329B2) to create a single magnetic base that both provides the necessary magnetic field for the isolators and acts as a mounting platform, thereby reducing component count and simplifying assembly in a compact optical subassembly. This would be a predictable variation to integrate functionality, especially given the "desire to provide higher transmit/receive speeds in increasingly space-constrained optical transceiver modules".

• Motivation for a plurality of parallel isolators (US9866329B2 + JPH0730207A): US9866329B2 highlights multi-channel optical transmitters, implying the need for multiple optical components for different channels. JPH0730207A shows a semiconductor laser array module, demonstrating the existing concept of arrays of active optical components. A PHOSITA would naturally apply the array concept to optical isolators (known from US2010/0002988A1 or US2014/0146389A1) to serve multiple channels in parallel, matching the array of laser diodes in a TOSA, as taught by US9866329B2. The parallel disposition is inherent to multi-channel optical alignment.

• Motivation to use adhesive for mounting and positioning: The use of adhesive for mounting and precisely positioning small optical components is a widely known and utilized technique in optical manufacturing, recognized for enabling fine-grain adjustments. This common knowledge, combined with the need to securely attach optical isolators to a base in an array configuration, would make the use of adhesive obvious.

Therefore, the combination of these prior art references and general knowledge in the field would lead a PHOSITA to the claimed optical isolator array.

Independent Claim 11 Analysis:

Claim 11: An optical transceiver, the optical transceiver comprising: a transceiver housing; at least one optical transmitter subassembly (TOSA) arrangement disposed in the transceiver housing, the at least one TOSA arrangement comprising: a substrate defined by at least one mounting surface; a plurality of laser diodes mounted to the at least one mounting surface of the substrate, each laser diode of the plurality of laser diodes to emit a different associated channel wavelength along a corresponding light path of a plurality of light paths; and an optical isolator array mounted to the at least one mounting surface adjacent the plurality of laser diodes such that the plurality of light paths intersect with the optical isolator array, the optical isolator array comprising a at least a first magnetic base and a plurality of optical isolators coupled thereto, and wherein each optical isolator is optically aligned with a corresponding laser diode of the plurality of laser diodes via a corresponding light path; an optical receiver subassembly (ROSA) disposed in the transceiver housing.

Prior Art References:

• US9866329B2 (Applied Optoelectronics, Inc.): Discloses a multi-channel optical transmitter or transceiver including TOSA modules directly aligned to optical multiplexer inputs. It explicitly mentions a transceiver housing, TOSA arrangement with a base supporting lasers, and an optical multiplexer for combining channel wavelengths. It also describes a multi-channel ROSA for receiving and demultiplexing optical signals.
• JPH0730207A (Mitsubishi Electric Corp.): Discloses a semiconductor laser array module and its assembling method.
• US2010/0002988A1 (Duke University): Discloses an optical isolator.
• US2014/0146389A1 (Ye): Discloses an optical isolator.
• WO2003093896A1 (Corning Inc.): Discloses optical isolators, including those with permanently magnetized materials.
• PGA Series (Excelitas Technologies): Describes multi-epi pulsed semiconductor lasers with multiple active lasing cavities on a single substrate.
• Link-PP article on TOSA: Defines a TOSA as a key component of an optical transceiver that converts electrical signals to optical signals for transmission over fiber-optic networks. It typically includes a laser source, monitor photodiode, and optical coupling elements packaged in a compact, thermally stable module.
• HUBER+SUHNER Cube Optics: Describes multi-lambda TOSAs designed for high-speed transceivers, receiving multiple electrical channels and converting them via integrated laser diodes to multiple optical signals, which are then multiplexed. It also mentions ROSAs.

Differences and Obviousness:

Claim 11 combines elements well-known in optical transceivers with the optical isolator array features of Claim 1.

1. "A transceiver housing; at least one optical transmitter subassembly (TOSA) arrangement disposed in the transceiver housing...":

   • US9866329B2 explicitly describes a multi-channel optical transmitter or transceiver with a housing, and TOSA modules mounted to the housing. The Link-PP article and HUBER+SUHNER Cube Optics also describe TOSAs as key components within optical transceivers. This element is clearly taught by prior art.

2. "...the at least one TOSA arrangement comprising: a substrate defined by at least one mounting surface; a plurality of laser diodes mounted to the at least one mounting surface of the substrate, each laser diode of the plurality of laser diodes to emit a different associated channel wavelength along a corresponding light path of a plurality of light paths":

   • US9866329B2 mentions TOSA modules with a base supporting at least a laser, and the multi-channel nature implies a plurality of lasers emitting different channel wavelengths.
   • JPH0730207A teaches a semiconductor laser array module, further supporting the concept of multiple laser diodes on a substrate.
   • The PGA Series describes multi-epi semiconductor lasers with up to four active lasing cavities on a single substrate, emphasizing multiple light sources.
   • This arrangement of multiple laser diodes on a substrate emitting different channel wavelengths is a standard feature of multi-channel optical transmitters.

3. "An optical isolator array mounted to the at least one mounting surface adjacent the plurality of laser diodes such that the plurality of light paths intersect with the optical isolator array, the optical isolator array comprising a at least a first magnetic base and a plurality of optical isolators coupled thereto, and wherein each optical isolator is optically aligned with a corresponding laser diode of the plurality of laser diodes via a corresponding light path":

   • As established in the analysis of Claim 1, the optical isolator array with a first magnetic base and plurality of isolators is a combination of known elements.
   • The placement of optical isolators in the light path of laser diodes within a TOSA to prevent back reflections and maintain laser stability is a well-known function in optical systems. US2010/0002988A1 and US2014/0146389A1 disclose optical isolators generally. Many laser applications are prone to specular reflections back into the source, causing overheating and decreased stability and lifetime, and optical isolators are used to eliminate such back reflections.
   • US9866329B2 teaches that TOSA modules are "directly aligned with mux input ports of an optical multiplexer." This implies precise alignment of components within the TOSA.
   • A PHOSITA would understand the necessity of integrating optical isolators into the light path of laser diodes in an optical transceiver to maintain signal integrity and laser performance. The arrangement of such an array "adjacent the plurality of laser diodes" with corresponding optical alignment is a direct application of known principles in optical design.

4. "An optical receiver subassembly (ROSA) disposed in the transceiver housing":

   • US9866329B2 explicitly describes a multi-channel optical transceiver as including a multi-channel ROSA. The HUBER+SUHNER Cube Optics also discusses ROSAs as components in high-speed transceivers. This is a conventional element of a full optical transceiver.

Combination of References and Motivation:

A combination of US9866329B2, JPH0730207A, WO2003093896A1, and general knowledge regarding optical isolator function would render Claim 11 obvious.

• Motivation to integrate an optical isolator array into a TOSA (US9866329B2 + WO2003093896A1 + JPH0730207A): US9866329B2 describes multi-channel TOSAs with laser diodes and emphasizes direct alignment with multiplexer inputs. Optical isolators (as taught by WO2003093896A1 or the Duke/Ye patents) are known components for protecting lasers from back reflections and ensuring stable operation. Given that JPH0730207A teaches laser arrays, and US9866329B2 teaches multi-channel TOSAs, a PHOSITA would be motivated to integrate an array of optical isolators into the TOSA module, positioned after the laser diodes, to protect all channels simultaneously. This is a predictable application of a known component (optical isolator) to a known system (multi-channel TOSA with laser array) to achieve its intended and known function (preventing back reflection and improving laser stability). The "first magnetic base" for the isolator array, as discussed for Claim 1, would further simplify this integration. The optical alignment of each isolator with its corresponding laser diode is an inherent requirement for any optical system.

• Motivation for the complete transceiver structure (US9866329B2): US9866329B2 explicitly describes an optical transceiver including both a TOSA and a ROSA within a transceiver housing. This patent serves as a strong primary reference for the overall structure of Claim 11.

Therefore, the combination of these prior art references would lead a PHOSITA to the claimed optical transceiver.