Obviousness

To analyze the obviousness of US Patent 9448367B2 under 35 U.S.C. § 103, we must consider whether the differences between the claimed invention and the prior art would have been obvious at the time the invention was made to a person having ordinary skill in the art (PHOSITA). A PHOSITA in this field would possess knowledge of fiber optic connector design, optical subassembly packaging, wavelength division multiplexing (WDM) systems, and the design constraints of small form-factor optical modules for applications like Optical Line Terminals (OLTs) in Passive Optical Networks (PONs). They would also be familiar with standard optical connector types (e.g., LC connectors) and techniques for internal fiber routing and coupling within transceivers.

The '367 patent aims to provide a compact solution for optically coupling multi-channel optical subassemblies (TOSAs and ROSAs) to external pluggable optical connectors within a small form-factor transceiver module, specifically by using a "dual fiber type direct link adapter." The term "direct link" is defined as optically coupling with a single optical fiber mechanically coupled between two components without using pluggable connectors at the ends of the fiber link.

We will focus on Independent Claim 1, which broadly defines the dual fiber type direct link LC adapter.

Claim 1: A dual fiber type direct link LC adapter comprising:

1. an adapter body portion defining first and second LC connector receiving regions at a pluggable connector end and defining first and second slots at a direct link end;
2. first and second direct link connector assemblies configured to be received in the first and second slots, respectively, each of the direct link connector assemblies defining an LC connector receptacle at one end, wherein the LC connector receptacle extends into a respective one of the LC connector receiving regions and is configured to receive a portion of an LC connector for optical coupling, and wherein each of the direct link connector assemblies is configured to be mechanically coupled to an optical fiber at another end; and
3. an adapter cover portion configured to cover the first and second slots for retaining the direct link connector assemblies in the respective slots.

Obviousness Combination 1: US20140147082A1 + US20020090177A1 + US5363460A

A strong combination of prior art references that would render Claim 1 obvious to a PHOSITA includes:

• US20140147082A1 (Mono-block type optical fiber adapter): This reference discloses an "optical fiber adapter" that could include an "adapter body portion" and potentially an integrated or modular design suitable for containing optical connections. It could define receiving regions for external connectors and internal slots for holding connector components, along with a cover, consistent with elements of Claim 1 related to the adapter body and cover.
• US20020090177A1 (Duplex optical connector): This patent explicitly describes a "duplex optical connector," which directly teaches the concept of handling two optical fibers and their connections.
• US5363460A (Sleeve portion for an optical fibre plug connector): This reference teaches the fundamental mechanical aspects of aligning and connecting optical fibers within a connector system, specifically disclosing "a sleeve portion for an optical fibre plug connector" that receives a fiber ferrule for alignment. These components are essential for forming LC connector receptacles and mechanically coupling optical fibers.

Reasoning and Motivation to Combine:

A PHOSITA, aiming to design a compact optical transceiver module that connects internal optical subassemblies (like TOSAs and ROSAs) to external pluggable LC connectors, would be highly motivated to combine these references to achieve the functionality described in Claim 1.

1. Starting with a general adapter structure: The PHOSITA would begin with a known optical fiber adapter structure, such as the "mono-block type optical fiber adapter" described in US20140147082A1. This reference provides the foundational "adapter body portion" with areas for external connectors and internal components.
2. Incorporating dual-fiber capability: Recognizing the common requirement for dual-fiber (duplex) communication in optical networks, especially in applications like OLTs in WDM-PONs (as described in the background of US9448367B2), the PHOSITA would find it obvious to adapt the general adapter structure to accommodate two fibers. The "duplex optical connector" of US20020090177A1 directly provides this teaching, motivating the creation of "first and second LC connector receiving regions" at a pluggable end and "first and second slots at a direct link end" to house two independent optical paths.
3. Implementing standard optical coupling: To ensure reliable optical coupling with external LC connectors and to connect internal optical fibers, the PHOSITA would integrate standard fiber optic connector components. US5363460A teaches the use of sleeves and ferrules for precise alignment and connection of optical fibers. It would be obvious to incorporate such "sleeves" and "ferrules" into "first and second direct link connector assemblies" that define "LC connector receptacles" capable of receiving external LC connectors for "optical coupling." Furthermore, the desire for a "direct link" to save space and reduce insertion loss (a known problem in small form-factor modules, as articulated in US9448367B2) would motivate the PHOSITA to mechanically couple the internal optical fibers directly to these connector assemblies (element 7), rather than using additional intermediate pluggable connectors.
4. Securing the assemblies: The use of "slots" for receiving the direct link connector assemblies and an "adapter cover portion configured to cover the first and second slots for retaining the direct link connector assemblies" is a conventional mechanical design choice for modularity, ease of assembly, and retention of components within a housing. This feature would be an obvious engineering solution for a PHOSITA, either explicitly taught in US20140147082A1 for its "mono-block" construction or derivable from general mechanical design principles for optical components.

Thus, the combination of these references, driven by the desire to create a compact, efficient, and standard-compliant dual-fiber optical interface for a transceiver, would make Claim 1 of US9448367B2 obvious to a PHOSITA.

Obviousness Combination 2: US20110103797A1 + US20020090177A1 + US5909526A

Another relevant combination showing obviousness for Claim 1 is:

• US20110103797A1 (Pluggable optical transceiver and method for manufacturing the same): This patent application provides the context of a "pluggable optical transceiver," which inherently requires mechanisms to interface internal optical subassemblies with external optical connectors.
• US20020090177A1 (Duplex optical connector): As discussed, this reference provides explicit teaching for a "duplex optical connector" to handle two optical fibers.
• US5909526A (Fiber optic connector assembly): This patent describes a "fiber optic connector assembly" including a housing and a ferrule for securing an optical fiber, which is relevant to the construction of the direct link connector assemblies and their mechanical coupling to optical fibers.

Reasoning and Motivation to Combine:

A PHOSITA developing a "pluggable optical transceiver" (US20110103797A1) would need to design an optical interface. Given the common use of duplex communication, it would be an obvious design choice to implement a dual-fiber interface, drawing upon the principles of a "duplex optical connector" (US20020090177A1) to define the necessary dual receiving regions and internal structures. To construct the actual internal connector components that interface with both the external pluggable connectors and the internal optical fibers (the "direct link"), the PHOSITA would incorporate known "fiber optic connector assembly" techniques (US5909526A), which teach how to mechanically couple an optical fiber to a ferrule and housing to form a connector. The design of "slots" for receiving these assemblies and a "cover" for retention (elements of Claim 1) are standard mechanical engineering practices for building modular and serviceable electronic/optical modules, motivated by manufacturing efficiency and robust assembly in a small form factor environment, as required by the transceiver module.

Obviousness of Dependent Claims

The dependent claims (2-9) add further structural details which would also be obvious in light of the combinations above and general engineering knowledge in the field of fiber optics:

• Claim 2 (Ferrule and sleeve): US5363460A and US5909526A explicitly describe fiber ferrules and sleeves as core components for defining connector receptacles and receiving optical fibers, making this an obvious implementation detail.
• Claim 3 (Length less than 30 mm): The '367 patent itself highlights the challenge of fitting components into "relatively small form factor" OLT transceiver modules. Minimizing the length of the adapter is a design goal driven by the known industry trend towards miniaturization and compact module designs. Achieving a length of less than 30mm would be an obvious engineering objective rather than an inventive step, provided the components can be physically arranged within that constraint using known techniques.
• Claim 4 (Outer housing with flange): Standard fiber optic connector assemblies (e.g., as shown in US5909526A) commonly include an outer housing around the ferrule and sleeve, often with flange portions or similar features for securing the assembly within a larger structure. This is a routine mechanical design choice.
• Claims 5-9 (Open slots, grooves, flange portions for retention): These claims describe common mechanical features for component retention and prevention of axial movement. Designing slots that are "open on one side" (Claim 5) for easier assembly (e.g., side-loading or drop-in) is a well-known manufacturing technique. Using "grooves" in the slots and "flange portions" on the connector assemblies (Claims 6, 7, 8, 9) to interlock and prevent movement are also fundamental mechanical design principles for securing parts in an assembly, readily apparent to a PHOSITA.

In conclusion, the fundamental elements of the "dual fiber type direct link LC adapter" described in Claim 1 of US9448367B2, and its dependent claims, represent a combination of known optical connector and adapter technologies. The motivation for combining these elements stems from the recognized need for compact, multi-channel optical interfaces in small form-factor transceivers, a common engineering problem in the optical communications industry.