Obviousness

The obviousness analysis under 35 U.S.C. § 103 requires identifying combinations of prior art references that would have rendered the claimed invention obvious to a person having ordinary skill in the art (PHOSITA) at the time of the invention. The motivation to combine these references is a key element.

The independent claims of US 10379301 generally describe a multi-channel parallel optical receiving device with a carrier, a light receiving chip, and optoelectronic diodes on the carrier. An optical fiber connector is present, and an arrayed waveguide grating (AWG) divides optical signals into multi-channel signals based on wavelength. A critical feature is the top surface of the AWG's output end being at a predetermined angle (41-46 degrees, specifically 42 degrees in Claim 7) to reflect these signals to the photosensitive surfaces of the optoelectronic diodes.

A PHOSITA in fiber optical communications at the time of the invention (priority date May 23, 2016) would have been familiar with the general principles of optical receiving modules, wavelength division multiplexing (WDM), arrayed waveguide gratings, and the coupling of optical components.

Here's an analysis of potential obviousness combinations based on the cited prior art:

Combination 1: US20170307819A1 (Applied Optoelectronics, Inc.) in view of general knowledge of AWG designs.

• US20170307819A1 ("Techniques for direct optical coupling of photodetectors to optical demultiplexer outputs and an optical transceiver using the same"): This patent application, with a priority date of April 25, 2016, describes direct optical coupling of photodetectors to optical demultiplexer outputs. While it doesn't explicitly mention the 41-46 degree angled surface of the AWG, it teaches the concept of directly aligning and coupling photodetectors with the outputs of a demultiplexer (which an AWG is). The abstract states: "An optical transceiver and methods for fabricating an optical transceiver are provided. The optical transceiver generally includes an optical demultiplexer and an array of photodetectors that are directly optically coupled to outputs of the optical demultiplexer. In some embodiments, the optical demultiplexer and the photodetectors are directly optically coupled by butt coupling.". [cite: US20170307819A1]
• Motivation to Combine: A PHOSITA would understand that an AWG is a type of optical demultiplexer. Given the teaching of direct optical coupling of photodetectors to demultiplexer outputs in US20170307819A1, a PHOSITA would be motivated to explore various coupling mechanisms to achieve this direct coupling efficiently and reliably. It was a known challenge in the field to simplify the design and reduce manufacturing cost of such modules, as explicitly stated in the background of US10379301. The use of an angled surface for reflection within an AWG to redirect light is a known optical principle. For example, the patent US9509433B2 also by Applied Optoelectronics, Inc. (priority date May 14, 2013), discusses "aligning and directly optically coupling photodetectors to optical demultiplexer outputs in a multichannel receiver optical subassembly," which highlights the ongoing effort in this area. [cite: US95099433B2]
• A PHOSITA, seeking to implement the "direct optical coupling" taught by US20170307819A1 while simplifying the alignment and manufacturing process for an AWG, would consider an angled reflective surface as a straightforward optical solution to redirect the light from the AWG output to an array of photodetectors positioned on the same carrier. The specific angle of 41-46 degrees (or 42 degrees) is a matter of optimizing the reflection based on the refractive indices of the materials and the desired angle of incidence, which would be within the skill set of an optical engineer. The background of US10379301 notes that existing solutions lead to "higher cost" and the present disclosure "simplif[ies] the design of the structure and reduc[es] the length of the bonding wire to enhance the integrity of the entire structure and lower the manufacturing cost". The angled surface eliminates the need for complex lens coupling between the AWG and the diodes, thereby achieving the goals of simplification and cost reduction.

Combination 2: US9509433B2 (Applied Optoelectronics, Inc.) in view of US20030174964A1 (Photon-X, Inc.) or similar lens coupling art.

• US9509433B2 ("Aligning and directly optically coupling photodetectors to optical demultiplexer outputs in a multichannel receiver optical subassembly"): This patent, again from the same assignee as US10379301 and with an earlier priority date (May 14, 2013), directly addresses the problem of aligning and coupling photodetectors to optical demultiplexer outputs in a multi-channel receiver optical subassembly. While it teaches direct coupling, it may not explicitly detail the angled reflective surface of the AWG output as claimed in US10379301. [cite: US9509433B2]
• US20030174964A1 ("Lens coupling fiber attachment for polymer optical waveguide on polymer substrate"): This reference teaches lens coupling in optical systems, specifically for waveguides. [cite: US20030174964A1]
• Motivation to Combine: A PHOSITA, starting with the goal of directly coupling photodetectors to AWG outputs as taught by US9509433B2, would recognize that precisely directing light from the AWG to the photodetectors is crucial. If the outputs of the AWG are in a plane that isn't perfectly aligned for direct butt coupling to an array of photodetectors (e.g., if the photodetectors are on a surface parallel to the AWG's main plane), optical redirection becomes necessary. Known optical techniques for redirecting light include using mirrors or angled surfaces. A PHOSITA would be motivated to integrate an angled reflective surface at the output of the AWG to achieve the desired optical path redirection to the photodetectors, thereby optimizing the "direct optical coupling" described in US9509433B2. The inclusion of a lens for coupling the optical fiber to the AWG (as described in dependent claim 5 of US10379301) is also a well-known technique, as evidenced by references like US20030174964A1.

Combination 3: US7376308B2 (National Research Council of Canada) in view of the background section of US10379301.

• US7376308B2 ("Optical off-chip interconnects in multichannel planar waveguide devices"): This patent discusses optical off-chip interconnects in multichannel planar waveguide devices, demonstrating the general knowledge of integrating optical components and routing signals in a multi-channel setup. It addresses methods for coupling light from planar waveguides to other devices. [cite: US7376308B2]
• Motivation to Combine: The background of US10379301 explicitly states the need to "improve the overall performance of the datacenter whose limited physical space puts restraint on density of the products" and to enable "multi-channel paralleling lights in the optical module" while reducing cost. [cite: US10379301B2] Given the general teaching of multichannel planar waveguide devices and optical interconnects in US7376308B2, a PHOSITA would be motivated to adapt such teachings to address the specific problems of cost and density mentioned in the background of US10379301. The use of an AWG with an angled reflective surface, as claimed in US10379301, provides a compact and efficient way to achieve multi-channel parallel reception and direct coupling to photodetectors on the same carrier, thus addressing the motivation of reducing cost and improving density in multi-channel parallel optical receiving modules. The integration of a light receiving chip and optoelectronic diodes on the same surface of the carrier, as claimed, would further contribute to a compact design, a known goal in the art.

It is important to note that the prior art search provided lists a significant number of patents from Applied Optoelectronics, Inc., including US9509433B2 and US20170307819A1, which have similar subject matter. This indicates that the concepts of direct coupling and integration of AWGs with photodetectors were areas of active development for the assignee prior to the filing of US10379301. This ongoing development by the same entity suggests that the claimed invention in US10379301 might represent an incremental improvement or a specific implementation of previously explored concepts, making it potentially obvious in light of their own prior art and general knowledge in the field.

The specific angle range of 41-46 degrees (or 42 degrees) for the reflective surface is likely an optimization of known optical reflection principles rather than a fundamentally new concept. Once the idea of using an angled surface for reflection is conceived (motivated by simplifying alignment and reducing coupling losses, as discussed), determining the optimal angle is a routine design choice for a PHOSITA.

Therefore, a PHOSITA would have been motivated to combine these elements to create a more compact, cost-effective, and efficiently coupled multi-channel parallel optical receiving device, overcoming the drawbacks of existing modules as articulated in the background of US10379301.