Obviousness — US Patent 10379301B2

To analyze the obviousness of US patent 10379301B2 under 35 U.S.C. § 103, we identify combinations of prior art references that disclose all the elements of the claims and explain the motivation a person having ordinary skill in the art (PHOSITA) would have to combine them.

The key distinguishing feature of US10379301B2, particularly as articulated in independent Claim 1, is the multi-channel parallel optical receiving device that includes an arrayed waveguide grating (AWG) where a top surface of its output end is at a predetermined angle (41 to 46 degrees) to reflect multi-channel optical signals to photosensitive surfaces of a plurality of optoelectronic diodes arranged in parallel on a carrier. The optoelectronic diodes and a light receiving chip are also disposed directly on the same top surface of an end of the carrier and electrically connected via bonding wires.

Combination of Prior Art for Obviousness of Claim 1:

A strong argument for obviousness can be made by combining US9509433B2 with the general knowledge of a PHOSITA in optical engineering regarding light redirection techniques.

Primary Reference: US9509433B2 - "Aligning and directly optically coupling photodetectors to optical demultiplexer outputs in a multichannel receiver optical subassembly" (Priority date: 2013-05-14, Publication date: 2016-11-29).
- This patent explicitly teaches a "multichannel receiver optical subassembly" that aims for "directly optically coupling photodetectors to optical demultiplexer outputs". An Arrayed Waveguide Grating (AWG) is a well-known type of optical demultiplexer, as stated in the background of US10379301B2 itself.
- It covers the foundational elements of Claim 1, including a carrier (inherent in "subassembly"), a plurality of optoelectronic diodes (photodetectors), and a demultiplexer (AWG) for multi-channel operation, with the goal of direct coupling between them.
- The general arrangement of placing optoelectronic components (like diodes and a light receiving chip) on a common carrier surface for compactness and efficient electrical connection via bonding wires is a standard practice in optoelectronic packaging, as further supported by references like US9553671B1 - "Package structure for photonic transceiving device" (Priority date: 2015-07-07, Publication date: 2017-01-24).
Secondary Reference/General Knowledge: The use of angled reflective facets in integrated optics for redirecting light from planar waveguides to surface-normal detectors.
- A PHOSITA in optical engineering would be well aware of techniques for redirecting light within integrated optical circuits, particularly for coupling light from in-plane waveguides (like the outputs of an AWG) to vertically oriented, surface-mounted components such as photodetector arrays.
- A common and effective method to achieve such 90-degree redirection is to incorporate an angled reflective surface or facet, often cleaved or etched at approximately 45 degrees, at the end of the waveguide. This can utilize total internal reflection (TIR) or a reflective coating.
- This general knowledge is corroborated by references like US7376308B2 - "Optical off-chip interconnects in multichannel planar waveguide devices" (Priority date: 2003-12-24, Publication date: 2008-05-20), which discusses the challenges and methods for coupling light from planar waveguides to off-chip components.

Motivation to Combine:

A PHOSITA, seeking to implement the "direct optical coupling of photodetectors to optical demultiplexer outputs in a multichannel receiver optical subassembly" as taught by US9509433B2, would be motivated to find a manufacturable and efficient method for this coupling. The background of US10379301B2 itself highlights the demand for reduced cost and improved density in optical modules. The PHOSITA would recognize that using an angled reflective surface at the output end of the AWG, as described in US10379301B2, is a straightforward and effective way to achieve this direct coupling. This approach simplifies the assembly process by redirecting the in-plane light from the AWG to the surface-mounted photodetectors, reducing the need for complex active alignment or intermediate optical elements. This directly addresses the stated advantages in US10379301B2 of easier installation and eliminating the need for coupling between the AWG and optoelectronic diodes.

The selection of a "predetermined angle" within the range of 41 to 46 degrees (or specifically 42 degrees, as in Claim 4 and Claim 7 of US10379301B2) would be a routine engineering optimization. A 45-degree angle is a standard choice for 90-degree redirection, and variations within this range would be determined by the refractive indices of the materials involved and manufacturing tolerances to ensure efficient reflection, all well within the capabilities of a PHOSITA.

Obviousness of Dependent Claims:

Claim 2 (Circuit Board): The idea of the carrier's top surface being a circuit board, where optoelectronic diodes and a light receiving chip are directly disposed, is a common practice in optoelectronic packaging for electrical connectivity and mechanical support. This is a conventional design choice, also supported by US9553671B1.
Claim 3 (Amount of Diodes): It is inherently obvious to a PHOSITA that the number of optoelectronic diodes must correspond to the number of optical paths (channels) divided by the AWG for a functional multi-channel receiver.
Claim 4 (42 Degrees): This is a specific preferred embodiment of the angle claimed in Claim 1. As explained above, selecting a precise angle within the obvious range (41-46 degrees) is a matter of routine optimization.
Claim 5 (First Lens for Coupling): The use of a lens for coupling an optical fiber to an integrated waveguide (AWG) is a well-known technique to improve coupling efficiency. US20030174964A1 - "Lens coupling fiber attachment for polymer optical waveguide on polymer substrate" (Priority date: 2002-01-08, Publication date: 2003-09-18) explicitly teaches lens coupling for fiber attachment.
Claim 6 (Direct Insertion with Graded Index Lens): Direct insertion of a waveguide into an optical fiber connector with a graded index (GRIN) lens is a known method for compact and efficient optical coupling, serving as an alternative or improvement to other lens-based coupling methods. US7162124B1 - "Fiber to chip coupler" (Priority date: 2003-03-14, Publication date: 2007-01-09) highlights fiber-to-chip coupling techniques.
Claim 7: This claim is an independent claim essentially combining the features of Claim 1 with the specific angle of 42 degrees from Claim 4. For the reasons stated above for Claim 1 and Claim 4, Claim 7 would also be rendered obvious.

In conclusion, the claimed multi-channel parallel optical receiving device, particularly the use of an angled reflective surface on the AWG output to redirect light to parallel photodetectors, would have been obvious to a PHOSITA given the prior art, especially US9509433B2, in combination with the general knowledge of optical redirection techniques in integrated optics. The motivation stems from the continuous drive in the industry for simpler, more compact, and cost-effective optical module designs.