Arrayed Waveguide Grating Circuit Integration
Solution Overview
Problem
Conventional arrayed waveguide grating (AWG) circuits face challenges in reducing size while maintaining high-density integration and suffer from manufacturing errors that cause deviated center wavelengths, leading to narrow transmission bandwidth and crosstalk issues.
Innovation Solution
The integration of two AWG circuits with input and output waveguides positioned at specific intervals and orientations relative to the slab waveguides, incorporating parabolic and tapered connecting sections to enhance spectral bandwidth without inducing crosstalk, and using a 1.5x interval arrangement to minimize signal misallocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of array waveguides is increased to handle more optical waves, then the multiplexing capacity is improved, but the circuit area occupied increases
Solution Approach 1:
The patent combines a demultiplexer AWG circuit and a multiplexer AWG circuit into a single integrated structure. The array waveguides are shared between both functions, with the demultiplexer using waveguides 13a-13n and the multiplexer using waveguides 13b-13m. This merging allows two complete AWG circuits to be implemented in approximately the same area as one conventional AWG circuit, effectively doubling the functional capacity without proportionally increasing the circuit area.
2Area of stationary object
If array waveguides are superposed to reduce circuit area, then the area is reduced, but manufacturing errors cause deviated center wavelengths
Solution Approach 1:
The patent arranges the array waveguides in a two-dimensional configuration where waveguides for the demultiplexer (13a-13n) and multiplexer (13b-13m) are positioned side-by-side in the same planar space rather than stacking them vertically or overlapping them. This spatial arrangement in another dimension allows both sets of waveguides to coexist without mutual interference, maintaining manufacturing precision while achieving compact integration.
3Device complexity
If input waveguides are positioned at the center of output waveguides to share array waveguides, then the circuit integration is improved, but the transmission bandwidth becomes narrow
Solution Approach 1:
The patent implements different interval arrangements for different regions of the waveguide system. The first interval (pitch) is used for output waveguides in the demultiplexer section, while a different second interval (pitch) is used for input waveguides in the multiplexer section. This local differentiation of spatial parameters allows each region to be optimized for its specific function, maintaining both high integration and adequate transmission bandwidth.
4Quantity of substance
If parabolic and tapered connecting sections are added to increase transmission bandwidth, then the bandwidth is expanded, but crosstalk is caused between input waveguides and neighboring output waveguides
Solution Approach 1:
The patent introduces a mode converter as an intermediary component between the array waveguides and the input/output waveguides. This mode converter transforms the optical mode distribution to achieve broadband transmission while controlling the field distribution to prevent crosstalk. The mode converter acts as a mediator that decouples the bandwidth expansion function from the crosstalk generation problem, allowing both requirements to be satisfied simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for compact integration of AWG circuits with improved multiplexing/demultiplexing quality, preventing signal misallocation and crosstalk, and expanding spectral transmission bandwidth.
Implementation Method 1
The array waveguide 13 is structured so that neighboring waveguides are arranged with a fixed difference in the light path length
Implementation Method 2
Planar Lightwave Circuit (PLC) has been known as one of such techniques. The PLC is an optical circuit obtained by integrating optical waveguides and waveguide-type optical devices on a silicon substrate or a quartz substrate
Data Source
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AI summary
Two AWG circuits are integrated while preventing degradation in quality of a multiplexing/demultiplexing function. An arrayed waveguide grating circuit includes: a first slab waveguide (52) connected to a first input waveguide (51a) and second output waveguides (55b); a second slab waveguide (54) connected to first output waveguides (55a) and a second input waveguide (51b); and an array waveguide (53) connecting the first slab waveguide (52) and the second slab waveguide (54), wherein the input waveguides (51a, 51b) are connected to the slab waveguides (52, 54) at an interval of 1.5x from the outermost second output waveguide out of the second output waveguides (55a, 55b) connected at an interval x depending on a wavelength.