Integrated Optical Source With Shared Echelle Grating
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Solution Overview
Problem
Current silicon photonic technologies face challenges in producing low-cost wavelength-division-multiplexing (WDM) optical sources due to the high cost and bulkiness of conventional laser sources, which are difficult to integrate onto silicon chips, and existing alternatives like broad-spectrum light emitters are limited by size, cost, and power consumption.
Innovation Solution
An integrated optical source utilizing a shared echelle grating as a wavelength-selective filter for multiple lasing cavities, which achieves self-registered and accurate lasing-channel spacing without inter-channel gain competition, allowing for all wavelength channels to be provided in one optical waveguide or separate waveguides, using cascaded ring-resonator modulators and electro-absorption-based broadband modulators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional laser sources are used to generate multiple wavelength channels for WDM transmission, then accurate wavelength registration and channel spacing can be achieved, but the system becomes very expensive and bulky
Solution Approach 1:
The patent combines multiple laser sources into a single integrated photonic chip that generates multiple wavelength channels simultaneously. The shared optical path and common gain medium merge what would traditionally be separate laser systems into one compact device, achieving both wavelength accuracy and reduced complexity.
Solution Approach 2:
The invention creates a multi-functional device where a single optical source performs the work of multiple laser sources. The device can generate multiple wavelength channels with accurate spacing while providing all functions (amplification, wavelength selection, beam generation) in one integrated unit, eliminating the need for separate components for each wavelength channel.
2Measurement precision
If multiple laser sources are used for WDM transmission with different wavelength grids, then wavelength requirements can be met, but integration onto silicon chips becomes very difficult
Solution Approach 1:
The patent integrates multiple laser sources and their associated optical paths into a single photonic chip structure. By merging the gain media, optical cavities, and wavelength-selective elements into one integrated device, the system achieves accurate wavelength channel spacing while becoming compatible with silicon chip manufacturing processes.
Solution Approach 2:
The invention uses parameter changes in the optical cavity design, such as adjusting cavity lengths and refractive indices, to achieve precise wavelength channel spacing. These parameter adjustments are made during the chip fabrication process, allowing for accurate wavelength control without requiring separate discrete components for each channel.
3Device complexity
If a single broad-spectrum light emitter is used instead of multiple laser sources, then system cost and size are reduced, but wavelength channel spacing accuracy and registration become problematic
Solution Approach 1:
The patent introduces wavelength-selective elements (such as diffraction gratings or arrayed waveguide gratings) as intermediaries between the broad-spectrum light emitter and the output channels. These intermediary components separate the broad spectrum into discrete wavelength channels with precise spacing, maintaining accuracy while using a single compact light source.
Solution Approach 2:
The invention segments the broad-spectrum light output into multiple discrete wavelength channels using optical filtering and wavelength division multiplexing components. This segmentation allows the single light emitter to produce multiple accurately spaced wavelength channels, combining the simplicity of a single source with the precision of multiple channels.
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 solution enables low-cost WDM optical sources that improve bandwidth density and reduce power consumption in silicon-photonic links, facilitating efficient optical interconnects and computing systems by eliminating the need for multiple expensive laser sources and minimizing channel spacing errors.
Implementation Method 1
an optical device that images and diffracts the first optical signal using a reflective geometry in one propagation direction, and that images and diffracts second optical signals having the wavelengths using the reflective geometry in another propagation direction
Implementation Method 2
An integrated optical source utilizing a shared echelle grating as a wavelength-selective filter for multiple lasing cavities, which achieves self-registered and accurate lasing-channel spacing
Implementation Method 3
optical gain mechanisms that amplify the second optical signals
Implementation Method 4
a first mirror that at least partially reflects a first optical signal having multiple wavelengths; second mirrors that at least partially reflect the second optical signals
Data Source
AI summary
An integrated optical source is described. This optical source outputs one or more optical signals that provide a comb of wavelengths for use in wavelength-division-multiplexing (WDM) optical interconnects or links. In particular, a shared echelle grating is used as a wavelength-selective filter or control device for multiple lasing cavities to achieve self-registered and accurate lasing-channel spacing without inter-channel gain competition. Furthermore, the optical source can be used to provide all the wavelength channels in one optical waveguide or in separate optical waveguides. Therefore, the optical source may be used with cascaded ring-resonator modulators and/or electro-absorption-based broadband modulators.