Evanescent-Coupled Laser Array for Compact Single-Mode Multiplexing
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Solution Overview
Problem
Existing wavelength multiplexing light sources are bulky and operate in multimode, making them unsuitable for compact, single-mode operation required for wavelength multiplexing communication.
Innovation Solution
A wavelength multiplexing light source comprising a plurality of semiconductor lasers with diffraction gratings and a single waveguide proximity to the lasers via a low refractive index material, where evanescent light is generated and coupled to the waveguide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a laser array or integrated element with arrayed waveguide diffraction grating is used for wavelength multiplexing, then wavelength multiplexing function is achieved, but the device size becomes large
Solution Approach 1:
The patent merges multiple semiconductor lasers and a single waveguide into an integrated structure where evanescent light from multiple lasers is coupled to a single waveguide. This consolidation eliminates the need for separate waveguides for each laser and removes the requirement for large arrayed waveguide diffraction gratings, achieving wavelength multiplexing in a compact footprint of approximately 100×100 μm².
Solution Approach 2:
The patent implements a nested configuration where multiple semiconductor lasers are arranged in close proximity to a single waveguide, with the low refractive index material filling the space between them. This nested arrangement allows evanescent fields from multiple lasers to overlap and couple to the central waveguide, achieving efficient light collection in a compact, space-efficient geometry.
2Area of stationary object
If a compact wavelength multiplexing light source is achieved using integrated elements, then device size is reduced, but the light source operates in multimode which is unsuitable for wavelength multiplexing communication
Solution Approach 1:
The patent applies local quality control by introducing a low refractive index material in the specific region between the semiconductor lasers and the waveguide. This localized refractive index modification creates an evanescent coupling mechanism that selectively guides light from each laser at its specific wavelength to the waveguide, ensuring single-mode operation at each wavelength while maintaining compact dimensions.
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
The solution enables a compact, single-mode wavelength multiplexing light source, reducing size by about ⅕ compared to conventional designs and achieving favorable single-mode characteristics with a side mode suppression ratio of 40 dB or more.
Implementation Method 1
a single waveguide in proximity to the semiconductor lasers via a low refractive index material, in which evanescent light is generated at an interface between the semiconductor lasers and the low refractive index material, and the evanescent light is coupled to the waveguide
Implementation Method 2
each of the plurality of semiconductor lasers has a diffraction grating and oscillates at a different wavelength
Data Source
AI summary
A wavelength multiplexing light source includes: a plurality of semiconductor lasers; and a single waveguide in proximity to the semiconductor lasers via a low refractive index material, in which each of the plurality of semiconductor lasers has a diffraction grating and oscillates at a different wavelength, evanescent light is generated at an interface between the semiconductor lasers and the low refractive index material, and the evanescent light is coupled to the waveguide. Accordingly, the present invention can provide a wavelength multiplexing light source that is compact and operates in a single mode.