Hybrid Semiconductor Evanescent Laser Array for DWDM
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Solution Overview
Problem
Current optical transmitters in DWDM and Gigabit Ethernet systems require separate, expensive lasers for each transmission channel, leading to high costs and inefficiencies due to the use of fixed-wavelength lasers and external modulators.
Innovation Solution
The development of an electrically pumped hybrid semiconductor evanescent laser array, where a single layer of semiconductor material is used with an active gain medium evanescently coupled to passive material, allowing for the creation of multiple lasers without alignment issues, reducing fabrication complexity and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate fixed-wavelength lasers are used for each transmission channel, then reliable light emission is achieved, but device complexity and cost increase significantly
Solution Approach 1:
The patent merges multiple laser functions into a single hybrid semiconductor device that can operate at multiple wavelengths. The structure combines aIII-V semiconductor gain medium with a silicon nitride waveguide on a silicon substrate, creating an integrated platform that replaces multiple separate lasers with one multi-wavelength capable device.
Solution Approach 2:
The hybrid semiconductor laser structure is designed to be universal by supporting multiple wavelength operations through the evanescent coupling mechanism. The same basic structure can be configured to emit at different wavelengths by adjusting the gain medium composition and waveguide parameters, making it applicable to various transmission channels without requiring separate specialized components.
2Ease of operation
If external modulators are used with fixed-wavelength lasers, then data transmission is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent combines the laser generation and modulation functions into a single integrated structure. The hybrid semiconductor device integrates the gain medium, waveguide, and modulation capability in one compact platform, eliminating the need for separate external modulators and reducing the number of alignment-critical interfaces.
Solution Approach 2:
The silicon nitride waveguide acts as an intermediary that couples the III-V gain medium to the silicon substrate while enabling evanescent field interaction. This intermediary structure provides a tolerant interface that reduces sensitivity to alignment errors while maintaining effective optical coupling and modulation capability.
3Reliability
If multiple separate lasers are fabricated, then each laser can be optimized for its wavelength, but fabrication complexity and cost increase
Solution Approach 1:
The patent segments the laser functionality by wavelength within a single integrated structure. Different regions of the hybrid device can be designed with different gain medium compositions to support different wavelengths, allowing wavelength-specific optimization while maintaining a unified fabrication process for the overall structure.
Solution Approach 2:
The invention uses composite materials combining III-V semiconductor gain media with silicon nitride waveguides on silicon substrates. This composite structure enables integration of multiple material advantages in a single device, allowing optimization for different wavelengths through material composition variations while simplifying the overall fabrication process compared to assembling multiple separate lasers.
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 the production of a broadband laser with reduced fabrication complexity and lower costs, achieving efficient multi-wavelength transmission with integrated semiconductor modulators, capable of high-speed data transmission over a single optical fiber.
Implementation Method 1
an active gain medium evanescently coupled to passive material
Data Source
AI summary
Embodiments of a method comprising guiding an optical mode with an optical waveguide disposed in silicon, overlapping both the optical waveguide and an active semiconductor material evanescently coupled to the optical waveguide with the optical mode guided through the optical waveguide, electrically pumping the active semiconductor material to inject current directed through the active semiconductor material and through the optical mode, and generating light in the active semiconductor material in response to the injected current. Other embodiments are disclosed and claimed.