Tunable Laser Diode Resonator Length Control
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Solution Overview
Problem
Existing oscillation wavelength adjustment type tunable laser diodes (TLDs) face limitations in continuous wavelength adjustment due to dependence on physical property values of waveguide materials and mechanical issues with external resonator structures using MEMS technology, such as vulnerability to mechanical vibrations and slow adjustment speeds.
Innovation Solution
Integration of an optical gain waveguide, a multi-mode interference waveguide, and a reflective delay line array on a common substrate, where the reflective delay line array adjusts light intensity with wavelength changes, allowing independent control of resonator length without relying on external MEMS structures or physical property values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If external resonator structures using MEMS technology are used to adjust resonator length, then wavelength adjustment capability is improved, but mechanical reliability deteriorates due to vulnerability to mechanical vibrations and slow adjustment speeds
Solution Approach 1:
The patent replaces the mechanical MEMS resonator structure with an all-optical implementation using a multi-mode interference waveguide and reflective delay line array. The resonator length adjustment is achieved by optically controlling the effective path length through the delay lines rather than mechanically moving components, eliminating mechanical vibrations and improving reliability while maintaining wavelength adjustment capability
Solution Approach 2:
The patent introduces an optical intermediary system consisting of the multi-mode interference waveguide and reflective delay line array that mediates between the light source and the external resonator. This intermediary allows electronic control of the effective resonator length without direct mechanical interaction, resolving the contradiction between adjustability and mechanical reliability
2Measurement precision
If phase adjuster is used to adjust resonator length, then wavelength control is improved, but adjustment range is limited by physical property values of waveguide material
Solution Approach 1:
The patent segments the resonator length adjustment function into multiple independent reflective delay lines with different path lengths. By selectively activating combinations of these delay lines, the system achieves a broader adjustment range than a single phase adjuster while maintaining precise wavelength control through the multi-mode interference waveguide
Solution Approach 2:
The patent adds a spatial dimension to the adjustment mechanism by using multiple delay lines with different physical lengths arranged in parallel. This dimensional approach allows the system to achieve broader adjustment ranges by selecting different path length combinations while the multi-mode interference waveguide maintains precise wavelength control
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
Enables continuous and independent adjustment of resonator length, enhancing wavelength control and reducing mechanical limitations, thereby improving spectral purity and communication quality while reducing the size and power consumption of laser modules.
Implementation Method 1
a multi-mode interference waveguide configured to include M input ports and N output ports
Implementation Method 2
the N reflective delay lines are configured to adjust an intensity of reciprocating light in accordance with a wavelength change of the light transmitted through the N reflective delay lines
Data Source
AI summary
An oscillation wavelength adjustment type TLD for adjusting a control amount of a resonator length L, independently from physical property values of a waveguide material when a waveguide is used in the phase adjustment, without an external resonator structure in accordance with a MEMS technology employs a reflective phase adjuster (20) including a multi-mode interference waveguide (21), which is optically coupled to an optical gain waveguide and has a configuration including one input port and five output ports, and a reflective delay line array (25) connected to an output waveguide on a side of the five output ports of the multi-mode interference waveguide (21). Five reflective delay lines (24-0 to 24-4) provided in the reflective delay line array (25) are capable of adjusting the intensity of reciprocating light in accordance with a wavelength change of transmitted light. The intensity of the reciprocating light can also be adjusted by an electric signal applied from the outside.