Si Substrate Planar Waveguide Thermal Control
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Solution Overview
Problem
Conventional OBO planar waveguide devices for demultiplexing multiplexed signals in WDM optical communication suffer from significant propagation loss and high power consumption, particularly when using macromolecular materials, and have limited control over temperature distribution, leading to inefficient demultiplexing and response times.
Innovation Solution
The design incorporates a Si substrate with an insulating layer and parallel Si optical waveguides, featuring a heater on one side end surface and a heat sink on the other, with controlled thermal resistance between 20 K/W and 2000 K/W, and optionally includes a reinforcing substrate or multiple heat generating portions to enhance thermal management and mechanical strength, allowing for finer control over temperature distribution and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a macromolecular material is used for optical waveguides in OBO planar waveguide devices, then the device can be manufactured with standard materials, but significant propagation loss occurs
Solution Approach 1:
The patent changes the material parameter from macromolecular material to silicon material for the optical waveguides. This parameter change fundamentally improves the propagation loss characteristic while maintaining manufacturability through established silicon processing techniques, directly resolving the contradiction between ease of manufacture and energy loss.
2Temperature
If heater power is increased to control temperature distribution, then temperature control improves, but power consumption increases
Solution Approach 1:
The patent introduces local quality by providing heaters at specific locations (one end of the substrate) rather than uniform heating. This localized heating approach, combined with the thermal resistance design of the substrate, enables effective temperature distribution control with reduced overall power consumption, resolving the contradiction between temperature control and energy usage.
Solution Approach 2:
The patent changes the thermal resistance parameter of the substrate to a specific range (20-2000 K/W) to optimize the balance between temperature control effectiveness and heater power consumption. This parameter optimization allows adequate temperature distribution control while minimizing energy consumption.
3Use of energy by moving object
If substrate thickness is reduced to lower power consumption, then heater power consumption decreases, but mechanical strength decreases
Solution Approach 1:
The patent optimizes the substrate thickness parameter to balance power consumption and mechanical strength. By selecting an appropriate thickness range and combining it with the optimized thermal resistance (20-2000 K/W), the design achieves reduced heater power consumption while maintaining sufficient mechanical strength to support the optical waveguides and other components.
Solution Approach 2:
The patent employs a composite structure combining the substrate with optimized thermal resistance properties and the optical waveguide layer. This composite approach allows the substrate to be thinner (reducing power consumption) while the overall structure maintains mechanical strength through the combined design of multiple layers and materials.
4Temperature
If multiple heat generating portions are used, then temperature distribution control improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the heating function into multiple heat generating portions positioned at different locations. This segmentation enables independent control of temperature distribution in different regions, improving overall temperature control while the modular structure keeps the added complexity manageable.
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 reduces power consumption, improves response time, and enhances controllability of the demultiplexing process, achieving lower propagation losses and more efficient demultiplexing of signal waves while maintaining mechanical integrity.
Implementation Method 1
a heater for controlling gradient of temperature distribution of the Si substrate in a direction in which the plurality of Si optical waveguides are aligned
Implementation Method 2
a plurality of Si optical waveguides aligned substantially in parallel to each other on one main surface of the insulating layer
Data Source
AI summary
An OBO planar waveguide device includes an Si substrate, an SiO2 layer formed on the Si substrate, and a plurality of Si optical waveguides provided on the Si substrate in parallel to each other. A heater and a heat sink are provided on opposing side end portions of the Si substrate respectively. As a result of a function of the heater and the heat sink, gradient of temperature distribution of the Si substrate is formed in a direction in which the plurality of Si optical waveguides are aligned. Thermal resistance of the Si substrate in the direction in which the gradient of temperature distribution is formed is greater than 20 K/W and lower than 2000 K/W. The OBO planar waveguide device attaining reduced power consumption is thus obtained.