Optical Semiconductor Device With Narrow Stripe Region For Wavelength Tuning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wavelength-tunable semiconductor lasers face challenges in enlarging the wavelength controllable range due to limitations in heat generation by heaters, which require high electrical power to achieve sufficient temperature changes in the optical waveguide, making it difficult to control the lasing wavelength effectively with low power consumption.
Innovation Solution
The optical semiconductor device features a semiconductor region with a stripe shape and a heater positioned above the optical waveguide layer, where the distance from the lower end of the semiconductor region to the waveguide layer is more than half its width, enhancing thermal resistance and allowing effective heat distribution to control the temperature of the waveguide layer efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the electrical power provided to the heater is increased to enlarge the wavelength controllable range, then the temperature change of the optical waveguide is improved, but the electrical power consumption increases which is not preferable for optical system requirements
Solution Approach 1:
The patent applies local quality by creating a narrow semiconductor region (5-20 μm width) specifically above the optical waveguide layer, while the rest of the substrate remains wide. This localized narrow region concentrates thermal resistance exactly where needed (in the heat conduction path from heater to waveguide), enabling efficient temperature control of the waveguide with low power consumption without requiring high electrical power to the heater
2Loss of energy
If the width of the semiconductor region is reduced to increase thermal resistance, then the heating efficiency to the optical waveguide is improved, but the structural stability may be affected
Solution Approach 1:
The patent segments the semiconductor substrate into two distinct regions: a narrow semiconductor region (5-20 μm) directly above the optical waveguide layer that provides high thermal resistance for efficient heating, and a wide substrate region that provides mechanical support and structural stability. This segmentation allows each region to fulfill its specific function without compromising the other
Solution Approach 2:
The patent solves the stability issue by extending the narrow semiconductor region vertically to a sufficient height (50-200 μm), creating a tall narrow structure. This dimensional change (making the region tall rather than wide) maintains high thermal resistance while the vertical extent provides adequate mechanical support. The narrow region is also positioned at a sufficient distance (more than half the width) from the lower end of the waveguide layer, further ensuring structural integrity
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 enables effective heating of the optical waveguide layer with reduced heat diffusion, resulting in a larger temperature gradient and improved control over the lasing wavelength with lower electrical power consumption.
Implementation Method 1
The heater needs an electrical power when generating heat. And so, Japanese Patent Application Publication No. 9-92934 discloses a method of controlling a refractive index of a reflection region by providing an electrical power to a heater.
Implementation Method 2
thermal resistance in the semiconductor region is large because the width of the semiconductor region is smaller than that of the semiconductor substrate. In this case, the heater can heat the optical waveguide layer effectively.
Implementation Method 3
The temperature of the optical waveguide of the SG-DR region is changed when the heater generates heat. As a result, the refractive index of the SG-DR region changes.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An optical semiconductor device (100) has a semiconductor substrate (101), a semiconductor region (102) and heater (104). The semiconductor region (102) has a stripe shape demarcated with a top face and a side face thereof. The strip shape has a width (W) smaller than a width of the semiconductor substrate (101). An optical waveguide layer (106) is located in the semiconductor region (102). A distance (D2) from a lower end of the side face of the semiconductor region to the optical waveguide layer is more than half of the width (W) of the semiconductor region. The heater (104) is provided above the optical waveguide layer (106).