Silicon Tunable Laser Resonator Using SiN Core to Cut Optical Loss
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Solution Overview
Problem
The challenge is to develop a smaller wavelength tunable laser on a silicon substrate without impairing its properties and yield, as existing materials like InP and Si exhibit high non-linear optical constants and refractive index differences that lead to increased two-photon absorption loss and dimensional errors in optical waveguides, affecting the laser's performance and integration.
Innovation Solution
A semiconductor optical element with a wavelength tunable laser formed on a silicon substrate, featuring a III-V compound semiconductor light emitting portion and an external resonator with a SiN or SiON core, optically connected via a spot-size converting portion, and a heater for wavelength control, which reduces non-linear effects and enhances optical confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If InP or Si is used as the material of the optical waveguide core, then the laser can be formed on a silicon substrate, but two-photon absorption loss increases due to high non-linear optical constant
Solution Approach 1:
The patent introduces an intermediary material (SiN, SiON, or SiOn with n<2) between the silicon substrate and the III-V compound semiconductor light emitting portion. This intermediary core material has lower non-linear optical constant than InP or Si, thereby reducing two-photon absorption loss while still enabling integration on silicon substrate through wafer bonding technology
Solution Approach 2:
The patent changes the material parameter (refractive index and non-linear optical constant) of the optical waveguide core from high non-linear materials (InP, Si) to low non-linear materials (SiN, SiON, SiOn with n<2). This parameter change reduces two-photon absorption loss while maintaining optical confinement through appropriate cladding layer design
2Ease of manufacture
If InP or Si is used as the optical waveguide core material, then the laser can be integrated on silicon substrate, but dimensional errors or variation in width and thickness remarkably impair the properties of the optical resonator
Solution Approach 1:
The patent uses an intermediary material (SiN, SiON, or SiOn with n<2) as the optical waveguide core that has lower refractive index than InP or Si. This reduces the relative refractive index difference with SiO2 cladding, making the optical resonator properties less sensitive to dimensional errors and variations in waveguide width and thickness
Solution Approach 2:
The patent changes the refractive index parameter of the core material to be closer to that of SiO2 cladding (using SiN, SiON, or SiOn with n<2 instead of InP or Si). This parameter change reduces the relative refractive index difference, thereby reducing the sensitivity of optical resonator properties to manufacturing dimensional errors
3Area of moving object
If the size of the wavelength tunable laser is reduced, then the device cost and area are reduced, but the non-linear optical effects and two-photon absorption loss increase due to higher power density
Solution Approach 1:
The patent introduces an intermediary core material (SiN, SiON, or SiOn with n<2) with lower non-linear optical constant that mediates between the high power density in small-size devices and the two-photon absorption loss. This allows compact device design while minimizing non-linear optical effects through the material's inherent properties
Solution Approach 2:
The patent changes the non-linear optical constant parameter of the core material to a lower value (using SiN, SiON, or SiOn instead of InP or Si). This parameter change reduces two-photon absorption loss, enabling smaller device size without the penalty of excessive non-linear optical effects and power density-related losses
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 allows for the creation of a smaller, high-power, narrow-linewidth wavelength tunable laser on a silicon substrate with improved integration and reduced power consumption, minimizing non-linear optical effects and maintaining high laser performance and yield.
Implementation Method 1
the oscillation wavelength of the laser is controlled by controlling the optical wavelength characteristics of this optical filter using heat
Implementation Method 2
the oscillation wavelength of the laser is controlled by controlling the optical wavelength characteristics of this optical filter using heat, a carrier plasma effect
Implementation Method 3
Optical confinement is realized by adjusting the composition of the III-V compound semiconductor and imparting a difference in a refractive index between a core and a cladding
Implementation Method 4
the light emitting portion and the external resonator are optically connected via a spot-size converting portion
Data Source
AI summary
A wavelength tunable laser formed on a substrate made of single-crystal silicon is provided. The wavelength tunable laser includes a light emitting portion made of a III-V compound semiconductor, and external resonators provided with an optical filter. Cores included in the external resonators are made of one of SiN, SiON, and SiOn (n is smaller than 2).