External Resonator Laser Element with Optical Coupler
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Solution Overview
Problem
The existing external resonator-type semiconductor laser elements face challenges in achieving high output due to light loss in the ring resonator, which affects the luminous efficiency, especially when using silicon as the substrate material, as silicon-based light emitters have lower efficiency compared to InP-based emitters.
Innovation Solution
The implementation of an optical coupler that branches part of the light conducting from the optical amplifier to an output waveguide within the optical resonator, minimizing light loss by adjusting the optical axes and using an InP-based semiconductor optical amplifier with a silicon substrate, forming a high-reflective film and distributed Bragg reflector to create a Fabry-Perot optical resonator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If light is taken out from the terminal face of the semiconductor optical amplifier, then optical axis adjustment is required between the optical circuit and semiconductor optical amplifier, but this increases alignment complexity and reduces manufacturing ease
Solution Approach 1:
An optical waveguide is introduced as an intermediary component between the semiconductor optical amplifier and the ring resonator. The waveguide receives light from the terminal face of the semiconductor optical amplifier and guides it to the ring resonator, eliminating the need for direct optical axis alignment between the amplifier and subsequent optical components. This mediator structure simplifies the overall alignment process while maintaining optical functionality.
2Ease of manufacture
If a ring resonator is placed between the semiconductor optical amplifier and the output port, then integration with silicon substrate is improved, but light loss in the ring resonator reduces output power
Solution Approach 1:
The output light is extracted from the system before it enters the ring resonator by using the through port of the ring resonator as the output port. This allows the ring resonator to remain integrated with the silicon substrate for manufacturing benefits, while the output light is taken out at a point where it has not yet undergone the lossy circulation through the resonator, thereby preserving higher output power.
Solution Approach 2:
Instead of taking the output light after it has circulated through the ring resonator (which would maximize filtering but increase loss), the configuration inverts the approach by taking the output at the through port before the light completes a full circulation. This inversion prioritizes output power while still maintaining the resonator's filtering function through the drop port.
3Ease of manufacture
If silicon is used as the substrate material for integrated optical circuits, then cost reduction is achieved, but luminous efficiency decreases compared to InP-based emitters
Solution Approach 1:
The system employs a composite structure combining silicon substrate with InP-based semiconductor optical amplifier. The silicon substrate provides cost-effective integrated optical circuit fabrication, while the InP-based amplifier material maintains high luminous efficiency. This composite approach allows the system to benefit from both the manufacturing advantages of silicon and the optical performance of InP materials.
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 a high power output by reducing light loss and enabling easy connection to integrated optical circuits, achieving a mode suppression ratio of 40 dB and higher output power compared to traditional configurations.
Implementation Method 1
forming a high-reflective film and distributed Bragg reflector to create a Fabry-Perot optical resonator
Implementation Method 2
an optical coupler that branches part of the light conducting from the optical amplifier to the ring resonator within the optical resonator off to the output optical waveguide
Implementation Method 3
a ring resonator optically connected to the optical amplifier
Implementation Method 4
a ring resonator optically connected to the optical amplifier
Implementation Method 5
forming a high-reflective film and distributed Bragg reflector to create a Fabry-Perot optical resonator
Data Source
AI summary
A ring resonator is connected to an optical amplifier. The ring resonator and optical amplifier are contained within the optical path of an optical resonator formed by a first and second reflector. The optical coupler branches part of the light conducting from the optical amplifier to the ring resonator within the optical resonator off to an output optical waveguide.