Micro-Ring External Cavity Laser Feedback for Narrower Linewidth
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Solution Overview
Problem
Existing integrated micro-ring external cavity lasers suffer from low self-injection locking optical power reflected back to the gain chip, leading to frequency drift and limited linewidth narrowing effects due to process deviations in external cavity reflection structures.
Innovation Solution
An optical chip with a structure that includes a substrate, waveguide layer, and optical waveguides forming multiple light output and return paths, utilizing a bidirectional power splitting optical waveguide and a micro-ring optical waveguide to enhance self-injection locking by increasing the power fed back to the gain chip, along with a frequency modulation structure to adjust resonance frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If process deviations occur in external cavity reflection structures, then frequency drift of reflected light occurs, but using discrete structures allows for easier manufacturing
Solution Approach 1:
The patent integrates all external cavity components (optical waveguide, micro-ring resonator, bidirectional power splitting waveguide, and reflective waveguide) onto a single optical chip using semiconductor fabrication processes. This integration eliminates frequency drift caused by misalignment in discrete structures while maintaining manufacturability through standardized semiconductor manufacturing techniques.
Solution Approach 2:
The integrated optical chip structure is designed to be self-aligning, where the components automatically align during fabrication processes. The waveguides and micro-ring resonator are formed using standard semiconductor processes that inherently provide precise alignment, eliminating the need for additional alignment steps and reducing sensitivity to process deviations.
2Reliability
If a bidirectional power splitting optical waveguide is added to increase reflected power, then the structure complexity increases, but this enables better self-injection locking
Solution Approach 1:
The bidirectional power splitting optical waveguide acts as an intermediary component that efficiently divides and redirects optical power between different paths. It mediates between the micro-ring resonator and the gain chip, ensuring maximum power is reflected back to enable strong self-injection locking while maintaining a relatively simple structural implementation.
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
The solution increases the power reflected back to the gain chip, enhancing linewidth narrowing and stability of the external cavity laser without introducing frequency deviations, and allows for frequency modulation capabilities.
Implementation Method 1
The micro-ring optical waveguide is configured to: resonate the light coupled from the first optical waveguide and the light coupled from the second optical waveguide
Implementation Method 2
The reflective optical waveguide is configured to reflect, back to the second optical waveguide, the light emitted from the second optical wave
Implementation Method 3
The bidirectional power splitting optical waveguide is configured to: split the light input from the first port for output through the second port and the third port
Data Source
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AI summary
An optical chip (2a), an external cavity laser (101), a laser module (100), and a laser sensing system (1000) are disclosed, and belong to the laser field, to resolve a problem of low self-injection locking optical power reflected back to a gain chip (11) from a micro-ring external cavity in a narrow-linewidth integrated micro-ring external cavity laser. The optical chip (2a) includes a substrate (201) and a waveguide layer (202) disposed on the substrate (201). A first optical waveguide (21a), a bidirectional power splitting element (22) having a first port (221), a second port (222), and a third port (223), a second optical waveguide (23a), a reflection element (24), and a micro-ring optical waveguide (25a) are formed on the waveguide layer (202). A first end of the first optical waveguide (21a) is coupled to or connected to an end face of the gain chip (11) in the laser (10), and a second end of the first optical waveguide (21a) is connected to the first port (221) of the bidirectional power splitting element (22). The micro-ring optical waveguide (25a) is located on a side of the first optical waveguide (21a). One end of the second optical waveguide (23a) is connected to the second port (222) of the bidirectional power splitting element (22), and the other end of the second optical waveguide (23a) extends to another side that is of the micro-ring optical waveguide (25a) and that is away from the first optical waveguide (21a), and is connected to the reflection element (24). The first optical waveguide (21a) and the second optical waveguide (23a) are coupled to the micro-ring optical waveguide (25a).