Optical Semiconductor Device Phase Regulator Spectral Line Width
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Solution Overview
Problem
Conventional optical semiconductor devices experience an increase in spectral line width due to reflected light being amplified and fed back to semiconductor lasers, which deteriorates signal quality, especially in high-speed digital coherent systems.
Innovation Solution
An optical semiconductor device is designed with a phase regulator in optical waveguides to adjust the phase of reflected light, minimizing the spectral line width by varying the reflectivity and light path length, thereby inhibiting the increase of spectral line width caused by feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the laser length LDFB is lengthened to narrow the spectrum line width, then the spectrum line width is reduced, but the device complexity and loss of energy increase
Solution Approach 1:
An optical isolator is introduced as an intermediary component between the semiconductor laser and optical amplifying section. This isolator allows light to pass in one direction while blocking reflected light from returning to the laser, thereby narrowing the spectrum line width without requiring an increase in laser length or device complexity
Solution Approach 2:
The harmful reflected light is extracted and removed from the system using the optical isolator. By taking out the reflected light before it can re-enter the semiconductor laser, the spectrum line width is narrowed without affecting the overall device structure or requiring longer laser lengths
2Illumination intensity
If the reflectivity on the front end surface is increased to improve light output, then the light output is improved, but the spectrum line width increases due to feedback
Solution Approach 1:
The optical isolator serves as a mediator that permits high reflectivity at the front end surface for improved light output while simultaneously preventing the reflected light from feeding back into the laser. This breaks the feedback loop that would otherwise cause spectrum line width increase
Solution Approach 2:
The reflected light that would normally be harmful and cause spectrum broadening is converted into a beneficial situation. By using the optical isolator, the system can maintain high reflectivity for efficient light output while the isolator redirects the reflected light away from the laser, turning a potential harm into a non-issue
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 effectively reduces spectral line width, improving signal quality by optimizing the phase of reflected light, thus addressing the issue of increased line width in high-speed optical communication systems.
Implementation Method 1
a phase regulator provided in at least one of the first, second, and third optical waveguides, and regulating a phase of reflected light that is reflected at a reflecting point present in the optical semiconductor device and returns to the plurality of semiconductor lasers
Implementation Method 2
the phase regulator adjusts the phase of the reflected light so as to decrease line width of the output light of the plurality of semiconductor lasers
Data Source
AI summary
An optical semiconductor device includes: semiconductor lasers; a wave coupling section multiplexing light output by the semiconductor lasers; first optical waveguides respectively optically connecting respective semiconductor lasers to the wave coupling section; a phase regulator regulating phase of reflected light that is reflected at a reflecting point located in the optical semiconductor device and that returns to the semiconductor lasers; a second optical waveguide optically connecting the wave coupling section to the phase regulator; an optical amplifying section amplifying output light of the phase regulator; and a third optical waveguide optically connecting an output of the phase regulator to the optical amplifying section. The phase regulator adjusts the phase of reflected light that returns to the semiconductor lasers to decrease line width of the light output by the semiconductor lasers.