Semiconductor Laser Module With Bending Waveguide
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Solution Overview
Problem
The asymmetrical far-field pattern caused by leakage light in semiconductor laser modules with bending waveguides complicates accurate wavelength locking control, as it leads to inconsistent optical power monitoring between power and wavelength monitors.
Innovation Solution
A semiconductor laser module with a bending waveguide having a bending radius of 1000 μm or more, which shapes the far-field pattern to be symmetrical and reduces leakage light, ensuring accurate wavelength locking control by maintaining a linear relation between output and detection values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bending waveguide is used to reduce back-reflected light, then wavelength locking control stability is improved, but the far-field pattern becomes asymmetrical causing measurement precision degradation
Solution Approach 1:
The patent intentionally introduces asymmetry through a prism element to counterbalance the asymmetry caused by the bending waveguide. The prism is positioned and oriented to shift the light flux in a direction that compensates for the asymmetrical far-field pattern, making the overall pattern symmetrical and enabling accurate monitoring by both power and wavelength monitors.
2Shape
If the bending radius of the waveguide is increased to reduce leakage light, then far-field pattern symmetry is improved, but device complexity increases
Solution Approach 1:
The patent specifies a bending radius of 1000 μm or more for the waveguide to minimize leakage light and achieve a symmetrical far-field pattern. This parameter optimization allows the system to maintain pattern symmetry without requiring additional complex structural modifications.
3Device complexity
If a single beam splitter is used to branch light to both power monitor and wavelength monitor, then device complexity is reduced, but measurement precision deteriorates due to FFP asymmetry
Solution Approach 1:
The patent introduces a prism as an intermediary element in the optical path between the beam splitter and the monitors. The prism modifies the light flux distribution to compensate for asymmetry, enabling both monitors to accurately measure optical parameters despite using a single beam splitter configuration.
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 stabilizes wavelength locking control by minimizing optical output loss and maintaining a consistent far-field pattern, even with changes in optical power, allowing for precise monitoring and control.
Implementation Method 1
a bending waveguide having a bending radius of 1000 μm or more, which shapes the far-field pattern to be symmetrical
Implementation Method 2
a beam splitter to which the laser light propagated through the bending waveguide is input, which splits the laser light into a first laser light and a second laser light
Implementation Method 3
a plurality of detectors respectively arranged at different positions in a cross section of a light flux of the second laser light to detect the second laser light
Data Source
AI summary
A semiconductor laser module includes a semiconductor device including a semiconductor laser and a bending waveguide through which a laser light emitted from the semiconductor laser propagates, a beam splitter splitting the laser light into a first laser light and a second laser light, a plurality of detectors respectively arranged at different positions in a cross section of a light flux of the second laser light to detect the second laser light, and a waveform shaping unit provided on an optical path of the laser light. The waveform shaping unit is configured to make a relation between an output of the semiconductor laser and detection values of the detectors approach a linear relation.