Optical Module Linear Polarizer Extinction Ratio
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Solution Overview
Problem
Optical modules using semiconductor lasers often output light with low extinction ratio and high temperature dependency, particularly for red and infrared light, which affects their efficiency and accuracy in applications requiring polarized light.
Innovation Solution
Incorporating a linear polarizer in the emission direction of the semiconductor laser to transmit only linearly polarized light components, along with a light-receiving element to adjust and monitor the intensity, and optionally using a protective member and lens to maintain internal conditions and adjust spot size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a semiconductor laser is used to emit red or infrared light, then the device can operate at high temperatures and provide high power output, but the extinction ratio of the emitted light becomes low and temperature dependency increases
Solution Approach 1:
A linear polarizer is introduced as an intermediary component between the semiconductor laser and the external environment. This polarizer selectively transmits light with specific polarization states while blocking others, thereby achieving high extinction ratio without modifying the semiconductor laser itself. The polarizer acts as a mediator that converts the unpolarized or poorly polarized laser output into highly polarized light suitable for precision applications.
Solution Approach 2:
The invention changes the polarization state parameter of the emitted light by using a linear polarizer. By adjusting the polarization characteristics through the polarizer, the extinction ratio is improved while maintaining the high power output capability of the semiconductor laser. This parameter transformation allows the system to meet both high power and high extinction ratio requirements.
2Power
If a semiconductor laser emits red or infrared light, then high power output is achieved, but the temperature dependency of the emitted light increases
Solution Approach 1:
The linear polarizer serves as a temperature-stable intermediary that processes the laser output regardless of temperature fluctuations. While the semiconductor laser's output characteristics may vary with temperature, the polarizer consistently transmits only the desired polarization component, thereby stabilizing the effective output and reducing temperature dependency effects on the final beam quality.
Solution Approach 2:
By transforming the light through a polarizer, the invention changes the polarization parameter to a state that is less sensitive to temperature variations. This parameter transformation effectively decouples the temperature dependency from the useful output, allowing high power operation with improved thermal stability.
3Device complexity
If light from a semiconductor laser is directly used, then the device structure remains simple, but the extinction ratio of the output light is low
Solution Approach 1:
A linear polarizer is added as a minimal intermediary component to the optical path. This single element provides the necessary polarization filtering to achieve high extinction ratio without requiring complex modifications to the semiconductor laser structure or multiple additional optical components, thus maintaining relative structural simplicity while dramatically improving performance.
Solution Approach 2:
The invention achieves high extinction ratio through a simple parameter change - adding polarization filtering - rather than through complex structural modifications. The linear polarizer introduces only one additional component that transforms the polarization parameter of the light, providing an elegant solution that balances simplicity and performance.
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 optical module achieves a high extinction ratio and accurately adjusted intensity for red and infrared light, even with group III-V compound semiconductor lasers, enhancing its performance and stability across varying temperatures.
Implementation Method 1
a linear polarizer that is disposed in an emission direction of the semiconductor laser and that is configured to transmit, of light emitted by the semiconductor laser, only light containing a linearly polarized light component in a specific direction
Data Source
AI summary
An optical module includes a semiconductor laser and a linear polarizer that is disposed in an emission direction of the semiconductor laser and that is configured to transmit, of light emitted by the semiconductor laser, only light containing a linearly polarized light component in a specific direction.