Optical Semiconductor Modulator Eliminating Polarization Rotator
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Solution Overview
Problem
Current polarization multiplexing type optical semiconductor modulators face challenges with high optical loss, low yield, and increased cost due to the integration of polarization rotators with other optical components, which hinders cost-saving, size-saving, and power consumption-saving goals.
Innovation Solution
An optical semiconductor device is integrated on a semiconductor substrate with two wavelength-tunable light sources and optical modulators, eliminating the need for a polarization rotator by using distributed feedback type lasers and a polarization multiplexer to generate light signals of different polarizations, which are then multiplexed, allowing for precise wavelength control to improve extinction ratio and reduce optical loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a polarization rotator is integrated on the same substrate with other optical components, then the number of components is reduced and coupling loss is reduced, but optical loss increases and polarization extinction ratio deteriorates
Solution Approach 1:
The patent extracts and eliminates the polarization rotator component from the integrated optical device. By using two separate light sources with different polarizations instead of a polarization rotator, the device achieves component reduction without suffering from the optical loss and polarization extinction ratio deterioration that plague semiconductor-based polarization rotators.
Solution Approach 2:
The patent employs light sources that serve multiple functions: they provide both the optical signal and the desired polarization state. This eliminates the need for separate polarization control components, reducing overall device complexity while maintaining low optical loss.
2Device complexity
If a polarization rotator is integrated on the same substrate, then component count is reduced, but manufacturing yield decreases due to manufacturing errors in the polarization rotator
Solution Approach 1:
By removing the polarization rotator from the integrated device architecture, the patent eliminates the manufacturing errors and yield issues associated with semiconductor-based polarization rotators. The solution uses standard light sources with inherent polarization characteristics, avoiding the problematic polarization rotation function.
3Manufacturing precision
If wavelength control is implemented to adjust polarization rotation amount, then polarization extinction ratio improves, but additional electric power sources are needed and costs increase
Solution Approach 1:
The patent employs light sources that inherently provide the desired polarization states without requiring external polarization control mechanisms. The light sources self-generate the appropriate polarization, eliminating the need for additional electric power sources and wavelength control systems.
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 enhances the polarization extinction ratio, reduces optical loss, and decreases manufacturing costs by eliminating the polarization rotator, enabling more efficient and cost-effective optical modules with improved performance and reduced power consumption.
Implementation Method 1
at least one of the first light source and the second light source is a wavelength-tunable laser
Implementation Method 2
the first optical modulator is optically connected to an output side of the first light source and modulates the light
Data Source
AI summary
In an optical semiconductor device related to the present invention, a first light source outputting light having a first polarization, a second light source outputting light having a second polarization, a first optical modulator being optically connected to an output side of the first light source and modulating the light that is output from the first light source to output a light signal, a second optical modulator being optically connected to an output side of the second light source and modulating the light that is output from the second light source to output a light signal, and an optical multiplexer coupling the light signal that is output from the first optical modulator with the light signal that is output from the second optical modulator to output a coupled light signal, are integrated on a semiconductor substrate together.