Optical Transmitter Gain Control via Feedback Detectors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical transmitters with semiconductor optical amplifiers (SOAs) face challenges in maintaining equal light output intensity between orthogonal polarized waves, leading to variations due to ambient temperature and SOA element differences, requiring complex configurations with polarization separators and rotators.
Innovation Solution
An optical transmitter design that integrates first and second Mach-Zehnder optical modulators and their respective semiconductor optical amplifiers on the same substrate, with detectors and controllers to perform feedback control on gain settings, ensuring equal light output intensity and reducing size and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional optical transmitter configuration with SOA is used to amplify modulated light beams, then light output intensity can be increased, but light output intensity varies due to ambient temperature and SOA element differences
Solution Approach 1:
The patent implements feedback control by detecting the light output intensity from each SOA and using this detection information to control the gain of the respective SOA. This closed-loop feedback mechanism compensates for variations caused by ambient temperature and element differences, maintaining stable light output intensity while preserving the amplification capability.
2Reliability
If detectors and polarization control units are added to compensate for intensity variations, then light output intensity stability is improved, but device complexity increases
Solution Approach 1:
The patent divides the optical transmitter into independent channels, with each channel containing its own detector and SOA gain control unit. This segmentation allows each channel to be controlled independently based on its own detection feedback, avoiding the need for complex centralized polarization control units while achieving intensity stability through distributed feedback control.
3Volume of moving object
If integration of modulators and amplifiers on the same substrate is performed, then device size and power consumption are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent merges the modulators and semiconductor optical amplifiers onto the same substrate, creating an integrated optical transmitter. This consolidation reduces device size and power consumption by eliminating separate mounting requirements and interconnections, while the feedback control mechanism compensates for any performance variations introduced by the integration process.
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 allows for precise control of light output intensity, reducing variations and simplifying the system while maintaining high accuracy in amplification, thus enhancing the quality of combined modulated light beams.
Implementation Method 1
a configuration is known that includes a semiconductor optical amplifier (SOA) located in a subsequent stage of a modulator to increase optical output
Implementation Method 2
first and second optical modulators 101, 102 of a Mach-Zehnder type that modulate each of the light beams
Data Source
AI summary
An optical transmitter includes: a splitter; a first optical modulator and a second optical modulator that modulate each of light beams split by the splitter; a first semiconductor optical amplifier (SOA) and a second SOA that are connected to a subsequent stage of the first optical modulator and a subsequent stage of the second optical modulator, respectively; a first detector and a second detector that detect light output intensity of the first SOA and light output intensity of the second SOA, respectively; a controller that sets gains of the first and second SOAs such that the first and second SOAs are equal in the light output intensity based on detection values of the first and second detectors; and a combiner that combines an output light beam of the first SOA and an output light beam of the second SOA.