Spatial Optical Receiver Angle Shift Compensation
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Solution Overview
Problem
Conventional spatial optical communication systems face complications in configuration and signal-to-noise power ratio degradation due to the need for wavelength multiplexing of beacon light and the use of separate sensors for angular error detection, especially when the transceiver is mounted on a moving object like an aircraft or satellite.
Innovation Solution
A spatial optical communication receiver is designed with a telescope, pointing mirror, multi-core fiber, splitter, coherent detectors, and a digital signal processing unit that includes an adaptive equalizer, phase compensation unit, and angle shift detecting unit, allowing for coherent detection and compensation of optical signals without the need for separate sensors or wavelength multiplexing, using a multi-core fiber to transmit and process optical signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wavelength multiplexing of beacon light is performed in the transmitter, then angular error detection is enabled, but the configuration becomes complicated
Solution Approach 1:
The patent combines the beacon light transmission function with the signal light transmission function by using the same wavelength for both. The beacon light is modulated with angular error information and transmitted through the same optical path as the signal light, eliminating the need for separate wavelength multiplexing components in the transmitter.
Solution Approach 2:
The optical path is designed to serve multiple functions: it transmits both the signal light for communication and the beacon light for angular error detection simultaneously. The receiver processes both functions through the same optical path, reducing transmitter complexity while maintaining detection capability.
2Measurement precision
If separate sensors are used for angular error detection, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the angular error detection function with the signal processing function by using the same photodetector and processing circuitry for both beacon light detection and signal light detection. The angular error information is extracted from the beacon light through the same optical path and detection system used for signal reception.
Solution Approach 2:
The system uses its own received optical signal to detect angular errors by analyzing the beacon light component that is already present in the received signal. No separate dedicated sensor system is required because the existing detection infrastructure can process both signal and beacon light simultaneously.
3Reliability
If wavefront distortion compensation is performed with deformable mirror, then signal-to-noise ratio is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical deformable mirror system with a digital signal processing approach. Wavefront distortion is compensated by processing the received signal in the digital domain rather than by physically deforming a mirror, thereby maintaining signal-to-noise ratio while reducing mechanical complexity and cost.
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 spatial optical communication by improving the signal-to-noise power ratio and simplifying the system configuration, enabling effective angle shift compensation and reducing the complexity of the communication setup.
Implementation Method 1
a telescope for focusing a spatially propagated optical signal and outputting the optical signal collimated
Implementation Method 2
a pointing mirror for compensating for an angle shift of the optical signal output from the telescope
Implementation Method 3
a multi-core fiber having a plurality of cores for transmitting the optical signal focused
Implementation Method 4
coherent detectors for performing coherent detection on the optical signals from each single mode fiber
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An optical signal from a pointing mirror (102) is focused by a focusing optical system (103). The optical signal focused is transmitted via a multi-core fiber (104). The optical signal transmitted is subjected to coherent detection by coherent detectors (108) and decoded by a digital signal processing unit (110). The digital signal processing unit (110) detects an angle shift of the optical signal input to the focusing optical system (103). The pointing mirror (102) updates a compensation angle correspondingly to the angle shift detected by the digital signal processing unit (110).