Phase-Lock-Free Laser Receiver for Multi-Format Demodulation
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Solution Overview
Problem
Existing laser communication systems are limited by their inability to support multiple modulation formats, leading to reduced network compatibility and scalability, as well as high costs for system upgrades and resource allocation, due to the need for separate terminals for each modulation format.
Innovation Solution
A phase-lock-free system and method for receiving high-speed laser signals that are compatible with multiple modulation formats, including IM, BPSK, DPSK, QPSK, and DQPSK, utilizing a control instruction unit, low-noise high-gain optical amplifier, optical switch, optical delay interferometers, balanced detectors, and anti-coding switch unit, which allows for transparent signal transmission and demodulation across different formats without requiring a phase-lock mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single laser terminal supports only one specific modulation format, then the receiving system can achieve reliable demodulation for that format, but the network compatibility and scalability are limited
Solution Approach 1:
The receiving terminal is designed with multi-functionality to support multiple modulation formats (IM, BPSK, DPSK, QPSK, DQPSK) through a unified receiving system. The optical switch can route signals to different demodulation paths, and the parallel-serial conversion unit adapts to different format requirements, allowing one terminal to perform multiple demodulation functions without requiring separate terminals for each format.
Solution Approach 2:
The receiving system is segmented into modular functional units including optical switch, optical delay interferometer, balanced detector, anti-coding switch unit, and parallel-serial conversion unit. Each unit handles specific demodulation tasks for different modulation formats, enabling the system to process multiple formats through coordinated operation of these segmented modules rather than requiring completely separate receiving systems.
2Reliability
If separate laser communication terminals are allocated for each communication system to support multiple high-speed laser signals, then each system can achieve optimal performance, but the cost for system performance upgrade and resource costs are high
Solution Approach 1:
Multiple demodulation functions for different modulation formats are merged into a single receiving terminal. The system combines optical switch, optical delay interferometer, balanced detector, anti-coding switch unit, and parallel-serial conversion unit into one integrated terminal that can handle IM, BPSK, DPSK, QPSK, and DQPSK formats, thereby reducing the total number of terminals required while maintaining reliable demodulation performance.
Solution Approach 2:
The receiving terminal is designed as a universal platform capable of demodulating multiple modulation formats through configurable signal routing and processing paths. The optical switch directs incoming signals to appropriate demodulation circuits, and the parallel-serial conversion unit adapts to different format requirements, allowing one terminal to replace multiple format-specific terminals.
3Productivity
If higher-order modulation formats (QPSK, DQPSK) are used to transmit more data at the same symbol rate, then the data transmission capacity increases, but the system complexity and requirements for optical signal-to-noise ratio increase
Solution Approach 1:
The demodulation system is segmented into specialized units for handling different modulation formats. The optical delay interferometer is configured with specific delay times (e.g., 1 bit for BPSK/DPSK, 1/2 bit for QPSK/DQPSK) to match the requirements of different formats. The anti-coding switch unit and parallel-serial conversion unit are segmented to handle the specific processing needs of higher-order formats, allowing complex demodulation tasks to be divided into manageable modular operations.
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 solution enhances the compatibility and scalability of laser communication systems, reduces the complexity and cost of terminal devices, and enables adaptive demodulation of high-speed laser signals across various data rates, improving the overall efficiency and compatibility of the communication network.
Implementation Method 1
an optical delay interferometer I, an optical delay interferometer Q, wherein a phase shift difference between the optical delay interferometer I and the optical delay interferometer Q is π/2
Implementation Method 2
a first balanced detector, a second balanced detector; the filter is connected to one input port of the first balanced detector, two output ports of the optical delay interferometer I are connected to two input ports of the first balanced detector
Data Source
AI summary
A phase-lock-free system includes a control instruction unit, a low-noise high-gain optical amplifier, an optical switch, a filter, an optical delay interferometer I, an optical delay interferometer Q, a first balanced detector, a second balanced detector, an anti-coding switch unit, a parallel-serial conversion unit, and a data processing unit. The control instruction unit is connected to the optical switch, the anti-coding switch unit, and the parallel-serial conversion unit, respectively; the low-noise high-gain optical amplifier is connected to the optical switch; the optical switch is connected to the first balanced detector and the second balanced detector by means of the filter, the optical delay interferometer I, and the optical delay interferometer Q, respectively. This system improves the compatibility of a communication system at a relay node in an existing laser communication network.