Optical Subcarrier Clock Synchronization for Frequency Locking
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Solution Overview
Problem
Optical system components face challenges in processing multiplexed subcarriers due to differing frequency rates, leading to improper processing and potential interference during data transmission.
Innovation Solution
Implementing a technique where the optical system and leaf systems use coherent detection and digital signal processing to synchronize clock frequencies, allowing each leaf system to adjust and lock onto the correct transmit frequency of incoming subcarriers, preventing spectral overlap and enabling proper demodulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple subcarriers are transmitted at different frequency rates to increase data transmission capacity, then the data transmission rate is improved, but the receiving component's ability to process each subcarrier properly deteriorates due to frequency misalignment
Solution Approach 1:
The patent implements a feedback mechanism where the receiving component detects the actual frequency rate of each received subcarrier and generates a control signal to adjust the local oscillator frequency accordingly. This closed-loop feedback ensures that the local oscillator is synchronized with the transmitted subcarrier frequency, resolving the frequency misalignment problem while maintaining high data transmission rates
Solution Approach 2:
The patent dynamically changes the frequency parameter of the local oscillator based on the detected subcarrier frequency. By adjusting the local oscillator frequency to match the transmitted subcarrier frequency, the system maintains accurate frequency alignment even when multiple subcarriers are transmitted at different rates, thus resolving the contradiction between high data rate and frequency precision
2Measurement precision
If the receiver adjusts sampling frequency to lock onto actual transmit frequency to improve detection accuracy, then measurement precision is improved, but processing time increases due to iterative adjustment
Solution Approach 1:
The patent performs preliminary frequency estimation and coarse alignment before fine-tuning the sampling frequency. By initially setting the sampling frequency close to the expected transmit frequency based on prior knowledge or rough estimation, the system reduces the number of iterative adjustments needed, thereby minimizing the time required to achieve frequency lock while maintaining high detection accuracy
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
Ensures accurate and interference-free data transmission by synchronizing clock frequencies across the optical system and leaf systems, allowing for efficient aggregation and demodulation of multiplexed subcarriers.
Implementation Method 1
a local oscillator laser providing a local oscillator signal
Implementation Method 2
a detector circuit operable to receive a first optical signal and detect first data carried by the first optical signal
Data Source
AI summary
Methods, systems, and apparatus, including computer programs encoded on computer storage media, for clock synchronizing an optical system and multiple leaf systems. In some implementations, a method includes: first data is received from an optical system. The first data is detected using a local oscillator signal provided by a local oscillator laser. The first data is processed using a first sampling rate. A frequency of a clock signal supplied by a reference clock is adjusted based on the processed first data. Second data is transmitted to the optical system at a rate based on the clock signal.