Optical Transmitter Phase Control for Fiber Length Variations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical transmitters face challenges in automatically matching the phases of modulating signals input to multiple optical modulators, especially when the length of optical fibers changes due to reconnection or temperature variations, leading to increased processing time and accuracy issues in compensating for delays.
Innovation Solution
An optical transmitter with a phase control unit that uses a hill-climbing method or synchronous detection to automatically match the phases of modulating signals by controlling a phase shifter, ensuring optimal phase alignment without the need for frequent recalibration, even in the presence of temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the length of optical fiber changes due to reconnection or temperature variations, then the transmission path is maintained, but the phase matching accuracy deteriorates
Solution Approach 1:
The patent implements feedback control by monitoring the phase difference between modulating signals and automatically adjusting the phase shifter to maintain optimal phase matching. The control unit continuously monitors phase alignment and makes real-time corrections, ensuring accurate phase matching even when fiber length changes due to reconnection or temperature variations.
Solution Approach 2:
The patent employs dynamic phase adjustment by making the phase shifter adjustable rather than fixed. The phase control unit dynamically changes the phase shift amount based on current operating conditions, allowing the system to adapt to changing fiber lengths and temperature conditions while maintaining precise phase matching accuracy.
2Measurement precision
If manual phase adjustment is used, then phase matching can be achieved, but processing time increases
Solution Approach 1:
The patent implements self-service through automatic phase matching. The control unit autonomously monitors phase differences and adjusts the phase shifter without requiring manual intervention. The system self-corrects phase misalignment caused by fiber length changes or temperature variations, achieving both accurate phase matching and reduced processing time through automated operation.
Solution Approach 2:
The patent ensures continuous phase matching by maintaining constant monitoring and adjustment of phase alignment. The control unit continuously operates to keep the phases of modulating signals matched, eliminating the need for periodic manual recalibration and ensuring uninterrupted accurate transmission despite changing conditions.
3Measurement precision
If frequent recalibration is performed, then phase matching accuracy is maintained, but system stability deteriorates
Solution Approach 1:
The feedback control mechanism continuously monitors phase alignment and makes only necessary adjustments, avoiding frequent recalibration. The system maintains stability by operating smoothly with real-time corrections, while the control unit detects when recalibration is actually needed based on monitored phase differences, preventing unnecessary disruptions to system stability.
Solution Approach 2:
The patent applies preliminary action by proactively adjusting phase alignment before significant drift occurs. The control unit continuously monitors phase differences and makes preemptive adjustments to maintain optimal matching, preventing the need for frequent recalibration and maintaining both accuracy and stability through anticipatory control.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An optical transmitter includes: a data generating unit (6) configured to generate a plurality of modulating signals; a driver (9) configured to amplify the plurality of modulating signals generated by the data generating unit (6); a phase shifter (7) configured to control a phase of at least one signal among the plurality of modulating signals to be input to the driver (9); a plurality of optical modulators (2) connected in series to each other, and configured to modulate an optical signal on a basis of each of the modulating signals amplified by the driver (9); an optical coupler (3) configured to branch the optical signal modulated by the optical modulator (2) arranged at a last stage in the series; a photodiode (4) configured to detect the optical signal branched by the optical coupler (2) and converts the optical signal into an electric signal; and a phase control unit (5a) configured to control an amount of phase control of the phase shifter (7) to maximize an intensity of the electric signal converted by the photodiode (4).