Optical Transmitter Phase Modulation Timing Adjustment
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Solution Overview
Problem
Current methods for setting the timing of phase modulation in high order xPSK optical transmitters are complex, costly, and lack the necessary precision and tuning range for both serial and parallel configurations, particularly at higher symbol rates, leading to suboptimal bit error rates and manufacturing challenges.
Innovation Solution
A method involving a specific pattern fed to the transmitter, which uses a delay interferometer to convert phase differences into amplitude differences, detected by a photo-detector and peak-to-peak detector, with a feedback circuit to adjust the phase modulation timing to minimize peak-to-peak values, enabling precise timing setting across a wider range than one symbol period for both serial and parallel transmitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex timing setting methods are used to achieve precise phase modulation timing, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the peak-to-peak value detected from the optical signal is fed back to adjust the timing of phase modulation. This closed-loop feedback system automatically optimizes the timing setting, achieving high precision without requiring complex manual calibration procedures or sophisticated measurement equipment.
Solution Approach 2:
The system performs self-calibration by using its own output signal to adjust its internal timing. The optical signal generated by the modulator is fed back through a delay interferometer and photodetector to automatically tune the phase modulation timing, eliminating the need for external complex timing measurement devices.
2Manufacturing precision
If conventional timing setting methods are used, then manufacturing cost is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The timing setting mechanism uses the transmitter's own optical output to automatically calibrate itself through the delay interferometer and peak-to-peak detection system. This self-calibrating approach achieves high manufacturing precision without requiring complex external equipment or sophisticated manufacturing processes.
Solution Approach 2:
The system adjusts the timing parameter dynamically by varying the phase modulation timing based on the detected peak-to-peak value. This parameter optimization approach allows precise timing setting to be achieved through simple iterative adjustment rather than complex manufacturing procedures.
3Adaptability or versatility
If timing setting is limited to one symbol period range, then device complexity is reduced, but adaptability deteriorates
Solution Approach 1:
The delay interferometer-based timing adjustment system serves multiple functions: it can adjust timing across more than one symbol period, work with different modulation formats, and provide both coarse and fine timing adjustment. This universal mechanism replaces multiple specialized adjustment systems, achieving wide adaptability without proportionally increasing complexity.
4Measurement precision
If complex timing adjustment procedures are used, then measurement precision improves, but productivity deteriorates
Solution Approach 1:
The automatic feedback loop continuously monitors the peak-to-peak value and adjusts the timing in real-time, eliminating the need for slow manual measurement and adjustment procedures. This automated closed-loop system achieves both high precision and fast convergence, significantly improving productivity compared to conventional manual timing setting methods.
Solution Approach 2:
The patent replaces manual mechanical timing adjustment with an automated electronic control system that uses electrical signals to adjust the timing. This substitution of mechanical procedures with electronic automation achieves both precise measurement and rapid adjustment, improving productivity while maintaining 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
This approach simplifies and speeds up the timing setting process, providing a compact, cost-effective solution that optimizes phase modulation timing, reducing bit error rates and enhancing transmitter performance across various symbol rates.
Implementation Method 1
A light signal emitted from the delay interferometer is converted into an electrical signal... The timing of the phase modulation is set so as to minimize a peak to peak value of the electrical signal
Implementation Method 2
A light signal emitted from the delay interferometer is converted into an electrical signal
Data Source
AI summary
A method is provided for setting a timing of phase modulation by a target phase modulator within an optical transmitter which performs 2n order phase shift keying, n being a natural number equal to or more than two. The method is provided with: feeding a specific pattern to the optical transmitter to allow the xPSK transmitter to emit an optical carrier in accordance with the specific pattern; receiving the optical carrier by a delay interferometer; converting a pair of light signals emitted from constructive and destructive outputs of the delay interferometer into an electrical signal; detecting a peak to peak value of the electrical signal; and setting the timing of the phase modulation by the target phase modulator so as to minimize the peak to peak value of the electrical signal.