Wavelength Converter Phase Modulation SBS Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wavelength converters face challenges in suppressing degradation of signal characteristics due to modulation components remaining after wavelength conversion, particularly when using high-power pump light that can induce stimulated Brillouin scattering (SBS) in optical fibers with small core diameters.
Innovation Solution
A wavelength converter system that includes phase modulators for both pump and signal lights, with a detection unit to monitor and adjust phase timing and modulation differences between the two, generating phase modulation signals to minimize these differences and cancel out modulation components, thereby reducing SBS and signal degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-power pump light is input to increase wavelength conversion efficiency, then wavelength conversion efficiency is improved, but stimulated Brillouin scattering (SBS) occurs causing light to scatter backward
Solution Approach 1:
The patent applies frequency shifting to the pump light by modulating it with a sinusoidal wave at a specific frequency (e.g., 100 MHz). This parameter change in the pump light frequency prevents SBS by ensuring that the frequency-shifted pump light does not match the Brillouin gain bandwidth, thereby suppressing backward scattering while maintaining high conversion efficiency.
Solution Approach 2:
The patent employs periodic modulation of the pump light using a sinusoidal waveform. This periodic frequency shifting creates a time-varying pump signal that avoids continuous resonance conditions that would otherwise trigger SBS, allowing sustained high-power operation without scattering issues.
2Reliability
If phase modulation is performed on pump light and signal light to cancel modulation components, then signal characteristic degradation is suppressed, but device complexity increases due to additional phase modulators and control mechanisms
Solution Approach 1:
The patent implements a feedback control system where the phase modulation applied to the pump light is synchronized with the phase modulation of the signal light. By detecting the modulation components and adjusting the phase modulation signals to achieve cancellation, the system maintains optimal signal characteristics while managing the complexity through coordinated control.
Solution Approach 2:
The patent combines the phase modulation functions for both pump light and signal light within a unified wavelength conversion system. By coordinating these modulations to work together for modulation component cancellation, the system achieves signal quality improvement while consolidating control mechanisms rather than adding entirely separate systems.
Data Source
AI summary
A wavelength converter includes a first phase modulator configured to perform phase modulation on pump light in accordance with a first phase modulation signal, a second phase modulator configured to perform phase modulation on signal light in accordance with a second phase modulation signal, a wavelength converter configured to multiplex the signal light having undergone the phase modulation with the pump light having undergone the phase modulation, the wavelength converter configured to perform wavelength conversion on the signal light in accordance with the pump light, a detector configured to detect a modulation component from the signal light having undergone the phase modulation and the pump light having undergone the phase modulation, and a generator configured to generate the first phase modulation signal and the second phase modulation signal so as to minimize the detected modulation component.