DQPSK Optical Receiver Operating Point Control
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Solution Overview
Problem
Optical signals modulated by DQPSK or DPSK schemes face challenges in maintaining signal reception quality due to wavelength dispersion and non-linear effects in optical fibers, and changes in operating conditions such as temperature or age can disrupt the optimal operating points of interferometers, leading to degraded waveforms and failure in satisfying logical relations.
Innovation Solution
A signal reception device with a front end featuring two delay interferometers and opto-electric conversion elements that convert DQPSK or DPSK optical signals into in-phase and quadrature-phase signals, a clock and data recovery system, a multiplexer, and a controller that performs logical inversion and timing control to maintain frame synchronization and correct signal reception states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If delay interferometers are used to demodulate DQPSK/DPSK optical signals, then signal demodulation capability is improved, but operating point stability deteriorates due to temperature changes and aging
Solution Approach 1:
The patent implements automatic operating point control mechanisms that continuously monitor the performance of delay interferometers and adjust their operating conditions in real-time. This feedback system compensates for temperature drift and aging effects, maintaining stable demodulation performance without manual intervention.
Solution Approach 2:
The patent employs dynamic parameter adjustment of delay interferometers, including tuning the delay time and bias conditions based on environmental conditions. By changing operational parameters adaptively, the system maintains optimal demodulation performance across varying temperatures and aging conditions.
2Reliability
If automatic operating point control is implemented, then reception stability is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service mechanisms where the delay interferometer system automatically monitors and corrects its own operating points without external control. The system uses built-in detection circuits and automatic adjustment mechanisms that eliminate the need for complex external control systems while maintaining stable reception.
Solution Approach 2:
The patent combines the operating point control functions directly within the delay interferometer structure itself, merging monitoring and adjustment capabilities into the core demodulation component. This integration reduces overall system complexity by eliminating separate control subsystems.
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
The solution ensures stable signal reception by automatically adjusting logical operations and timing to maintain the object signal reception state, even under conditions of temperature changes or aging, thereby ensuring normal logical relations and frame synchronization.
Implementation Method 1
two delay interferometers and opto-electric conversion elements which receive the DQPSK optical signal and convert the DQPSK optical signal into an in-phase signal and a quadrature-phase signal
Implementation Method 2
two delay interferometers and opto-electric conversion elements which receive the DQPSK optical signal and convert the DQPSK optical signal into an in-phase signal and a quadrature-phase signal
Data Source
AI summary
An optical signal reception device is disclosed that receives and demodulates an optical signal modulated by DQPSK and performs logical inversion and other controls to transit to the object reception state. The signal reception device includes a front end including a delay interferometer and an opto-electric conversion element that receive the DQPSK optical signal and convert it into an in-phase signal and a quadrature-phase signal, a clock regenerator that regenerates a clock signal based on the in-phase signal and the quadrature-phase signal, a multiplexer that multiplexes the in-phase signal and the quadrature-phase signal, a reception frame processing unit that detects frame synchronization based on the signal multiplexed by the multiplexer and de-maps the received frames, and a controller that, based on out-of-frame-synchronization information (LOF/OOF) from the reception frame processing unit, performs logical inversion control in the clock regenerator, multiplexing timing control in the multiplexer, and controls the delay interferometer in the front end so as to transit to the object reception state.