Birefringent Element Triggered by Half-Bitrate Signal
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Solution Overview
Problem
Existing optical transmission systems with bit-to-bit polarization interleaved bitstreams face challenges in compensating for polarization mode dispersion, as current methods using birefringent elements and decision circuits are not effective due to polarization-dependent losses and require an eye monitor that struggles with this format.
Innovation Solution
Triggering the birefringent element and decision circuits with a frequency half of the bitrate ensures that only every second bit is processed, aligning with the same polarization, thereby isolating the impact of polarization-dependent losses and allowing for effective compensation of polarization mode dispersion without affecting the eye monitor's output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an eye monitor is used to compensate polarization mode dispersion with birefringent elements, then polarization mode dispersion compensation is achieved, but the eye monitor cannot cope well with bit-to-bit polarization interleaved bitstreams due to polarization-dependent losses
Solution Approach 1:
The patent divides the bitstream processing into two separate decision circuits, each handling one polarization state. The trigger signal operates at half the bitrate to process only bits of the same polarization, effectively segmenting the processing path to avoid polarization-dependent loss issues that plague conventional eye monitors.
Solution Approach 2:
The patent introduces a polarization separation mechanism that acts as an intermediary between the incoming polarization-interleaved bitstream and the decision circuits. This intermediary separates the mixed polarization states into distinct paths, allowing each decision circuit to process only one polarization type without interference from polarization-dependent losses.
2Device complexity
If conventional decision circuits are used with bit-to-bit polarization interleaved bitstreams, then the system structure is simple, but polarization-dependent losses affect subsequent bits and prevent effective polarization mode dispersion compensation
Solution Approach 1:
The patent segments the single decision circuit into two parallel decision circuits, each triggered at half the bitrate. This segmentation allows each circuit to process only bits of one polarization state, eliminating the polarization-dependent loss problem that occurs when a single circuit attempts to process alternating polarization states.
Solution Approach 2:
The patent employs periodic triggering of the decision circuits at half the bitrate, creating a periodic sampling pattern that consistently selects bits of the same polarization. This periodic action ensures that polarization-dependent losses do not affect the decision-making process, as the same polarization state is sampled repeatedly.
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 enables the optical transmission system to compensate for polarization mode dispersion, ensuring that the quality criteria of the bitstream are independent of polarization-dependent losses, thereby maintaining transmission quality.
Implementation Method 1
The invention relates to a method of operating an optical transmission system with a bit-to-bit polarization interleaved bitstream having a given bitrate wherein the optical transmission system comprises a birefringent element and/or a decision circuit
Data Source
AI summary
A method of operating an optical transmission system is described. The transmission system is provided with a bit-to-bit polarization interleaved bitstream having a given bitrate. The transmission system comprises a birefringent element and/or a decision circuit. The birefringent element and/or the decision circuit are triggered by a trigger signal having a frequency of half of the bitrate.