Temporal Polarization Interleaver for DWDM Nonlinearity Mitigation
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Solution Overview
Problem
Next-generation dense wavelength division multiplexed (DWDM) optical transport technologies face significant non-linear penalties when delivering DWDM signals with more modulation levels through legacy dispersion-managed networks, as many established PolMUX-RZ-QPSK products lack the functionality for temporal polarization interleaving, which is essential for mitigating nonlinearity impairments.
Innovation Solution
The proposed solution involves integrating temporal polarization interleaving (TPI) into DWDM optical signal transmitting systems by using external stand-alone TPI modules in conjunction with established optical transmitters, such as PolMUX-QPSK transmitters, to introduce a predefined phase delay between x-polarized and y-polarized tributaries, thereby reducing peak transmitting power and improving non-linear tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temporal polarization interleaving is implemented to reduce nonlinearity impairment, then non-linear tolerance is improved, but device complexity increases due to requiring additional optical time delay components
Solution Approach 1:
The patent introduces a temporal polarization interleaver as an intermediary component that applies a predefined phase delay to one of the polarized tributaries. This interleaver acts as a mediator between the optical transmitter and the optical network, enabling non-linearity mitigation without requiring changes to the transmitter itself. The interleaver uses polarization-maintaining fiber or waveguide with specific length to create the required time delay, thus resolving the contradiction by adding a dedicated functional component rather than complicating the existing transmitter architecture.
2Productivity
If pulse-to-pulse aligned polarized tributaries are transmitted to maximize data throughput, then productivity is improved, but non-linear penalty increases in legacy dispersion-managed networks
Solution Approach 1:
The patent applies preliminary action by introducing the temporal polarization interleaving function before the signal enters the legacy dispersion-managed network. The predefined phase delay is applied in advance to offset the x- and y-polarized time pulses by half of the symbol rate, which proactively reduces the peak transmitting power and mitigates non-linear effects before they can occur in the network. This allows the system to maintain high data throughput while preemptively addressing the non-linear penalty issue.
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 enhances the non-linear tolerance of DWDM optical signal transmitting systems, allowing for efficient delivery of high modulation levels over existing networks by maintaining stable transmitting power and reducing bit error rates, as demonstrated by improved optical signal-to-noise ratio (OSNR) and bit error rate performance.
Implementation Method 1
The temporal polarization interleaver is configured to receive the output signal from the optical transmitter and cause a predefined phase delay to one of the x-polarized tributaries and the y-polarized tributaries
Data Source
AI summary
An optical signal transmitting system, comprising: an optical transmitter including one or more input terminals and an output terminal; and a temporal polarization interleaver including an input terminal and an output terminal, wherein the output terminal of the optical transmitter is communicatively coupled to the input terminal of the temporal polarization interleaver, wherein: the optical transmitter is configured to receive one or more input signals through its one or more input terminals, generate an output signal using the one or more input signals, the output signal including a x-polarized tributary and a y-polarized tributary that is pulse-to-pulse aligned with the x-polarized tributary, and transmit the output signal to the temporal polarization interleaver; and the temporal polarization interleaver is configured to receive the output signal from the optical transmitter and cause a predefined phase delay to one of the x-polarized tributary and the y-polarized tributary.