Orthogonal Stokes Vector Mapping for Polarization-Dependent Deterioration
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Solution Overview
Problem
Existing optical transmission systems face challenges in resisting polarization-dependent deterioration phenomena, such as polarization-dependent loss and cross polarization modulation, due to uneven polarization states caused by data patterns, leading to low resistance against these effects.
Innovation Solution
The method involves mapping information into patterns of two or more orthogonal Stokes vectors across slots in a multi-time slot system, generating and transmitting an optical signal, and performing de-mapping to select high-likelihood bit information, enhancing resistance against polarization-dependent deterioration with simple signal processing and hardware configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polarization multiplexing is used to double the number of bits transmitted per symbol, then transmission capacity is increased, but resistance against polarization-dependent deterioration phenomena decreases
Solution Approach 1:
The patent changes the parameter of signal point arrangement by using orthogonal Stokes vectors instead of conventional independent polarization allocation. This parameter change ensures that signal points in different polarization states are orthogonally arranged, which maintains resistance against polarization-dependent deterioration while enabling polarization multiplexing for increased transmission capacity.
Solution Approach 2:
The patent introduces asymmetry in the signal point arrangement by using orthogonal Stokes vectors that are specifically designed to be asymmetric with respect to polarization-dependent deterioration. This asymmetric arrangement ensures that no single polarization state is more vulnerable than others, thereby maintaining reliability while achieving high transmission capacity through polarization multiplexing.
2Productivity
If m-ary phase-shift keying or m-ary quadrature amplitude modulation with increased signal points is used, then transmission capacity is increased, but complexity of signal processing increases
Solution Approach 1:
The patent segments the signal processing into distinct components: mapping to orthogonal Stokes vectors, polarization multiplexing, and coherent detection. By segmenting the processing and using orthogonal Stokes vectors for mapping, the system achieves high transmission capacity while keeping each processing segment relatively simple and manageable.
Solution Approach 2:
The orthogonal Stokes vector mapping provides a universal framework that can accommodate different modulation formats (PSK, QAM) while maintaining a consistent processing approach. This multi-functional mapping method reduces the need for separate complex processing circuits for different modulation types, thereby reducing overall device complexity while maintaining high transmission capacity.
3Reliability
If high optical power is used to secure signal quality at the reception end, then signal quality is improved, but non-linear optical effects cause waveform distortion
Solution Approach 1:
The patent applies preliminary anti-action by using orthogonal Stokes vector mapping that pre-compensates for polarization-dependent deterioration. This preliminary arrangement of signal points in orthogonal polarization states creates inherent resistance against polarization-dependent effects, allowing the system to maintain signal quality at lower optical powers and thereby avoiding non-linear optical effects that cause waveform distortion.
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 significantly enhances the resistance against polarization-dependent deterioration phenomena, maintaining signal quality and stability, even when polarization states change, while reducing computational load and hardware complexity.
Implementation Method 1
a local oscillation light source and a reception signal are caused to mix with and interfere with each other at a reception end to detect the resultant wave by coherent detection
Implementation Method 2
signals can be allocated independently to a vertically polarized wave and a horizontally polarized wave, which are two polarized wave components orthogonal to each other
Data Source
AI summary
Provided is an optical transmission method including: executing mapping processing (112) so that information of one unit of one system, or one unit of each of a plurality of systems, is mapped in a pattern of two or more Stokes vectors orthogonal between slots of a multi-time slot; generating an optical signal from an electric signal processed by the mapping processing; and transmitting the optical signal. A reception side receives the optical signal and converts the received optical signal into an electric signal, and executes de-mapping processing (322) for conversion into the information of one unit of one system, or one unit of each of a plurality of systems, by selecting high-likelihood bit information in association with the mapping processing in which the information is mapped in the pattern of Stokes vectors orthogonal between the slots of the multi-time slot.