Coherent Optical Receiver for Random Polarization States
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Solution Overview
Problem
The coherent optical transmission technology is limited in application scenarios like data center networks due to the inability of existing receivers to function properly when the polarization state of local oscillator light changes randomly, leading to poor universality and increased costs with polarization maintaining optical fibers.
Innovation Solution
A coherent optical receiving apparatus with an optical splitting unit, polarization control unit, and combiner unit is introduced to decompose and hybridize signal and local oscillator light into multiple beams, adjusting polarization to ensure normal operation, using conventional optical fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarization maintaining optical fibers are used to maintain fixed polarization state of local oscillator light, then receiver reliability is improved, but system cost increases
Solution Approach 1:
The patent changes the parameter of polarization state from fixed to variable by introducing a polarization controller. The controller dynamically adjusts the polarization state of local oscillator light to match the signal light's polarization state, replacing the need for expensive polarization maintaining fibers while ensuring reliable receiver operation.
Solution Approach 2:
The patent introduces dynamic polarization control to adapt to changing polarization conditions. The polarization controller continuously adjusts the polarization state of local oscillator light in real-time, transforming the static polarization maintenance approach into a dynamic adaptation mechanism that achieves reliability without high cost.
2Manufacturing precision
If optical hybrid apparatus requires fixed polarization state of local oscillator light, then optical hybridization performance is improved, but adaptability to different network scenarios deteriorates
Solution Approach 1:
The patent makes the optical receiving apparatus universal by adding a polarization controller that can adapt to any polarization state of incoming signal light. The apparatus can now function in diverse network scenarios including data center networks with random polarization changes, transforming a specialized fixed-polarization device into a universal multi-scenario solution.
Solution Approach 2:
The patent enables the optical hybrid apparatus to handle variable polarization states by introducing dynamic polarization control. The polarization controller adjusts the local oscillator light's polarization state to match the signal, allowing the apparatus to maintain high optical hybridization performance across different network scenarios with varying polarization conditions.
3Reliability
If polarization control unit is added to adjust polarization of local oscillator light, then receiver reliability is improved, but device complexity increases
Solution Approach 1:
The patent introduces a polarization controller as an intermediary component between the local oscillator and the optical hybrid apparatus. This mediator adjusts the polarization state of local oscillator light to match the signal light, improving reception reliability while adding only a single modular component rather than fundamentally redesigning the entire apparatus.
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
Enables stable and cost-effective coherent optical reception by maintaining normal work despite random polarization changes, improving system stability and reducing precision and cost requirements.
Implementation Method 1
the optical splitting unit is configured to: receive signal light and local oscillator light in any polarization mode, and decompose the signal light into a plurality of beams of sub signal light, and decompose the local oscillator light into a plurality of beams of sub local oscillator light
Implementation Method 2
the optical hybrid unit is configured to perform optical hybridization on the obtained sub signal light and the obtained sub local oscillator light, to obtain a plurality of beams of hybrid light
Implementation Method 3
the combiner unit is configured to perform optical-to-electrical conversion on the plurality of beams of hybrid light to obtain and output a plurality of coherent electrical signals
Implementation Method 4
the polarization control unit is configured to control polarization of the local oscillator light, so that a first digital signal processor (DSP) obtains service data based on the plurality of coherent electrical signals
Data Source
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AI summary
This application relates to the field of optical communication, and in particular, to a coherent optical receiving apparatus and an optical system that uses the coherent optical receiving apparatus. The coherent optical receiving apparatus includes an optical splitting unit, a polarization control unit, an optical hybrid unit, and a combiner unit. The polarization optical splitting unit is connected to an input terminal of the optical hybrid unit, and an output terminal of the optical hybrid unit is connected to the combiner unit. The optical splitting unit is configured to: receive signal light and local oscillator light in any polarization mode, and decompose the signal light into a plurality of beams of sub signal light, and decompose the local oscillator light into a plurality of beams of sub local oscillator light. The optical hybrid unit is configured to perform optical hybridization on the sub signal light and the sub local oscillator light, to obtain a plurality of beams of hybrid light. The combiner unit is configured to perform optical-to-electrical conversion on the plurality of beams of hybrid light to obtain and output a plurality of coherent electrical signals. The polarization control unit is configured to control polarization of the local oscillator light, so that a digital signal processor obtains service data based on the plurality of coherent electrical signals.