Coherent Optics Transceiver Crosstalk Compensation
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Solution Overview
Problem
Existing coherent optical transceivers are unable to fully leverage bidirectional transmission capabilities in access networks due to significant crosstalk issues when using a single fiber for both upstream and downstream communication, limiting spectral efficiency and requiring separate fibers for each direction.
Innovation Solution
A full-duplex communication network employing coherent optics transceivers with dual polarization signals and compensation modules to filter crosstalk and reflections, enabling simultaneous bidirectional transmission over a single fiber using the same wavelength, thereby doubling spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single fiber is used for bidirectional transmission with the same laser source, then spectral efficiency is improved, but crosstalk increases significantly
Solution Approach 1:
The patent divides the optical signal into two separate polarization components (orthogonal polarizations) that can be transmitted simultaneously over the same fiber. By segmenting the signal space into orthogonal polarization dimensions, the system achieves bidirectional transmission on a single fiber while managing crosstalk through polarization division multiplexing.
Solution Approach 2:
The patent introduces a compensation module as an intermediary component that actively compensates for crosstalk and reflection effects. This module processes the received signals to cancel out the harmful interference from the remote transmitter, enabling clean separation of upstream and downstream signals despite their coexistence on the same fiber.
2Object-generated harmful factors
If separate fibers are used for upstream and downstream communication, then crosstalk is reduced, but spectral efficiency decreases
Solution Approach 1:
The patent merges the upstream and downstream transmission channels by combining them on a single fiber through polarization division multiplexing. The orthogonal polarization states allow both directions to share the same physical medium, effectively doubling the utilization of available fiber resources while maintaining signal integrity through active compensation.
3Productivity
If the same wavelength is used for both directions, then spectral efficiency is improved, but signal separation becomes difficult
Solution Approach 1:
The patent transitions from frequency/wavelength domain separation to polarization domain separation. Instead of using different wavelengths for upstream and downstream, the system uses orthogonal polarization states as an additional dimension for signal differentiation, allowing same-wavelength bidirectional transmission while maintaining clear signal separation through polarization filtering and compensation.
Data Source
AI summary
A full duplex communication network includes a first coherent optics transceiver having (i) a first receiver, and (ii) a first transmitter configured to transmit a first dual polarized signal. The network further includes a second coherent optics transceiver having (i) a second receiver configured to receive the first dual polarized signal, and (ii) a second transmitter configured to transmit a second dual polarized signal. The network further includes an optical transport medium operably coupling the first coherent optics transceiver to the second coherent optics transceiver, and a first compensation module configured to filter (i) crosstalk between orthogonal components of the first dual polarized signal, and (ii) reflections between the first dual polarized signal and the second dual polarized signal.