Coherent Optics Transceiver Crosstalk Reduction

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Solution Overview

Problem

Existing coherent transceiver designs for bidirectional transmission in communication networks suffer from significant crosstalk, limiting the effectiveness of coherent optics technology in access networks due to the use of conventional single laser sources for both transmitter and local oscillator, which impedes the integration of coherent optics into access networks.

Innovation Solution

The implementation of a communication network architecture utilizing coherent optics transceivers with optical circulators to separate downstream and upstream signals, allowing for simultaneous bidirectional transmission over a single fiber with improved spectral efficiency by using the same wavelength for both directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional single laser sources are used for both transmitter and local oscillator in bidirectional transmission, then device complexity is reduced, but significant crosstalk occurs that prevents effective bidirectional transmission

Engineering Contradiction:

Improvetransceiver design complexityVSAvoidcrosstalk

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the laser sources into separate components: one laser source for the transmitter and another laser source for the local oscillator. This segmentation eliminates the crosstalk problem that occurs when a single laser source is used for both functions, allowing effective bidirectional coherent transmission.

Inventive Principle:

Principle #1Segmentation

2Productivity

If bidirectional transmission is implemented on a single fiber, then spectral efficiency is improved and fiber infrastructure cost is reduced, but crosstalk from conventional transceiver designs limits transmission effectiveness

Engineering Contradiction:

Improvespectral efficiencyVSAvoidtransmission effectiveness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

By segmenting the laser sources and using separate local oscillators at each end of the bidirectional link, the system achieves reliable transmission over single-fiber infrastructure without the crosstalk that plagues conventional designs.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the operational parameters by using coherent detection with separate laser sources, operating at higher frequencies (e.g., 100 GHz spacing), and implementing full-duplex simultaneous transmission, thereby achieving both high spectral efficiency and reliability.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If additional fiber infrastructure is deployed to increase capacity, then bandwidth capacity is improved, but investment cost and deployment time increase significantly

Engineering Contradiction:

Improvebandwidth capacityVSAvoiddeployment cost

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent makes existing single-fiber infrastructure multi-functional by enabling bidirectional coherent transmission, allowing the same fiber to carry multiple high-capacity channels in both directions simultaneously, thereby increasing bandwidth capacity without additional fiber deployment.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If coherent optics technology is integrated into access networks, then transmission distance and capacity are improved, but conventional transceiver designs with single laser sources create crosstalk that impedes integration

Engineering Contradiction:

Improvecoherent optics integrationVSAvoidcrosstalk

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies segmentation by using separate laser sources for transmission and local oscillation functions, enabling coherent optics technology to be integrated into access networks without the crosstalk that prevents conventional transceiver designs from working effectively in bidirectional configurations.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12107628B2Systems and methods for full duplex coherent optics

Publication Date: 2024.10.01 CABLE TELEVISION LAB INC

AI summary

A full duplex communication network includes an optical transmitter end having a first coherent optics transceiver, an optical receiver end having a second coherent optics transceiver, and an optical transport medium operably coupling the first coherent optics transceiver to the second coherent optics transceiver. The first coherent optics transceiver is configured to (i) transmit a downstream optical signal at a first wavelength, and (ii) simultaneously receive an upstream optical signal at a second wavelength. The second coherent optics transceiver is configured to (i) receive the downstream optical signal, and (ii) simultaneously transmit the upstream optical signal. The first wavelength has a first center frequency separated from a second center frequency of the second wavelength.