US 12,003,317 B2 · Bidirectional single-fiber coherent transmission system

Abstract

The Bi-Di coherent transmission system is configured with at least one pair of modules coupled to one another via a single fiber. The modules each are configured with a pair of laser outputting two reference signals at respective different wavelengths λ1o and λ2o, photonic transceiver and a wavelength division multiplexer (WDM) coupler. The photonic transceivers each have transmitter and receiver branches integrated in a photonic circuit and receiving the reference signals. The transmitter is configured to modulate the received reference signals λ1oT and λ2oT which are further coupled into the WDM coupler. The WDM couplers each sort out one of the modulated signals and transmit the other modulated signal such that the transmitted modulated signal at different wavelengths λ1oT and λ2oT are coupled into respective opposite ends of the fiber and propagate towards one another in opposite directions. The transmitted modulated signals are coupled into respective branches through the WDM couplers with each transmitted modulated signal interfering with the reference signals at wavelengths λ1o and λ2o. The photodiodes of respective receiving branches are configured to detect a beat frequency of the interfering signals at the same wavelength.

Claims20

Dependent claims

A bidirectional (BiDi) coherent transmission system comprising:

at least one pair of spaced modules each configured with:
two lasers outputting respective reference signals at different wavelengths λ1o and λ2o,
a photonic transceiver including transmitting and receiving branches which both receive the reference signals, the transmitting branches of respective transceivers each being configured to output respective modulated signals λ1oT and λ2oT,
a Bi-Di wavelength division multiplexer (WDM) coupler receiving modulated signals λ1oT and λ2oT and sorting out one of them, so that only modulated signals at respective different wavelengths λ1oT and λ2oT are transmitted by respective WDMs, and
a single fiber guiding transmitted modulated signals λ1oT and λ2oT in respective directions opposite to one another towards respective receiving branches which each have a photodiode (PD), the transmitted modulated signals each interfering with the reference signals at respective wavelengths λ1o and λ2o such that each PD detects a beat frequency of the reference and transmitted modulated signals at the same wavelength but is not responsive to a beat frequency of the reference and transmitted modulated signals at respective different wavelengths.

2 more elements

Dependencies are inferred from the claim text.

Bidirectional single-fiber coherent transmission system

Life of this patent

Bidirectional single-fiber coherent transmission system

Life of this patent

Abstract

Claims20