Probabilistically shaped unamplified optical signaling
AssigneeJuniper Networks, Inc.
InventorsZhen Qu, Xiao Han, Yang Yue
Life of this patent
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Abstract
An optical transmitter can generate probabilistically shaped quadrature amplitude modulation (PS-QAM) signaling for transmission over a fiber to a destination without optical amplification. The single fiber can transmit the PS-QAM signaling using dense wavelength division multiplexing having a relatively large number of channels that are closely spaced. A coherent receiver can receive the PS-QAM signaling for decoding without implementing chromatic dispersion compensation.
Claims16
An intra-datacenter optical switch network comprising:
- a plurality of probabilistically shaped quadrature amplitude modulation (PS-QAM) transmitters that each generate probabilistically shaped QAM symbols using a probability distribution to generate a PS-QAM signal, the PS-QAM signal having a modulation order of at least 64-QAM;
- a multiplexer that combines the PS-QAM signals from the plurality of PS-QAM transmitters to generate a dense wavelength division multiplexed (DWDM) signal for transmission over fiber within the intra-datacenter optical switch network, the DWDM signal comprising at least 80 DWDM channels at different wavelengths that each comprise one of the PS-QAM signals, the at least 80 DWDM channels in the DWDM signal having spacings of 75 GHz or less;
- a demultiplexer that separates the DWDM channels of the DWDM signal;
- a PS-QAM coherent receiver to receive one of the DWDM channels after the demultiplexer;
- and
- one or more fiber links less than 2 km in length that transmit the DWDM signal from the multiplexer to the demultiplexer without optical amplification,
- wherein:
- the at least 80 channels and the spacings of the channels result in the DWDM signal spanning a wavelength band greater than a passband of an Erbium-Doped Fiber Amplifier;
- and
- each PS-QAM transmitter shapes the QAM symbols to reduce cross-talk between the channels of the DWDM signal at the spacings of the channels of the DWDM signal.
A method for optically transmitting data within an intra-datacenter optical switch network, the method comprising:
- generating, using a plurality of probabilistically shaped quadrature amplitude modulation (PS-QAM) transmitters in a first node of the intra-datacenter optical switch network, QAM symbols that are shaped using a probability distribution to generate a plurality of PS-QAM signals, the PS-QAM signal having a modulation order of at least 64-QAM;
- combining, using a multiplexer, the plurality of PS-QAM signals into a dense wavelength division multiplexed (DWDM) optical signal comprising at least 80 DWDM channels at different wavelengths, each of the channels comprising one of the PS-QAM signals, the at least 80 DWDM channels in the DWDM signal having spacings of 75 GHz or less;
- transmitting, using one or more fiber links less than 2 km in length, the DWDM optical signal from the first node to a second node in the intra-datacenter optical switch network without optical amplification;
- separating, using a demultiplexer in the second node, the DWDM optical signal into separate PS-QAM signals;
- and
- receiving and processing one of the separate PS-QAM signals with a PS-QAM coherent receiver,
- wherein:
- the at least 80 channels and the spacings of the channels result in the DWDM signal spanning a wavelength band greater than a passband of an Erbium-Doped Fiber Amplifier;
- and
- each PS-QAM transmitter shapes the QAM symbols to reduce cross-talk between the channels of the DWDM signal at the spacings of the channels of the DWDM signal.
Dependencies are inferred from the claim text.