US 11,115,125 B2Granted

Monolithic integrated coherent transceiver

AssigneeSifotonics Technologies Co., Ltd.

InventorsPengfei Cai, Zhou Fang, Yi Li, Ning Zhang, Rangchen Yu, Ching-yin Hong, Dong Pan

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Abstract

Various embodiments of a monolithic transceiver are described, which may be fabricated on a semiconductor substrate. The monolithic transceiver includes a coherent receiver module (CRM), a coherent transmitter module (CTM), and a local oscillation splitter to feed a local oscillation to the CRM and the CTM with a tunable power ratio. The monolithic transceiver provides tunable responsivity by employing avalanche photodiodes (APDs) for opto-electrical conversion. The monolithic transceiver also employs a polarization beam rotator-splitter (PBRS) and a polarization beam rotator-combiner (PBRC) for supporting modulation schemes including polarization multiplexed quadrature amplitude modulation (PM-QAM) and polarization multiplexed quadrature phase shift keying (PM-QPSK).

Claims16

Dependent claims

A monolithic coherent transceiver, comprising:

a first input port to receive an optical input, the optical input comprising a carrier modulated by a signal through a modulation scheme;
a second input port to receive an optical local oscillation (LO), a frequency of the optical LO substantially equal to a frequency of the carrier;
a LO splitter to split the optical LO into a first LO and a second LO with a splitting ratio between the first LO and the second LO;
a coherent receiver module (CRM) to detect the signal based on the optical input and the first LO;
a third input port to receive an electrical modulation signal;
a coherent transmitter module (CTM) to generate an optical output signal based on the second LO and the electrical modulation signal;
and
an output port to transmit the optical output signal,
wherein the modulation scheme comprises polarization multiplexed quadrature amplitude modulation (PM-QAM) or polarization multiplexed quadrature phase shift keying (PM-QPSK),
wherein the CTM comprises:
a first IQ modulator configured to modulate, based on a first half of information represented by the electrical modulation signal, the second LO into a first portion of the optical output signal;
a second IQ modulator configured to modulate, based on a second half of the information represented by the electrical modulation signal, the second LO into a second portion of the optical output signal;
and
a polarization beam rotator-combiner (PBRC) configured to combine the first portion of the optical output signal and the second portion of the optical output signal into the optical output signal,
wherein the first portion of the optical output signal is combined as a transverse electric (TE) component of the optical output signal, and wherein the second portion of the optical output signal is combined as a transverse magnetic (TM) component of the optical output signal,
wherein each of the first and second IQ modulators comprises:
an I-arm comprising a first Mach-Zehnder modulator (MZM) and configured to generate an I-arm output;
a Q-arm comprising a second MZM and configured to generate a Q-arm output;
a 3 dB coupler to combine the I-arm output and the Q-arm output into an IQ output;
a monitoring photodiode (MPD) to monitor a power of the IQ output;
and
an IQ phase tuner configured to tune, based on a reading of the MPD, a phase difference between the I-arm output and the Q-arm output so that the phase difference is substantially 90 degrees,
wherein each of the first and second MZMs comprises a dual-drive push-pull configuration, and wherein the dual-drive push-pull configuration comprises two serpentine optical paths, and
wherein each of the two serpentine optical paths comprises a plurality of p-n junction diodes connected in parallel, and wherein each of the first and second MZMs comprises an electrical pad to receive a direct-current bias voltage that biases the plurality of p-n junction diodes.

21 more elements

A monolithic coherent transceiver, comprising:

a first input port to receive an optical input, the optical input comprising a carrier modulated by a signal through a modulation scheme;
a second input port to receive an optical local oscillation (LO), a frequency of the optical LO substantially equal to a frequency of the carrier;
a LO splitter to split the optical LO into a first LO and a second LO with a splitting ratio between the first LO and the second LO;
a coherent receiver module (CRM) to detect the signal based on the optical input and the first LO;
a third input port to receive an electrical modulation signal;
a coherent transmitter module (CTM) to generate an optical output signal based on the second LO and the electrical modulation signal;
and
an output port to transmit the optical output signal,
wherein the modulation scheme comprises polarization multiplexed quadrature amplitude modulation (PM-QAM) or polarization multiplexed quadrature phase shift keying (PM-QPSK),
wherein the LO splitter comprises:
a 1×2 optical coupler having an input, a first output and a second output;
a tunable phase shifter having an input and an output, the tunable phase shifter configured to provide a phase shift based on an electrical voltage;
and
a 2×2 optical coupler having a first input, a second input, a first output and a second output, and
wherein:
the 1×2 optical coupler is configured to receive the optical LO at the input of the 1×2 optical coupler,
the first output of the 1×2 optical coupler is coupled to the input of the tunable phase shifter,
the output of the tunable phase shifter is coupled to the first input of the 2×2 optical coupler,
the second output of the 1×2 optical coupler is coupled to the second input of the 2×2 optical coupler,
the 2×2 optical coupler is configured to generate the first LO at the first output of the 2×2 optical coupler,
the 2×2 optical coupler is further configured to generate the second LO at the second output of the 2×2 optical coupler, and
the splitting ratio between the first LO and the second LO is determined by the phase shift based on the electrical voltage.

19 more elements

A monolithic coherent transceiver, comprising:

a first input port to receive an optical input, the optical input comprising a carrier modulated by a signal through a modulation scheme;
a second input port to receive an optical local oscillation (LO), a frequency of the optical LO substantially equal to a frequency of the carrier;
a LO splitter to split the optical LO into a first LO and a second LO with a splitting ratio between the first LO and the second LO;
a coherent receiver module (CRM) to detect the signal based on the optical input and the first LO;
a third input port to receive an electrical modulation signal;
a coherent transmitter module (CTM) to generate an optical output signal based on the second LO and the electrical modulation signal;
and
an output port to transmit the optical output signal,
wherein the modulation scheme comprises polarization multiplexed quadrature amplitude modulation (PM-QAM) or polarization multiplexed quadrature phase shift keying (PM-QPSK),
wherein the LO splitter comprises:
a polarization beam rotator-splitter (PBRS) having an input, a first output and a second output;
a first 2×2 optical coupler having a first input, a second input, a first output and a second output;
a tunable phase shifter having an input and an output, the tunable phase shifter configured to provide a phase shift based on an electrical voltage;
and
a second 2×2 optical coupler having a first input, a second input, a first output and a second output, and
wherein:
the PBRS is configured to receive the optical LO at the input of the PBRS,
the first output of the PBRS is coupled to the first input of the first 2×2 optical coupler,
the second output of the PBRS is coupled to the second input of the first 2×2 optical coupler,
the first output of the first 2×2 optical coupler is coupled to the input of the tunable phase shifter,
the output of the tunable phase shifter is coupled to the first input of the second 2×2 optical coupler,
the second output of the first 2×2 optical coupler is coupled to the second input of the second 2×2 optical coupler,
the second 2×2 optical coupler is configured to generate the first LO at the first output of the second 2×2 optical coupler,
the second 2×2 optical coupler is further configured to generate the second LO at the second output of the second 2×2 optical coupler, and
the splitting ratio between the first LO and the second LO is determined by the phase shift based on the electrical voltage.

22 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/843,795Filed 8 Apr 2020 · us provisional application
Priority: 8 Apr 2019
Published: US 2020/0322057 A18 Oct 2020
Granted: 7 Sep 2021
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

H04B 10/40
Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing…
G02B 27/283
For polarising: used for beam splitting or combining
G02F 1/0147
For the control of the intensity, phase, polarisation or colour: based on thermo-optic effects
G02F 1/21
For the control of the intensity, phase, polarisation or colour: by interference