Future Wei Technologies, Inc.

Chromatic Micro Optics, Inc.

Huawei Technologies Co., Limited

Fei Zhu

Yu Sheng Bai

Zhuhong Zhang

Chuandong Li

Zhihong Li

Qing Guo

Yuanjie Chen

Clarence Kan

Yong Qin Chen

Yan Cui

YuSheng Bai

Murali Krishnan

Yi Cai

Yangjing Wen

Samina Chowdhury

Yanming Li

Yanjun Zhu

Jianfeng Wang

Shengyu Bai

An apparatus comprises an uncooled laser; a splitter coupled to the laser; a first wavelength component coupled to the splitter; a local oscillator (LO) port coupled to the first wavelength component; a modulator coupled to the splitter; a second wavelength component coupled to the modulator; and a signal port coupled to the second wavelength component. A method comprises emitting an input light; splitting the input light into a first local oscillator (LO) optical signal and a first unmodulated optical signal; modulating the first unmodulated optical signal using polarization-multiplexed, high-order modulation to produce a first modulated optical signal; transmitting the first LO optical signal to a first duplex fiber; and transmitting the first modulated optical signal to a second duplex fiber.

Optical transceiver using duplex media, self-homodyne detection (SHD), coherent detection, and uncooled laser

An optical transceiver comprises a transmitter configured to transmit a first signal, and a receiver coupled to the transmitter and configured to receive a first compensation, wherein the first compensation is based on a pattern-dependent analysis of the first signal, and provide the first compensation to the transmitter, wherein the transmitter is further configured to compensate a second signal based on the first compensation to form a first compensated signal, and transmit the first compensated signal. An optical transmitter comprises a digital signal processor (DSP) comprising a compensator, a digital-to-analog converter (DAC) coupled to the DSP, a radio frequency amplifier (RFA) coupled to the DAC, and an electrical-to-optical converter (EOC) coupled to the RFA. An optical receiver comprises an optical-to-electrical converter (OEC), an analog-to-digital converter (ADC) coupled to the OEC, and a digital signal processor (DSP) coupled to the ADC and comprising a calibrator.

Compensation of non-linear transmitter impairments in optical communication networks

A system comprises: a polarization state aligner (PSA) comprising: an input port; a first polarization beam splitter (PBS) coupled to the input port; a first phase shifter (PS) coupled to the first PBS; a first polarization rotator (PR) coupled to the first PBS; a first beam splitter (BS) coupled to the first PS and the first PR; a first output port coupled to the first BS; and a second output port coupled to the first BS.

Polarization state aligner (PSA)

An optical transceiver in an optical communications network, comprising a receiver configured to receive an optical signal comprising an X-polarization component and a Y-polarization component. The optical transceiver further comprises a processor coupled to the receiver and configured to determine a chromatic dispersion (CD) estimate and a local oscillator frequency offset (LOFO) estimate based on a relationship between a plurality of CD values and a plurality of LOFO values. The optical transceiver further comprises a transmitter coupled to the processor and configured to transmit the CD estimate, the LOFO estimate, and the optical signal to a downstream component in the optical communications network.

Joint acquisition of chromatic dispersion and frequency offset in optical systems

An optical transceiver in an optical communications network, comprising a receiver configured to receive an optical signal comprising an X-polarization component that comprises a first frame and a Y-polarization component that comprises a second frame. The optical transceiver also comprises a processor coupled to the receiver and configured to determine, in a time domain, a phase estimate according to the first frame and the second frame, determine, in a frequency domain, a channel estimate for the optical signal according to a relationship between the first frame, the second frame, and the phase estimate, and determine a compensated optical signal according to the channel estimate. The optical transceiver further comprises a transmitter coupled to the processor and configured to transmit the compensated optical signal to a downstream component in the optical communications network.

Frequency domain optical channel estimation

A first optical transceiver node comprises: a laser configured to emit an input optical signal; a first splitter coupled to the laser and configured to split the input optical signal into a local oscillator (LO) optical signal and an unmodulated optical signal; and a receiver coupled to the first splitter and configured to: receive the LO optical signal from the first splitter; receive a modulated optical signal from a second optical transceiver node, wherein the modulated optical signal is a modulated version of the unmodulated optical signal; and perform phase noise cancellation of the modulated optical signal using the LO optical signal.

Optical transceiving using self-homodyne detection (SHD) and remote modulation

A signal processing method including obtaining, using an optical receiver, a data signal that comprises one or more pairs of pilot tones and a plurality of subcarrier signals, identifying the one or more pairs of pilot tones, determining a local oscillator frequency offset estimation for the data signal using the one or more pairs of pilot tones, wherein the local oscillator frequency offset estimation indicates a frequency offset, and compensating the data signal in accordance with the local oscillator frequency offset estimation. A signal processing method including obtaining, using an optical receiver, a data signal that comprises one or more pairs of pilot tones and a plurality of subcarrier signals, identifying the one or more pairs of pilot tones, determining a chromatic dispersion estimation for the data signal using the one or more pairs of pilot tones, and compensating the data signal in accordance with the chromatic dispersion estimation.

Estimation and compensation of local oscillator frequency offset and chromatic dispersion using pilot tones in spectral-shaping subcarrier modulation

A method comprising applying an In-phase (I) offset to an I component of an orthogonal pseudo-random coded direct current (DC) bias signal, applying a Quadrature-phase (Q) offset to a Q component of the orthogonal pseudo-random coded DC bias signal, applying an I dither signal to an I Mach-Zehnder modulator (MZM), wherein the I dither signal is based on the I component of the orthogonal pseudo-random coded DC bias signal, applying a Q dither signal to a Q MZM, wherein the Q dither signal is based on the Q component of the orthogonal pseudo-random coded DC bias signal, and performing arbitrary waveform generation (AWG) by modulating an analog data signal onto an optical carrier signal via the MZMs, wherein the I offset and the Q offset are selected to mitigate crosstalk between the I MZM and the Q MZM due to a finite extinction ratio.

Mach-Zehnder modulator bias control for arbitrary waveform generation

An optical receiver comprising a frontend configured to receive an optical signal and convert the optical signal into a plurality of digital electrical signals comprising a plurality of spectrally shaped subcarrier signals carrying symbol mapped data information, and a digital signal processor (DSP) unit coupled to the frontend and configured to receive the digital signals from the frontend, demulitplex the digital signals into the subcarrier signals, and compensate chromatic dispersion (CD) for each of the subcarrier signals by applying an equalizer, wherein each of the subcarrier signals is associated with a unique tone frequency and a unique spectral shape. Also disclosed is an optical transmitter comprising a digital signal processor (DSP) unit configured to map data symbols onto a plurality of electrical subcarrier signals that are non-overlapping and spectrally shaped in a frequency domain.

Resource-efficient digital chromatic dispersion compensation in fiber optical communication using spectral shaping subcarrier modulation

A method comprising receiving digital samples from an optical communication system, assigning the samples into bins based on signal levels of the samples, computing an average signal level for each bin, determining a level adjustment transformation function for the samples based on the average signal levels of the bins, and applying the level adjustment transformation function to the samples. Also, disclosed is an optical receiver comprising a frontend configured to receive an optical signal over an optical channel, and convert the optical signal into a plurality of sequences of digital samples, and a processor coupled to the frontend and configured to perform a channel equalization on the samples of the sequences, assign the channel equalized samples of each sequence into bins based on signal levels of the channel equalized samples, determine a level adjustment transformation function for each sequence, and apply the level adjustment transformation function to each sequence.

Level equalization to compensate for implementation impairments in optical communication systems with high-order modulations

An optical signal receiver tracks local oscillator frequency offset (LOFO) and compensates for the phase distortion introduced in the received signals as a result of utilizing the local oscillator within a coherent detection scheme. This phase distortion is basically a constant phase rotation caused by the LOFO and implementation of the receiver using coherent detection and a digital interferometer instead of a conventional (yet complex) carrier phase estimation or recovery scheme. With an optical receiver implemented in this manner, the requirement of using a precise local oscillator laser with low frequency offset is less important.

Method with improved phase robustness in coherent detected optical system

Method and system for band blocking in an optical telecommunication network. According to an embodiment, the present invention provides a system for optical network. The system includes an input that is configured to receive an input signal through a first optical input. The system also includes a band splitting module that is coupled to the input. The band splitting module is configured to separate the input signal into a plurality of bands. The plurality of bands includes a first band and a second band. The first band includes a first plurality of wave channels. The first plurality of wave channels is characterized by a first channel spacing. The second band includes a second plurality of wave channels, which is characterized by a second channel spacing.

Method and system for band blocking in an optical telecommunication network

An apparatus comprising a frequency-domain equalizer that has been iteratively generated to compensate for filtering effects of a wavelength selective switch, wherein the FDEQ is configured to process in a frequency domain digital samples of a polarization multiplexed phase-shift-keying signal that has been transported over an optical channel.

Method and apparatus of using digital equalizer for cascaded wavelength selective switch compensation

A digital apparatus comprising a fast Fourier transform (FFT) module configured to transform a time domain optical signal into a frequency domain optical signal, a circular shifter coupled to the FFT module and configured to provide coarse frequency offset compensation to the frequency domain optical signal based on an estimated frequency offset; and a frequency offset estimation module coupled to the circular shifter and configured to provide the estimated frequency offset based on a power spectrum of the frequency domain optical signal or a data block header autocorrelation of the time domain optical signal.

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San Jose, CA, United States of America

Fei Zhu