Inphi Corporation

Marvell Asia Pte., Ltd.

Clariphy Communications, Inc.

Shu Hao Fan

Shih Cheng Wang

Jinwoo Cho

Mario Rafael Hueda

Damian Alfonso Morero

A digital signal processor (DSP) of an optical receiver processes one or more digital domain signals, which correspond to a received optical signal, to recover receive data from the one or more digital domain signals. The DSP compensates for a two-dimensional (2-D) warping of transmission symbols at a transmitter of the optical signal at least by: calculating a first adjustment of an in phase (I) component of the transmission symbol; modifying the I component of the transmission symbol using the first adjustment; calculating a second adjustment of a quadrature (Q) component of the transmission symbol; and modifying the Q component of the transmission symbol using the second adjustment

Receiver compensation for low extinction ratio at transmitter

Apparatus and method for digital signal constellation transformation are provided herein. In certain configurations, an integrated circuit includes an analog front-end that converts an analog signal vector representing an optical signal into a digital signal vector, and a digital signal processing circuit that processes the digital signal vector to recover data from the optical signal. The digital signal processing circuit generates signal data representing a signal constellation of the digital signal vector. The digital signal processing circuit includes an adaptive gain equalizer that compensates the signal data for distortion of the signal constellation arising from biasing errors of optical modulators used to transmit the optical signal.

Apparatus and methods for digital signal constellation transformation

Systems and methods described herein include methods and systems for controlling bias voltage provided to an optical modulating device. The optical modulating device is biased at a bias point that is different from a null point of the device such that an offset to the received optical power due to limited extinction ratio is reduced.

Systems and methods for biasing optical modulating devices

Apparatus and method for transmitter alignment in an optical communication system are provided. In certain configurations, a method of correcting for transmitter skew is provided. The method includes generating an optical signal using a transmitter based on an in-phase (I) component and a quadrature-phase (Q) component of a transmit signal, the optical signal having a baud rate that is based on a timing tone. The method further includes receiving the optical signal as an input to a receiver, and generating a signal vector representing the optical signal using the receiver. The signal vector includes an I component and a Q component. The method further includes calculating a power of the timing tone based on processing the signal vector using a tone power calculator of the receiver, and correcting for a skew of the transmitter based on the calculated power.

Apparatus and methods for timing tone based transmitter skew alignment in an optical communication system

Apparatus and method for compensating for transmitter errors in an optical communication system are provided. In certain configurations herein, a receiver is provided for processing an analog signal vector representing an optical signal received from a transmitter. The receiver includes an analog front-end that converts the analog signal vector into a digital signal vector including a digital representation of an I component and a Q component of the optical signal. The receiver further includes a digital signal processing circuit configured to process the digital signal vector to recover data, and the digital signal processing circuit includes a transmitter error compensation system that compensates the digital signal vector for at least one of a transmit skew error of the transmitter or a modulator biasing error of the transmitter.

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Sunnyvale, CA, United States of America

Shu Hao Fan