Macom Technology Solutions Holdings, Inc.

Leland Stanford Junior University

Ikanos Communications, Inc.

Macom Connectivity Solutions, LLC

Echere Iroaga

Naga Rajesh Doppalapudi

Mahmoud Reza Ahmadi

Aniket Kadkol

Qasem Aldrubi

Boris Murmann

Jason C Hu

Nanda Govind Jayaraman

Jian Wang

Sylvain Flamant

Amaaduddin Zoab Quraishi

The present invention facilitates optical modulation skew adjustment. Components of an on chip optical device driver system can cooperatively operate to provide modulated driver signals to drive configuration of optical signals. A serializer is configured to receive parallel data signals and forward corresponding serial data signals. A multiplexing component is configured to selectively output an in-phase component and a quadrature component of the serial data signals, including implementing skew adjustments to aspects of a first output signal and a second output signal. An output stage is configured to output signals that modulate an optical signal, including the first output signal and the second output signal. An on chip skew detector is configured to detect a skew difference between the first output signal and the second output signal. A skew calibration component is configured to direct skew adjustment between the first output signal and the second output signal.

Optical modulation skew adjustment systems and methods

Various aspects provide for error detection and compensation for a multiplexing transmitter. For example, a system can include an error detector circuit and a duty cycle correction circuit. The error detector circuit is configured to measure duty cycle error for a clock associated with a transmitter to generate error detector output based on a clock pattern for output generated by the transmitter in response to a defined bit pattern. The duty cycle correction circuit is configured to adjust the clock associated with the transmitter based on the error detector output. Additionally or alternatively, the error detector circuit is configured to measure quadrature error between an in-phase clock and a quadrature clock in response to the defined bit pattern. Additionally or alternatively, the system can include a quadrature error correction circuit configured to adjust phase shift between the in-phase clock and the quadrature clock based on quadrature error.

Error detection and compensation for a multiplexing transmitter

A system for calibration of a multi-channel transceiver includes a plurality of voltage regulator circuits, wherein each circuit is configured to produce a voltage for circuitry of one channel of a multi-channel transceiver. The system also includes an analog multiplexer circuit configured to selectively route the output of one of the plurality of voltage regulator circuits to a single comparison circuit. The single comparison circuit is configured to compare an output of one of the plurality of voltage regulator circuits to a target reference voltage and produce an error signal representing a difference between the output of one of the plurality of voltage regulators and the target reference voltage. The system further includes a processor configured to accept the error signal and produce a feedback signal for the one of the plurality of voltage regulator circuits. The feedback signal is operable to adjust the voltage to minimize the difference.

System and method for calibration of multi-channel transceivers

A system for transmitting signals via serial links includes a plurality of lanes for combining data onto a transmission media, a skew detector configured to detect skew among two of the plurality of lanes, and a variable delay circuit controlled by the skew detector, configured to delay the start of a clock signal to circuitry of one of the plurality of lanes.

Closed loop lane synchronization for optical modulation

Various aspects provide for a digitally programmable analog duty-cycle correction circuit. For example, a system includes a duty-cycle correction circuit and a duty-cycle distortion detector circuit. The duty-cycle correction circuit adjusts a clock associated with the transmitter. The duty-cycle distortion detector circuit facilitates digital control of a duty-cycle of the clock associated with the duty-cycle correction circuit based on duty-cycle distortion error associated with output of the transmitter.

Digitally programmable analog duty-cycle correction circuit

Various aspects provide for a multiplexer for high-speed serial links. For example, a system can include a first stage data path multiplexer circuit and a second stage data path multiplexer circuit. The first stage data path multiplexer circuit comprises a first inverter circuit to select a first data signal from a set of data signals and a second inverter circuit to select a second data signal from the set of data signals. The first inverter circuit comprises a first set of inverters and a first set of transmission gates. The second inverter circuit comprises a second set of inverters and a second set of transmission gates. The second stage data path multiplexer circuit is configured as a third inverter circuit to select the first data signal or the second data signal as an output data signal. The third inverter circuit comprises a third set of inverters and a third set of transmission gates.

CMOS quarter-rate multiplexer for high-speed serial links

A voltage regulator operable to selectively supply an extended range of regulated voltages by using multiple levels of unregulated voltages and a single amplifier. The voltage regulator is coupled to a plurality of passing elements in parallel via enabling switches. Each passing element is configured to receive a respective level of unregulated voltage and, when enabled, can pass current to the voltage regulator and thereby induce a corresponding level of regulated voltage at the output terminal of the voltage regulator. To output a specific regulated voltage, the voltage regulator can operate in a single passing mode in which only the passing element receiving the corresponding unregulated voltage is enabled to pass current. Alternatively, in a parallel passing mode, two or more passing elements receiving different levels of unregulated voltages can be enabled to pass current.

On-chip voltage regulator providing extended range of voltage supplies

An analog-based architecture is used to produce tap spacings in an n-tap UI-spaced equalizer without the need for digital clock-driven elements. The analog voltage-controlled delay cell circuits control the amount of applied delay based on the measured phase difference between quarter-rate clock signals. Because low speed clock signals are sufficient for comparison purposes, the analog delay cells can be placed before the quarter-rate multiplexors in the data path. The use of analog-based delay cells eliminates the need to route high-speed clock signals to multiple digital delay elements that are typically used to achieve UI-spaced data signals in n-tap FIR equalizers. Timing margin issues can also be eliminated since digital clocked elements are not used to produce the UI spaced delays. The analog-based delay approach also consumes less power relative equalizers that use multiple digital delay elements requiring high speed clock signals.

Analog delay based T-spaced N-tap feed-forward equalizer for wireline and optical transmitters

An analog-based architecture is used to produce tap spacings in an n-tap fractionally-spaced equalizer without the need for digital clock-driven elements. The analog voltage-controlled delay cell circuits control the amount of applied delay based on the measured phase difference between quarter-rate clock signals. Because low speed clock signals are sufficient for comparison purposes, the analog delay cells can be placed before the quarter-rate multiplexors in the data path. The use of analog-based delay cells eliminates the need to route high-speed clock signals to multiple digital delay elements that are typically used to achieve fractionally spaced data signals in n-tap FIR equalizers. Timing margin issues can also be eliminated since digital clocked elements are not used to produce the fractionally spaced delays. The analog-based delay approach also consumes less power relative equalizers that use multiple digital delay elements requiring high speed clock signals.

Analog delay based fractionally spaced n-tap feed-forward equalizer for wireline and optical transmitters

Peak-to-average ratio reduction is achieved by detecting peaks in an original analog signal that exceed a given threshold. Segments of the original analog signal containing such peaks are treated (e.g., by attenuation) and a composite analog signal is assembled that includes treated and untreated segments of the original analog signal. The composite analog signal is processed to perform analog-to-digital conversion to generate a composite digital signal. Segments of the composite digital signal corresponding to the treated segments of the original analog signal are reverse-treated or otherwise treated again to undo treatment of the segments of the original analog signal. A final output digital signal is generated that corresponds to the original analog signal in digital form.

Method and apparatus for peak-to-average ratio reduction

Driver circuits for switched-capacitor circuits are implemented using a variety of methods and devices. According to one such circuit, a switched-capacitor driver circuit is implemented for producing an output signal by driving a capacitive output load in response to step input signals. The driver circuit includes output circuitry that drives the capacitive output load toward a steady-state mode responsive to one of the step input signals and control circuitry that, before realizing the steady-state mode, inhibits the output circuitry from driving the capacitive output load to the steady-state mode.

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Santa Clara, CA, United States of America

Echere Iroaga