Abstract: Examples described herein generally relate to a temperature-locked loop for optical elements. In an example, a device includes a controller and a digital-to-analog converter (DAC). The controller includes a DC-controllable transimpedance stage (DCTS), a slicer circuit, and a processor. The DCTS is configured to be coupled to a photodiode. An input node of the slicer circuit is coupled to an output node of the DCTS. The processor has an input node coupled to an output node of the slicer circuit. The DAC has an input node coupled to an output node of the processor and is configured to be coupled to a heater. The processor is configured to control (i) the DCTS to reduce a DC component of a signal on the output node of the DCTS and (ii) an output voltage on the output node of the DAC, both based on a signal output by the slicer circuit.

Abstract: Apparatus and associated methods relate to a high-speed data serializer with a clock calibration module including a main multiplexer (MMUX), a replicated multiplexer (RMUX), a duty cycle calibration module (DCC), and a set of adjustable delay lines (ADLs), the ADLs generating calibrated clocks from a set of system clocks, the DCC sensing duty cycle and phase of the calibrated clocks. In an illustrative example, the DCC may generate error signals indicative of deviation from an expected duty cycle using low-pass filters. The error signals control the ADLs, which may provide continuous corrections to the calibrated clocks, for example. The MMUX and RMUX may receive the calibrated clocks, the RMUX generating a duty cycle indicating clock-to-data phasing, the MMUX providing live data multiplexing, for example. Various multiplexer calibration schemes may reduce jitter, which may facilitate increased data rates associated with high-speed serial data streams.

Abstract: A quadrature clock correction (QCC) circuit includes: a first pair of clock correction circuits that output in-phase and anti-in-phase clock signals, respectively, of a four-phase clock signal; a second pair of clock correction circuits that output quadrature-phase and anti-quadrature-phase clock signals, respectively, of the four-phase clock signal; a detector circuit configured to detect duty cycle error and in-phase/quadrature-phase (IQ) phase mismatch in the four-phase clock signal; and a calibration circuit configured to supply a first pair of control signals to each the first pair of clock correction circuits, and a second pair of control signals to each of the second pair of clock correction circuits, to correct both the duty cycle error and the IQ phase mismatch based output of the detector circuit.

Abstract: Systems and methods for calibrating a ring modulator are described. A system may include a controller configured to provide a first test signal to the ring modulator, determine a first candidate temperature control signal for a heater of the ring modulator when the first test signal is provided to the ring modulator, determine a first optical swing of an optical signal at a drop port of the ring modulator, determine a second candidate temperature control signal for the heater when the first test signal is provided to the ring modulator, determine a second optical swing of an optical signal at the drop port, select an optimal optical swing from the first optical swing and the second optical swing, and select one of the first candidate temperature control signal or the second candidate temperature control signal based on the optimal optical swing selected.

Abstract: A data driver includes pre-driver circuitry coupled to a digital-to-analog converter (DAC) via a plurality of bit lines. The pre-driver circuitry is configured to receive a plurality of first voltages corresponding to respective bits of a digital codeword. Each of the first voltages may have one of a first voltage value or a ground potential based on a value of the corresponding bit. The pre-driver circuitry is further configured to drive a plurality of second voltages onto the plurality of bit lines, respectively, by switchably coupling each of the bit lines to ground or a voltage rail based at least in part on the voltage values of the plurality of first voltages. The voltage rail provides a second voltage value that is greater than the first voltage value. The DAC converts the plurality of second voltages to an electrical signal which is an analog representation of the digital codeword.

Abstract: A quadrature clock correction (QCC) circuit includes: a first pair of clock correction circuits that output in-phase and anti-in-phase clock signals, respectively, of a four-phase clock signal; a second pair of clock correction circuits that output quadrature-phase and anti-quadrature-phase clock signals, respectively, of the four-phase clock signal; a detector circuit configured to detect duty cycle error and in-phase/quadrature-phase (IQ) phase mismatch in the four-phase clock signal; and a calibration circuit configured to supply a first pair of control signals to each the first pair of clock correction circuits, and a second pair of control signals to each of the second pair of clock correction circuits, to correct both the duty cycle error and the IQ phase mismatch based output of the detector circuit.