Abstract: An apparatus includes an optical receiver that includes a processor. The receiver is configured to direct a digital-electrical representation of a received symbol value of a pulse-amplitude modulated signal to a frequency-domain processing path of the processor and to a time-domain processing path of the processor. The processor is configured to compute, in the frequency-domain processing path, a first product of the received symbol value and a first coefficient, and to compute a second product of the received symbol value and a second coefficient. The processor is further configured to compute, in the time-domain processing path, an estimated error metric based on the first and second products, and to determine an updated first coefficient and an updated second coefficient based on said error metric. The processor is further configured to equalize a subsequent received symbol using the updated coefficients.

Abstract: We disclose a transceiver module having two optical transceivers, each connectable to a different respective optical line, and a pluggable electrical connector that can be mated with a matching electrical connector in a connection slot of the host network device. The transceiver module also has an electrical interface circuit that can transfer data between the optical transceivers and the host network device in a manner that provides a route for transferring data between two optical transceivers without crossing the electrical connectors. This architecture advantageously enables the optical-line rates to not be limited by the electrical data rate of data transfer through the electrical connectors. In some embodiments, the transceiver module is configurable in a manner that can change the optical-line rates of the optical transceivers and/or the electrical data rate. The latter feature enables the transceiver module to be compatible with both older and newer network devices.

Abstract: We disclose an optical add-drop multiplexer that can apply different routing operations to different subcarriers of a data frame. In an example embodiment, the digital signal processor (DSP) of the optical add-drop multiplexer carries out subcarrier-specific add, drop, and pass-through operations in the electrical frequency domain, which enables the DSP to only partially unwrap the pass-through subcarriers, thereby at least partially avoiding some of the more processing-power-hungry DSP operations and reducing the sub-wavelength routing latency accordingly. Also disclosed is an example data-frame structure that can be used to provide subcarrier-specific routing instructions to the optical add-drop multiplexer.

Abstract: We disclose an optical add-drop multiplexer that can apply different routing operations to different subcarriers of a data frame. In an example embodiment, the digital signal processor (DSP) of the optical add-drop multiplexer carries out subcarrier-specific add, drop, and pass-through operations in the electrical frequency domain, which enables the DSP to only partially unwrap the pass-through subcarriers, thereby at least partially avoiding some of the more processing-power-hungry DSP operations and reducing the sub-wavelength routing latency accordingly. Also disclosed is an example data-frame structure that can be used to provide subcarrier-specific routing instructions to the optical add-drop multiplexer.

Abstract: Various embodiments relate to a method, device, and machine-readable storage medium including: an optical modem, the optical modem being configured to negotiate a format of an optical communication session with a remote optical transceiver via an optical fiber link; and wherein the optical modem is configured to select a transmission optical wavelength channel for transmitting data of the optical communication session in response to sensing the optical fiber link for light emission and determining that the transmission optical wavelength channel is unused based on the sensing.

Abstract: An apparatus includes an optical modulator and an electrical driver. The electrical driver is configured to provide to the modulator an input drive signal comprising multiple input electrical drive levels of a pulse-amplitude modulation (PAM) signal. The electrical driver is further configured to provide unequal spacing between adjacent ones of the multiple input electrical drive levels, and is still further configured to provide a non-zero bias to the input drive signal. The electrical driver may be a component of an optical transmitter, and the input drive signal may be a differential drive signal. The electrical driver may be further configured such that the bias configures the modulator to produce PAM-modulated optical field output levels that are more evenly spaced than the input electrical drive levels.

Abstract: We disclose an opto-electronic circuit having an optical modulator and a driver circuit configured to generate a plurality of electrical drive signals for the optical modulator in a manner that causes the opto-electronic circuit to operate as a finite-impulse-response (FIR) filter. Different electrical drive signals generated by the driver circuit represent different taps of the FIR filter and are individually applied to different respective electrodes in the optical modulator without first being combined with one another prior to said individual application. The optical modulator represents an adder of the FIR filter and is configured to use the applied electrical drive signals to perform signal summation in the optical domain, thereby alleviating some of the limitations associated with the electrical RF circuitry used in the driver circuit.