A calibration system comprises control circuitry and waveform capture circuitry. The control circuitry selects a first calibration waveform for input to a digital predistortion circuit of a transmitter. The capture circuitry captures a first waveform output by the transmitter in response to the first calibration waveform. The control circuitry compares the first calibration waveform to the captured first waveform. The control circuitry selects a first one of a plurality of mapping circuit configurations based on the result of the comparison, wherein the mapping circuit is configured to map outputs of a plurality of delay circuits among inputs of a plurality of filter taps. The control circuitry stores the one of the mapping circuit configurations in nonvolatile memory associated with the transmitter.

A calibration system comprises control circuitry and waveform capture circuitry. The control circuitry selects a first calibration waveform for input to a digital predistortion circuit of a transmitter. The capture circuitry captures a first waveform output by the transmitter in response to the first calibration waveform. The control circuitry compares the first calibration waveform to the captured first waveform. The control circuitry selects a first one of a plurality of mapping circuit configurations based on the result of the comparison, wherein the mapping circuit is configured to map outputs of a plurality of delay circuits among inputs of a plurality of filter taps. The control circuitry stores the one of the mapping circuit configurations in nonvolatile memory associated with the transmitter.

Embodiments of the present disclosure include optical transmitters and transceivers with improved reliability. In some embodiments, the optical transmitters are used in network devices, such as in conjunction with a network switch. In one embodiment, lasers are operated at low power to improve reliability and power consumption. The output of the laser may be modulated by a non-direct modulator and received by integrated optical components, such as a modulator and/or multiplexer. The output of the optical components may be amplified by a semiconductor optical amplifier (SOA). Various advantageous configurations of lasers, optical components, and SOAs are disclosed. In some embodiments, SOAs are configured as part of a pluggable optical communication module, for example.

Embodiments of the present disclosure include optical transmitters and transceivers with improved reliability. In some embodiments, the optical transmitters are used in network devices, such as in conjunction with a network switch. In one embodiment, lasers are operated at low power to improve reliability and power consumption. The output of the laser may be modulated by a non-direct modulator and received by integrated optical components, such as a modulator and/or multiplexer. The output of the optical components may be amplified by a semiconductor optical amplifier (SOA). Various advantageous configurations of lasers, optical components, and SOAs are disclosed. In some embodiments, SOAs are configured as part of a pluggable optical communication module, for example.

A method includes illuminating a photonic integrated circuit (PIC) of a transmit aperture of a laser communication terminal and a PIC of a receive aperture of the laser communication terminal with multi-wavelength light, where each PIC includes multiple antenna elements forming an optical phased array (OPA). The method also includes determining light intensities of different wavelengths of the multi-wavelength light after the multi-wavelength light has passed through each PIC. The method further includes estimating phases of light associated with the antenna elements based on variations in the light intensities. In addition, the method includes adjusting one or more phase shifters of at least one of the PICs based on the estimated phases of light.

An adjusting method for stabilizing optical characteristic parameters applicable to transmitter optical subassemblies with silicon photonic chips is provided. The adjusting method might include: sensing an initial optical signal emitted by the transmitter optical subassembly with first control component, controlling phase setting parameter of the silicon photonic chip with the first control component to change the transmitter optical subassembly from emitting the initial optical signal to emitting a first modified optical signal, transmitting a power target value to second control component when the first modified optical signal conforms to the phase target value and sensing the first modified optical signal with the second control component, and controlling a bias current of the transmitter optical subassembly according to the first modified optical signal and the power target value to change the transmitter optical subassembly from emitting the first modified optical signal to emitting a second modified optical signal.

A method for automatic power and modulation management in a communication network includes (a) generating a discontinuous management function that is a weighted function of at least spectral efficiency and power consumption of the communication network, (b) determining, from the discontinuous management function, an optimal modulation format, an optimal forward error correction (FEC) rate, and an optimal output power of a transmitter of the communication network, which collectively achieve a maximum value of the management function, and (c) causing the transmitter to operate according to the optimal modulation format, the optimal FEC rate, and the optimal output power.

A method for automatic power and modulation management in a communication network includes (a) generating a discontinuous management function that is a weighted function of at least spectral efficiency and power consumption of the communication network, (b) determining, from the discontinuous management function, an optimal modulation format, an optimal forward error correction (FEC) rate, and an optimal output power of a transmitter of the communication network, which collectively achieve a maximum value of the management function, and (c) causing the transmitter to operate according to the optimal modulation format, the optimal FEC rate, and the optimal output power.

A first optical transceiver includes a transmission signal processor that generates a multi-valued pulse amplitude modulation signal including a fixed bit pattern. The first optical transceiver includes an optical transmitter that transmits the multi-valued pulse amplitude modulation signal as an optical transmission signal. The first optical transceiver includes an optical receiver that receives an optical adjustment signal from a second optical transceiver to reproduce an adjustment signal from the optical adjustment signal. The first optical transceiver includes a first controller that controls the transmission signal processor based on a bit error rate included in the optical adjustment signal to adjust light power at each level of the optical transmission signal.

An optical network communication system utilizes a passive optical network (PON) and includes an optical line terminal (OLT) having a downstream transmitter and an upstream receiver, and an optical network unit (ONU) having a downstream receiver and an upstream transmitter. The downstream transmitter is configured to provide a coherent downlink transmission, and the downstream receiver is configured to obtain one or more downstream parameters from the coherent downlink transmission. The system further includes a long fiber configured to carry the coherent downlink transmission between the OLT and the ONU. The ONU is configured to communicate to the OLT a first upstream ranging request message, the OLT is configured to communicate to the ONU a first downstream acknowledgement in response to the upstream first ranging request message, and the ONU is configured to communicate to the OLT a second upstream ranging request message based on the first downstream acknowledgement.