Abstract: Optical switches and methods of switching include a first hybrid coupler configured to accept an input and to provide two branches. A phase tuner on a first branch includes a Mach-Zehnder phase shifter configured to shift a signal on the first branch by a selected phase. A loss compensator on a second branch is configured to match a loss incurred on the first branch. A second hybrid coupler is configured to recombine the two branches such that the phase shift generated by the phase tuner determines which output of the second hybrid coupler is used.

Abstract: Methods and systems for bias control in an optical switch fabric include monitoring optical power at outputs of a plurality of switch elements in an N×N switch fabric that has N inputs, N outputs, and M?2 stages, each switch element having a respective unique radio frequency tone. A bias control of each of the plurality of switch elements is adjusted. It is determined whether the optical power at the outputs of each respective switch element after bias control adjustment conform more closely to a predetermined criterion relative to the monitored optical power at the outputs of the respective switch element prior to adjustment.

Abstract: Optical switches include a phase shifter on a first branch, a first heater on the first branch, and a second heater on a second branch. A hybrid coupler combines the first branch and the second branch. A first photodetector and a second photodetector are at outputs of the second hybrid coupler to measure crosstalk between the outputs of the second hybrid coupler. A controller is configured to activate the first heater or the second heater to reduce the measured crosstalk.

Abstract: A device and method of optical equalization using an optical modulator is provided. An electrical modulation signal is split into a first modulation signal and a second modulation signal. The second modulation signal is delayed relative to the first modulation signal. An amplitude of the second modulation signal is attenuated relative to the first modulation signal. The first modulation signal is applied to a first waveguide segment of the optical modulator. The second modulation signal that is delayed and attenuated relative to the first modulation signal is applied to a second waveguide segment of the optical modulator. Both the applied first and second modulation signals generate a feed-forward equalized optical signal that is recombined in the optical domain.

Abstract: Optical switches include a phase shifter on a first branch, a first heater on the first branch, and a second heater on a second branch. A hybrid coupler combines the first branch and the second branch. A first photodetector and a second photodetector are at outputs of the second hybrid coupler to measure crosstalk between the outputs of the second hybrid coupler. A controller is configured to activate the first heater or the second heater to reduce the measured crosstalk.

Abstract: Methods and systems for bias control in an optical switch fabric include monitoring optical power at outputs of a plurality of switch elements in an N×N switch fabric that has N inputs, N outputs, and M?2 stages, each switch element having a respective unique radio frequency tone. A bias control of each of the plurality of switch elements is adjusted. It is determined whether the optical power at the outputs of each respective switch element after bias control adjustment conform more closely to a predetermined criterion relative to the monitored optical power at the outputs of the respective switch element prior to adjustment.

Abstract: A communication system includes first and second devices. The first device includes a first transmitter and a first receiver. The first transmitter transmits one data of a first type using one or more first channels over a first communication link to the second device. The first receiver receives one data of a second type, from the second device, using one or more second channels over the first communication link. The second device includes a second transmitter and a second receiver. The second receiver receives the one data of the first type using the one or more first channels over the first communication link, and to generate the one data of the second type based on the one data of the first type. The second transmitter transmits the one data of the second type using one or more second channels over the first communication link to the first device.

Abstract: Optical switches include a first hybrid coupler configured to accept an input and to provide two branches. A phase tuner on a first branch includes a phase shifter. A first heater is positioned on the first branch and a second heater is positioned on the second branch, each configured to compensate for phase error. A second hybrid coupler configured to recombine the two branches. A first photodetector and a second photodetector are positioned at outputs of the second hybrid coupler and are configured to measure crosstalk between the outputs of the second hybrid coupler. A controller is configured to activate the first heater or the second heater to reduce the measured crosstalk.

Abstract: A communication system includes first and second devices. The first device includes a first transmitter and a first receiver. The first transmitter transmits one data of a first type using one or more first channels over a first communication link to the second device. The first receiver receives one data of a second type, from the second device, using one or more second channels over the first communication link. The second device includes a second transmitter and a second receiver. The second receiver receives said one data of the first type using the one or more first channels over the first communication link, and to generate said one data of the second type based on said one data of the first type. The second transmitter transmits said one data of the second type using one or more second channels over the first communication link to the first device.

Abstract: Optical switches include a first hybrid coupler configured to accept an input and to provide two branches. A phase tuner on a first branch includes a phase shifter. A first heater is positioned on the first branch and a second heater is positioned on the second branch, each configured to compensate for phase error. A second hybrid coupler configured to recombine the two branches. A first photodetector and a second photodetector are positioned at outputs of the second hybrid coupler and are configured to measure crosstalk between the outputs of the second hybrid coupler. A controller is configured to activate the first heater or the second heater to reduce the measured crosstalk.

Abstract: A communication system includes first and second devices. The first device includes a first transmitter and a first receiver. The first transmitter transmits one data of a first type using one or more first channels over a first communication link to the second device. The first receiver receives one data of a second type, from the second device, using one or more second channels over the first communication link. The second device includes a second transmitter and a second receiver. The second receiver receives the one data of the first type using the one or more first channels over the first communication link, and to generate the one data of the second type based on the one data of the first type. The second transmitter transmits the one data of the second type using one or more second channels over the first communication link to the first device.

Abstract: A method for transmitting data between a first device and a second device over a communication link includes transmitting, by the first device, data of a first type using one or more first channels, receiving, by the second device, the data of the first type from the first device using the one or more first channels, generating, by the second device, data of a second type based on the data of the first type, and transmitting, by the second device, the generated data of the second type using one or more second channels. The data of the first type and the data of the second type are different. The one or more second channels are channels dedicated to transmit the data of the second type.

Abstract: Optical switches and methods of switching include a first hybrid coupler configured to accept an input and to provide two branches. A phase tuner on a first branch includes a Mach-Zehnder phase shifter configured to shift a signal on the first branch by a selected phase. A loss compensator on a second branch is configured to match a loss incurred on the first branch. A second hybrid coupler is configured to recombine the two branches such that the phase shift generated by the phase tuner determines which output of the second hybrid coupler is used.

Abstract: A device and method of optical equalization using an optical modulator is provided. An electrical modulation signal is split into a first modulation signal and a second modulation signal. The second modulation signal is delayed relative to the first modulation signal. An amplitude of the second modulation signal is attenuated relative to the first modulation signal. The first modulation signal is applied to a first waveguide segment of the optical modulator. The second modulation signal that is delayed and attenuated relative to the first modulation signal is applied to a second waveguide segment of the optical modulator. Both the applied first and second modulation signals generate a feed-forward equalized optical signal that is recombined in the optical domain.

Abstract: A device and method of optical equalization using an optical modulator is provided. An electrical modulation signal is split into a first modulation signal and a second modulation signal. The second modulation signal is delayed relative to the first modulation signal. An amplitude of the second modulation signal is attenuated relative to the first modulation signal. The first modulation signal is applied to a first waveguide segment of the optical modulator. The second modulation signal that is delayed and attenuated relative to the first modulation signal is applied to a second waveguide segment of the optical modulator. Both the applied first and second modulation signals generate a feed-forward equalized optical signal that is recombined in the optical domain.

Abstract: A method and system of optical communication are provided. An optical modulator device includes a first and a second waveguide segment, and is configured to modulate an incident optical signal. A first feed-forward equalization (FFE) circuit including an inner first tap and an inner second tap, is configured to equalize the first waveguide segment. A second FFE circuit including a first inner tap and a second inner tap, is configured to equalize the second waveguide segment. An FFE recombination of the first inner tap and the second inner tap of the first and second FFE circuits, is in the electrical domain, respectively. An FFE recombination of the first and second modulation signals, operative to equalize a combination of the first second waveguide segments, is in the optical domain.

Abstract: Methods and systems for bias control in an optical switch fabric include monitoring optical power at outputs of a plurality of switch elements in an N×N switch fabric that has N inputs, N outputs, and M?2 stages. A bias control of a first of the plurality of switch elements is adjusted. It is determined whether the optical power at the outputs of the first switch element after bias control adjustment conform more closely to a predetermined criterion relative to the monitored optical power at the outputs of the first switch element prior to adjustment. The adjusting and determining steps are repeated for each of the remainder of the plurality of switch elements.

Abstract: A photonic waveguide structure for performing polarization rotation includes a first waveguide layer including input and output waveguides. The input and output waveguides are separate and discontinuous structures. The input and output waveguides are configured in the first waveguide layer to have a lateral offset therebetween. The photonic waveguide structure further includes a second waveguide layer including a waveguide structure disposed under or over the first waveguide layer. The waveguide structure includes a polarization conversion region configured within the second waveguide layer to overlap the input or output waveguides in the first waveguide layer.

Abstract: A method for transmitting data between a first device and a second device over a communication link includes transmitting, by the first device, data of a first type using one or more first channels, receiving, by the second device, said data of the first type from the first device using the one or more first channels, generating, by the second device, data of a second type based on said data of the first type, and transmitting, by the second device, said generated data of the second type using one or more second channels. Said data of the first type and said data of the second type are different. The one or more second channels are channels dedicated to transmit said data of the second type.

Abstract: A communication system includes first and second devices. The first device includes a first transmitter and a first receiver. The first transmitter transmits one data of a first type using one or more first channels over a first communication link to the second device. The first receiver receives one data of a second type, from the second device, using one or more second channels over the first communication link. The second device includes a second transmitter and a second receiver. The second receiver receives said one data of the first type using the one or more first channels over the first communication link, and to generate said one data of the second type based on said one data of the first type. The second transmitter transmits said one data of the second type using one or more second channels over the first communication link to the first device.