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: 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: 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: 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: 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: An apparatus comprises a digitally controlled circuit having a variable capacitance and a controller configured to adjust a magnitude of the variable capacitance of the digitally controlled circuit. The digitally controlled circuit comprises a plurality of gain elements, the plurality of gain elements comprising one or more positive voltage-to-frequency gain elements and one or more negative voltage-to-frequency gain elements. The controller is configured to adjust the magnitude of the capacitance by adjusting the gain provided by respective ones of the gain elements in an alternating sequence of the positive voltage-to-frequency gain elements and the negative voltage-to-frequency gain elements.

Abstract: A method includes forming a resonator comprising a plurality of switched impedances spatially distributed within the resonator, selecting a resonant frequency for the resonator, and distributing two or more transconductance elements within the resonator based on the selected resonant frequency. Distributing the two or more transconductance elements may include non-uniformly distributing the two or more transconductance elements within the resonator.

Abstract: A method includes forming a resonator comprising a plurality of switched impedances spatially distributed within the resonator, selecting a resonant frequency for the resonator, and distributing two or more transconductance elements within the resonator based on the selected resonant frequency. Distributing the two or more transconductance elements may include non-uniformly distributing the two or more transconductance elements within the resonator.

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 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: An apparatus comprises a digitally controlled circuit having a variable capacitance and a controller configured to adjust a magnitude of the variable capacitance of the digitally controlled circuit. The digitally controlled circuit comprises a plurality of gain elements, the plurality of gain elements comprising one or more positive voltage-to-frequency gain elements and one or more negative voltage-to-frequency gain elements. The controller is configured to adjust the magnitude of the capacitance by adjusting the gain provided by respective ones of the gain elements in an alternating sequence of the positive voltage-to-frequency gain elements and the negative voltage-to-frequency gain elements.

Abstract: A method and system are disclosed for measuring a specified parameter in a phase-locked loop frequency synthesizer (PLL). In one embodiment, the method comprises introducing multiple phase errors in the PLL, measuring a specified aspect of the introduced phase errors, and determining a value for the specified parameter using the measured aspects of the introduced phase errors. In one embodiment, the phase errors are introduced repetitively in the PLL, and these phase errors produce a modified phase difference between the reference signal and the feedback signal in the PPL. In one embodiment, crossover times, when this modified phase difference crosses over a preset value, are determined, and these crossover times are used to determine the value for the specified parameter. In an embodiment, the parameter is calculated as a mathematical function of the crossover times. The parameter may be, for example, the bandwidth of the PLL.

Abstract: Methods an systems for low-power transmission include biasing an emitter in a non-linear operating range of the emitter near a threshold current of the emitter. A data signal is distorted to add a precursor pulse to a rising edge of a data waveform to quickly bring the emitter into a linear operating range. The distorted data signal is transmitted at the emitter.

Abstract: A method includes forming a resonator comprising a plurality of switched impedances spatially distributed within the resonator, selecting a resonant frequency for the resonator, and distributing two or more transconductance elements within the resonator based on the selected resonant frequency. Distributing the two or more transconductance elements may include non-uniformly distributing the two or more transconductance elements within the resonator.