Abstract: An analog pulse capture circuit is disclosed. The circuit may include one or more input sources configured to receive one or more optical signals and generate one or more electrical input signals. The circuit may include one or more distributed capacitors configured to store a target charge, the one or more distributed capacitors including one or more top plates and one or more bottom plates. The circuit may include one or more amplifiers coupled to the one or more distributed capacitors, the one or more amplifiers configured to generate one or more electrical output signals. The circuit may include one or more dump switches coupled to the one or more input sources, the one or more dump switches configured to release the stored target charge of the one or more distributed capacitors.

Abstract: A circuit and method for timing-tolerant optical pulse energy electrical conversion receives a current pulse stream converted from an input optical pulse stream (which may be periodic or nonperiodic), converts the current pulse stream to an electrical waveform of voltage pulses and detects each voltage pulse, e.g., by its leading edge. The conversion circuit may include a divider circuit for receiving the electrical waveform, dividing the waveform into a multi-channel output of divided electrical waveforms, and sequential logic circuits for adjusting a width window of each voltage pulse according to an adjustable delay.

Abstract: A circuit and method for timing-tolerant optical pulse energy electrical conversion receives a current pulse stream converted from an input optical pulse stream (which may be periodic or nonperiodic), converts the current pulse stream to an electrical waveform of voltage pulses and detects each voltage pulse, e.g., by its leading edge. The conversion circuit may include a divider circuit for receiving the electrical waveform, dividing the waveform into a multi-channel output of divided electrical waveforms, and sequential logic circuits for adjusting a width window of each voltage pulse according to an adjustable delay.

Abstract: A non-uniform sampling pADC is disclosed. The pADC may include an optical pulse source configured to generate uniform optic pulses. The pADC may include a non-uniform sampling system. The non-uniform sampling system may include an inter-pulse timing modulation sub-system configured to convert the uniform optic pulses into non-uniform optic pulses. The non-uniform sampling system may include a timing control sub-system configured to control the timing of the optical pulse source. The pADC may include an optical modulator configured to modulate the non-uniform optical pulses. The pADC may include a photodetector configured to convert the modulated non-uniform optic pulses into electronic pulses. The pADC may include a pulse capture assembly configured to capture a pulse amplitude of the electronic pulses and generate sampled radio frequency output pulses. The pADC may include a quantizer configured to quantize the sampled radio frequency output pulses and generate digital radio frequency output signals.

Abstract: An analog pulse capture circuit is disclosed. The circuit may include one or more input sources configured to receive one or more optical signals and generate one or more electrical input signals. The circuit may include one or more distributed capacitors configured to store a target charge, the one or more distributed capacitors including one or more top plates and one or more bottom plates. The circuit may include one or more amplifiers coupled to the one or more distributed capacitors, the one or more amplifiers configured to generate one or more electrical output signals. The circuit may include one or more dump switches coupled to the one or more input sources, the one or more dump switches configured to release the stored target charge of the one or more distributed capacitors.

Abstract: A system and method for wavelength detection includes one or more detection stages configured for receiving at least a portion of an optical carrier. Each stage includes a splitter for splitting the signal into two arms. A 90-degree optical hybrid and in-phase (I-channel)/quadrature (Q-channel) differential detectors generate I-channel and Q-channel differential signals based on the hybrid outputs. A gas cell or like multi-point wavelength reference path also receives the input signal and provides a set of reference absorption wavelengths converted into the electrical domain by a reference photodetector. A logic device receives sets of detection signals (including I-channel and Q-channel differential signals and the set of reference wavelengths, all corresponding to a common measurement time) and determines a wavelength of the optical carrier based on an arctangent of a ratio of the Q-channel and I-channel differential signals, mapped to the set of reference absorption wavelengths.

Abstract: A system for Nyquist zone disambiguation of a received broadband RF signal is disclosed. The system includes continuous-wave (CW) and pulsed photonic sources whose outputs may be combined into a single input. Both CW and pulsed components of the combined photonic input are modulated by sampling the received RF input signal. The system includes hybrid couplers for IQ demodulation of the modulated combined photonic signal. The system demultiplexes the demodulated inphase and quadrature differential photonic signals into their CW and pulsed component signals. The pulsed component signals may be digitized by narrowband multibit analog-digital converters (ADC) while the CW component signals are digitized by high speed low latency mono-bit ADCs to determine frequency components (e.g., bandwidth information) and other spectrum information of the RF input signal.

Abstract: A wavelength detection system may include one or more wavelength detection stages configured to receive at least a portion of an input light signal, where each stage may include a splitter to split a portion of the input light signal into two arms, a 90-degree optical hybrid, and two differential detectors configured to generate I-channel and Q-channel differential signals based on the outputs from the 90-degree optical hybrid. Further, a free spectral range is associated with an optical path length difference between the two arms of each stage. The system may further include a logic device to receive at least one set of detection signals including I and Q channel differential signals associated with different free spectral ranges and determine the wavelength of the input light signal based on an arctangent of a ratio of the Q-channel and I-channel differential signals for at least one set of detection signals.

Abstract: A wavelength division multiplexing (WDM)-based photonic radar architecture is disclosed. The WDM-based photonic radar incorporates a WDM photonic input of N component wavelengths modulated by an IF-LFM input signal and its 90-degree phased counterpart. The modulated WDM photonic signal is split one branch sent to a photodetector for generation of an RF outbound signal and transmission of the signal, which is reflected by a target and received as an RF echo signal after a time delay. The other branch has each component wavelength time-adjusted by a second time delay for each wavelength. The resulting time-delayed WDM photonic signal is modulated again based on the received RF echo signal and split into wavelength selective channels. Filters in each channel extract two adjacent photonic signals converted to RF output signals by photodetectors. RF filters select a single RF signal for processing based on the closest difference between the two time delays.

Abstract: An integrated photonics monopulse comparator includes an array of squinted monopulse elements, each monopulse element producing an RF signal in response to a received inbound signal and each RF signal having a squinted RF voltage. The comparator includes a laser source for producing a wavelength division multiplexed (WDM) optical signal comprising multiple components having discrete wavelengths. The component signals may be multiplexed and demultiplexed and routed through cascading optical phase modulators, each phase modulator connected to a monopulse element and capable of modulating a component signal according to the voltages of the RF signals produced by the corresponding monopulse element. The resulting modulated component optical signals undergo coherent photodetection by arrays of paired photodiodes, each pair receiving component signals of like wavelength.

Abstract: A current-mode analog-digital conversion (ADC) circuit directly samples and digitizes an input signal in the current domain; the input signal may be a current signal or a photonic signal. Input capacitors may be coupled to the current source by a series of switches and configured to store a target charge. The target charge may be compared to a reference voltage by comparators of the system to generate digital output. The current-mode ADC circuit may be adapted to flash, successive-approximation, and pipeline architectures, or embodied in a photonic receiver incorporating current-mode ADC circuits configured to sample and digitize photonic signals.

Abstract: A system for optically down-converting a radio-frequency signal includes phase modulators in a push-pull configuration. Separately tuned optical bandpass filters pass through one or more harmonics and inverse harmonics based on the RF signal to produce a local oscillator. A balanced photo-detector receives a coherent interference signal and derives the down-converted local oscillator from a filtered harmonic and inverse harmonic.

Abstract: A method and related system for linearizing a photonic ADC sampling system of an ELINT receiver includes modulating optical pulse trains of varied pulse amplitudes based on a generated ramped-voltage calibration signal. The modulated pulse trains are demodulated into I/Q components to generate signal constellations. Equivoltage radials are defined by points of the signal constellations sharing a common calibration voltage and a common phase angle of the modulator. A lookup table is generated by mapping the signal constellations and equivoltage radials to a coordinate system to determine, for each coordinate bin, a corresponding pulse amplitude and phase angle. The generated lookup table may be used to correct nonlinear distortions in recovered output signals, preserving high-ENOB performance and increasing the dynamic range of the receiver.

Abstract: A photonic processor can include a first input for a phase-modulated optical pulse signal, a second input for an optical reference signal, and a plurality of states. Each stage is configured to receive the phase-modulated optical pulse signal and a phase-delayed version of the optical reference signal. The phase-delayed version is phase-delayed in accordance with a phase position of the stage. Each stage is comprised of a reference path, a signal path, a coupler and a balanced photo detector. The coupler receives the phase-modulated optical pulse signal and provides as stage phase-modulated optical pulse signal to the signal path. The signal path is coupled to a first input of the balanced photo detector. The coupler also receives the phase-delayed version and provides a stage optical reference signal to the reference path. The reference path is coupled to a second input of the detector. The detector provides an electronic output signal corresponding to a phase relationship.

Abstract: Thermo-optical devices providing heater recirculation in an integrated optical device are described. The thermo-optical devices include at least one waveguide having a non-linear path length in thermal communication with a thermal device. Methods of fabrication and use are also disclosed.

Abstract: Thermo-optical devices providing heater recirculation in an integrated optical device are described. The thermo-optical devices include at least one waveguide having a non-linear path length in thermal communication with a thermal device. Methods of fabrication and use are also disclosed.

Abstract: Thermo-optical devices providing heater recirculation in an integrated optical device are described. The thermo-optical devices include at least one waveguide having a non-linear path length in thermal communication with a thermal device. Methods of fabrication and use are also disclosed.

Abstract: Thermo-optical devices providing heater recirculation in an integrated optical device are described. The thermo-optical devices include at least one waveguide having a non-linear path length in thermal communication with a thermal device. Methods of fabrication and use are also disclosed.

Abstract: Thermo-optical devices providing heater recirculation in an integrated optical device are described. The thermo-optical devices include at least one waveguide having a non-linear path length in thermal communication with a thermal device. Methods of fabrication and use are also disclosed.

Abstract: An intermediate structure used to form an integrated optics device comprising a substrate, a cladding on the substrate, at least one real waveguide on the cladding, and at least one dummy waveguide optically coupled with the real waveguide. The real waveguide forms a part of a predetermined planar lightwave circuit. The dummy waveguide does not form a part of the predetermined planar lightwave circuit.