Abstract: A transmitter, receiver and transceiver system that may be used for both transmitting and receiving modulated signals are disclosed. The system includes an Electrical-to-Optical (E2O) converter that receives a Radio Frequency (RF) signal and transmits an optical signal and/or an Optical-to-Optical (O2O) that performs a wavelength translation from one wavelength to another wavelength. The Electrical-to-Optical (E2O) converter includes a vapor cell that converts the RF signal to an optical signal.

Abstract: Optical receivers and methods for balanced signal detection using an optical resonator.

Abstract: Optical receivers configured to demodulate phase modulated optical signals. In one example, an optical signal receiver includes an optical resonator configured to receive an arriving optical signal and to emit an output optical signal in response to receiving the arriving optical signal, the optical resonator being further configured to transform phase transitions corresponding to phase modulation of the arriving optical into intensity modulation of the output optical signal, an opto-electrical converter configured to convert the output optical signal into an electrical signal, a pulse detector configured to detect pulses in the electrical energy indicative of the phase transitions in the arriving optical signal, and a memory configured to record timing information associated with the pulses detected by the pulse detector.

Abstract: Optical transmitters configured to modulate optical signals with a path-dependent phase modulation scheme. In certain examples, an optical transmitter includes an optical source that emits a carrier waveform, a modulator configured to modulate the carrier waveform according to a path-dependent phase modulation scheme to produce a modulated optical signal, a mapping module configured to map a data payload to the path-dependent phase modulation scheme, each symbol in the path-dependent phase modulation scheme including a concatenation of at least one location bit and a path bit, the at least one location bit identifying an amount of a phase transition in the modulated optical signal and the path bit identifying a direction of the phase transition, and a pulse-shaping filter configured to control the modulator, based on an output from the mapping module, to impose the path-dependent phase modulation scheme on the carrier waveform to generate the modulated optical signal.

Abstract: A free-space optical signal receiver includes a plurality of detectors whose individual outputs are delayed to correct for variations in arrival time caused by aberration in the medium through which the optical signal propagates, and combined to provide a single output. Each of the plurality of detectors sense the free-space modulated optical signal and provide a detector signal representative of the modulation of the optical signal. Each detector signal is delayed by a delay value to generate a delayed signal, and each delay value is selected to correct for variation in arrival time of the optical signal at each of the detectors, resulting in the delayed signals being substantially time-aligned. The delayed signals are constructively combined into a combined signal representative of the modulation aspect, and the combined signal is provided as an output.

Abstract: Aspects are generally directed to free-space transmitters, free-space receivers, and free-space communication methods. In one example, a free-space communication method includes acts of mapping a data payload to one or more symbols based on a symbol set defined by a digital modulation scheme, varying one or more properties of a signal waveform to phase modulate the signal waveform with the data payload, the one or more symbols each having a symbol duration that defines a timing structure of the modulated signal waveform, and fragmenting the timing structure of the modulated signal waveform to conceal one or more waveform properties of the modulated signal waveform.

Abstract: Optical signal receivers and methods are provided that include multiple optical resonators, each of which receives a portion of an arriving optical signal. Various of the optical resonators are tuned or detuned from a carrier wavelength, and produce an intensity modulated output signal in response to modulation transitions in the arriving optical signal. A detector determines phase transitions in the arriving optical signal, by analyzing the intensity modulation output signals from the optical resonators, and distinguishes between differing phase transitions that result in a common final state of the arriving optical signal.

Abstract: Photo-resonator optical detectors and optical receiver systems incorporating same, In one example, an optically resonant detector includes a housing having an optical window, a photodetector disposed within the housing, and an optical resonator disposed in optical alignment with the photodetector within the housing and positioned between the optical window and the photodetector, the optical resonator being configured to receive an input optical signal via the optical window and to provide an output optical signal to the photodetector.

Abstract: Optical receivers and methods for balanced signal detection using an optical resonator.

Abstract: Optical receivers and methods for balanced signal detection using an optical resonator. In one example, an optical receiver includes an optical resonator that receives an optical signal, accumulates resonant optical signal energy, and emits first output optical signal energy from a first output and second output optical signal energy from the second output. In response to a modulation of the optical signal, the optical resonator is configured to disrupt the first and second output optical signal energies to convert the modulation of the optical signal into an intensity modulation of the first and second output optical signal energies. The optical receiver includes a first detector that receives the first output optical signal energy and detects the intensity modulation of the first output optical signal energy, and a second detector that receives the second output optical signal energy and detects the intensity modulation of the second output optical signal energy.

Abstract: Optical receivers configured to demodulate phase modulated optical signals. In one example, an optical signal receiver includes an optical resonator configured to receive an arriving optical signal and to emit an output optical signal in response to receiving the arriving optical signal, the optical resonator being further configured to transform phase transitions corresponding to phase modulation of the arriving optical into intensity modulation of the output optical signal, an opto-electrical converter configured to convert the output optical signal into an electrical signal, a pulse detector configured to detect pulses in the electrical energy indicative of the phase transitions in the arriving optical signal, and a memory configured to record timing information associated with the pulses detected by the pulse detector.

Abstract: Methods and apparatus for measuring thickness and related properties of transparent objects, such as glass.

Abstract: Optical signal receivers and methods are provided that include an optical resonator that allows optical signal energy of multiple wavelengths to enter and accumulate inside the optical resonator. A portion of optical signal energy of each wavelength is emitted from the optical resonator at an output, and the individual wavelengths may be separated. A detector aligned with the output detects the emitted optical signal energy of at least one of the wavelengths. The detector is configured to detect disturbances to the emitted optical signal energy and determine a modulated characteristic in the received optical signal energy of the wavelength.

Abstract: Examples of passive diode-based transmitter detuning circuits and low-voltage active diode-based and receiver detuning circuits are provided.

Abstract: A system and method for detecting a nucleus of interest in a chemical using a nuclear quadrupole resonance transition. An excitation pulse is used to excite one or more nuclei of interest, if they present in a sample, to an excited state, the energy of which depends on the magnetic field in the sample. The magnetic field in the sample is modulated, after the end of the excitation pulse, while the nuclei of interest decay from the excited state, so that the radiation they emit is frequency modulated. The frequency modulation is detected in the emitted radiation. In some embodiments a DC magnetic field is applied to the sample, during the application of the excitation pulse, to tune the frequency of the transition being excited.

Abstract: Aspects are generally directed to receivers and methods for actively demodulating optical signals. In one example, a receiver includes an optical resonator to receive an optical signal, the optical resonator including an active optical medium interposed between first and second semi-reflective surfaces, where the active optical medium is configured to accumulate resonant optical signal energy inside the optical resonator based on the received optical signal, the second semi-reflective surface is positioned to emit output optical signal energy, and the optical resonator is configured to disturb the output optical signal energy in response to a variation in the received optical signal. The receiver may further include a detector configured to detect the disturbance in the output optical signal energy, and a pump source coupled to the active optical medium to excite the active optical medium to generate an optical gain in the received optical signal.

Abstract: Optical signal receivers and methods are provided that include multiple optical resonators, each of which receives a portion of an arriving optical signal. Various of the optical resonators are tuned or detuned from a carrier wavelength, and produce an intensity modulated output signal in response to modulation transitions in the arriving optical signal. A detector determines modulation transitions in the arriving optical signal by analyzing the intensity modulation output signals from the optical resonators.

Abstract: Optical signal receivers and methods are provided that include an optical resonator that allows optical signal energy of multiple wavelengths to enter and accumulate inside the optical resonator. A portion of optical signal energy of each wavelength is emitted from the optical resonator at an output, and the individual wavelengths may be separated. A detector aligned with the output detects the emitted optical signal energy of at least one of the wavelengths. The detector is configured to detect disturbances to the emitted optical signal energy and determine a modulated characteristic in the received optical signal energy of the wavelength.

Abstract: Aspects are generally directed to receivers and methods for optically demodulating optical signals. In one example, a receiver includes an optical resonator to receive an optical signal, the optical resonator including an optical medium interposed between first and second semi-reflective surfaces, where the first and second semi-reflective surfaces are positioned to resonate optical signal energy, and the optical resonator is configured to disrupt the optical signal energy resonance responsive to a variation in the received optical signal. The receiver may further include a probe source positioned to provide an optical probe beam to the optical medium, the optical medium being configured to interrupt the optical probe beam during the optical signal energy resonance and to transmit at least a portion of the optical probe beam in response to the disruption of the optical signal energy resonance, and a detector to detect the transmitted portion of the optical probe beam.

Abstract: An optical receiver and communication method receives an optical signal by an optical resonator to provide an intensity modulated signal indicative of a modulation of the optical signal. The intensity modulated signal is provided to a channel receiver of a plurality of channel receivers, and the channel receiver recovers from the intensity modulated signal a multipath version of a transmitted signal embedded in the modulation of the optical signal. The channel receiver's output is combined with an output of at least one other of the plurality of channel receivers to provide a combined output signal.