Provided are, among other things, systems, methods and techniques for providing remote location-based customer service for in-store customers. One such system includes: (a) a central server; (b) wireless transceivers coupled to the central server at different locations within each of multiple different retail shopping sites; and (c) handheld wireless devices, carried by customers at such retail shopping sites and in wireless communication with such wireless transceivers. Each of the handheld wireless devices is configured with a user interface that allows a customer to designate a user-interface element to request a customer-service session. Upon designation of the user-interface element on one of such handheld wireless devices, the request is forwarded to the central server. The central server establishes a two-way real-time communication link between the handheld wireless device and a customer-service representative.

An optical wireless transmission device according to an embodiment of the present invention comprises: a modulation unit for receiving input of a first input signal and outputting a first output signal; and a light source control unit for controlling a first light source in accordance with the first output signal. The first output signal repeats “0” and “1” in a first phase during clock time if a binary value of the first input signal is 0, and repeats “0” and “1” in a phase opposite from the first phase during the clock time if a binary value of the first input signal is 1.

Modulated entangled photon pairs are used to transmit data between a sender and receiver subsystem. The sender subsystem comprises at least one data input, a modulator to modulate the photons, a photon combiner and a transmitter coupler to direct the modulated entangled photon pairs towards a receiver. The receiver subsystem comprises a receiver coupler, a photon de-combiner to direct the photons to polarization analyzers to transmit photons of a specified polarization to detectors, and a processor to record the information transmitted by the detectors. The sender subsystem transmits information to the receiver subsystem through the modulation of the entangled photon state. The present system and method is quantum which provides advantages over classical and optical communications. These advantages include using less power to transmit information, and allowing transmission through and around obstructions and adverse environments.

Disclosed are a method for achieving ultrahigh spectral resolution and a photonic spectral processor, which is designed to carry out the method. The disclosed photonic spectral processor overcomes the current 0.8 GHz spectral resolution limitation. The new spectral processor uses a Fabry-Perot interferometer array located before the dispersive element of the system, thus significantly improving the spectral separation resolution, which is now limited by the full width at half maximum of the Fabry-Perot interferometer rather than the spectral resolution of the dispersive element spectral as is the current situation. A proof of concept experiment utilizing two Fabry-Perot interferometers and a diffractive optical grating with spectral resolution of 6.45 GHz achieving high spectral resolution of 577 MHz is described.

Systems and methods for encoding a data signal as a pulse position modulation (PPM) signal and decoding a PPM signal to output the original data signal. The method of encoding may comprise receiving an input data signal; converting the data within the input data signal to a sequence of PPM symbol values; and generating a PPM signal comprising an alternating sequence of synchronisation pulses and data pulses. The PPM signal may be generated by generating a plurality of synchronisation pulses at a fixed pulse repetition rate; and generating a sequence of data pulses with each data pulse having a time delay from a preceding synchronisation pulse, whereby the sequence of data pulses represent the sequence of PPM symbol values.

A coherent optical receiver for AM optical signals has a photonic integrated circuit (PIC) as an optical front-end. The PIC includes a polarization beam splitter followed by two optical hybrids each followed by an opto-electric (OE) converter. Each OE converter includes one or more differential detectors and one or more squaring circuits, which outputs may be summed. The PIC may further include integrated polarization controllers, wavelength demultiplexers, and/or tunable dispersion compensators.

A demodulator can include an optical resonator. The optical resonator can include a resonant cavity that extends between a first surface that is partially reflective and a second surface that is at least partially reflective. The first surface can receive a phase-modulated optical signal that has a time-varying phase. The resonant cavity can accumulate resonant optical signal energy based at least in part on the phase-modulated optical signal. The first surface can direct a fraction of the resonant optical signal energy out of the optical resonator to form an intensity-modulated optical signal that has a time-varying intensity. A data detector can receive at least a portion of the intensity-modulated optical signal and, in response, generate an intensity-modulated electrical signal that has a time-varying intensity that corresponds to the time-varying phase of the phase-modulated optical signal.

Disclosed are optical communications systems and optical receivers including one or more optical cavity resonators. In particular, disclosed are methods and apparatus that allow for beam pointing to be maintained while permitting the receiver to tune the optical resonator to suit the wavelength, data rate and modulation format of the incoming optical signal, without requiring a coherent receiver or adaptive optics in addition to optical resonators.

Systems and methods for performing operations based on LIDAR communications are described. An example device may include one or more processors and a memory coupled to the one or more processors. The memory includes instructions that, when executed by the one or more processors, cause the device to receive data associated with a modulated optical signal emitted by a transmitter of a first LIDAR device and received by a receiver of a second LIDAR device coupled to a vehicle and the device, generate a rendering of an environment of the vehicle based on information from one or more LIDAR devices coupled to the vehicle, and update the rendering based on the received data. Updating the rendering includes updating an object rendering of an object in the environment of the vehicle. The instructions further cause the device to provide the updated rendering for display on a display coupled to the vehicle.

Apparatus, systems, and methods include leveraging the angular dependence of the angle of arrival of the incoming optical signal at an optical resonator and the output response signal to adjust the operating condition of the optical resonator. The optical resonator is dynamically tuned by rotating the optical resonator to optimize signal-to-noise ratio or other parameters for different modulation formats of the incoming optical signal or other different operating conditions.