Abstract: An optical communication system which is tunable and polarization insensitive is provided herein. The optical communication system may comprise an optical bench coupling an optical transmit pathway and an optical receiving pathway to an external pathway. The optical bench includes a polarization insensitive optical circulator. The system may further include a tunable component positioned along the optical receiving pathway, and a controller coupled to the tunable component.

Abstract: An optical communication system using a photonic lantern for fine point tracking is disclosed. The optical communication system may comprise a photonic lantern, a signal processing unit including one or more fiber splitters to sample a fraction of a received signal in each single mode fiber of the photonic lantern, and one or more intensity sensors positioned in one arm of each fiber splitter, and used for monitoring fiber-specific intensity data associated with each of the single-mode fibers. The system may further include a fine pointing assembly and a controller for controlling a driver of the fine pointing assembly.

Abstract: An optical communication system which is tunable and polarization insensitive is provided herein. The optical communication system may comprise an optical bench coupling an optical transmit pathway and an optical receiving pathway to an external pathway. The optical bench includes a polarization insensitive optical circulator. The system may further include a tunable component positioned along the optical receiving pathway, and a controller coupled to the tunable component.

Abstract: Various embodiments are disclosed herein with generally relate to an optical communication system using a photonic lantern. In at least one embodiment, the optical system comprises: an optical transmitter coupled to a signal transmitting path; an optical receiver coupled to a signal receiving path; a photonic lantern, the photonic lantern extending between a first open end and a second open end, the first end comprising an opening to a single multi-mode fiber, and the second end comprising a plurality of single mode fibers that are adiabatically coupled to the multi-mode fiber, the plurality of single-mode fibers includes a single-mode fiber adapted to carry a fundamental optical mode and the remaining single-mode fibers adapted to carry higher-order optical modes, wherein, the single-mode fiber is coupled to the optical transmitting path, the remaining single-mode fibers are coupled to the optical receiving path.

Abstract: An optical transmitter for quantum key distribution includes a plurality of spatially separated light sources configured to emit a light signal with the same wavelength. Each light source emits a light signal with a unique encoding. A beam combiner receives the light signals from the plurality of light sources and combines the received light signals into a combined light signal. A spatial filter is optically coupled to the beam combiner and includes an aperture that receives the combined light signal and emits a filtered light signal. The aperture has an aperture diameter less than or equal to the specified wavelength. A collimator is optically coupled to the spatial filter and receives the filtered light signal and emits a collimated light signal. An output aperture receives the collimated light signal and outputs the collimated light signal as an output light signal towards an optical receiver.

Abstract: Various embodiments are disclosed herein with generally relate to an optical communication system using a photonic lantern. In at least one embodiment, the optical system comprises: an optical transmitter coupled to a signal transmitting path; an optical receiver coupled to a signal receiving path; a photonic lantern, the photonic lantern extending between a first open end and a second open end, the first end comprising an opening to a single multi-mode fiber, and the second end comprising a plurality of single mode fibers that are adiabatically coupled to the multi-mode fiber, the plurality of single-mode fibers includes a single-mode fiber adapted to carry a fundamental optical mode and the remaining single-mode fibers adapted to carry higher-order optical modes, wherein, the single-mode fiber is coupled to the optical transmitting path, the remaining single-mode fibers are coupled to the optical receiving path.

Abstract: An optical transmitter for quantum key distribution includes a plurality of spatially separated light sources configured to emit a light signal with the same wavelength. Each light source emits a light signal with a unique encoding. A beam combiner receives the light signals from the plurality of light sources and combines the received light signals into a combined light signal. A spatial filter is optically coupled to the beam combiner and includes an aperture that receives the combined light signal and emits a filtered light signal. The aperture has an aperture diameter less than or equal to the specified wavelength. A collimator is optically coupled to the spatial filter and receives the filtered light signal and emits a collimated light signal. An output aperture receives the collimated light signal and outputs the collimated light signal as an output light signal towards an optical receiver.

Abstract: Various embodiments for a system and method for a range-enhanced high-speed free-space optical communication are described herein. Generally, the optical communication system may include a first modulator, a second modulator and an average-power limited optical amplifier. The first modulator may receive an input optical signal and generate a modulated optical signal. The second modulator may receive the modulated signal and may be operable to turn-off a select number of pulses in each modulated pulse frame of the modulated signal to generate a low-duty cycle modulated signal. The average-power limited optical amplifier may then generate an amplified modulated signal from the low-duty cycle signal, wherein the amplified modulated signal comprises a plurality of amplified pulse frames with each amplified pulse frame defining an amplified version of a corresponding each low-duty cycle pulse frame.

Abstract: A system for detecting trace-gas includes an optical sensor mounted on a vehicle and processing circuitry. The optical sensor includes a plurality of interferometers configured to collect samples. The processing circuitry is configured to generate a digitized signal based on the samples, apply a forward Fourier-transform on the digitized signal to generate spectrum information for the plurality of interferometers, and determine a gas species has been detected using one or more intensity of absorption features of the spectrum information corresponding to the gas species from the spectrum information.

Abstract: This disclosure is related to devices, systems, and techniques for precisely measuring a wavelength of an optical signal. For example, a wavemeter system includes processing circuitry, a detector array, a set of optical chips, and a coarse wavelength unit configured to generate a coarse wavelength measurement of the input optical signal. The processing circuitry is configured to select an optical chip from a plurality of optical chips. The detector array is configured to generate a partial interferogram based on the at least the portion of the input optical signal. The processing circuitry is further configured to calculate an optical spectrum of the input optical signal based on the partial interferogram corresponding to the at least the portion of the input optical signal and the calibration matrix and identify, based on the optical spectrum of the input optical signal, the precise wavelength of the input optical signal.

Abstract: A system for detecting trace-gas includes an optical sensor mounted on a vehicle and processing circuitry. The optical sensor includes a plurality of interferometers configured to collect samples. The processing circuitry is configured to generate a digitized signal based on the samples, apply a forward Fourier-transform on the digitized signal to generate spectrum information for the plurality of interferometers, and determine a gas species has been detected using one or more intensity of absorption features of the spectrum information corresponding to the gas species from the spectrum information.

Abstract: A spectrometer and method for determining an emitted light spectrum. An input light signal is received and directed to an array of interferometers using waveguides. A plurality of self-interfering signals are detected from a first plurality of interferometers in the array of interferometers. The first plurality of interferometers has fewer interferometers than required to satisfy the Nyquist criterion for reconstructing the emitted light spectrum. The emitted light spectrum is reconstructed from the plurality of self-interfering signals using compressive sensing. The plurality of self-interfering signals can provide an interference pattern used to reconstruct the emitted light spectrum. A second plurality of interferometers may output a second plurality of self-interfering signals to reconstruct a low resolution spectrum of the input light signal satisfying the Nyquist criterion. Low resolution signal components can be detected from the low resolution spectrum and used to pre-process the interference pattern.

Abstract: A spectrometer and method for determining an emitted light spectrum. An input light signal is received and directed to an array of interferometers using waveguides. A plurality of self-interfering signals are detected from a first plurality of interferometers in the array of interferometers. The first plurality of interferometers has fewer interferometers than required to satisfy the Nyquist criterion for reconstructing the emitted light spectrum. The emitted light spectrum is reconstructed from the plurality of self-interfering signals using compressive sensing. The plurality of self-interfering signals can provide an interference pattern used to reconstruct the emitted light spectrum. A second plurality of interferometers may output a second plurality of self-interfering signals to reconstruct a low resolution spectrum of the input light signal satisfying the Nyquist criterion. Low resolution signal components can be detected from the low resolution spectrum and used to pre-process the interference pattern.