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: A communication system has a plurality of LEO satellites in a specified orbital plane and a plurality of trunk satellites in a medium earth orbit. Each LEO satellite acquires satellite-specific data and includes inter-satellite links with adjacent LEO satellites. Each trunk satellite includes inter-satellite links adjacent trunk satellites. One of the trunk satellites operates as a relay trunk satellite in position to maintain optical communication with a specified ground station on the Earth. Each LEO satellite has a limited field of regard to establish optical communication with any trunk satellite. A relay LEO satellite is configured to establish optical communication with a corresponding trunk satellite. The plurality of LEO satellites relay aggregated data to the relay LEO satellite. The relay LEO satellite relays the aggregated data to the corresponding trunk satellite. The relay trunk satellite relays the received aggregated data to the corresponding ground station.

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: Disclosed are systems for transmitting and receiving a radio frequency (RF) signal and an optical signal. One system may include a communication terminal comprising a primary concave reflector providing a first focal length to a focal point, and a secondary concave reflector providing a second focal length to the focal point. The communication terminal may further comprise an optical transceiver facing the secondary concave reflector, and one or more RF transceivers facing the primary concave reflector. The optical transceiver may be configured to transmit and receive the optical signal via the primary and secondary concave reflectors through the focal point, and the one or more RF transceivers may be configured to transmit and receive the RF signal via the primary concave reflector. The one or more RF transceivers may be positioned adjacent to the focal point and offset from a path of the optical signal.

Abstract: An optical system includes a plurality of internal apertures, a plurality of external optical assemblies and a telescope assembly positioned between the plurality of internal apertures and the plurality of external optical assemblies. Each internal aperture is operable to receive a corresponding aperture-specific optical signal. Each external optical assembly corresponds to one of the internal apertures, and each external optical assembly is operable to direct the aperture-specific optical signal of the corresponding internal aperture in a corresponding external direction. The external direction for each external optical assembly is independently controllable and the telescope assembly defines a shared optical train arranged to direct the aperture-specific optical signals between each internal aperture and the corresponding external optical assembly.

Abstract: An optical system includes a plurality of internal apertures, a plurality of external optical assemblies and a telescope assembly positioned between the plurality of internal apertures and the plurality of external optical assemblies. Each internal aperture is operable to receive a corresponding aperture-specific optical signal. Each external optical assembly corresponds to one of the internal apertures, and each external optical assembly is operable to direct the aperture-specific optical signal of the corresponding internal aperture in a corresponding external direction. The external direction for each external optical assembly is independently controllable and the telescope assembly defines a shared optical train arranged to direct the aperture-specific optical signals between each internal aperture and the corresponding external optical assembly.

Abstract: A thermostat having a simple to see and use setup-setback visual indicator. One temperature control is used to set temperature while a second temperature control is used to activate the setup or setback. The second temperature control is offset from the body of the thermostat in the setup or setback mode to provide simple visual indication of the setup or setback.

Abstract: In variable air volume systems of buildings, a vortex valve is used for varying the volume of the air moving through the system.