Abstract: A method includes receiving a modulated optical signal at a ring resonator. The ring resonator has a ring with a ring length and includes a coupling region. The method also includes splitting the modulated optical signal into a first portion and a second portion. The method further includes mixing a previous first portion of the modulated optical signal with the second portion of the modulated optical signal to obtain a mixed signal. In addition, the method includes measuring a measured energy of the mixed signal using a photodetector. The symbol has a symbol length. A coupling coefficient expressing a measured energy of the first portion relative to a measured energy of the modulated optical signal has a value of less than 50%.

Abstract: A system includes an optical transceiver configured to transmit and receive optical signals. The optical transceiver includes a Faraday rotator and a waveplate. The Faraday rotator and the waveplate are collectively configured to provide a relative polarization change between (i) light propagating in a first direction through the Faraday rotator and the waveplate and (ii) light propagating in a second direction opposite the first direction through the Faraday rotator and the waveplate. The waveplate may include a quarter waveplate or a half waveplate.

Abstract: An apparatus includes polarization beamsplitters that each separate incoming and outgoing optical signals having different polarizations. The apparatus also includes directionally-dependent polarization rotation optical assemblies that each maintain a polarization of one of the incoming and outgoing optical signals and to rotate a polarization of another of the incoming and outgoing optical signals. The apparatus further includes a third polarization beamsplitter that combines the outgoing optical signals to produce transmit optical signals and separate receive optical signals to produce the incoming optical signals.

Abstract: Disclosed is a microwave cavity resonator used as a phase change (phase modulation) to intensity change (intensity or amplitude modulation) converter. Certain aspects and embodiments include resonant circuits, such as a resistor, inductor and capacitor (RLC) circuit. Certain aspects and embodiments convert changes in phase to changes in output voltage to perform analog demodulation of a phase modulated microwave carrier. Certain aspects and embodiments use resonance when the reactive components of the circuit (capacitive and inductive components) are equal in magnitude and 180 degrees out of phase with one another, thereby cancelling out the reactance component of the circuit's impedance.

Abstract: Aspects and examples are directed to programmable optical finite impulse response filters and optical infinite impulse response filters, which may be implemented as photonic integrated circuits.

Abstract: An apparatus includes an antenna, a transmitter configured to generate an outgoing electrical signal, and a receiver configured to receive an incoming electrical signal. The apparatus also includes a transformer configured to couple the antenna and the transmitter such that the outgoing electrical signal causes the antenna to radiate outgoing electromagnetic energy, couple the antenna and the receiver such that the incoming electrical signal is based on incoming electromagnetic energy received by the antenna, and electrically isolate the transmitter and the receiver. The antenna may include inner and outer compensating coils, the compensating coils may be configured to additively radiate the outgoing electromagnetic energy, and the incoming electrical signal may be based on a difference between the incoming electromagnetic energy as received by the compensating coils.

Abstract: An optical signal receivers, systems including the optical signal receivers, and methods of operating the same include a multimode fiber circulator including a first port, a second port, and a third port, a first multimode fiber cable coupled to the first port and having an input configured to receive a complex modulated optical signal and provide the complex modulated optical signal to the first port of the multimode fiber circulator, a second multimode fiber cable including a low Q optical resonator coupled to the second port of the multimode fiber circulator that is configured to receive the complex modulated optical signal from the second port of the multimode circulator, and a third multimode fiber cable coupled to the third port of the multimode fiber circulator that is configured to receive a reflected optical signal from the third port of the multimode circulator, the reflected optical signal being reflected from the low Q optical resonator.

Abstract: Disclosed is a microwave cavity resonator used as a phase change (phase modulation) to intensity change (intensity or amplitude modulation) converter. Certain aspects and embodiments include resonant circuits, such as a resistor, inductor and capacitor (RLC) circuit. Certain aspects and embodiments convert changes in phase to changes in output voltage to perform analog demodulation of a phase modulated microwave carrier. Certain aspects and embodiments use resonance when the reactive components of the circuit (capacitive and inductive components) are equal in magnitude and 180 degrees out of phase with one another, thereby cancelling out the reactance component of the circuit’s impedance.

Abstract: Aspects and examples are directed to programmable optical finite impulse response filters and optical infinite impulse response filters, which may be implemented as photonic integrated circuits.

Abstract: An optical signal receiver includes a multimode waveguide for receiving a complex modulated optical signal, an optical resonator that receives the complex modulated optical signal from the multimode waveguide and converts the complex modulated optical signal to an intensity modulated signal, and a detector that is configured to convert the intensity modulated signal into an electrical signal, the electrical signal having an amplitude indicative of an intensity of the intensity modulated signal from the optical resonator, and that provides a detected signal.

Abstract: Disclosed is a microwave cavity resonator used as a phase change (phase modulation) to intensity change (intensity or amplitude modulation) converter. Certain aspects and embodiments include resonant circuits, such as a resistor, inductor and capacitor (RLC) circuit. Certain aspects and embodiments convert changes in phase to changes in output voltage to perform analog demodulation of a phase modulated microwave carrier. Certain aspects and embodiments use resonance when the reactive components of the circuit (capacitive and inductive components) are equal in magnitude and 180 degrees out of phase with one another, thereby cancelling out the reactance component of the circuit's impedance.

Abstract: An optical signal receivers, systems including the optical signal receivers, and methods of operating the same include a multimode fiber circulator including a first port, a second port, and a third port, a first multimode fiber cable coupled to the first port and having an input configured to receive a complex modulated optical signal and provide the complex modulated optical signal to the first port of the multimode fiber circulator, a second multimode fiber cable including a low Q optical resonator coupled to the second port of the multimode fiber circulator that is configured to receive the complex modulated optical signal from the second port of the multimode circulator, and a third multimode fiber cable coupled to the third port of the multimode fiber circulator that is configured to receive a reflected optical signal from the third port of the multimode circulator, the reflected optical signal being reflected from the low Q optical resonator.

Abstract: Optical signal receivers, systems, and methods of operating the same include a non-line of sight optical signal receiver configured to receive and detect a complex modulated optical signal through a non-line of site propagation path from an optical transmitter, comprising an optical resonator configured to receive the complex modulated optical signal through the non-line of sight propagation path, and to convert the complex modulated optical signal to an intensity modulated signal, and a detector configured to convert the intensity modulated signal into an electrical signal, the electrical signal having an amplitude indicative of an intensity of the intensity modulated signal from the optical resonator, and to provide a detected signal.

Abstract: A system and method for recovering encoded data from a modulated baseband signal is disclosed. Aspects and embodiments of the system and method include receiving an analog input signal representing a modulated baseband signal, counting clock cycles of a reference clock, detecting a first transition and a second transition of the analog input signal indicating a first change and a second change in the modulated baseband signal, storing a first counter value corresponding to an amount of clock cycles elapsed between the first transition and the second transition, and determining a binary-valued bit sequence corresponding to the first counter value.

Abstract: Aspects and examples are directed to programmable optical finite impulse response filters and optical infinite impulse response filters, which may be implemented as photonic integrated circuits.

Abstract: An apparatus includes an antenna, a transmitter configured to generate an outgoing electrical signal, and a receiver configured to receive an incoming electrical signal. The apparatus also includes a transformer configured to couple the antenna and the transmitter such that the outgoing electrical signal causes the antenna to radiate outgoing electromagnetic energy, couple the antenna and the receiver such that the incoming electrical signal is based on incoming electromagnetic energy received by the antenna, and electrically isolate the transmitter and the receiver. The antenna may include inner and outer compensating coils, the compensating coils may be configured to additively radiate the outgoing electromagnetic energy, and the incoming electrical signal may be based on a difference between the incoming electromagnetic energy as received by the compensating coils.

Abstract: A system includes an optical transceiver configured to transmit and receive optical signals. The optical transceiver includes a Faraday rotator and a waveplate. The Faraday rotator and the waveplate are collectively configured to provide a relative polarization change between (i) light propagating in a first direction through the Faraday rotator and the waveplate and (ii) light propagating in a second direction opposite the first direction through the Faraday rotator and the waveplate. The waveplate may include a quarter waveplate or a half waveplate.

Abstract: An apparatus includes polarization beamsplitters that each separate incoming and outgoing optical signals having different polarizations. The apparatus also includes directionally-dependent polarization rotation optical assemblies that each maintain a polarization of one of the incoming and outgoing optical signals and to rotate a polarization of another of the incoming and outgoing optical signals. The apparatus further includes a third polarization beamsplitter that combines the outgoing optical signals to produce transmit optical signals and separate receive optical signals to produce the incoming optical signals.

Abstract: Monostatic optical transceivers, systems, and methods of operating the same include a single aperture, a transmitter that provides a modulated and polarized optical transmit beam, a receiver that receives a modulated and polarized optical receive beam at an optical resonator included therein and processes the received optical receive beam to determine information from the received optical receive beam, a polarizing beam splitter that reflects the optical transmit beam, a polarization rotator that rotates the polarization of the reflected optical transmit beam by a fixed number of degrees in a transmit direction in a coordinate system of the monostatic transceiver, and a waveplate that modifies the polarization of the rotated optical transmit beam.

Abstract: A system and method for recovering encoded data from a modulated baseband signal is disclosed. Aspects and embodiments of the system and method include receiving an analog input signal representing a modulated baseband signal, counting clock cycles of a reference clock, detecting a first transition and a second transition of the analog input signal indicating a first change and a second change in the modulated baseband signal, storing a first counter value corresponding to an amount of clock cycles elapsed between the first transition and the second transition, and determining a binary-valued bit sequence corresponding to the first counter value.