Abstract: A system may include an optical phased array, a photodiode array, and a radiofrequency (RF) antenna element array. The optical phased array may be configured to: receive a laser signal from a signal laser; and output an optical beam. Each photodiode may be configured to: receive at least a portion of the optical beam and at least a portion of an optical plane wave beam, wherein the optical plane wave beam is formed based at least on a local oscillator (LO) laser that outputs a laser beam having a different wavelength from the signal laser; and output an electronic signal based on the at least the portion of the optical beam and the at least a portion of the optical plane wave beam. The RF antenna element array may be configured to output an RF beam based on received electronic signals from the photodiode array.

Abstract: A system and related method for multiple-sensitivity optical phase modulation splits an optical carrier generated by a photonic source into at least two copies and directs the copies through an electro-optical (EO) phase modulator wherein the optical field associated with the optical carrier overlaps with a radio frequency (RF) electrical field associated with a radio frequency (RF) input signal, such that the EO modulator phase-modulates each optical copy according to the RF input signal of interest based on characteristics distinct to each optical copy (e.g., relative strength of, or proximity of the optical carrier to, the overlapping electrical field) that provide for phase modulation of each optical copy at a different sensitivity voltage. The variably modified optical copies are directed to a photonic processor for further signal processing in the optical domain.

Abstract: A system and method for radio frequency (RF) signal processing via photonic local oscillator (LO) phase control generates a set of N optical carriers and M sets of control inputs, each control input including an amplitude and/or phase control for the nth carrier. Each nth optical carrier is split into an RF path and M LO paths, the RF path including N electro-optical (EO) modulators for amplitude/phase modulation of each nth carrier per a set of N RF input signals and each mth LO path including a set of N EO modulators for amplitude/phase modulation of each nth carrier per the mth control input. Demodulators generate M in-phase and quadrature (I/Q) balanced optical outputs based on the multiplexed N combined RF optical outputs and each mth set of N combined LO optical outputs. The M I/Q balanced optical outputs are converted to the electrical and then to the digital domain.

Abstract: A computationally efficient real-time photonic cyclic autocorrelation function (CAF) analysis device and method are disclosed. In embodiments, the CAF analyzer generates a photonic carrier which is converted into upper and lower comb signals (comprising a set of N tones) by upper and lower optical frequency comb generators (OFCG), the lower comb signal offset from the upper. An inbound radio frequency (RF) signal is received and modulates the upper and lower comb signals via amplitude modulation. An optical delay line (e.g., ring resonator) introduces a delay into the modulated lower comb signal. The upper and lower comb signals are demultiplexed into their modulated frequency component and sent to a bank of N coherent I/Q receivers, which generate a slice of the CAF for the received RF signal based on the selected delay.

Abstract: A photonic processor includes a modulator, an optical filter, and a polarization combiner. The modulator is configured to receive an electronic signal, first optical control signal, and first optical operating signal, the first optical operating signal received from an optical source circuit on a first path having a first length, the first optical control signal received from an optical control circuit on the first path; modulate the first optical operating signal using the electronic signal to provide an intensity-modulated optical operating signal comprising a first optical operating carrier, first sideband, and second sideband; and modulate the first optical control signal using the electronic signal to provide an intensity-modulated control signal comprising a first optical control carrier. The optical filter is configured to extract the first optical operating carrier and first sideband from the intensity-modulated optical operating signal and provide the second sideband and the control carrier.

Abstract: A system may include an optical phased array, a photodiode array, and a radiofrequency (RF) antenna element array. The optical phased array may be configured to: receive a laser signal from a signal laser; and output an optical beam. Each photodiode may be configured to: receive at least a portion of the optical beam and at least a portion of an optical plane wave beam, wherein the optical plane wave beam is formed based at least on a local oscillator (LO) laser that outputs a laser beam having a different wavelength from the signal laser; and output an electronic signal based on the at least the portion of the optical beam and the at least a portion of the optical plane wave beam. The RF antenna element array may be configured to output an RF beam based on received electronic signals from the photodiode array.

Abstract: A computationally efficient real-time photonic cyclic autocorrelation function (CAF) analysis device and method are disclosed. In embodiments, the CAF analyzer generates a photonic carrier which is converted into upper and lower comb signals (comprising a set of N tones) by upper and lower optical frequency comb generators (OFCG), the lower comb signal offset from the upper. An inbound radio frequency (RF) signal is received and modulates the upper and lower comb signals via amplitude modulation. An optical delay line (e.g., ring resonator) introduces a delay into the modulated lower comb signal. The upper and lower comb signals are demultiplexed into their modulated frequency component and sent to a bank of N coherent I/Q receivers, which generate a slice of the CAF for the received RF signal based on the selected delay.

Abstract: A photonic N-to-one single-mode combiner is disclosed. In embodiments, the combiner receives multiple single-mode photonic inputs (e.g., via single-mode optical fibers) and combines the single-mode inputs into a multi-mode photonic output via photonic lantern. The multi-mode photonic output is converted via high-power, high-speed photodiode into an RF/electrical output which in turn drives an electro-optical modulator, modulating a second optical beam (e.g., a laser generated by a laser emitter of the combiner) to generate a single-mode photonic output signal.

Abstract: An integrated photonics monopulse comparator includes an array of squinted monopulse elements, each monopulse element producing an RF signal in response to a received inbound signal and each RF signal having a squinted RF voltage. The comparator includes a laser source for producing a wavelength division multiplexed (WDM) optical signal comprising multiple components having discrete wavelengths. The component signals may be multiplexed and demultiplexed and routed through cascading optical phase modulators, each phase modulator connected to a monopulse element and capable of modulating a component signal according to the voltages of the RF signals produced by the corresponding monopulse element. The resulting modulated component optical signals undergo coherent photodetection by arrays of paired photodiodes, each pair receiving component signals of like wavelength.

Abstract: A multi-beam photonic monopulse comparator is disclosed. Photonic inputs incorporating M component wavelengths are split into equivalent inputs for each quadrant subarray and array element (e.g., N array elements in each quadrant subarray). Within each array element, the component wavelengths are apodized by attenuators and the apodized input signal modulated by a received inbound RF signal (via broadband Mach-Zehnder electro-optical modulators). The resulting positive-polarity and negative-polarity modulated photonic signals are demultiplexed and each component wavelength time-delayed. Time-delayed wavelength-selective optical delay channels are copied and combined by single mode/multi-mode (SM/MM) couplers into photonic antenna beams and simultaneously generated photonic comparator outputs (elevational difference, sum, azimuthal difference) for each component wavelength.

Abstract: An optical receiver for receiving a signal from an optical fiber in a fiber-optic digital transmission system that includes a first low noise optical amplifier to amplify an input optical signal. The first low noise optical amplifier has an input 3 dB compression point lower than the desired system input sensitivity at a desired bit rate. A high power optical amplifier further amplifies the amplified optical signal, and has an automatic gain control for output signal leveling at a desired operation point of the transmission system. A high current photodetector converts the further amplified optical signal from the high power optical amplifier to an electrical signal that drives a retiming circuit without requiring further amplification of the electric signal.

Abstract: The fiber-optic true time-delay array antenna feed is a device for dynamically generating a plurality of identical electromagnetic radiation (EMR) signals with continuously variable time-delay separations. The EMR signal to be transmitted modulates a continuous-wave optical signal from a laser source which is applied to a plurality of high dispersion single-mode optical fibers acting as synchronized true time-delay modulators forming an array antenna feed system. Each fiber is chosen to have the same nominal time delay but a different net dispersion. Photodetectors convert the optical intensity back into an EMR electrical signal to feed each of the elements of the array antenna.

Abstract: The wideband single-sideband modulator generates single-sideband (SSB) modulation with suppressed carrier utilizing traveling-wave LiNbO3 modulators in a Sagnac loop. In the wideband single-sideband modulator, optical light from a linearly-polarized source is injected into polarization-maintaining fiber (PolMF) where it is split equally via a polarization-maintaining (PolM) directional fiber coupler, resulting in counterpropagating lightwaves in a Sagnac loop. These counterpropagating waves are &pgr;/2 out of phase due to the action of the coupler and remain so when they return to the coupler because they travel equal distances around the loop. Because the coupler is a reciprocal device, if the waves return to the coupler with equal amplitudes, they will recombine and exit the original port toward the polarized light source.

Abstract: A new fiber optic based beamforming architecture for a time steered phased rray antenna based on chirped fiber gratings. All of the gratings are identical in length and period chirp so that they all have the same dispersion, thus at a given optical wavelength they have the same time delay. In a preferred embodiment an optical signal is modulated with an RF signal. The RF modulated optical is split and a portion propagates through a length of fiber to a photodetector feeding an antenna array. The second portion of the optical signal is routed through a circulator, which feeds the optical signal to a chirped fiber grating. The grating reflects and delays the optical signal back to the circulator which routes the reflected optical signal to a second coupler. The amount of delay incurred is determined by the grating dispersion and the wavelength of the optical source.

Abstract: A system that uses all optical elements for transmission, regeneration and reception of solitons in point-to-point, broadcast, ring and multi-user trunk type communication systems. Soliton pulses from an optical clock source are modulated by optical data pulses in an optical modulator producing a modulated channel of data pulses. Several channels are combined by an optical multiplexer into a network optical bit stream. This stream is carried by an optical fiber and one or more of optical regenerators which recover the system clock and regenerate the signal with the recovered system clock rather than just amplifying the signal. Each of the regenerators can, in addition to regenerating the data, act as part of a data drop or insert node in a ring network where the node can synchronously remove data from or insert data into the stream. Intermediate nodes can include packet drop/replace nodes if the network is a packet type network.

Abstract: An optical device includes a polarization section having a port, the polarization section being for receiving light at the port and for outputting light at the port with a state of polarization orthoconjugate to the light received at the port. The polarization section includes a reflector, a bidirectional nonreciprocal rotator and a bidirectional polarizer. The bidirectional nonreciprocal rotator has first and second ends, the first end being operatively coupled to the port. The bidirectional polarizer has first and second ends, the first polarizer end being operatively coupled to the reflector and the second polarizer end being operatively coupled to the second rotator end.

Abstract: An intracavity-modulated laser includes a gain element, an electro-optic modulator (EOM), a frequency selective coupler (FSOC), and an optical isolator coupled in such a way that a ring laser cavity is formed. The EOM selectively affects the optical input in intensity, phase, or frequency according the radio frequency (RF) input signal applied. The FSOC is a three-port device that receives light at a first port and passes narrowbands of light out a second port and directs the remaining optical spectrum out a third port. The optical isolator assures single direction lasing. When the gain is sufficient to overcome the ring losses, the laser cavity will oscillate with longitudinal modes corresponding to the pass bands of the FSOC. The light exiting the second port of the FSOC is amplified by the laser gain element and is directed to the EOM. The EOM modulates each carrier (longitudinal mode) of the laser cavity thereby creating optical modulation sidebands associated with each carrier.

Abstract: The fiber optic true time delay modulator generates a continuously variable true time-delay (i.e., phase shift) by utilizing the dispersion characteristic of a single mode optical fiber. The signal to be variably delayed modulates a continuous wave optical signal from a tunable laser source which is applied to a dispersive optical fiber wherein the phase shift occurs. The optical intensity output of the dispersive optical fiber is converted back into electrical energy by a photodetector for use in radio frequency, microwave and millimeter wave electronic devices. The invention can be used to generate multiple synchronized output signals by using a multiple wavelength laser or by combining outputs from several independently tuned lasers. Also. frequency and phase shifting is inherently provided by modulating the time delay.

Abstract: A sensor system includes a sensor head, an optical source, and a measurement apparatus. The sensor head includes a beamsplitter having first, second, third, and fourth ports, the beamsplitter being responsive to light selectively applied to the first, second and third ports for passing light of a first input polarization state from the first port to the second port, for passing light of a second input polarization state orthogonal to the first input polarization state from the first port to the third port, and for collectively passing light of a first output polarization state and light of a second output polarization state orthogonal to the first output polarization state from the third port to the fourth port. The optical source means provides light to the first port.

Abstract: In the transmission electrical signals using an optical carrier the signal power carried by an optical carrier is proportional to the optical power. High optical power levels are desired for optical carriers that are modulated by weak electrical signals, however, significant unmodulated power is left in the original carrier after processing. To maximize the radio frequency (RF) signal power generated by a given (maximized) photodetector current (for a given input power), in this invention, the optical carrier power is reduced. This is accomplished by the addition of a narrowband optical filter, such as a Fabry-Perot filter, to reduce the average optical carrier power without reducing the modulation sidebands, which results in an increased modulation depth. Therefore, greater RF and microwave power is generated by a photodetector with the same photocurrent.