Abstract: A system of coupling optical energy in a waveguide mode, into a resonator that operates in a whispering gallery mode. A first part of the operation uses a fiber in its waveguide mode to couple information into a resonator e.g. a microsphere. The fiber is cleaved at an angle &PHgr; which causes total internal reflection within the fiber. The energy in the fiber then forms an evanescent field and a microsphere is placed in the area of the evanescent field. If the microsphere resonance is resonant with energy in the fiber, then the information in the fiber is effectively transferred to the microsphere.

Abstract: A system of coupling optical energy in a waveguide mode, into a resonator that operates in a whispering gallery mode. A first part of the operation uses a fiber in its waveguide mode to couple information into a resonator e.g. a microsphere. The fiber is cleaved at an angle &PHgr; which causes total internal reflection within the fiber. The energy in the fiber then forms an evanescent field and a microsphere is placed in the area of the evanescent field. If the microsphere resonance is resonant with energy in the fiber, then the information in the fiber is effectively transferred to the microsphere.

Abstract: Opto-electronic devices and techniques using Brillouin scattering to select a sideband in a modulated optical carrier signal for amplification. Two lasers respectively provide a carrier signal beam and a Brillouin pump beam which are fed into an Brillouin optical medium in opposite directions. The relative frequency separation between the lasers is adjusted to align the frequency of the backscattered Brillouin signal with a desired sideband in the carrier signal to effect a Brillouin gain on the sideband. This effect can be used to implement photonic RF signal mixing and conversion with gain, conversion from phase modulation to amplitude modulation, photonic RF frequency multiplication, optical and RF pulse generation and manipulation, and frequency-locking of lasers.

Abstract: Techniques for producing optical pulses based on Brillouin selective sideband amplification by using a common modulation control signal to modulate both a signal beam to produce multiple sideband signals and a single pump beam to produce multiple pump beams.

Abstract: Opto-electronic devices and techniques using Brillouin scattering to select a sideband in a modulated optical carrier signal for amplification. Two lasers respectively provide a carrier signal beam and a Brillouin pump beam which are fed into an Brillouin optical medium in opposite directions. The relative frequency separation between the lasers is adjusted to align the frequency of the backscattered Brillouin signal with a desired sideband in the carrier signal to effect a Brillouin gain on the sideband. This effect can be used to implement photonic RF signal mixing and conversion with gain, conversion from phase modulation to amplitude modulation, photonic RF frequency multiplication, optical and RF pulse generation and manipulation, and frequency-locking of lasers.

Abstract: Optical variable delay devices for providing variable true time delay to multiple optical beams simultaneously. A ladder-structured variable delay device comprises multiple basic building blocks stacked on top of each other resembling a ladder. Each basic building block has two polarization beamsplitters and a polarization rotator array arranged to form a trihedron; Controlling an array element of the polarization rotator array causes a beam passing through the array element either going up to a basic building block above it or reflect back towards a block below it. The beams going higher on the "ladder" experience longer optical path delay. An index-switched optical variable delay device comprises of many birefringent crystal segments connected with one another, with a polarization rotator array sandwiched between any two adjacent crystal segments.

Abstract: A coupled opto-electronic oscillator that directly couples a laser oscillation with an electronic oscillation to simultaneously achieve a stable RF oscillation at a high frequency and ultra-short optical pulsation by mode locking with a high repetition rate and stability. Single-mode selection can be achieved even with a very long opto-electronic loop. A multimode laser can be used to pump the electronic oscillation, resulting in a high operation efficiency. The optical and the RF oscillations are correlated to each other.

Abstract: Opto-electronic oscillators having at least one Brillouin feedback loop based on the Brillouin selective sideband amplification to provide a sufficient gain for the oscillator to start and sustain an electro-optic oscillation. Such an oscillator can generate high frequency, high spectral purity, and tunable microwave signals in both optical and electrical domains.

Abstract: An ladder-structured variable delay device for providing variable true time delay to multiple optical beams simultaneously. The device comprises multiple basic units stacked on top of each other resembling a ladder. Each basic unit comprises a polarization sensitive corner reflector formed by two polarization beamsplitters and a polarization rotator array placed parallel to the hypotenuse of the corner reflector. Controlling an array element of the polarization rotator array causes an optical beam passing through the array element to either go up to a basic unit above it or reflect back towards output. The beams going higher on the "ladder" experience longer optical path delay. Finally, the ladder-structured variable device can be cascaded with another multi-channel delay device to form a new device which combines the advantages of the two individual devices. This programmable optic device has the properties of high packing density, low loss, easy fabrication, and virtually infinite bandwidth.

Abstract: A linear swept frequency generator includes a signal generator that generates an output signal having a frequency that varies between a first frequency and a second frequency. A delay element, such as an optical fiber having a reflector at one end, is configured to receive the output signal and to produce a delayed version of the output signal. This delayed version of the output signal is provided, along with the output signal, to a mixer that combines the signals to produce a reference signal. Finally, a feedback path between the mixer and the signal generator provides the reference signal to the signal generator so that the signal generator controls the frequency of the output signal in response to the reference signal.

Abstract: An electro-optical oscillator includes an electro-optical modulator having an electrical input port that accepts an electrical control signal and an optical output port. The electro-optical modulator is operable to generate at the optical output port an optical signal that oscillates at a frequency related to the electrical control signal. The oscillator also includes a photodetector that converts a portion of the optical signal from the optical output port of the electro-optical modulator to an electrical signal and provides the electrical signal to the electrical input port of the electro-optical modulator as the electrical control signal. An open loop gain of a feedback loop including the optical output port, the photodetector and the electrical input port is greater than one.

Abstract: A polarization insensitive electro-optic modulator is constructed by providing a polarization beamsplitter to separate an incoming light beam into two orthogonally plane polarized beams. Each of the polarized beams passes through a separate electro-optic modulator where each beam is modulated by the same data signal. After modulation the beams are combined to yield a modulated beam having modulated components that are orthogonally polarized. Not only is this device insensitive to changes in polarization of the input beam, the final modulated beam can be detected by optical receivers without regard to polarization alignment of the modulated beam and the receiver.

Abstract: A fiber optic apparatus for controlling the polarization state of light, for connecting polarization sensitive devices, and for providing a controlled variable attenuation in a fiber optic system. The center portion of a strand of optical fiber is placed in a rotatable fiber squeezer and is squeezed to produce a birefringent medium having a birefringent axis in the direction of squeezing pressure and the magnitude of the birefringence is controlled by the amount of pressure imposed by the fiber squeezer on the fiber center portion. Rotating the squeezer causes the birefringent axis to change and hence changes the polarization of light passing through the fiber strand. A desired polarization state is obtained by controlling the squeezing pressure and the rotation angle of the fiber squeezer.