USA As Represented by Secretary of the Navy

Carl A Villarruel

Ross Schermer

William K Burns

Frank Bucholtz

A Fenner Milton

Janet W Lou

Thomas G Giallorenzi

Richard B Thompson

Irl N Duling, Iii

Ronald D Esman

Keith J Williams

Michael L Dennis

Alan D Kersey

Colin McLaughlin

Moges Abebe

Chin-Lin Chen

A system testing the speed of a microwave photonic system, having a Mach Zehnder interferometer that includes a first arm with a photonic system to be tested and an amplifier arranged to amplify the output of the photonic system, and a second arm with an attenuator configured to match the output power of the amplifier, with at least one filter arranged at the output of the Mach Zehnder interferometer, the filter having a pass band that includes the center frequency of a continuous wave microwave signal applied to the Mach Zehnder interferometer arms. A continuous wave microwave signal is applied to the input of the Mach Zehnder interferometer, a signal is applied to only the second arm with the photonic link, and the output of the bandpass filter is measured with an oscilloscope and a microwave power detector.

System and method for testing the speed of a microwave photonics system

A true time delay system for optical signals includes a hollow core optical waveguide, a droplet of reflective liquid metal disposed in the hollow core, and an actuator coupled to a first end of the waveguide to move the droplet longitudinally within the hollow core. In one example, the waveguide is a hollow core photonic bandgap fiber. In one example, the actuator is a pressure actuator that introduces or removes gas into the core. Light enters the optical fiber, is transmitted through the fiber toward the reflective surface of the droplet, and is reflected back through the fiber and exits at the same end of the photonic bandgap optical fiber that it entered. The fiber optic device can provide a continuously-variable optical path length of over 3.6 meters (corresponding to a continuously-variable true-time delay of over 12 ns, or 120 periods at a 10 GHz modulation frequency), with negligible wavelength dependence across the C and L bands.

Reconfigurable liquid metal fiber optic mirror

A true time delay system and method for an optical carrier signal modulated with a microwave signal. The system includes a beam deflector, with the optical signal being imaged onto the beam deflector, a stationary reflective diffractive grating arranged in a Littrow configuration, a focusing element arranged between the beam deflector and the stationary reflective diffractive grating. In operation, the beam deflector steers the optical beam across the clear aperture of the focusing element and the focusing element transmits the steered beam to the reflective diffractive grating. A change in optical path length experienced by the optical beam as the beam is scanned across the grating surface results in a relative phase delay in the optical beam. The beam deflector can be a rotating mirror, an acousto-optic beam deflector, or an electro-optic beam deflector. The focusing element can be a lens or a curved mirror.

Microwave photonic true-time-delay

An apparatus for creating sheathed flow includes an inlet section comprising an array of tubes including at least one sheath inlet port and a sample inlet port, a flow focusing section downstream from the inlet section, an optical access section downstream from the flow focusing region and comprising opposing flat surfaces, and an outlet section downstream from the optical access section, wherein the apparatus is operable to create a sheathed flow around a fluid introduced into the sample inlet port and to maintain the sheathed flow through the optical access section. Applications of the apparatus and method include bead/particle counting, flow cytometry, waveguiding, and fluid control.

Tubular array for fluidic focusing with integrated optical access region

The application of an optical beam redirects sheathed micro-fluidic flow without direct interaction with the sample. The hydrodynamic properties of the sheath are locally modified due to optical absorption and heating, resulting in a spatial shift of the sample flow. The technique can result in up to 100 &#x3bc;m shift at peak flow velocities of 19 mm/sec.

Method of changing fluid flow by using an optical beam

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.

High-sensitivity, high-speed digital optical photoreceiver

An interferometric fiber optic sensor and method are provided for controlling the optical phase of a fiber interferometer by an optically induced change in the refractive index for one arm of the fiber interferometer and providing a passive all-optical phase shift interrogation in response to this dependency on the optically induced change in the refractive index. The interferometric fiber optic sensor includes a laser source for generating light at a first predetermined wavelength, a fiber interferometer coupled to the laser source and having first and second fiber arms with a predetermined optical path difference between the fiber arms, a predetermined one of the first and second fiber arms being doped with an element for introducing an optically adjustable absorption spectrum, and a pump laser coupled to the predetermined fiber arm for generating light at a second predetermined wavelength so that an effective index for a guided mode in the predetermined fiber arm and a phase delay of the light passing through the fiber interferometer are changed. As a result, the interferometric fiber optic sensor and method allows the phase interrogation of the fiber interferometer by using a passive all-optical approach based on a pump induced refractive index change in the doped fiber arm so that balanced all fiber interferometer elements are used as sensors for eliminating laser induced phase noise.

Interferometric fiber optic sensor configuration with pump-induced phase

An optical waveguide-binding sensor which increases sensor sensitivity to fluorescence detection during assays of liquids based on adjustments in the V number along the optical waveguide. The sensing waveguide includes a mode converting section where the V number of the wavguide gradually increases from the distal sensing end of the mode converting section to the proximal end of the mode converting section. The gradually change in V number can be accomplished by either gradually inwardly tapering waveguide along the sensor portion from the proximal end, or by gradually varying the dopant concentration along the sensing portion. The sensor tapers in diameter to change the V number along the distal end of the optical waveguide. The present invention increases the efficiency of fluorescence detection by converting weakly-guided high-order modes of fluorescence radiation at the distal end into lower-order modes at the proximal and increases the efficiency of fluorescent excitation by converting low order mode entering the proximal end into weakly-guided high order modes at the sensing end. At the sensing end, these weakly guided modes cn strengthen the evanescent excitation wave.

Waveguide-binding sensor for use with assays

A method for correcting birefringence in a fiber optic coupler comprising measuring the intrinsic birefringent retardation, fast axis orientation and rotation of separate paths through the coupler and adding lumped birefringent elements to the ports of the coupler in a fashion to compensate for the intrinsic birefringence.

Method for eliminating birefringence in a fiber optic coupler and a

A polarization-preserving single mode fiber coupler, fabricated by a method which does not require mutually aligning the fiber polarization axes provided the actual misalignment angle is not close to 90.degree.. The protective jackets from two or more polarization-preserving single mode birefringent fibers are partially removed and the fibers are twisted around each other to bring them into contact over the jacketless region and provide a coupling length that is large compared to the birefringent beat length of the fibers. Next, the cladding layers of the fibers in the contacting region are partially etched without degrading the birefringent beat length over their coupling length. Then, the etched region is heated to the softening point of the fibers while axial tension is applied to taper and fuse the etched region until a desired coupling of the fibers is achieved. Finally, a mechanical supporting structure is added to the tapered and fused region of the fibers.

Polarization-preserving single mode fiber coupler

A method and means for forming an in-line integrated optical fiber polarizer comprising the steps of providing a length of highly birefringent optical fiber, and thermal tapering one or more separated but approximately adjacent small sections of that optical fiber in order to reduce the core diameter at those sections. This core diameter reduction adjusts the V-value for the fiber so that polarization-dependent transmission effects become evident at the wavelength of operation.

In-line optical fiber polarizer

An attachment tool and method for attaching a connector to a plastic-cove optic fiber, said connector formed with a bore slightly smaller than the covered fiber but slightly larger than the fiber core, the tool comprising a block of rigid material having a flat surface containing a straight groove running into and away from a central excision, the dimensions of the groove and excision being such that when the fiber is thread through the connector, and the connector is laid in the excision and the fiber in the groove, the fiber is substantially straight and centrally placed within the connector bore. A heater is used to heat the connector and soften the covering so that the fiber can be pulled through the bore by extrusion of the covering. The covering, which now fills the bore around the fiber core, is allowed to cool and harden, and the protruding fiber is cut off flush with the end of the connector.

Fiber optic connection method

Optical access and duplex couplers for multimode, fiber, data transmission ines. Access couplers are for use with multiterminal communication systems whereas duplex couplers allow a single fiber to be used for data transmission in both directions. Grooves of different depths and widths are etched into silicon along natural crystal planes to position fibers of different diameters and to provide reflective silvered surfaces. Optical communication signals pass through smaller-diameter transmission lines to larger lines. Light surrounding the smaller-diameter line from the larger line is reflected by the reflective surfaces. Thus, information may be received and added as desired.

Access coupler and duplex coupler for single multimode fiber

A bidirectional optical communication system which includes a transmission ine which directs radiation onto a reflective surface through which a smaller-diameter fiber is inserted. The smaller-diameter fiber directs radiation into the larger-diameter fiber for transmission away from the reflective surface simultaneous with radiation transmitted through the larger-diameter fiber toward the reflective surface. A reflective surface and small fiber may be at each end of the larger-diameter fiber for bidirectional operation.

Growing community of inventors

Burke, VA, United States of America

Carl A Villarruel