摘要:
Methods are disclosed for providing a rugged attachment of an optical fiber to an integrated optics chip. A first plate is attached to a first surface of the chip, the thickness of the chip is reduced to a value less than the diameter of the fiber but of sufficient optical thickness so that the evanescent field of a guided mode is negligible outside the chip, a second plate is attached to a second major surface of the reduced-thickness chip, the fiber is coaxially jacketed with a material suitable for attachment to the first and second plates, the fiber is positioned with respect to a waveguide on the chip, and the jacket of the fiber at its end face is symmetrically attached to both the first and second plates at a plurality of locations. Alternatively, a single plate can be attached to the first surface of the chip without reducing the thickness of the chip and either a jacket on the fiber or the curved periphery of the fiber itself can be attached symmetrically to both the plate and the substrate. The resulting connection between the optical fiber and the integrated optics chip is rugged, thermally insensitive, and suited for batch production processes. A wafer comprising a plurality of chips can be sandwiched between first and second plates or reinforced with a single plate, and subsequently subdivided into individual chips to which optical fibers can then be attached.
摘要:
An integrated optics decorrelator device with a first integrated optics junction. The first optics junction has two input paths and at least one output path formed as a Y-shaped assembly of two mono-modal optical waveguides joined at a node with a central multi-modal optical waveguide. The central multi-modal optical waveguide segment has an output end. A second integrated optics junction has two output paths formed as a Y-shaped assembly of two output mono-modal optical waveguides joined at the output end of the central multi-modal optical waveguide segment. The first integrated optics junction and the second integrated optics junction are formed inside a refractive medium having a lower refractive index than the refractive index of the waveguides. The central multi-modal optical waveguide segment has an elongated multi-modal waveguide for decorrelating symmetric mode light passing through the central multi-modal optical waveguide with respect to anti-symmetric mode light passing through the substrate to the second integrated optics junction coupled to a tapered waveguide segment.
摘要:
This invention provides a sensor array using a plurality of fiber optic sensors connected between transmit fibers and receive fibers. The laser transmitter supplies pulses to the transmit fiber and fiber optic couplers couple the pulses from the transmit fiber into the fiber optic sensors. The pulses from the laser transmitter may be frequency chirped or frequency stepped to provide passive sampling of interferometric sensors in addition to intensity sensors, or otherwise frequency modulated. Each sensor is configured to respond to changes in a predetermined physical parameter by altering the shape of the pulse input thereto. Fiber optic couplers couple the sensor output signals into the receive fiber for input to a receiver, which converts the optical signals into electrical signals for input to a processer. A timing reference correlates the sensor output pulses with the sensors.
摘要:
Attenuation of an optical signal at the end of an optical fiber is achieved by positioning a high absorption region at the end of the fiber. A first embodiment teaches highly doped wedges within a tapered end of the fiber. The highly doped wedges adjacent the light transmitting core serve to absorb light at the end of the fiber. The light transmitting core of the fiber is reduced in diameter due to the tapering, causing the field of light to expand beyond the core. The highly doped wedges are in proximity to the core due to the tapering. The wedges, which are preferably heavily doped with a rare earth such as erbium, absorbs the escaping light in sufficient quantities, both in the initial pass through the tapered region and again upon reflection of the light at the end of the tapered region, such that the attenuation of the reflected light is within acceptable limits without regard to the condition of the fiber's end surface.
摘要:
The optical interconnection apparatus includes one or more terminator blocks which hold a plurality of jacketed optical fibers and a flexible matrix which encloses the jacketed optical fibers and partially surrounds the terminator blocks so as to anchor the terminator blocks within the matrix. Each terminator block comprises a jacket holder and a jacket clamp. The jacket holder has a surface with a plurality of grooves for receiving a plurality of jacketed optical fibers. The jacket clamp clamps a plurality of jacketed optical fibers in the plurality of grooves of a jacket holder. The terminator blocks are used with a mold having one or more guide structures for use in guiding each of the terminator blocks into the mold, a terminator block having one or more guide followers which engage and follow the guide structures of the mold when the terminator block is inserted into the mold. The optical interconnection apparatus further comprises one or more connector blocks, each of which is attachable to two terminator blocks. The connector block holds the bare optical fibers protruding from a terminator block when the connector block is attached to the terminator block and bare optical fibers are protruding from the terminator block. Each connector block comprises a fiber holder and a fiber clamp. The fiber holder has a surface with a plurality of grooves dimensioned to receive a plurality of bare optical fibers. The fiber clamp provides the means for clamping the bare optical fibers in the grooves of a fiber holler.
摘要:
Single and multiple axis fiber optic gyroscope systems employ orthogonal sequences to minimize the effects of both intra and inter-axis crosstalk. Sequences for driving electro-optic modulators are derived by examination of underlying primary and secondary demodulation sequences. Such underlying sequences are examined for orthogonality in accordance with a number of selection rules. When the selection rules are satisfied, the corresponding modulation sequences for driving the gyro(s) are identified and applied. By selecting the modulation waveforms in accordance with orthogonality criteria, one is assured of mean-zero bias errors within a predetermined number of loop transit times.
摘要:
A fiber gyroscope provides improved bias stability and repeatability and has a greatly reduced polarizer extinction ratio requirement compared previous devices. This fabrication technique is compatible with both an all fiber gyroscope configuration and an integrated optics or bulk optics device. The present invention comprises a substrate that is preferably formed of fused silica. A pair of optical fibers, or two lengths of one fiber, are mounted to the substrate, and first planar surfaces are formed in the cladding. Optical couplers, polarizers and other components used in forming the rotation sensor are formed on the planar cladding surfaces of the fibers. Polarizers formed on the fibers have a transmission axis aligned with an axis of birefringence of the fiber to remove undesired linear polarization components from optical signals guided by the fibers while permitting a desired linear polarization component to propagate unattenuated. A sensing coil of optical fiber is arranged to guide light between the first and second optical fibers, the first and second optical fibers and the optical coupler cooperating to introduce counterpropagating light waves in the sensing coil.
摘要:
Apparatus for producing a three phase signal from two or three optical beams at different optical frequencies, such signal having a frequency equal to the difference frequency or frequencies between the optical frequencies of said beams including, preferably, an equal energy single mode fiber optic coupler and optical focusing means, such as gradient index rods, for directing said light beams onto light conducting fibers, preferably single mode fibers, thence through the coupler, thence onto light detectors to produce a substantially balanced three phase electrical signal at said difference frequency or frequencies.In a preferred embodiment, the light beams are two in number, connected to only two input ports of said coupler, and the light beam sources are the output beams of counter- propagating ring laser beams in a ring laser gyro.
摘要:
This invention relates to fiber optic apparatus and methods for polarizing light for use in fiber optic devices, such as rotation sensors. A phase grating formed of alternating layers of dielectrics having different indices of refraction is placed adjacent a half coupler that includes a fiber having a cladding thickness which forms an interaction region. The evanescent field of light of a selected polarization interacts with the phase grating to cople out of the fiber while light of a second selected polarization remains in the fiber.
摘要:
Attenuation of an optical signal at the end of an optical fiber is achieved by positioning a high absorption region at the end of the fiber. A first embodiment teaches highly doped cylinders within a tapered end of the fiber. The highly doped cylinders adjacent the light transmitting core serves to absorb light at the end of the fiber. The light transmitting core of the fiber is reduced in diameter due to the tapering, causing the field of light to expand beyond the core. The highly doped cylinders are in proximity to the core due to the tapering. The cylinders, which are preferably heavily doped with a rare earth such as erbium, absorb the escaping light in sufficient quantities, both in the initial pass through the tapered region and again upon reflection of the light at the end of the tapered region, such that the attenuation of the reflected light is within acceptable limits without regard to the condition of the fiber's end surface.