Abstract: A housing for a seismic sensor station has a base and a removable lid, which when assembled together form a shell whereby the base and the removable lid both have a shell side and an exterior side. A sensor spike, protruding outward from the shell, may be attached to the base on the exterior side of the base. The housing is further provided with two cable docking ports, each allowing passage of a fiber optical cable from outside to inside the shell. The two cable docking ports are exclusively provided in the removable lid.

Abstract: A seismic sensor station employs a sensor unit that is mounted on a central mounting post attached to the base of a sensor station housing. The only path of mechanically supporting contact that exists between the sensor unit and the base is through the central mounting post.

Abstract: A housing for a seismic sensor station has a base and a removable lid, which when assembled together form a shell whereby the base and the removable lid both have a shell side and an exterior side. A sensor spike, protruding outward from the shell, may be attached to the base on the exterior side of the base. The housing is further provided with two cable docking ports, each allowing passage of a fiber optical cable from outside to inside the shell. The two cable docking ports are exclusively provided in the removable lid.

Abstract: A seismic sensor station employs a sensor unit that is mounted on a central mounting post attached to the base of a sensor station housing. The only path of mechanically supporting contact that exists between the sensor unit and the base is through the central mounting post.

Abstract: Sensor stations, system and methods for sensing seismic parameters of a subsurface structure are provided. The sensor station includes a sensor housing and a sensor unit. The sensor housing includes a base with a removable lid and receptacles for receiving the fiber optic cable therethrough. The base has a cavity therein accessible upon removal of the removable lid. The sensor unit is positionable in the cavity of the sensor housing. The sensor unit is operatively connectable to a portion of the optical fibers of the fiber optic cable for communicating seismic data sensed by the sensor unit.

Abstract: A fiber optic acoustic sensor that detects pressure waves from all incident angles features multiple mandrels orthogonally disposed to provide omni-directional sensing capability. The topology of the mandrels prevents frequency response drop-off characteristic of cylindrical sensors at wavelengths smaller than ½ the length of the acoustic cylinder. The larger operating bandwidth and omni-directional sensing capability makes this fiber optic acoustic sensor a suitable choice for a wide range of applications.

Abstract: A fiber optic acoustic transducer includes a mandrel having a first portion that preferably formed generally as a cylinder having a projection extending from one end. A grating collar also preferably formed in a generally cylindrical configuration. The grating collar has a passage extending therethrough so that it may mounted on the projection. An optical fiber has a sensor portion wound around the first portion of the mandrel and a second portion wound around the grating collar with a fiber Bragg grating being formed in the second portion of the optical fiber.

Abstract: A fiber optic acoustic transducer includes a mandrel having a first portion that preferably formed generally as a cylinder having a projection extending from one end. A grating collar also preferably formed in a generally cylindrical configuration. The grating collar has a passage extending therethrough so that it may mounted on the projection. An optical fiber has a sensor portion wound around the first portion of the mandrel and a second portion wound around the grating collar with a fiber Bragg grating being formed in the second portion of the optical fiber.

Abstract: A fiber optic acoustic sensor that detects pressure waves from all incident angles features multiple mandrels orthogonally disposed to provide omni-directional sensing capability. The topology of the mandrels prevents frequency response drop-off characteristic of cylindrical sensors at wavelengths smaller than ½ the length of the acoustic cylinder. The larger operating bandwidth and omni-directional sensing capability makes this fiber optic acoustic sensor a suitable choice for a wide range of applications.

Abstract: Methods and apparatus for reducing noise in optical apparatus comprising a delay line by utilizing a plurality of wavelength specific delay lines to delay an input waveform such as a pulse rather than a single delay line. In a preferred embodiment an apparatus is configured to generate an optical waveform by distributing an input optical waveform among a plurality of environmentally isolated legs, wherein each leg contributes to the generated optical waveform by reflecting back at least a portion of light distributed to the leg, and the distribution among the plurality of legs is at least partially wavelength dependent.

Abstract: Methods and apparatus for generating an optical waveform by distributing an input optical waveform among a plurality of environmentally isolated legs wherein each leg comprises a Bragg grating and contributes to the generated optical waveform by using the Bragg grating to reflect back at least a portion of light distributed to the leg.

Abstract: Methods and apparatus for generating an optical waveform by distributing an input optical waveform among a plurality of environmentally isolated legs wherein each leg comprises a Bragg grating and contributes to the generated optical waveform by using the Bragg grating to reflect back at least a portion of light distributed to the leg.

Abstract: An improved pressure vessel comprises a tubular casing having an internal cavity and a first and second opening at each end. The internal cavity is divided into a first and second cylindrical plug region extending inward from the first and second opening and a hollow interior region. An optical component in the hollow interior has at least a plurality of optical fiber pigtails extending therefrom. A first and second cylindrical plug is force fit into the plug regions. At least one plug has a through-hole for receiving optical fiber pigtails. At least one plug has a ceramic adhesive plug formed by inserting adhesive into the through-hole and preferably filing the void space therein. The adhesive encapsulates the optical fibers passing through the through-hole. The plug has a channel machined into its outer circumference to receive an O-ring. A cap covers over and beyond the outer surface of the plug.

Abstract: A pressure vessel capable of withstanding elevated hydrostatic pressures, and elevated temperature comprises a tubular cylindrical casing capable of withstanding extreme hydrostatic pressures having an internal cavity and a first and second opening at each end permitting access to said internal cavity. The internal cavity is divided into a first and second cylindrical plug region extending inward from the first and second opening and a hollow interior region.

Abstract: A sensor array includes a fiber optic cable and at least one electro-optical conversion unit connected to the cable. The electro-optical conversion unit includes a housing formed of mating upper and lower covers. The housing includes an interior cavity for receiving a phase modulator module, a strength member and an interferometer formed by fibers connected to various splices and couplers in combination with the phase modulator module. The interior of the housing is filled with a fill material for holding the position of optical fibers to thereby protect against environmental factors such as shock and moisture.

Abstract: A connector includes a pair of connector members for simultaneously contacting a first plurality of optical fibers with a second plurality of optical fibers. A cup for fixing the ferrule-tipped ends of mating optical fibers is wholly contained within each of a plurality of channels through the members. The cup is capable of axial movement within a channel through a body element of a connector member. A spring member is located in the channel between a back plate and the cup to act upon the base of the cup. Aligned dowel channels are provided for receiving a thick external dowel that resides within the aligned dowel channels of the body member of one of the connector members and the holder of the other. An internal dowel is press fit within the body element and holder dowel channels of the other connector member to enhance the ruggedness and durability of the device.

Abstract: A seal assembly for a multichannel fiber optic connector. The seal is engaged to the portion of the connector mounted within a receptacle housing that may be mounted to the turret of the hull penetrator of a vessel. An elongated symmetrical seal housing is sealably secured with the receptacle at the back of the connector. A retainer member having a plurality of channels therethrough is held at a rear portion of the seal housing by an annular shoulder thereof. A plurality of elongated standoff spacers define a strain relief chamber between the rear of the connector and the retainer member. O-rings seal individual optical fibers passing through the channels of the retainer member, which is sealably secured to the seal housing.

Abstract: A readily-serviced junction for a fiber optic telemetry system includes at least one box for receiving cables that communicate with downstream optical sensors. The cables comprise commingled input-path and return-path optical fibers. A manifold-type arrangement of metallic enclosure tubes is arranged to direct the optical fibers, once stripped of the outer jackets of the cables, toward the light source and detectors of the telemetry system. A splice protection box houses couplers of the telemetry system. The boxes of the junction are easily assembled and dissembled to facilitate installation and servicing.

Abstract: A connector for making and securing low loss optical contact between a first plurality of optical fibers, each including a ferrule-encapsulated terminal end, and a second plurality of optical fibers, each also including a ferrule-encapsulated terminal end. Each of the ferrules is individually fixed to a cap that includes an asymmetrical keying member. Male and female connector members include internal channels for accepting ferrule-fixed cups with predetermined angular orientations. Springs are axially aligned within the channels for independently urging each cup-fixed ferrule into optical contact with a mating ferrule. In this way, multiple rotational and axial alignments are simultaneously and independently achieved and maintained between mated pairs of optical fibers.

Abstract: A photodetector includes a polarizer array and an array of photodetector elements. The polarizer array includes a plurality of polarizers having axes of polarization spaced apart by selected angles such that each optical signal incident on the polarizer array has a polarization component along at least one of the axes of polarization. The array of photodetector elements is arranged such that each of the photodetector elements receives light from a selected one of the polarizers. At least one of the photodetector elements receives parallel polarization components from the optical signals to form an electrical signal indicative of interference between the optical signals.