Abstract: A unitary optical-fiber connector assembly accepts a plurality of input channels and, by means of a common transfer lens of the graded-index type, transfers the input-channel data to a corresponding plurality of optical-fiber output channels.

Abstract: A loop, formed in a single suspended strand of a photo-elastic material, serves as an inertia mass that is rotatable about the axis of the suspended strand. The angular displacement of the loop, due to an accelerating force, is measured as a function of the change in polarization angle of a radiant beam passing through the strand.

Abstract: A preloaded vibrator assembly wherein each leg of a stilt structure is preloaded in compression during construction. The linear actuator is preloaded prior to operation by supplying hydraulic fluid under pressure between one end of the linear actuator piston and the hub of the stilt-structure spider. A structural deflection of the spider away from the piston rod is created by the hydraulic pressure. At a predetermined load, a mechanical lock is engaged, fixing the relative positions of the spider and the piston rod. Hydraulic pressure is removed leaving the structure preloaded.

Abstract: A system and method for forming a model of an underground geological formation is disclosed wherein a quantity of non-solid material of the type which solidifies at volumetric positions impinged upon by preselected incident energy as used. Memory means are provided which have uniquely addressable location for storing data indicative of the desired and actual material states at respective volumetric positions. Means are additionally for scanning the data and sequentially directing the energy at supported, non-blocking, volumetric positions in the medium volume.

Abstract: A connector for fiber optic cables includes an elongated tubular housing and a pair of termination assemblies which surround the end of each fiber optic cable. A lens element is adjacent one end of each termination assembly, and a sleeve surrounds each lens element and a portion of the termination assembly, and a lip on the sleeve spaces and coaxially aligns the lens elements one from the other.

Abstract: A plurality of streamer-cable bulkheads mounted within a streamer cable in cascade for radially scattering tube-wave noise from a streamer-cable. Each bulkhead consists of an annular body with conical surfaces converging at a desired angle, extending outwards from both ends of the annular body. An axial hole and a plurality of off-axial holes extending through the bulkhead for receiving therethrough, electrical conductors and stress members respectively. Noise traveling within the tube in a waveguide mode, impinges upon the conical surfaces of the cascaded bulkheads, and is reflected out of the streamer-cable jacket.

Abstract: A first sweep signal consists of a plurality of waveforms having non-invariant fundamental periods exhibiting a monotonic frequency progression of at least one octave over the duration of the sweep. Each waveform may consist of an ordered set of asymmetrical pulses distributed within the period of the waveform in a prescribed sequence as a function of time. A second sweep signal is orthogonalized with respect to the first by time-reversing the distribution-sequence of the pulse set.

Abstract: A submersible positioning device, such as a paravane coupled to a distant end of a towing cable may include a front cylindrical stabilizer having a wing diametrically disposed therein and having a predetermined angle of attack coupled to a towing bridle which in turn is coupled to the towing cable. A rear stabilizer may be coupled to the front stabilizer by a shaft, extending from the lower surface of the wing, and a plurality of struts coupled to the perimeter of the front stabilizer. A buoy coupled to the uppermost point of the front stabilizer may be pulled underwater while under tow, but returns the paravane to the surface for recovery purposes while not under a tow.

Abstract: A baseplate for a seismic vibrator is formed from two identical cast plate members having stiffening ribs and alternating plug and socket cones along the ribs. The cast plate members are arranged together to align opposed plug and socket cones of the plates and are connected by attaching mechanisms passing through holes in the aligned cones. The aligned cones accomplish a wedging or clamping action on each other when the plate members are connected.

Abstract: An optical telemetric system for use in seismic exploration consists generally of a recorder, a plurality of transceivers, and a like number of cable sections interconnecting each transceiver in parallel with others and the recording unit. A fiber optic transmission channel is provided within each cable section and is interconnected by an optic-fiber delay loop within each transceiver, thus providing a contiguous, optically-continuous data and control channel. Within each transceiver, a logic circuit and associated data acquisition unit is optically coupled to the data and control channel so as to bidirectionally receive signals from, and transmit signals to the recorder. The logic circuit of each transceiver also is able to measure the strength of a received signal propagating in the data and control channel, and if necessary, augments the signal in the original propagation direction.

Abstract: I provide a combination land/bay cable capable for simultaneous use on land and in water-covered areas. When the cable section is placed in a water-covered area suitable for hydrophone use, a polarized plug containing an impedance matching transformer is detachably connected to a polarized socket. The transformer connects the hydrophones to a transmission line. If the cable is to be used on land, the transformer is unplugged deactivating the hydrophones and at least one geophone having a substantially identical plug is inserted in the socket. The plug connects the geophone to the transmission line and leaves the hydrophones inactive.

Abstract: A pressure gradient sensor is disclosed for optically sensing the direction and magnitude of an acoustic wave propagating through a fluid. Each sensor consists generally of at least three fiber-optic displacement sensors disposed within a circular array oriented perpendicular to the longitudinal axis of a streamer. Each sensor phase-modulates a coherent light signal indicative of the water pressure sensed outside the streamer. The output of the signals include a component due to transient pressure waves and a component due to hydrostatic pressure differences between the sensors.

Abstract: In a two-stage, time-division multiplexing method and apparatus, a plurality of sensors are disposed at equal intervals along a plurality of transmission channels. An interrogation signal is transmitted from a recording station to all of the sensors along each channel. Because of the spatial arrangement of each sensor along the telemetric system and different propagation path lengths along each channel, the output signals from the sensors are time-division multiplexed along each channel. The multiplexed signals along each channel are time-division multiplexed a second time upon arrival at the recording station where the signals from each channel are interleaved with each other.

Abstract: A dual mode vibrator assembly for selectively generating either pressure wave or shear wave signals in the earth has a single inertia mass with a plurality of vertically parallel offset cylinder bores and at least one horizontal cylinder bore extending therethrough. Each cylinder bore reciprocably retains a piston member and is in fluid communication with a fluid source. The lower ends of the vertical piston members are connected to a base plate to generate pressure waves. A foot member is connected to each end of the horizontal piston member and interconnected by anti-roll rails in sliding relationship with the inertia mass. Cleats are connected to the bottom of each foot member to engage the earth for generating shear waves. A manifold directs fluid from a servo-valve either to passages leading to the vertical cylinder bores for pressure wave operation or to the horizontal cylinder bore for shear wave operation.

Abstract: A ruggedized depth transducer for measuring ambient hydrostatic pressure adjacent an acoustic source wherein the transducer includes a housing having a depth sensor mounted therein. The housing further includes a bore for placing the depth sensor in fluid communication with the ambient pressure. Mounted within the housing bore are a series of mechanical filters for attenuating high-intensity pressure spikes generated by the acoustic source from damaging the depth sensor contained within the housing. The mechanical filters allow gradual changes in ambient pressure to pass into the bore and influence the depth sensor.

Abstract: A dual-mode vibrator for alternately injecting P-waves and S-waves in the earth including a hydraulically driven shaker assembly, a ground-contacting base plate, and a jacking means for raising and lowering the base plate relative to a vehicle. The shaker assembly is supported above, and coupled to the base plate by a supporting means. The supporting means has a first configuration for coupling the shaker assembly to the base plate for generating P-waves and a second configuration for pivotally coupling the shaker assembly to the base plate and to a rigid member associated with the vehicle for injecting S-waves.

Abstract: In this invention, the depth of lapping an optical flat on optic fibers is monitored while the fiber is mounted on the lapping fixture. A collimated light beam is tangentially incident upon the optical flat. A portion of the incident light is transmitted into the optic fiber. A light intensity monitor coupled to the end of the optic fiber measures the amount of transmitted light relative to a standard value. The amount of light transmitted is a function of the surface area of the optical flat. A monitor measurement of a predetermined intensity level indicates sufficient material has been removed from the optical fiber.

Abstract: An apparatus for preventing thermally-induced stress fatigue in a vibrator support housing consists of a stress compensator that absorbs thermal dimensional changes between major structural components made of dissimilar materials. The stress compensator consists of a hydraulic clamp wedged between the free end of a vibrator actuator piston shaft and the supporting housing. Actuated by the substantially-constant system hydraulic pressure, the hydraulic clamp maintains a substantially constant clamping force between the actuator piston shaft and the supporting housing. Thermally-induced stresses are absorbed by the hydraulic system.