Hughes Aircraft Company

Other

James R Rochester

Ronald B Chesler

Richard B Barnes

Michael S Glaser

James W Christy

Jerome J Krempasky

A blackbody radiation source includes an insulated enclosure having a viewing aperture defining a line of sight through the wall of the enclosure. A heat sink, preferably a pool of liquid nitrogen, is located within the insulated enclosure. There is a viewing surface in thermal contact with the heat sink but having an unobstructed view through the viewing aperture. The viewing surface is inclined to the line of sight through the viewing aperture. A sensor is calibrated by placing the sensor in facing relation to the aperture and measuring an output black body signal of the sensor. The viewing surface may be radiatively heated concurrently with the measuring to produce a higher equivalent radiometric temperature.

Low-temperature blackbody radiation source

An optical fiber evaluation test station (20) includes optical fiber supply (26), translation, and rewinding mechanisms (52), and at least one module performing a test of optical fiber quality through which the optical fiber (22) continuously passes. The test station (20) includes a supply section wherein the optical fiber (22) is paid out from a supply spool (24) and cleaned by a cleaning and static discharging unit (30). There is a high tension test section wherein tests such as a buffer cure test (46) and a bend proof test (48) are performed. In a low tension test section, tests such as an optical fiber diameter test (58), a buffer flaw test ( 60 ), and a visual observation test (64) are performed. Tension-isolating capstans (40, 44) separate the various sections, optical fiber guides (62) direct the optical fiber (22) and stabilize its movement, and spring-mounted dancers (36, 42) measure the tension in the optical fiber (22) in the tension-isolated sections.

Automated test station for performing a variety of tests on optical

The diameter of an optical fiber (36) moving past a measurement apparatus (20) is evaluated in a time of less than about 50 microseconds, permitting closely spaced individual measurements along the length of the optical fiber (36). The measurement apparatus (20) includes a number of discrete, stationary light sensors (22) arranged in a linear array (24), a light source (28) positioned to shine a beam of light (34) into the sensors (22) of the array (24), and a lens (38) that directs an enlarged image of the optical fiber (36) onto the array (24) of light sensors (22). The light sensors (22) each produce an output signal (26) responsive to the intensity of light reaching the sensor (22). The number of light sensors (22) having a signal below a threshold value at a selected moment is counted as a measure of the diameter of the portion of optical fiber (36) then lying between the light source (28) and the array of optical sensors (22).

Measurement of optical fiber diameter

An optical fiber payout canister (36) comprises a bobbin (42) upon which an optical fiber (34) is wound. A shroud (50) overlies the bobbin (42), and a layer (54) of an ablative material is coated onto at least a portion of the inside wall (48) of the shroud (50) adjacent to the bobbin (42), so that the optical fiber (34) may contact the ablative material (54) during payout. Desirably, the ablative material (54) has a hardness equal to or less than that of the buffer layer of the optical fiber (34). In one embodiment, the ablative material (54) has a composition similar to that of the polymer buffer layer, such as an urethane acrylate. The ablative material (54) removes energy from the optical fiber during payout, and in particular reduces the circumferential component of the energy, permitting the optical fiber (34) to be dispensed through a dispensing opening (58) in an end wall (60) of the shroud (50).

Optical fiber canister with ablative coating

An optical fiber canister (90) comprises a hollow housing (102) and an optical fiber pack (98) having a plurality of layers of optical fiber (20) supported on an inner surface of the housing (102) with a free end (96) of the optical fiber (20) positioned to pay out from an interior surface of the fiber pack (98). The optical fiber (20) of the optical fiber pack (98) has an amount of adhesive thereon ranging from zero to an amount sufficient to produce a peel force of less than about 2 grams. There is desirably a support layer (110) of a castable elastomeric material between the inner wall (108) of the hollow housing (102) and the outer surface of the optical fiber pack (98), and a release layer of a release material such as polytetrafluoroethylene between the inner surface of the support layer (110) and the outer surface of the optical fiber pack (98).

Inside payout optical fiber canister having reduced adhesive in the

A missile data link filament (12) dispenser (10) is located within an enclosure (20) having a single eyelet opening (26) through which the filament feeds on launch. A quantity of a damping gas having an effective density of at least about two times that of air (28) is provided within the enclosure (20). The gas serves to damp the helical motion of the filament by absorbing its rotational energy, to inhibit ballooning of the filament (12) as it is paid out from the dispenser (10).

Gas damped filament dispenser

The elastic properties of an optical fiber (10) are determined from measurements of the contact area (20, 24) of the optical fiber (10) against a surface (16, 22), under a loading perpendicular to the surface. In a preferred approach, an optical fiber is passed over a curved surface (22) of a transparent lens in the form of a pulley (38), with a tension applied to the optical fiber (10). The buffer layer (14) of the optical fiber (10) is flattened against the curved contact surface (22), forming a contact region (24) whose area is measurable. The relative elastic deformability of the buffer layer (14), a function of its elastic modulus, is determined from the contact area and other measurable parameters. Contact area measurement is performed continuously as the optical fiber (10) is passed over the pulley (38) by monitoring the amount of light that is transmitted through the contact region (24). The variations in the elastic properties of the optical fiber (10) may therefore be measured continuously as the optical fiber (10) is transported over the pulley (38).

Apparatus and method for determining elastic properties of optical

A moving optical fiber (10) is guided in its motion by an annular guide apparatus (40) which receives the optical fiber (10) within an inner bore (66) and stabilizes its transverse position as it moves longitudinally. The guide (40) has a plurality of gas jets extending into the inner bore (66) that create a cushion of gas to maintain the position of the optical fiber (10) in the center of the bore (66), without the need for any physical contact between the bore (66) and the optical fiber (10). The annular guide (40) is preferably formed from a housing (42) that defines a gas plenum (74) and a flow control plate (52) that fits to the housing (42) and has circumferentially spaced, radially extending gas flow passages (54) etched therein. A gas flow introduced into the plenum (74) from an external source is distributed to the gas flow passages (54) and thence to the inner bore (66) to prevent the optical fiber (10) from physically contacting the guide (40).

Annular optical fiber support with radial gas jets

A test system (10) for a laser rangefinder (12, 14) having signal transmission and reception paths comprises a thick lens collimator (20) which receives energy (18) from a transmitter (12) for input through an optical fiber (32). The fiber has a partial reflector (34) and a full reflector (38) to simulate sites of targets, and the reflected energy is transmitted back through collimator (20) to a receiver (14). Partial reflection of energy is provided by gold (64) placed on a surface (53) of one of two aligned and spaced termini (32a, 32b) of fiber (32).

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Tucson, AZ, United States of America

James R Rochester