Abstract: There is provided a system for measuring temperature and strain simultaneously utilizing Brillouin Scattering within an optical fiber. The system has a cladding, a first optical core within the cladding and a second optical core within the cladding and having a different refractive index profile and/or composition than the first core. Means to couple light into and out of said individual optical cores and/or from one optical core to the other within the fiber is provided along with means for calculating strain and temperature characteristics based on measured Brillouin frequencies for said optical cores.

Abstract: There is provided a system for measuring temperature and strain simultaneously utilizing Brillouin Scattering within an optical fiber. The system has a cladding, a first optical core within the cladding and a second optical core within the cladding and having a different refractive index profile and/or composition than the first core. Means to couple light into and out of said individual optical cores and/or from one optical core to the other within the fiber is provided along with means for calculating strain and temperature characteristics based on measured Brillouin frequencies for said optical cores.

Abstract: The present invention is directed to the creation of optical waveguiding devices from standard optical fibers by the creation of zones of permanently altered refractive index characteristics therein. A high intensity femtosecond laser beam is focused at a predetermined target region in the fiber so as to soften the glass material at the target region. After aligning the focal region with the target region in the fiber there will be relative movement between the focal region and the fiber, which has the effect of sweeping the focal region across the fiber in a predetermined path, so as to create a secondary waveguide path. A portion of the light traveling along the core is removed from the core along the secondary waveguide path such that the device can be utilized as an attenuator, an optical tap, or a polarimeter.

Abstract: The present invention is directed to the creation of optical waveguiding devices from standard optical fibers by the creation of zones of permanently altered refractive index characteristics therein. A high intensity femtosecond laser beam is focused at a predetermined target region in the fiber so as to soften the glass material at the target region. After aligning the focal region with the target region in the fiber there will be relative movement between the focal region and the fiber, which has the effect of sweeping the focal region across the fiber in a predetermined path, so as to create a secondary waveguide path. A portion of the light traveling along the core is removed from the core along the secondary waveguide path such that the device can be utilized as an attenuator, an optical tap, or a polarimeter.

Abstract: The present invention is directed to the creation of optical waveguiding devices from standard optical fibers by the creation of zones of permanently altered refractive index characteristics therein. A high intensity femtosecond laser beam is focused at a predetermined target region in the fiber so as to soften the glass material at the target region. After aligning the focal region with the target region in the fiber there will be relative movement between the focal region and the fiber, which has the effect of sweeping the focal region across the fiber in a predetermined path, so as to create a secondary waveguide path. A portion of the light traveling along the core is removed from the core along the secondary waveguide path such that the device can be utilized as an attenuator, an optical tap, or a polarimeter.

Abstract: A method and system for simultaneously measuring strain and temperature characteristics of an object involves the attachment to the object of a pair of optical fibers having different refractive indices, the fibers being connected together at least one end thereof, and directing laser light into at least one end of the fibers. The Brillouin frequency of each of the fibers is measure and the strain and temperature characteristics are calculated based on the coefficients of strain and temperature and the measured Brillouin frequencies of the fibers.

Abstract: The present invention relates to a method and apparatus for coating an optical fiber. A polyethylenimine-based polymer deposition precursor that includes titanium is prepared. The optical fiber is coated with the precursor in a polymer coater, after which the coated optical fiber is heated in an ammonia oven. The method and apparatus can be used to coat optical fibers that contain a cladding or optical fibers that are already covered with one or more fibers in a temperature-resistant outer cladding.

Abstract: A distributed Brillouin sensor system is provided. The system has two distributed feedback (DFB) lasers, which are locked at the Brillouin frequency of the optical fiber through offset locking method by coupler splitting into two parts. The split parts are sent to two photodiodes, the outputs of which are sent to a mixer. A PID controller means follows the mixer and a current controller follows the PID controller. The lasers have a wavelength of 1550 nm. The PID controller locks the frequency difference. An optical delay line is used to produce the frequency tuning of the two DFB lasers around the Brillouin frequency of the optical fibers. The lock-in amplifier is used to keep the DC level of the optical modulator at minimum.

Abstract: An apparatus for an optical time domain analyzer includes a pulsed laser source and a continuous wave (CW) laser source. The apparatus also has a computer readable memory for detection of a reflected pulse of an outgoing pulse from the pulsed laser source, the reflected pulse being reflected from a break in the fiber or an unterminated end of the fiber. In another embodiment, a computer program product having memory with computer readable code embodied therein is provided for determining a distance to a break or fiber end in an optical fiber. The computer program detects an outgoing pulse from a pulsed laser source in an optical time domain analyzer, detects a reflected pulse and determines the timing of the reflected pulse relative to the outgoing pulse.

Abstract: An adjustable focus connector with spring action is especially adapted for use with common FC or SAM fiber optic receptacles. The connector includes a ferrule holder which mounts a fiber-carrying ferrule at a distal end thereof. At its proximal end the ferrule holder is threadedly connected to a lead screw member. A thrust collar surrounds the ferrule holder and traps a compression spring in the cavity between the thrust collar and the ferrule holder. Because of appropriate interengagement between the components the ferrule holder cannot rotate relative to the trust collar. A traveler is threadedly connected to the lead screw and abuts against the thrust collar. A connection nut is provided at the distal end of the connector to connect it to the fiber optic receptacle. The spring action of the connector prevents damage to the fiber end during connection of the connector to the fiber optic receptacle.

Abstract: A method and system for simultaneously measuring strain and temperature characteristics of an object involves the attachment to the object of a pair of optical fibers having different refractive indices, the fibers being connected together at least one end thereof, and directing laser light into at least one end of the fibers. The Brillouin frequency of each of the fibers is measure and the strain and temperature characteristics are calculated based on the coefficients of strain and temperature and the measured Brillouin frequencies of the fibers.

Abstract: The present invention is directed to the creation of optical waveguiding devices from standard optical fibers by the creation of zones of permanently altered refractive index characteristics therein. A high intensity femtosecond laser beam is focused at a predetermined target region in the fiber so as to soften the glass material at the target region. After aligning the focal region with the target region in the fiber there will be relative movement between the focal region and the fiber, which has the effect of sweeping the focal region across the fiber in a predetermined path, so as to create a secondary waveguide path. A portion of the light traveling along the core is removed from the core along the secondary waveguide path such that the device can be utilized as an attenuator, an optical tap, or a polarimeter.

Abstract: The present invention is directed to the creation of optical waveguiding devices from standard optical fibers by the creation of zones of permanently altered refractive index characteristics therein. A high intensity femtosecond laser beam is focused at a predetermined target region in the fiber so as to soften the glass material at the target region. After aligning the focal region with the target region in the fiber there will be relative movement between the focal region and the fiber, which has the effect of sweeping the focal region across the fiber in a predetermined path. The result is a zone within the fiber in which the refractive index characteristics of the fiber have been permanently altered so as to control amplitude, phase, spatial propagation or polarization states of light within the material.

Abstract: The present invention is directed to the creation of zones of permanently altered refractive index characteristics in glass waveguiding devices, including optical fibers and optical waveguides pre-existed in a glass substrate. Such zones in which the refractive index has been permanently altered are created in glass using a very high intensity laser beam which is produced by focusing the light output from an ultrafast pulsed laser at a predetermined target region in the glass. The preferred laser is a Ti:Sapphire amplified, frequency-doubled Erbium-doped fiber laser system, providing light pulses of approximately 100 femtosecond duration, each with an energy of between about 1 nanojoule and 1 millijoule, and preferably at a pulse repetition rate of between 500 Hz and 1 GHz. The repetition rate is chosen to deliver pulses faster than the thermal diffusion time over the dimensions of the volume element being modified.

Abstract: An adjustable connector for optically connecting one optical fibre to another fibre or a light source is disclosed. In one embodiment a base plate mounting the fibre is connected to another base plate with a resilient member between the base plates. The fibre terminates at a beam expanding or imaging lens. Sets of alternating first and second screws axially extend from one base plate to the other such that when a test signal is transmitted to the fibre the first screws can be adjusted to coarsely tilt one base plate relative to the other until approximately the desired signal strength is achieved. The second screws are then rotated to finely adjust the base plates to achieve the desired signal strength. In other embodiments adjusting screws extend radially with respect to a cylindrical housing holding the fibre so as to adjust the relative position thereof. Adjustment can also be achieved using a temporary jig which can be removed and reused.

Abstract: An adjustable connector for optically connecting a pair of optical fibres in end-to-end relation, whereby insertion and tilt losses at the connector are minimized, is disclosed. The basic connector includes a pair of base plates, each of which can receive therein an optical fibre, the fibre terminating at a beam expanding lens held within the base plate. Confronting faces of the base plates abut a separating resilient washer member and a plurality of screws axially pass from one base plate to the other about and adjacent the outer edge thereof. With the fibres locked in place a test signal is passed through the connector along the fibres and the screws are individually rotated to angularly adjust the base plates relative to each other until the received test signal is optimized. The screws remain in the adjusted position and the connector may then be placed on service. Either fibre can be disconnected from and reconnected to its base plate without disturbing the adjustment.