Physical Optics Corporation

Other

Fitel USA Corporation

John D Prohaska

Robert A Lieberman

Lothar U Kempen

Malcolm C Smith

Elias Snitzer

David J Mazzarese

Kanishka Tankala

Disclosed and claimed herein is a device and method for generating carbon dioxide as an attractant for biting arthropods in combination with a trap, comprising: a reaction chamber charged with an aqueous acid solution when in use; a gas outlet from the reaction chamber connecting between the reaction chamber and the trap; a feeder reservoir containing a powder when in use, said powder comprising a bicarbonate salt; and means for controllably adding the powder to the reaction chamber; whereby carbon dioxide is generated in the reaction chamber, passed through the outlet and into the trap.

Apparatus and method for generating carbon dioxide as an attractant for biting arthropods

A tunable optical filter for simulating the waveband spectrums of selected substances. The filter includes an optical waveguide with a core material for transmitting light energy and a nominal core refractive index for the core material. Predetermined periodic variations are formed in the core material of the optical waveguide between the input and output ends that alter the core refractive index of the waveguide at the location of the periodic variations. Depending upon the periodic variations, the waveguide produces a predetermined reference waveband spectrum output that matches the waveband spectrum of a selected substance. A modulator is coupled to the waveguide to selectively modulate the periodic variations to intermittently shift the reference waveband spectrum output to fine tune the filter and reduce signal noise. The filter is useful as a reference cell for correlation spectroscopy, DIAL LIDAR, equipment calibration, and other uses where a predetermined or known waveband spectrum is useful or desirable.

Tunable filter

The present invention provides an optical fiber for use in fiber lasers and amplifiers wherein the optical fiber has a core member surrounded by a cladding member for receiving pump energy and transferring the pump energy to the core member. The optical fiber also has an outer layer surrounding the cladding member. The cladding member has a circular exterior periphery and a predetermined refractive index (n ). The cladding member has an index modified region that directs light to the core member. The index modified region has a stress field portion with a predetermined refractive index (n ). The difference between the refractive index of the cladding member and that of the stress field portion (n &minus;n ) is within such a range that the stress field portion does not affect the polarization properties of the light traveling in the core member. Preferably, the difference between the refractive index of the cladding member and that of the stress field portion (n &minus;n ) is less than 10 , and more preferably 10 .

Cladding member for optical fibers and optical fibers formed with the cladding member

A sensor system comprises a broadband light source, a birefringent sensor, a detection circuit, and a signal processing unit. The preferred detection circuit further includes a variable frequency oscillator, a modulator, and a photodetector. The modulator modulates the output of the birefringent sensor with a modulation signal from the variable frequency oscillator. The modulation produces an interference signal having a variable interference frequency. By determining the frequency of the modulation signal from the variable frequency oscillator that minimizes the interference frequency, the detection system is able to determine the difference in frequency between first and second spectral components of the output of birefringent sensor. The detector may be constructed using entirely solid state optics/electronics. The preferred fiber grating sensor comprises a birefringent optical fiber having a cladding and a core. The cladding has first and second side holes formed therein that extend substantially parallel to the core, and that are substantially coextensively located with respect to each other along the length of the optical fiber. The first and second side holes are preferable positioned such that, in transverse cross section of the optical fiber, a first radial line that extends from the core to the first side hole is substantially perpendicular to a second radial line that extends from the core to the second side hole.

Birefringent fiber grating sensor and detection system

A method of determining the wavelength of light transmitted in an optical fiber comprises the steps of filtering the light using a filter, and then detecting the filtered light, and then determining the wavelength of the filtered light. The filter comprises a fiber grating which is recorded in a portion of the optical fiber. The fiber grating preferably has a modulated index of refraction with a modulation amplitude that varies from a first end to a second end of the fiber grating, and a modulation period defined by a grating constant that varies from the first end to the second end of the fiber grating. The fiber grating at least partially prevents transmission of light within a wavelength spectrum, and prevents transmission of a substantially larger portion of the light at a first end of the wavelength spectrum than at a second end of the wavelength spectrum. Therefore, the wavelength of the filtered light can be determined by determining a proportion of the light which was transmitted by the filter. The proportion of light which is transmitted by the filter is preferably linearly related to the wavelength of the light.

Method and system for determining the wavelength of light transmitted

A fiber optic sensor system comprises an optical fiber, a first reflector and a second reflector. The first reflector provides a fixed reference for measuring the optical path length between the second reflector and a reference reflector. The first and second reflectors respectively receive first and second portions of light emitted by the optical fiber and then reflect the light back to the optical fiber. The optical path length between the first and second reflectors varies in accordance with a sensed parameter. In operation, first and second interferograms are acquired that are produced by the interference of light reflected from the first and second reflectors with light reflected from a reference reflector. The first and second interferograms are then used to determine an optical path length between first and second reflectors. Finally, the optical path length between the first and second reflectors is used to determine the value of the sensed parameter.

Self-referencing interferometric fiber optic sensor system having a

A Bragg grating is made in an optical path composed of material exhibiting change in index when exposed to radiation of an actuating frequency by passing radiation from a source of such actuating frequency through a mask with periodic variation in transmission to expose the material of the path to a diffraction pattern.

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Torrance, CA, United States of America

John D Prohaska