Abstract:
A sensing apparatus consisting of more than one diode laser having select lasing frequencies, a multiplexer optically coupled to the outputs of the diode lasers with the multiplexer being further optically coupled to a pitch side optical fiber. Multiplexed laser light is transmitted through the pitch side optical fiber to a pitch optic operatively associated with a process chamber which may be a combustion chamber or the boiler of a coal or gas fired power plant. The pitch optic is oriented to project multiplexed laser output through the process chamber. Also operatively oriented with the process chamber is a catch optic in optical communication with the pitch optic to receive the multiplexed laser output projected through the process chamber. The catch optic is optically coupled to an optical fiber which transmits the multiplexed laser output to a demultiplexer. The demultiplexer demultiplexes the laser light and optically couples the select lasing frequencies of light to a detector with the detector being sensitive to one of the select lasing frequencies.
Abstract:
A bulk optic (de)multiplexer (10) consists of a fiber pigtail array (20), a focusing optic (18) and a wavelength dispersive element or grating (16) in optical alignment along an optical axis (22). The focusing optic is rigidly affixed to the frame and the fiber pigtail array (20) and wavelength dispersive element (16) are attached by adjustable connectors (112, 56, 340) to facilitate al ignment. The frame (12) has thermally expansive elements to compensate for shifts in light beams processed by the (de)multiplexer as a function of temperature. Vibration dampers (150, 152, 154, 160, 200) isolate the frame and optical elements form vibrations applied to the (de)multiplexer.
Abstract:
A fiber pigtail template assembly (10) includes first and second silicon wafers (12, 14) each having a planar surface (22, 30) with a plurality of corresponding grooves (24, 32) therein extending from a leading edge toward a trailing edge. The plurality of corresponding grooves (24, 32), with the planar surfaces in abutment and the corresponding grooves aligned define a plurality of fiber channels (18). The first and second silicon wafers further cooperatively define a receptacle (26, 34) between the fiber channels and the trailing edges of the first and second silicon wafers with the planar surfaces of the silicon wafers in abutment with the grooves aligned. A minor diameter leading portion of an optical fiber (52) is received in each fiber channel and the receptacle is sized to receive major diameter trailing portions (54) of each fiber without causing a bending radius of the fiber sufficient to materially degrade wavelength propagation.
Abstract:
An apparatus and method are provided employing a single set of reduced-cost optics for (de)multiplexing optical signals whereby the resultant signals have a flat-top response with increased channel spacing. One aspect of the present invention uses an optical interleaver (310) to separate channels from an input multichannel (multiplexed) optical signal (302) with a select channel spacing into, for example, two input signals consisting of alternating channels at twice the select channel spacing. The separated signals are then directed to a multiple-input, such as dual-input, (parallel)(de)multiplexer device (320) which further spacially separates the channels for coupling with single channel transmission fibers (322 1-n , 324 1-n ). The input fibers to the (de)multiplexer are preferably offset relative to each other to accommodate channel shift resulting from the interleaver.
Abstract:
A method of measuring the combustion property in a measurement volume within a chamber defined in part by a chamber wall. The method includes providing a port in the chamber wall. Also provided is a fiber assembly comprising a single mode transmit core surrounded by a multimode receive core means. The fiber assembly is operatively coupled to the port to provide optical communication between the fiber assembly and measurement volume. A detection beam capable of detecting a select combustion property is transmitted from the single mode fiber and reflected off a reflection surface within the chamber, the reflection surface being configured to reflect and optically couple at least a portion of the detection beam to the multimode receive core means. The detection beam optically coupled to the multimode receive core means is then measured.
Abstract:
An absorption spectroscopy apparatus having at least one transmitting and receiving optic pair for obtaining absorption spectroscopy data through a quantity of gas. The absorption spectroscopy apparatus further includes means for moving one or both of the transmitting and receiving optics or otherwise altering the light path with respect to the quantity of gas while maintaining optical association between the transmitting and receiving optic. Thus, absorption spectroscopy data is obtained along more than one line of sight with the optic pair.
Abstract:
A method and apparatus for detecting the presence of a gas associated with fluid residing in a tank. The method includes transmitting radiation at a wavelength corresponding to that of a predetermined spectral absorption line of the gas into a space associated with a tank containing gas associated with a liquid. The transmitted radiation is then detected and analyzed. The apparatus includes a laser producing radiation at a wavelength corresponding to that of a predetermined spectral absorption line of the gas and plurality of pitch/catch optic pairs, each pair being configured to transmit radiation therebetween through a headspace of a tank. The laser is optically coupled to the pitch optics and a detector is optically coupled to each catch optic.
Abstract:
An embedded flight sensor system having a laser and one or more flight sensors in optical communication with the laser plus a data processing device in optical communication with the flight sensors. The flight sensors may be laser based optical components such as a fiber Bragg grating in combination with an optical detector, a spectroscopy grating and detector or an optical detector associated with catch optics. The parameters sensed by the flight sensors may be used to determine any flight parameter. Representative flight parameters include but are not limited to an airframe or external surface temperature, airstream velocity, combustion zone temperature, engine inlet temperature, a gas concentration or a shock front position.
Abstract:
A sensing apparatus (10) consisting of more than one diode laser (12) having select lasing frequencies, a multiplexer (16) optically coupled to the outputs of the diode lasers with the multiplexer being further optically coupled to a pitch side optical fiber. Multiplexed laser light is transmitted through the pitch side optical fiber to a pitch optic (20) operatively associated with a process chamber (22) which may be a combustion chamber or the boiler of a coal or gas fired power plant. The pitch optic (20) is oriented to project multiplexed laser output through the process chamber. Also operatively oriented with the process chamber is a catch optic (24) in optical communication with the pitch optic to receive the multiplexed laser output projected through the process chamber. The catch optic (24) is optically coupled to an optical fiber which transmits the multiplexed laser output to a demultiplexer (28). The demultiplexer (28) demultiplexes the laser light and optically couples the select lasing frequencies of light to a detector (25) with the detector being sensitive to one of the select lasing frequencies.
Abstract:
A (de)multiplexer (10) for use in optical communications systems for multiplexing and demultiplexing an optical signal consisting of optical channel(s) of different wavelength(s) (14, 16) includes a multiplex optical waveguide propagating a plurality of optical channels and a plurality of single channel optical waveguides, each propagating a single channel. Each of the waveguides has a receiving/transmitting end. A diffraction grating (22) is optically coupled between the multiplex optical waveguide and the single channel optical waveguides for diffracting an optical signal between the receiving/transmitting end of the multiplex optical waveguide and the receiving/transmitting end of the single channel optical waveguide. The grooves (24) of the diffraction (22) have spacing which varies according to an algorithm such that a portion of the optical signal diffracted by each groove (24) is offset in a direction of dispersion relative to the portions of the optical signal diffracted by the other surfaces to broaden the transmission band at the receiving/transmitting ends of the single channel and multiplex optical waveguides.