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.

Method and apparatus for the monitoring and control of combustion

A device for collection of energy from mechanical disturbances and distribution of that energy to an electrical load. A transducer converts mechanical energy in the form of forces and displacements into electrical energy in the form of charge pulses. The charge pulses are rectified into a Direct Current (DC) power signal and accumulated and stored in an input storage element. A controlled conversion circuit assures that the voltage on the storage element is maintained within a predetermined optimal range for energy harvesting from the transducer, avoiding the application of peak voltages. The controlled conversion circuit can be hard wired and/or controllably adjustable to match a given disturbance characteristic. Only when the voltage is within the optimal range for a given type of disturbance will the controlled conversion circuit enable a DC/DC converter to further convert the stored energy to a voltage that is coupled to an output storage element. This technique optimizes power conversion by controlling the high voltage to low version conversion process by, for example, sensing the disturbance with external sensor or internal voltage of the system, and then using this information about the disturbance to control how and when the electrical conversion process will occur.

System for optimal energy harvesting and storage from an electromechanical transducer

A method for measuring combustion parameters within a combustion zone of a gas turbine engine, the combustion zone being defined between an inner and outer casing. The method comprises transmitting a beam from a transmit optic optically coupled to a bore in the outer casing off a portion of the inner casing and receiving a portion of the beam reflected off the inner casing with a receiving optic optically coupled to a bore in the outer casing. An apparatus for practicing the method comprises a laser generating a beam and a transmitting/receiving optics pair, the transmitting/receiving optics pair being configured for operative association with a port in an outer casing of a gas turbine engine, whereby the transmitting/receiving optics are in optical communication by reflecting the beam off a portion of an inner casing.

Method and apparatus for spectroscopic measurements in the combustion zone of a gas turbine engine

A free space optical switch that uses open and closed loop control mode The open loop control mode is used to transition to a state where light is sensed at a destination port A closed loop control mode is then used, whereby a series of controlled dither signals (75) are adjusted for system dynamics Modifying the dither signals (75) allows moving actuators at a rate that is much closer to the natural frequency of the underlying system, and speeds up the system convergence process Variable modulation amplitudes may be employed on the dither signals (75) to maximize convergence speed In particular, changes in the dither signal can be made in accordance with the change in amplitude as a function of a gradient along a parabola that models the optical system response The dither signals (75) may be compensated for a desired and selectable attenuation level of output optical power

Multiple-axis control system for an optical switch

An optical mode noise averaging device (300) including a multimode optical fiber (302) and means (308) for averaging a modal noise induced signal level variation of light propagating within the multimode optical fiber (302). The device may average modal noise induced signal level variations by cyclically varying an index of refraction of the multimode optical fiber (302) over a select period of time, scrambling a light distribution within the multimode optical fiber (302), or both. The index of refraction of the multimode optical fiber may be cyclically varied by cyclically varying the temperature of the multimode optical fiber (302). Alternatively, the index for refraction may be varied or the light distribution within the multimode optical fiber may be scrambled by cyclically manipulating the multimode optical fiber (302).

Optical mode noise averaging device

An optical device comprises an optical fibre device having wavelength-dependent optical characteristics mounted on a bimorph element operable to bend in response to an electrical control signal, so that the wavelength-dependent optical characteristics of the optical fibre device vary in response to bending of the bimorph element.

Barcelos Sergio

Papers

Optical device for compensating the dispersion of optical signals