Abstract: There is provided a method and apparatus for optically filtering a communication signal. More specifically, in one embodiment, there is provided an apparatus comprising an optical filter having first and second input ports and first and second output ports, the optical filter being configured to transmit light in a target frequency range to the first output port in response to receiving light at the first input port and being configured to transmit light in the target frequency range to the second input port in response to receiving light at the second output port, and first and second photodiodes, the first diode being located to be illuminated by light from the first output port and the second photodiode being located to be illuminated by light from the second input port.

Abstract: The trailing edge region of a nozzle airfoil is provided with a cooling configuration wherein post-impingement cooling air flows between radially spaced ribs defining convective cooling channels into a generally radially extending plenum. Cooling air in the plenum is split between film cooling holes for film cooling the pressure side of the trailing edge region and for flow about downstream pins for pin cooling the downstream regions of the opposite sides of the airfoil. The cooling air exiting the pins is directed through convective channels defined by a second set of radially spaced ribs and through exit apertures on the pressure side of the trailing edge.

Abstract: A device and method for processing a signal e.g. equalizing a signal, is disclosed. Such processing involves dividing a signal into two portions that each traverses a wavepath and then are combined. The respective wavepaths impose a non-linear frequency-versus-phase dependency on a signal portion. The frequency-versus-phase dependencies that characterize the respective wavepaths are similar in shape but inverted from each other. A processed signal has significantly improved signal-to-noise ratio.

Abstract: A semiconductor waveguide includes a section containing free charge, either electrons or holes, which can be steered into or removed from the path of the beam under the control of electrical signals. The mobile charges come from a potential well which may be either filled or depleted under electrical control. When the well is filled, the charges speed the beam propagation, introducing a phase change. When the well is emptied the beam propagates with extra delay. The phase shifter allows very high speed modulation of the beam using low voltage and low power electronics. The device can be created using standard silicon processing techniques, and integrated with other optical components such as splitters and combiners to create amplitude modulators, attenuators and other optical devices.

Abstract: A turbine nozzle includes airfoil and sidewall surfaces. The airfoil and sidewall surfaces have profiles substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in Tables I–IV for the pressure and suction sides of the airfoil, and the outer and inner sidewall surfaces, respectively. The X, Y and Z values are distances in inches. The X and Y values for the airfoil, when connected by smooth continuing arcs, define airfoil profile sections at each distance Z. The profile sections at the Z distances are joined smoothly with one another to form a complete airfoil shape. The X, Y and Z values of Tables III and IV define the outer and inner sidewall surfaces, respectively, of the gas flowpath.

Abstract: A method and apparatus for transmission of optical signals across an optical transmission link wherein duobinary signals or inverse-data signals are transmitted when the chromatic dispersion of the transmission link is above or below a dispersion threshold, respectively, to significantly improve optical signal transmission performance.

Abstract: Various apparatus and methods for generating a 90° AP optical pulsetrain. In one embodiment, the apparatus includes: (1) a phase-modulated optical signal generator configured to generate a phase-modulated optical signal having a carrier band and sidebands phase-shifted relative thereto by multiples of 90° and (2) an optical filter coupled to the phase-modulated optical signal generator and configured to 180° phase-shift selected ones of the carrier band and sidebands to generate the 90° AP optical pulsetrain.

Abstract: An optical modulator is overdriven to increase its nonlinearity and therefore improve its response as it pertains to differential phase shift keyed (DPSK) transmission and a method of operating the same. In one embodiment, the MZM includes an MZM drive circuit coupled to the electrodes and configured to deliver to the electrode a DPSK drive signal bearing digital data and having a voltage that exceeds a normal drive voltage of the MZM by at least about 20%.

Abstract: An optical differential phase shift key (DPSK) receiver, a method of demodulating an optical DPSK modulated signal and an optical processor capable of operating as either a DPSK receiver or DPSK transmitter. In one embodiment, the DPSK receiver includes: (1) an optical waveguide and a delay line associated therewith configured to receive simultaneously an optical DPSK modulated signal, (2) a coupler having at least two inputs and at least four outputs, the at least two inputs configured to terminate the optical waveguide and the delay line, the delay line having a path length difference that delays the optical DPSK modulated signal by at least one timeslot relative to the optical waveguide and (3) photodetectors associated with the at least four outputs and configured to provide signals indicative of digital data contained in components of the optical DPSK modulated signal.

Abstract: Apparatus for creating a communication signal, comprising a modulator adapted to: modulate a first and a second beam of continuous wave electromagnetic radiation with a source signal, assemble modulated portions of the first and second beams into a first electromagnetic radiation signal of interposed regular and alternate data bit sequences comprising asserted non return to zero coded data bits, each of the data bit sequences being interposed by unasserted data bits, in which mutually adjacent asserted data bits are conjoined, and assemble modulated portions of the first and second beams into a second electromagnetic radiation signal of interposed regular and alternate data bar bit sequences comprising asserted non return to zero coded data bar bits representing the unasserted data bits, each of the data bar bit sequences being interposed by unasserted data bar bits representing the asserted data bits, in which mutually adjacent asserted data bar bits are conjoined.

Abstract: A structure of two interlocking members, such as two planks, comprises a first member having a pair of first rectilinear location edges and a second member having a pair of second rectilinear location edges, each first location edge comprising a pair of elongate flange formations which define therebetween an elongate recess and each second location edge having a tongue formation to engage in a respective recess of a first member by relative angular movement of the members, each flange formation of a first member comprising a longitudinally extending undercut zone and each tongue formation of each second member comprising a protrusion which is received in an undercut zone of one of the flange formations in an assembled condition of the members.