Abstract: A system and a method for detecting the existence of a target substance, the system includes a laser with a broad spectral output and a detector for detecting an absorption spectrum of a laser beam from the laser. The method includes emitting a laser beam into the atmosphere using a laser light with a broad spectral output; measuring the absorption spectrum of said laser beam; comparing the absorption spectrum to known absorption spectrums for target substances using a detector; and detecting the existence of a target substance.

Abstract: A system and a method for detecting the existence of a target substance, the system includes a laser with a broad spectral output and a detector for detecting an absorption spectrum of a laser beam from the laser. The method includes emitting a laser beam into the atmosphere using a laser light with a broad spectral output; measuring the absorption spectrum of said laser beam; comparing the absorption spectrum to known absorption spectrums for target substances using a detector; and detecting the existence of a target substance.

Abstract: A transmitter for optical communication systems includes a source of optical radiation, a source of complex non-information signals, and a modulator unit in communication with the source of optical radiation. The modulator unit is also in communication with the source of complex non-information signals. The modulator has an input adapted to receive information-bearing signals.

Abstract: A wavelength tunable filter for optical communication systems has an optical fiber containing a Bragg grating disposed within a compliant support block. A length of the fiber is wrapped in a spiral of fixed pitch around the longitudinal axis of a cylindrical polymer support block. The support block is placed within a support frame to which a micrometer screw assembly is attached and oriented to apply a variable mechanical load substantially parallel to the longitudinal axis of the cylindrical support block. Application of the load introduces a strain on the support block, changing the period of the refractive index in the fiber Bragg grating with a resulting shift in the Bragg reflection peak.

Abstract: A wavelength tunable filter for optical communication systems has an optical fiber containing a Bragg grating disposed within a compliant support block. A length of the fiber is wrapped in a spiral of fixed pitch around the longitudinal axis of a cylindrical polymer support block. The support block is placed within a support frame to which a micrometer screw assembly is attached and oriented to apply a variable mechanical load substantially parallel to the longitudinal axis of the cylindrical support block. Application of the load introduces a strain on the support block, changing the period of the refractive index in the fiber Bragg grating with a resulting shift in the Bragg reflection peak.

Abstract: A wavelength tunable filter for optical communication systems has an optical fiber containing a Bragg grating disposed within a compliant support block. A length of the fiber is wrapped in a spiral of fixed pitch around the longitudinal axis of a cylindrical polymer support block. The support block is placed within a support frame to which a micrometer screw assembly is attached and oriented to apply a variable mechanical load substantially parallel to the longitudinal axis of the cylindrical support block. Application of the load introduces a strain on the support block, changing the period of the refractive index in the fiber Bragg grating with a resulting shift in the Bragg reflection peak.

Abstract: An arrangement is provided for switching and routing large bandwidth continuous information from a consolidated information distribution center (CIDC). The CIDC generates an optical signal encoded with information of multiple channels carried by one or more dedicated optical carriers and sends the optical signal to a plurality of head ends via an optical fiber. When a head end receives the optical signal, it decodes the optical signal to obtain information intended for the head end from at least one optical carrier that is dedicated to carry the information desired by the head end.

Abstract: A transmitter for optical communication systems includes a source of optical radiation, a source of complex non-information signals, and a modulator unit in communication with the source of optical radiation. The modulator unit is also in communication with the source of complex non-information signals. The modulator has an input adapted to receive information-bearing signals.

Abstract: An arrangement is provided for consolidating equipment, services, and information and for distributing information from a consolidated information distribution center (CIDC) to a plurality of head ends using spectrally efficient transport. The CIDC generates an optical signal encoded with information of multiple channels aggregated through a multi-level encoding scheme and sends the optical signal to a plurality of head ends via an optical fiber. When a head end receives the optical signal, it decodes the optical signal in multiple stages to produce information of multiple data streams, from which desired data streams are selected.

Abstract: An image rejecting microwave photonic downconverter uses a microwave sub-carrier modulation technique without concern for image frequency interference in the shifted signal, thereby allowing telecommunications systems to downconvert densely multiplexed communications channels into a low frequency band where conventionqal electronics can perform signal-processing functions. The image rejecting microwave photonic downconveter incoming microwave signals can be processed without ambiguity in direction finding applications, allowing remotable, multioctave microwave signal processing for frequency and phase determination.

Abstract: A circuit for selectably generating a plurality of preselected digital output signals which are precise and accurate, and among which the circuit can switch rapidly. In one embodiment, the outputs are connected to analog circuit signals, and drive a optical laser such that choice of the particular outputs of the circuit permits controllable switching of the laser output wavelength.

Abstract: This is a technique using a fiber-optic, wideband array antenna beamformer having cascaded, chirped fiber gratings in a distributed architecture based upon the use of cascaded, fiber-optic, chirped Bragg gratings in a distributed architecture for use in wideband, time-steered array antennas. A wavelength tunable laser serves as a carrier for a microwave signal which is modulated upon it. The signal is corporately distributed to each feed of the array. Each feed then traverses a multi-port optical circulator and is reflected off a number of identical, chirped fiber gratings proportional to their position within the array. The signal is then demodulated and fed to the appropriate antenna element. All gratings are identical with the same length and dispersion (ps/nm). Time-steering is accomplished by tuning the laser wavelength such that the effective reflection point in an individual grating is changed due to the chirped nature of the grating.