Abstract: A compact dual-wavelength Raman probe using two laser sources each providing Raman excitation light at a different wavelength is disclosed causing Raman scattering in a fingerprint region associated with one excitation wavelength and causing Raman scattering in a stretch region, which are detected by the same detector array.

Abstract: A hybrid external cavity laser and a method for configuring the laser having a stabilized wavelength is disclosed. The laser comprises a semiconductor gain section and a volume Bragg grating, wherein a laser emission from the semiconductor gain section is based on a combination of a reflectivity of a front facet of the semiconductor gain section and a reflectivity of the volume Bragg grating and the reflectivity of the semiconductor gain section and the volume Brag grating are insufficient by themselves to support the laser emission. The hybrid cavity laser further comprises an etalon that provides further wavelength stability.

Abstract: A hybrid external cavity laser and a method for configuring the laser having a stabilized wavelength is disclosed. The laser comprises a semiconductor gain section and a volume Bragg grating, wherein a laser emission from the semiconductor gain section is based on a combination of a reflectivity of a front facet of the semiconductor gain section and a reflectivity of the volume Bragg grating and the reflectivity of the semiconductor gain section and the volume Bragg grating are insufficient by themselves to support the laser emission. The hybrid cavity laser further comprises an etalon that provides further wavelength stability.

Abstract: A hybrid external cavity laser and a method for configuring the laser having a stabilized wavelength are disclosed. The laser comprises a semiconductor gain section and a volume Bragg grating, wherein a laser emission from the semiconductor gain section is based on a combination of a reflectivity of a front facet of the semiconductor gain section and a reflectivity of the volume Bragg grating and the reflectivity of the semiconductor gain section and the volume Bragg grating are insufficient by themselves to support the laser emission. The hybrid cavity laser further comprises an etalon that provides further wavelength stability.

Abstract: A hybrid external cavity laser and a method for configuring the laser having a stabilized wavelength is disclosed. The laser comprises a semiconductor gain section and a volume Bragg grating, wherein a laser emission from the semiconductor gain section is based on a combination of a reflectivity of a front facet of the semiconductor gain section and a reflectivity of the volume Bragg grating and the reflectivity of the semiconductor gain section and the volume Bragg grating are insufficient by themselves to support the laser emission. The hybrid cavity laser further comprises an etalon that provides further wavelength stability.

Abstract: A compact Raman probe integrated with a wavelength-stabilized laser source is disclosed. The output beam of the laser source has an elongated cross-section that is focused onto a target of interest. Raman and Rayleigh scattered light is collected, collimated, and filtered by free-space optics to form a beam that is coupled to the input of a multimode optical fiber having an elongated core that is aligned to edge slits of an optical spectrometer.

Abstract: A hybrid external cavity laser (HECL) system comprises a diode laser, collection and collimation optics, and a volume Bragg grating, emits radiation at a single wavelength with a short-term wavelength stability in the order of at least one part in a billion The wavelength stability is achieved by use of a thermal management system, comprising inner and outer housings, each containing a temperature sensor, and electronic circuitry that monitors the temperatures and controls both the laser diode current and a thermoelectric cooler based on temperatures determined from said temperature sensors. The laser system is packaged in a compact enclosure that minimizes waste heat, facilitating use in applications that have heretofore employed stable, single-frequency lasers, including He—Ne lasers.

Abstract: A hybrid external cavity laser and a method for configuring the laser having a stabilized wavelength is disclosed. The laser comprises a semiconductor gain section and a volume Bragg grating, wherein a laser emission from the semiconductor gain section is based on a combination of a reflectivity of a front facet of the semiconductor gain section and a reflectivity of the volume Bragg grating and the reflectivity of the semiconductor gain section and the volume Bragg grating are insufficient by themselves to support the laser emission. The hybrid cavity laser further comprises an etalon that provides further wavelength stability.

Abstract: A hybrid external cavity laser and a method for configuring the laser having a stabilized wavelength is disclosed. The laser comprises a semiconductor gain section and a volume Bragg grating, wherein a laser emission from the semiconductor gain section is based on a combination of a reflectivity of a front facet of the semiconductor gain section and a reflectivity of the volume Bragg grating and the reflectivity of the semiconductor gain section and the volume Bragg grating are insufficient by themselves to support the laser emission. The hybrid cavity laser further comprises an etalon that provides further wavelength stability.

Abstract: Disclosed are systems and methods for using a semiconductor optical amplifier (SOA) as an optical modulator for pulsed signals. In accordance with the principles of the invention, the SOA can be biased with a negative voltage to suppress transmission and improve modulator extinction and biased with a positive pulsed signal with sufficient amplitude to forward bias the amplifier (SOA), both transmitting the carrier and increasing its amplitude by means of a gain provided by the SOA under forward biased conditions. In addition, the forward bias voltage may be selected to compensate for losses within the SOA.

Abstract: Disclosed are systems and methods for using a semiconductor optical amplifier (SOA) as an optical modulator for pulsed signals. In accordance with the principles of the invention, the SOA can be biased with a negative voltage to suppress transmission and improve modulator extinction and biased with a positive pulsed signal with sufficient amplitude to forward bias the amplifier (SOA), both transmitting the carrier and increasing its amplitude by means of a gain provided by the SOA under forward biased conditions. In addition, the forward bias voltage may be selected to compensate for losses within the SOA.

Abstract: A hybrid external cavity laser (HECL) system comprises a diode laser, collection and collimation optics, and a volume Bragg grating, emits radiation at a single wavelength with a short-term wavelength stability in the order of at least one part in a billion The wavelength stability is achieved by use of a thermal management system, comprising inner and outer housings, each containing a temperature sensor, and electronic circuitry that monitors the temperatures and controls both the laser diode current and a thermoelectric cooler based on temperatures determined from said temperature sensors. The laser system is packaged in a compact enclosure that minimizes waste heat, facilitating use in applications that have heretofore employed stable, single-frequency lasers, including He—Ne lasers.

Abstract: A semiconductor laser diode and method are described, wherein the path of the current through the device between the positive and negative conductors is controlled. Lateral spread of the gain current in the active region is prevented by implanting protons in areas of the active layer flanking a desired gain region. The implanted regions become less conductive, and prevent lateral spread of the gain current. The position of the implanted regions can be selected so that the gain current only crosses a portion of the active layer that supports desired lateral modes of the laser light.

Abstract: A semiconductor laser diode and method are described, wherein the path of the current through the device between the positive and negative conductors is controlled. Lateral spread of the gain current in the active region is prevented by implanting protons in areas of the active layer flanking a desired gain region. The implanted regions become less conductive, and prevent lateral spread of the gain current. The position of the implanted regions can be selected so that the gain current only crosses a portion of the active layer that supports desired lateral modes of the laser light.

Abstract: A semiconductor laser diode and method are described, wherein the path of the current through the device between the positive and negative conductors is controlled. Lateral spread of the gain current in the active region is prevented by implanting protons in areas of the active layer flanking a desired gain region. The implanted regions become less conductive, and prevent lateral spread of the gain current. The position of the implanted regions can be selected so that the gain current only crosses a portion of the active layer that supports desired lateral modes of the laser light.

Abstract: A closed-loop ring resonator including a closed loop formed on a substrate and including at least one coupling region having a first effective depth and at least one other region having a second effective depth, wherein the first and second depths are different.

Abstract: A closed-loop ring resonator including a closed loop formed on a substrate and including at least one coupling region having a first effective depth and at least one other region having a second effective depth, wherein the first and second depths are different.

Abstract: A distributed-feed back semiconductor laser diode comprises a substrate of n-type conductivity GaAs having a pair of opposed surfaces, a pair of sides and a pair of ends. In sequence on one of the opposed surfaces are a first clad layer of n-type conductivity graded AlGaAs; a first confining layer of undoped AlGaAs; a first quantum well layer of undoped GaAs; a barrier layer of undoped AlGaAs; a second quantum well layer of undoped GaAs; a second confining layer of undoped AlGaAs; a spacer layer of p-type conductivity graded AlGaAs; a plurality of spaced, parallel grating bars of p-type conductivity AlGaAs extending across the spacer layer parallel to the ends of the substrate; a second clad layer of p-type conductivity graded AlGaAs over and between the grating bars; and contact layer of p+ type conductivity GaAs. A first conductive contact layer contacts the contact layer and a second conductive contact layer is on the other opposed surface of the substrate.

Abstract: A chip package for an IC chip having at least an optical-signal input or output section comprises a container-like chip carrier for carrying the IC chip, a sealing cover bonded to the chip carrier and having a window for the optical-signal section, and a connector plate holding a plurality of optical signal transmission elements which are used to transmit a plurality of optical signals en bloc so that optical signals are input to or output from the optical-signal section through the window on the cover. The chip carrier and the connector plate are securely attached to a circuit board in the state where the connector plate has been separately positioned in a predetermined spatial relationship with the chip carrier.

Abstract: A distributed feedback semiconductor diode laser includes a substrate of n-type gallium arsenide having a channel along one surface thereof. A first clad layer of n-type aluminum gallium arsenide is on the surface of the substrate. The first clad layer fills the channel and has a planar surface. An active layer of undoped aluminum gallium arsenide is on the first clad layer and a first spacer layer of p-type conductivity aluminum gallium arsenide is on the active layer. A grating layer of p-type conductivity aluminum gallium arsenide is on the first spacer layer and has a second order grating therein which extends across the channel in the substrate. A second spacer layer of p-type conductivity aluminum gallium arsenide is on the grating layer and a second clad layer of p-type conductivity aluminum gallium arsenide is on the second spacer layer.