Abstract: A laser apparatus and method that uses active thermalization of a reflective element to minimize losses and provide wavelength stability. The laser comprises first and second reflectors defining an external cavity, and a compensating member coupled to at least one of the reflectors and configured to thermally position one reflector with respect to the other reflector. The compensating member may be coupled directly to the first reflector and configured to position first reflector with respect to said second reflector. The thermal positioning may be carried out by a thermoelectric controller operatively coupled to the compensating member and configured to thermally adjust the compensating member by heating or cooling thereof. The laser apparatus may comprise a gain medium having first and second output facets and emitting a coherent beam from the first output facet along an optical path.

Abstract: A micromachined pellicle beam splitter and method of manufacture thereof are disclosed. In one embodiment, the beam splitter includes a silicon frame with a silicon nitride membrane attached to the frame and covering an opening through the frame. Other materials may be utilized, however, the coefficient of thermal expansion (CTE) of the membrane should be greater than that of the frame. The beam splitter may be manufactured by coating a silicon substrate with a layer of silicon nitride, patterning an opposite side of the silicon substrate with a photoresist or a metallic layer to define an opening an etching an opening through the substrate to the silicon nitride with either a dry etch or wet etch technique. An improved tunable laser module incorporating the micromachined pellicle beam splitter and a method of tuning a laser diode are also disclosed.

Abstract: Anti-reflective coatings may be used on laser high index gain media to mitigate reflection. An absentee layer may be used to compliment the antireflective coating to improve its antireflective performance over a broader range of wavelengths. The absentee layer comprises a material having a higher index of refraction than that of the gain media and has a thickness corresponding to multiple halfwave thicknesses related to the center wavelength output by the laser.

Abstract: In embodiments of the invention, a wavelength-selective device is doped with n-type or p-type material to make the single-crystal silicon in the active region of the device electrically conductive. An electrically conductive and thermally conductive active region allows an external heater such as a platinum heater strip to be eliminated and current to be applied directly to the single-crystal silicon to thermally tune the laser.

Abstract: Methods and apparatus for optimizing feedback suppression of optical isolators when used with variable wavelength light sources. The methods comprise positioning an optical isolator in a light beam, and adjusting feedback suppression by the optical isolator according to wavelength of the light beam. Adjusting the feedback suppression may comprise adjusting temperature of the optical isolator or a non-reciprocal rotator associated with the isolator.

Abstract: A micromachined pellicle beam splitter and method of manufacture thereof are disclosed. In one embodiment, the beam splitter includes a silicon frame with a silicon nitride membrane attached to the frame and covering an opening through the frame. Other materials may be utilized, however, the coefficient of thermal expansion (CTE) of the membrane should be greater than that of the frame. The beam splitter may be manufactured by coating a silicon substrate with a layer of silicon nitride, patterning an opposite side of the silicon substrate with a photoresist or a metallic layer to define an opening an etching an opening through the substrate to the silicon nitride with either a dry etch or wet etch technique. An improved tunable laser module incorporating the micromachined pellicle beam splitter and a method of tuning a laser diode are also disclosed.

Abstract: A laser apparatus wherein all optical components are mounted on a unitary, rigid base. Natural frequency modes of the apparatus are above about 2 kHz. Tuning elements in the apparatus may have natural frequencies greater than about 10 kHz.

Abstract: Systems and methods for probing or evaluating optical loss characteristics associated with lasers by monitoring voltage across a laser gain medium, and a laser and method of laser operation wherein intra-cavity losses are determined by monitoring voltage across a gain medium and wherein the cavity loss profile is adjusted according to the voltage across the gain medium.

Abstract: Laser apparatus and methods that use active thermal adjustment of an external laser cavity to minimize losses and provide wavelength stability and provide wavelength tuning. The apparatus comprise a thermally conductive platform, a gain medium thermally coupled to the platform, the gain medium having a first facet emitting a first light beam from the first facet, and a reflective element positioned in the first light beam and coupled to the platform, the reflective element and the second facet defining an external laser cavity. The reflective element is mounted on the platform and may be thermally coupled to the platform. Selective thermal control of the external cavity optical path length during laser operation is provided by heating and cooling of the thermally conductive platform.

Abstract: A laser apparatus in a hermetically sealed container and methods for hermetically sealing the laser. The laser apparatus comprising an external cavity laser and a modulator in a single hermetically sealed enclosure.

Abstract: A quasi-monochromatic light beam carrier for a particular telecommunication channel is likely to experience drift because of age, temperature, or other factors, and may cause the centroid wavelength of the carrier to shift. Temperature adjustments by wavelength lockers to compensate for drift on one channel may affect the performance of other channels. Embodiments of the present invention couple a quasi-monochromatic light beam through a substrate-based grating, diffract the light beam from the edge of the substrate to free space, and detect the light beam from free space at a position detector to determine the centroid wavelength based on a position of the light beam incident on the detector. The diffracted light beam may be reflected within the substrate a number of times prior to exiting the substrate towards the detector.

Abstract: A laser employing a tapered, thin film interference filter as a tuning element. Tapered, thin film interference filters employing dielectric layers are disclosed for use in tuning lasers. Methods of tuning a laser by adjustably positioning a tapered thin film interference filter are disclosed. Also included are a method for tuning a laser to account for thermal wavelength drift, a method of mounting an etalon in a substantially stress free manner, and a mount therefor.

Abstract: Methods and apparatus for optimizing feedback suppression of optical isolators when used with variable wavelength light sources. The methods comprise positioning an optical isolator in a light beam, and adjusting feedback suppression by the optical isolator according to wavelength of the light beam. Adjusting the feedback suppression may comprise adjusting temperature of the optical isolator or a non-reciprocal rotator associated with the isolator.

Abstract: Laser apparatus and methods that use active thermal adjustment of an external laser cavity to minimize losses and provide wavelength stability and provide wavelength tuning. The apparatus comprise a thermally conductive platform, a gain medium thermally coupled to the platform, the gain medium having a first facet emitting a first light beam from the first facet, and a reflective element positioned in the first light beam and coupled to the platform, the reflective element and the second facet defining an external laser cavity. The reflective element is mounted on the platform and may be thermally coupled to the platform. Selective thermal control of the external cavity optical path length during laser operation is provided by heating and cooling of the thermally conductive platform.

Abstract: A method for selecting free spectral ranges (FSR) of intra-cavity optics to optimize reliability of the channel switching mechanism and corresponding apparatus. In particular, the optimal relationship between the FSR of the internal etalon and the FSR of the laser cavity is derived. For the external cavity diode lasers (ECDL) the optimal relationship between the FSR of the internal etalon and the FSR of the gain chip is also derived. Equations are derived for selecting free spectral ranges of various optical cavities so as to create a locally commensurate condition under which the relative position of the lasing mode with respect to the transmission peak of the laser's tunable filter (e.g., etalon plus channel selector) does not change when the laser hops between adjacent channels.

Abstract: Method and apparatus for producing a laser output having stimulated Brillouin scattering (SBS) suppression characteristics. An excitation signal is provided to an optical path length adjustment element in an external cavity laser to modulate the optical path length of the cavity. This produces a laser output having a wavelength modulation frequency and line width that are a function of the frequency and amplitude of the excitation signal. Under appropriate modulation frequency and line width combinations, the laser output comprises an optical signal with SBS suppression characteristics, thus enabling a higher power signal to be launched into a fiber link since the SBS suppression characteristics raise the SBS threshold of the link. The optical path length modulation also produces an intensity (amplitude) modulation in the laser output. A detector is employed to produce a feedback signal indicative of the intensity modulation that is used for tuning the laser in accordance with a wavelength locking servo loop.

Abstract: A laser apparatus and method that uses active thermalization of a reflective element to minimize losses and provide wavelength stability. The laser comprises first and second reflectors defining an external cavity, and a compensating member coupled to at least one of the reflectors and configured to thermally position one reflector with respect to the other reflector. The compensating member may be coupled directly to the first reflector and configured to position first reflector with respect to said second reflector. The thermal positioning may be carried out by a thermoelectric controller operatively coupled to the compensating member and configured to thermally adjust the compensating member by heating or cooling thereof. The laser apparatus may comprise a gain medium having first and second output facets and emitting a coherent beam from the first output facet along an optical path.

Abstract: A system for providing wireless telecommunications access is presented. The system includes a wireline assembly that provides access to a telecommunications system for one or more wireline subscribers. The system also includes a wireless assembly that provides access to a telecommunications system for one or more wireless subscribers. A common control and switching system is connected to the wireline assembly, the wireless assembly, and a switched network. The common control and switching assembly establishes telecommunications channels between the wireline assembly, the wireless assembly, and the switched network, and controls the telecommunications channels.

Abstract: Apparatus and methods usable for wavelength references and measurement of wavelength of a light beam. The apparatus comprise at least two wavelength reference or filter elements positioned in a light beam, each wavelength reference element having a different free spectral range and operable to define a joint free spectral range, and a detector positioned in the beam after the wavelength reference elements. The joint free spectral range provided by the multiple wavelength reference elements results in a joint transmission peak that is centered at a unique wavelength, and maximum optical power detectable from the beam by the detector occurs at the center wavelength of the joint transmission peak.

Abstract: A laser employing a tapered, thin film interference filter as a tuning element. Tapered, thin film interference filters employing dielectric layers are disclosed for use in tuning lasers. Methods of tuning a laser by adjustably positioning a tapered thin film interference filter are disclosed. Also included are a method for tuning a laser to account or thermal wavelength drift, a method of mounting an etalon in a substantially stress free manner, and a mount therefor.