Abstract: A laser apparatus wherein a gain medium and an optical output assembly are mounted on a common, thermally conductive substrate which provides selective thermal control of the gain medium and output components on the substrate while avoiding unnecessary thermal control of other laser components, and methods for selectively cooling a gain medium and output components of a laser apparatus.

Abstract: External cavity lasers apparatus and methods that allow fast tuning, high wavelength stability, low cavity losses, and form factors that are comparable to solid state, fixed wavelength lasers. The apparatus comprise a gain medium emitting a light beam, a tunable wavelength selection element positioned in the light beam and configured feed back light of a selected wavelength to the gain medium, and a microelectromechanical systems (MEMS) actuator element operatively coupled to the tunable wavelength selection element. The MEMS actuator element may be configured to actuate the tunable wavelength selection element according to a first degree of freedom to select the wavelength of the feedback to the gain medium, and to actuate the actuate the tunable wavelength selection element according to a second degree of freedom to provide phase control of the feedback.

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 servo technique for concurrently providing wavelength locking and stimulated Brillouin scattering (SBS) suppression in an external cavity laser. Respective wavelength locking and SBS suppression signals are generated by a controller and combined into a composite drive signal. The composite drive signal is used to drive an optical path length adjustment element to modulate the optical path length of the laser cavity. The wavelength locking and SBS suppression portions of the drive signals produce concurrent modulations of the laser optical path length having different modulation frequencies and causing different frequency (wavelength) excursions. These modulations produce corresponding wavelength and intensity amplitude modulations in the laser's output. A feedback signal indicative of the intensity amplitude modulations is filtered to attenuate the portion of the signal due to the SBS suppression modulation, and is received as a tuning feedback signal by the controller.

Abstract: A laser having a grid generator that is configured such that the grid transmission peaks can be changed or varied during laser operation. The grid generator is tunable between at least two different, selectable grid spacings. The laser may be of various configurations, and may be a tunable external cavity laser having a channel selector in the external cavity. The laser may further comprise a tuner or tuning assembly operatively coupled to the grid generator and configured to adjust the grid generator to the selectable communication grids.

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: 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: External cavity lasers apparatus and methods that allow fast tuning, high wavelength stability, low cavity losses, and form factors that are comparable to solid state, fixed wavelength lasers. The apparatus comprise a gain medium emitting a light beam, a tunable wavelength selection element positioned in the light beam and configured feed back light of a selected wavelength to the gain medium, and a microelectromechanical systems (MEMS) actuator element operatively coupled to the tunable wavelength selection element. The MEMS actuator element may be configured to actuate the tunable wavelength selection element according to a first degree of freedom to select the wavelength of the feedback to the gain medium, and to actuate the actuate the tunable wavelength selection element according to a second degree of freedom to provide phase control of the feedback.

Abstract: An external cavity laser apparatus and method wherein wavelength or channel selection is carried independently from adjustment of external cavity optical path length. The apparatus comprises a wavelength or channel selector tuner and an external cavity tuner, wherein the wavelength tuner is uncoupled from the external cavity tuner. The tuning mechanisms for wavelength selection and cavity optical path length are configured to operate independently or orthogonally with respect to each other. The wavelength tuner may operate according to a first, channel selection signal, while the external cavity tuner operates according to a second, external cavity adjustment signal. The wavelength tuner and external cavity tuner may operate under the control of the same, or of separate controllers.

Abstract: A laser apparatus wherein a gain medium and an optical output assembly are mounted on a common, thermally conductive substrate which provides selective thermal control of the gain medium and output components on the substrate while avoiding unnecessary thermal control of other laser components, and methods for selectively cooling a gain medium and output components of a laser apparatus.

Abstract: Apparatus and methods that utilize dual, tunable elements to provide for selective wavelength tuning of a light beam. The apparatus comprises a first tunable wavelength selection element positioned in a light beam and having a first adjustable free spectral range, a second tunable wavelength selection element positioned in the light beam and having a second adjustable free spectral range, with the first and second tunable wavelength selection elements configured to define a joint transmission peak that is adjustable in phase according to tuning of the first and second tunable wavelength selection elements.

Abstract: An error signal generation system and method for continuous and accurate positioning of a tunable element used in association with a coherent light source. A tunable element is positioned in a coherent light beam with a fixed frequency or wavelength, and a detector is positioned in association with the light beam and tunable element that is capable of generating an error signal indicative of spatial losses associated with the positioning of the tunable element in the light beam. A tuning assembly is operatively coupled to the tunable element and detector and is configured to position the tunable element according to the error signal generated by the detector.

Abstract: A method for holographic data storage comprises the step of formatting a page with calibration marks as well as data patterns representing data. The page is then stored in a holographic storage medium. A method for holographic data retrieval comprises the step of detecting locations of the calibration marks. A mathematical function is fitted to the locations, and the function is used to compensate for distortion in the detected image of the page. In the preferred embodiment, the calibration marks are also used to generate an inverse point spread function that is used to digitally sharpen the detected image of the page. In the preferred embodiment, the data patterns are dispersed throughout the page by an interleaving algorithm, so that subsequent data patterns are not stored consecutively in the page.

Abstract: A holographic center high mounted stop light (CHMSL) employing a linear lamp source comprising a long and narrow cylindrical gas discharge bulb, a non-imaging light concentrator cavity, a plastic light guide and a hologram. The CHMSL is characterized by previously unattainable compactness, weight savings, rear occupant headroom, driver rearward visibility, and electrical efficiency.