Abstract: An optically end-pumped amplifier with a plate-shaped optical gain medium has a plurality of pump laser units for optically pumping the gain medium through at least one of the narrow side surfaces thereof. The pump laser units are designed such that the pump laser radiation, upon passing through the gain medium, has an elongated beam cross section having a short axis and a long axis running parallel to the main surfaces of the gain medium and propagates freely through the gain medium with respect to the short axis. They are arranged such that in each case the principal axes of the beam bundles of the pump laser units impinge on one of the pumped side surfaces in a plane perpendicular to the short axis at an angle to one another, wherein the beam cross sections of the beam bundles are superimposed on one another.

Abstract: A method for optical dark section conditioning includes determining a section in an optical network is a dark section that includes connected fiber spans that are functional with no traffic carrying channels present thereon; and causing generation of at least one of broadband noise and a signal at a head end of the dark section. An apparatus configured to perform optical dark section conditioning includes logic configured to determine a section in an optical network is a dark section that includes connected fiber spans that are functional with no traffic carrying channels present thereon; and logic configured to cause generation of at least one of broadband noise and a signal at a head end of the dark section.

Abstract: Method and apparatus for beam coupling.

Abstract: The invention relates to optical system including light sources that amplify light using a gain medium. Systems and method of the invention are provided for amplifying light while inhibiting reflections at a peak gain of the gain medium, thereby suppressing parasitic lasing. This allows a system to use a broad range of wavelengths without parasitic lasing, thereby increasing the useable range of a tunable optical filter. In this manner, light at wavelengths not at a peak gain can be used effectively, and the gain medium of an optical amplifier does not limit use of a system to a narrow range of wavelengths associated with a peak gain of the gain medium. A single optical system according to the invention can thus be used for applications that require a broad range of wavelengths.

Abstract: An optical comb generator for generating multiple optical wavelengths from a single source simultaneously for many optical channels on a semiconductor substrate. The comb generator provides narrow channel spacing using chirped Bragg grating with uniformly spaced grating pitches but with tapered waveguide to facilitate the fabrication process and generate laser comb channels with uniform line widths across all channels. The laser comb generator facilitates monolithic integration of many photonic integrated circuit elements.

Abstract: The adjustment of tilt in an optical signal path of a repeater. The repeater includes an optical pump that optically powers a rare-Earth doped fiber amplifier, which amplifies the optical signal. The optical signal path also includes Raman gain stage implemented in a previous optical fiber span in the optical signal path, and which contributes tilt with respect to wavelength. Adjusting the Raman gain and/or the rare-Earth doped gain also adjusts the combined tilt contributed by these gain stages. However, the rare-Earth doped gain operates at least partially in the saturated regime, thereby stabilizing the gain at the output of the rare-Earth doped amplifier. Thus tilt control may be employed by adjusting optical pump power with reduced effect on overall gain.

Abstract: A laser pulse amplifier device (100) includes an amplifying cavity (10) comprising an amplifying laser gain medium (11) and multiple cavity mirrors (12.1 to 12.7) spanning a cavity light path (13), wherein the amplifying cavity (10) is configured for an amplification of laser pulses (1) circulating along the cavity light path, and a multi-pass amplifier (20) being optically coupled with the amplifying cavity (10) and comprising multiple deflection mirrors (22) spanning a multipass light path (23), wherein the multi-pass amplifier (20) is configured for a post-amplification of laser pulses (2) coupled out of the amplifying cavity (10), wherein the amplifying cavity (10) and the multi-pass amplifier (20) are arranged such that the laser gain medium (11) of the amplifying cavity (10) is included as an active medium in the multi-pass light path (23) of the multi-pass amplifier (20). Furthermore, a method of amplifying laser pulses is described.

Abstract: Disclosed is a high power ultra-short pulsed laser device increasing pulse energy by using resonators. A pulsed laser device may comprise a first resonator making a pump beam resonate primarily and passing the pump beam which resonated through a first output mirror; and a second resonator comprising a first multiple reflection mirror and a second multiple reflection mirror. Also, the first multiple reflection mirror includes at least one first small area mirror, and the second multiple reflection mirror includes at least one second small area mirror, and the second resonator makes the laser beam delivered from the first resonator resonate by reflecting the laser beam repetitively. Therefore, the pulsed laser device may increase pulse energy without using a multi-stage amplifier so that a high power ultra-short pulsed laser beam can be generated.

Abstract: A mode converter for use with a higher-order mode (HOM)-based fiber amplifiers takes the form of axicon-based configuration that is able to convert high power (tens of mW and higher) optical signals propagating in higher-order mode form into a diffraction-limited beam without experiencing the nonlinear effects (such as self-phase modulation) that are found when using a long-period grating (LPG) to create a diffraction-limited beam by performing mode conversion. The axicon may comprise a bulk optic device, a fiber-based device, or a GRIN-based configuration (where the refractive index profile of the GRIN element is formed to create a diffraction-limited signal).

Abstract: An optical fiber coupler in which damage to a pumping light source can be suppressed even if signal light leaks and an optical fiber amplifier using the optical fiber coupler are provided. An optical fiber coupler includes: a first optical fiber having a core and a clad coating the core; a second optical fiber having a core; and a fusion-drawn portion formed by arranging the first optical fiber and the second optical fiber so that their longitudinal directions are in the same direction and fusing the clad of the first optical fiber and the core of the second optical fiber. The clad of the first optical fiber has a larger refractive index than the core of the second optical fiber.

Abstract: An optical amplifier with network optimization techniques maximizes performance of a conventional optical amplifier with minimum user intervention. A circulator enables as much light as possible just below a stimulated Brillouin scattering threshold to be launched in to an optical fiber. An amount of reflected power directed by a circulator to a photo diode has a direct correlation to the quality of the received signal in a communications system.

Abstract: The present invention relates to a plasmonic optical waveguide using plasmonic coupling between a nano-aperture and a nano-particle. The plasmonic optical waveguide includes the nano-aperture formed with an opening of a nano-scale through which light enters; and a single metal nano-particle arranged at the focal point of the nano-aperture to generate plasmon coupling in association with the light output from the nano-aperture. The plasmonic optical waveguide has an effect of forming a small and strong high-intensity high-density light spot of a sub-wavelength size, in which an amplification rate is increased at the output surface of the nano-particle more than a few hundred times compared with the incident light, since the light is transmitted by plasmon coupling generated between the nano-aperture and the nano-particle.

Abstract: A method for directing a laser pulsed beam towards a selected area/surface of an object, comprising transmitting from a laser assembly that includes an optical transmitter module a pulsed laser beam having a first pulse duration and illuminating therewith an area/surface of the object, thereby obtaining a reflected pulsed laser beam, the reflected pulsed laser beam including a leading portion reflected from a first reflecting area/surface of the object which is the area of the object that defines the shortest optical path between the optical transmitter module, the object and an optical receiver module; receiving, in a second laser assembly that includes the optical receiver module, the reflected pulsed laser beam and converting it into an amplified phase conjugated pulsed beam of a second pulse duration, and transmitting from the second laser assembly the amplified phase conjugated pulsed beam and illuminating therewith on selected area/surface of the object.

Abstract: A polarization reducing apparatus includes a separating unit configured to separate input light into components having polarization directions orthogonal to each other; a winding waveguide of silicon formed on a silicon substrate in a winding manner, the winding waveguide transmitting a first component among the components separated by the separating unit; an optical path configured to have a shorter optical path length than the winding waveguide, the optical path transmitting a second component among the components separated by the separating unit; a combining unit configured to combine the first component and the second component; and an output unit configured to output light consisting of the first component and the second component combined by the combining unit.

Abstract: We disclose an optical buffer having a plurality of optical ports. In some embodiments, an optical signal to be stored may be injected into the buffer through any one of the optical ports and then may be ejected from the buffer, after being stored therein for a selectable amount of time, through any one of the optical ports as well. This feature advantageously enables the optical buffer to also function as an optical switch or router. In an example embodiment, the optical buffer comprises two optical recirculation loops, each of which can store the optical signal by causing it to circulate therein. The buffer is configured to compensate optical losses incurred by the optical signal during this circulation by transferring the optical signal from one loop to the other through an optical amplifier. Due to the latter feature, the optical buffer may be able to store an optical signal, with an acceptable OSNR, for a significantly longer time than certain conventional optical buffers.

Abstract: An amplifier may include a plurality of discharge tubes arranged in a designed path of a seed laser beam and an optical system arranged to steer the seed laser beam to travel along the designed path.

Abstract: The invention relates to an optical pumping device comprising: a fibre light source emitting controlled radiation having a very high transverse modal quality, with a wavelength shorter than 1000 nm; at least one element consisting of an amplifying material doped with a rare earth dopant; means for introducing a pumping light into said doped amplifying material element; and means for cooling said amplifying material. Said optical pumping device is characterised in that the pumping light is emitted by the fibre light source with an average power of higher than 2W and a modal quality characterised by an M2<5 factor.

Abstract: A Raman amplifier includes: a pump light generator that provides a plurality of pump light beams with different wavelengths for an optical transmission medium; a gain monitor that monitors an average Raman gain in the optical transmission medium; a storage unit that stores ratio information indicating a ratio of power of the plurality of pump light beams for a specified gain characteristic with respect to an average Raman gain in the optical transmission medium; and a controller that controls the power of the plurality of pump light beams based on the average Raman gain monitored by the gain monitor and the ratio information.

Abstract: A light source assembly (300) for emitting depolarized light, and comprising: at least one light source (312) configured to emit substantially polarized light; and a light depolarizer (318) arranged to receive light from the light source and comprising a high birefringence optical fiber having a longitudinal core and orthogonal birefringent axes having an angular displacement around the core that varies along the length of the fiber, wherein light emitted from the depolarizer comprises a plurality of polarization states.

Abstract: The present invention generally relates to methods and systems for narrowing a wavelength emission of light. In certain aspects, methods of the invention involve transmitting light through a filter and passing a portion of the filtered light through a gain chip assembly at least two times before that portion of light passes again through the filter.