Abstract: An optical transmission device according to the present invention comprises: a Raman amplification means; a main signal light sending means which sends first main signal light; a communication interruption detection light monitoring means which sends a first signal if it cannot detect communication interruption detection light; a main signal light monitoring means which sends a second signal if it cannot detect second main signal light; a light monitoring signal analysis means which sends a result of its analysis of a light monitoring signal as a third signal in a predetermined period of time; and a control means which makes the Raman amplification means suspend the generation of the excitation light, if it cannot receive the third signal even after the elapse of the predetermined period of time in the state it has received the first signal and has not received the second signal, and stops sending of the first main signal light from the main signal light sending means when receiving the second signal further.

Abstract: A system and method for controlling polarization in a fiber amplifier is disclosed. A polarization dither waveform is applied to a polarization controller so that dithering does not trigger PI-HOMI (Polarization-Induced High Order Mode Instability). The dither waveform may have a period that is much less than the thermal diffusion time across the fiber amplifier core. The dither waveform may also have a slew rate (defined in degrees/second on the Poincaré sphere) that is much slower than the thermal diffusion time across the fiber amplifier core.

Abstract: An optical amplifying device includes an optical amplification medium configured to be excited by excitation light and amplify signal light, a light loss detector configured to detect a light loss of an optical component optically connected to the optical amplification medium in the amplifying device, and a noise figure deterioration detector configured to detect, based on the light loss detected by the light loss detector, deterioration of a noise figure of the optical amplification medium.

Abstract: An optical amplification device includes a first optical amplification portion, an intermediate portion and a second optical amplification portion. The first optical amplification portion receives input light including signal light and pump light, generates idler light as wavelength converted light based on wavelengths of the signal light and the pump light, and outputs first output light including signal light, pump light and idler light. The intermediate portion outputs second output light, and includes a demultiplexing portion that demultiplexes the first output light into signal light, pump light and idler light, a multiplexing portion that generates the second output light by multiplexing signal light, pump light and idler light, and a polarization plane adjustment portion that exchanges mutually orthogonal polarization components of idler light. The second optical amplification portion amplifies an intensity of signal light included in the second output light.

Abstract: According to the invention, the optical signal (SE) is spatially divided into N elementary optical signals (SE.1, SE.2, . . . , SE.N), the spectral ranges thereof being adjacent in pairs and forming, substantially by juxtaposition, the spectral range of the optical signal; these N elementary signals are amplified respectively by means of N elementary amplifiers (4.1, 4.2, . . . , 4.N), the spectral ranges thereof respectively comprising the spectral ranges of said N elementary signals; the N amplified elementary signals (Ss.1, Ss.2, . . . , Ss.N) are assembled to form an amplified optical signal (Ss), the spectral range thereof substantially coinciding with a predetermined spectral range, and finally the spectral phases of the N initial elementary signals (Ss.1, Ss.2, . . . , Ss.N) are adjusted before amplification on the basis of the spectral phase of said amplified signal (Ss).

Abstract: A method and apparatus for suppressing pump-mode optical beat interference noise in a Raman amplified fiber link of an optical network, wherein a wavelength of a laser beam generated by a first pump laser and a wavelength of a laser beam generated by a second pump laser of a pair of polarization multiplexed pump lasers are detuned with respect to each other to suppress the optical beat interference, OBI, noise in the Raman amplified fiber link of said optical network.

Abstract: An optical amplifying device includes an optical system including a first end and a second end, the optical system configured to receive signal light through the first end, to lead the received signal light to an optical amplifying medium, and to output the signal light amplified by the optical amplifying medium through the second end, the optical system including a first optical isolator and a second optical isolator which are arranged on respective sides of the optical amplifying medium, wherein with respect to a direction in which the signal light propagates, each of the first optical isolator and the second optical isolator is capable of allowing light propagating in the same direction to pass therethrough and blocking light propagating in the opposite direction, and the first optical isolator and the second optical isolator have different center isolation wavelengths for the light propagating in the opposite direction.

Abstract: An optical device may include: an optical module disposed in a beam delivery path of a laser beam; a beam adjusting unit disposed in the beam delivery path for adjusting the beam delivery path of the laser beam; a measuring unit disposed in the beam delivery path for detecting the beam delivery path; and a control unit for controlling the beam adjusting unit based on a detection result of the beam delivery path of the laser beam detected by the measuring unit.

Abstract: The present invention relates to a system (1) for stabilizing the polarization of an input light beam (2?), including a means (3) for optically guiding the input light beam (2?). In said system, the optical guide means (3) has Kerr nonlinearity and low polarization mode dispersion. Additionally, said system (1) also includes a means (4) for generating a pump light beam (4?), the polarization of which is fixed over time and the spectrum of which is suited for the Brillouin scattering threshold in the optical guide means (3). Said generating means (4) is arranged such that the input light beam (2?) and pump light beam (4?) are contra-propagating in the optical guiding means (3).

Abstract: Raman amplifier includes: a pump-light generator configured to supply pump light to a transmission fiber; a measurement circuit configured to measure a relationship between power of the pump light and power of noise output from the transmission fiber with respect to a range from first pump-light power to second pump-light power; a signal detector configured to monitor a supervisory signal in output light of the transmission optical; and a decision unit configured to decide a state of the transmission fiber according to the monitoring result. When the supervisory signal is detected without the pump light, the measurement circuit measures the relationship while increasing the power of the pump light from the first pump-light power. When the supervisory signal is not detected without the pump light, the measurement circuit measures the relationship while decreasing the power of the pump light from the second pump-light power.

Abstract: An apparatus includes a multi-core optical fiber and first, second, and third optical couplers. The multi-core optical fiber is rare-earth doped to provide optical amplification in response to optical pumping thereof. The first optical coupler is configured to end-couple a first multi-mode optical fiber to an end of the multi-core optical fiber. The second optical coupler is configured to end-couple a second multi-mode optical fiber to an end of the multi-core optical fiber. The third optical coupler is configured to optically couple a pump light source to the multi-core optical fiber.

Abstract: A high-power pulse light generator includes: a master oscillator generating oscillated pulse light in synchronization with a master clock signal; an optical amplifier amplifying the oscillated pulse light output from the master oscillator and outputting high-power pulsed light; a driving unit driving a pumping semiconductor laser in synchronization with the master clock signal; and a control unit controlling the driving unit so that the driving current to be supplied to the pumping semiconductor laser becomes lower than or equal to a set value at which the pumping semiconductor laser is not in a laser oscillation state when returning light from an irradiated body with the high-power pulsed light reaches the pumping semiconductor laser connected to the optical amplifier, the control unit determining a timing of the control in accordance with an optical path length between the irradiated body and the pumping semiconductor laser.

Abstract: An optical amplifier includes: a first amplifier amplifying a signal light by a first excitation light; a variable optical attenuator attenuating the signal light; a second amplifier amplifying the signal light by a second excitation light; a mode selector selecting one of first and second modes; a gain controller, in first mode, controlling first and second excitation lights so that a gain of power of the signal light becomes constant; a first output controller, in second mode, controlling the first excitation light; a second output controller that, in second mode, controlling the second excitation light so that a spontaneous emission light having fixed level is outputted; and an attenuation controller controlling an attenuation of the variable optical attenuator according to an input level of the signal light in first mode, and controlling the attenuation to become a given value larger than a value of first mode in second mode.

Abstract: It is described an optical amplification device for receiving an optical input signal and transmitting an amplified optical output signal on the basis of the optical input signal comprising an optical amplifier that comprises an input and an output. An optical gain control unit is connected to the output path of the optical amplifier and the optical gain control unit is connected to the input path of the optical amplifier. The optical gain control unit is configured to control the gain of the optical output signal. Additionally, an electrical gain control unit is connected to the output path of the optical amplifier. The electrical gain control unit is also connected to the input path of the optical amplifier. The electrical gain control unit is configured to control the gain of the optical output signal. By providing both an electrical gain control unit and an optical gain control unit, a control characteristic can be improved.

Abstract: An optical output level control apparatus includes a detector configured to detect power of an input optical signal; an amplifier configured to amplify the input optical signal; a memory configured to store data that define a first curved line representing a relationship between the input power and a drive voltage of the amplifier for obtaining a first output level and data that defines a second curved line representing a relationship between the input power and the drive voltage of the amplifier for obtaining a second output level; a generator configured to correct at least one of the first and second curved lines and generate a target curved line representing a relationship between input power and a drive voltage of the amplifier for obtaining a target output level through interpolation based on the first and second curved lines at least one of which is corrected.

Abstract: A thin beam laser crystallization apparatus for selectively melting a film deposited on a substrate is disclosed having a laser source producing a pulsed laser output beam, the source having an oscillator comprising a convex reflector and a piano output coupler; and an optical arrangement focusing the beam in a first axis and spatially expanding the beam in a second axis to produce a line beam for interaction with the film.

Abstract: A laser processing device includes a light amplifying fiber, a seed semiconductor laser (LD) for pulsing seed light multiple times during an emission period, an excitation LD for generating the exciting light of power at a first level during a non-emission period immediately before the emission period and generating the exciting light of power at a second level higher than the first level during the emission period, a light receiving element and a peak value detector for detecting power of an output light pulse which is output from the light amplifying fiber, and a control device. The control device controls the power of the exciting light of the non-emission period based on the detected value from the peak value detector to cause the power of first output light pulses which are generated during the emission period to be the same as the power of final output light pulses.

Abstract: A method of determining a power correction factor for an optical power of an optical channel of a wavelength division multiplexed communications network. The method comprises configuring an optical source of the communications network to generate an unmodulated optical carrier signal for the optical channel. The method further comprises determining the optical power of the unmodulated optical carrier signal (PHIGH). The method further comprises configuring the optical source to apply a test modulation pattern to the optical carrier signal, to generate a modulated optical carrier signal. The method further comprises determining the optical power of the modulated optical carrier signal (PMOD). The method further comprises determining a power correction factor for the optical channel by determining the difference between the optical powers of the unmodulated optical carrier signal and the modulated optical carrier signal.

Abstract: An input light pulse Pi, input at a constant incident angle to a transmission-type diffraction grating 20, is dispersed according to the wavelengths to be output at output angles according to the wavelengths, to be reflected by reflecting mirrors 41, 42, and 43 in series, and thereafter, the light rays are input at incident angles according to their wavelengths to the transmission-type diffraction grating 20, to be output at a constant output angle from the transmission-type diffraction grating 20.

Abstract: An optical amplification component 1 includes a heat dissipation plate 10 and an amplification optical fiber 20 arranged on the heat dissipation plate 10. The amplification optical fiber 20 includes a first section SC1 extending from a reference position RP between a first end E1 and a second end E2 of the amplification optical fiber 20 up to a position at which a fiber portion 20A extending from the reference position RP toward the end E1 and a fiber portion 20B extending from the reference position RP toward the end E2 are aligned in one direction, and a second section SC2 where the fiber portions 20A and 20B aligned in one direction are wound in a spiral outside the first section SC1. The circumferences of one and the other end parts of the amplification optical fiber 20 are separated from side surfaces of the fiber portions wound in a spiral.

Abstract: In a light amplification system, a fiber-based oscillator, amplifier, and cascaded Raman resonator are coupled together in series. The oscillator output is provided as an input into the amplifier, the amplifier output is provided as a pumping input into the cascaded Raman resonator, and the cascaded Raman resonator provides as an output single-mode radiation at a target wavelength. A loss element is connected between the oscillator and amplifier, whereby the oscillator is optically isolated from the amplifier and cascaded Raman resonator. A filter is coupled between the isolator and the amplifier for filtering out backward-propagating Stokes wavelengths generated in the cascaded Raman resonator. The oscillator is operable within a first power level range, and the amplifier and cascaded Raman resonator are operable within a second power level range exceeding the first power level range.

Abstract: A network apparatus comprising an optical gain medium, a wavelength division multiplexing (WDM) filter coupled to the optical gain medium, and a Faraday Rotator Mirror (FRM) coupled to the WDM, and wherein the optical gain medium, the WDM filter, and the FRM are coupled by single mode fibers to form a self-seeded external cavity laser for a DWDM wavelength channel.

Abstract: A frequency-drift amplification device for a pulsed laser, including: a stretcher for time-stretching an incident laser pulse; at least one amplifying medium for amplifying the laser pulse; a main compressor for time-compressing the laser pulse to a desired duration for an output pulse of the amplification device; and at least one adjustment compressor between the stretcher and the main compressor, and in which the laser pulse undergoes four diffractions on diffraction gratings to time-compress the stretched laser pulse to a duration that is greater than the desired duration for the output pulse of the amplification device.

Abstract: An optical system having an input surface configured to receive an input optical signal having a polarization, and a polarization changer comprising the input surface and configured to generate two orthogonal polarization components from the input optical signal. The polarization changer also changes a direction of the polarization of the input optical signal in a controlled manner as a function of time while maintaining coherence of the two orthogonal polarization components in order to reduce stimulated Brillion scattering.

Abstract: There is provided an optical amplifier, which includes: an optical amplification medium; a pump light generator configured to generate pump light with a power corresponding to a set control value and supply the generated pump light to the optical amplification medium; a first controller including a level control circuit configured to generate the control value such that an output power of the optical amplification medium approaches a target power, and a limiter configured to limit a range of the control value in variable; and a latch circuit configured to set a specific control value to the pump light generator during a period in which the first controller is in a stop state.

Abstract: An optical amplification control apparatus is formed from a semiconductor optical amplifier, a temperature adjustment unit adjusting the temperature of the semiconductor optical amplifier, and an optical gain control unit adjusting the temperature of the semiconductor optical amplifier by controlling the temperature adjustment unit, and varying an optical gain of the semiconductor optical amplifier. Thus, a pattern effect is suppressed even if the output light intensity (the intensity of amplified light) is increased.

Abstract: An apparatus and method that provide optical isolation by permitting substantially all forward-propagating light into a delivery fiber from an optical amplifier and substantially preventing backward-traveling light from the delivery fiber entering the optical amplifier without the use of a conventional optical isolator. Eliminating the isolator improves efficiency and reduces cost. Some embodiments use a delivery fiber having a non-circular core in order to spread a single-mode signal into multiple modes such that any backward-propagating reflection is inhibited from reentering the single-mode amplifier.

Abstract: A combined large mode area, fiber cable amplifier and laser beam transport fiber cable is disclosed that transports laser beams output from a compact, high power, solid state laser to remote locations while improving the beam quality and amplifying the beam to compensate for losses in the fiber cable. The fiber cable is clad and is cladding pumped to compensate for the losses in the fiber cable.

Abstract: A stable, single mode fiber amplifier is described. The amplifier consists of a seed source, a passive single clad multimode fiber, an active double clad multimode fiber or a multimode fiber horn and a semiconductor laser pump source. The passive fiber is packaged on a mandrel with a compound radius of curvature such that high order modes in the fiber are stripped from the core leaving only the fundamental mode. This fiber is then spliced to a multimode active fiber of similar core diameter. By exciting only the fundamental mode of this active fiber, stable single mode amplification is achieved.

Abstract: According to an aspect of an embodiment, an apparatus includes an optical branching unit for branching an input signal light in four directions, a polarization component extraction unit extracting four polarization components having mutually different polarization parameters from lights branched in four directions by the optical branching unit, and a determination unit determining input/non-input of the signal light based on the four polarization components extracted by the polarization component extraction unit.

Abstract: Temporal focusing of spatially chirped femtosecond laser pulses overcomes previous limitations for ablating high aspect ratio features with low numerical aperture (NA) beams. Simultaneous spatial and temporal focusing reduces nonlinear interactions, such as self-focusing, prior to the focal plane so that deep (˜1 mm) features with parallel sidewalls are ablated at high material removal rates.

Abstract: The present invention relates to a device (1, 11) for amplifying light pulses (2, 12), the device comprised of a stretcher (4, 14) which temporally stretches the light pulses (2, 12), and comprised of at least one amplifier (5, 15) which amplifies the stretched light pulses (2, 12), and comprised of a compressor (6, 16) which recompresses the stretched and amplified light pulses (2, 12), the stretcher (4, 14) and the compressor (6, 16) being dispersive elements with essentially oppositely identical dispersion. To provide a device (1, 11) for amplifying light pulses (2, 12) which is of a compact setup and which can be flexibly applied, the present invention proposes that the dispersion of the amplifier (5, 15), the dispersion of further optical elements of the device (1) and/or a mismatch of dispersion of the stretcher (4, 14) and compressor (6, 16) are at least partly compensated by self-phase modulation of the light pulses (2, 12) and/or by at least one additional element (17) of variable dispersion.

Abstract: Systems and methods are disclosed to process an optical signal using a pre-processor to populate a non-linearity compensation data structure based on a set of predetermined rules in a non-real-time off-line mode; and an amplifier applying said predetermined rules in real-time to one or more channel input data using the data structure to determine a non-linearity compensation output.

Abstract: An optical modulator includes first and second modulation waveguides, a demultiplexer, first and second phase adjustment waveguides that changes phases of a light of the first and second modulation waveguides, a multiplexer that combines light outputs from the first and second phase adjustment waveguides, a gain controller and a modulator bias controller in which voltages of the first and second modulation signals are controlled so that a result of adding light from the first modulation waveguide to light from the second modulation waveguide where light from the first modulation waveguide has a predetermined phase is equal to a result of adding light from the first modulation waveguide to light from the second modulation waveguide where light from the second modulation waveguide has a predetermined phase. A phase-adjustment bias controller that controls phase amounts changed by the first and second phase adjustment waveguides so as to cancel phase errors.

Abstract: A laser system includes a seed laser operable to output a seed laser signal along an optical path and a phase modulator disposed along the optical path and operable to receive the seed laser signal. The laser system also includes a phase modulator driver coupled to the phase modulator. A drive signal from the phase modulator driver is operable to produce, as an output from the phase modulator, an unmodulated seed laser signal when the drive signal is associated with a first state and a modulated seed laser signal when the drive signal is associated with a second state. The laser system further includes a fiber amplifier disposed along the optical path and operable to receive the output of the phase modulator. A spectral bandwidth of an output of the fiber amplifier associated with the second state is less than a spectral bandwidth of the output of the fiber amplifier associated with the first state.

Abstract: The invention relates to pulsed optical sources formed of a source of seed optical radiation, a pulsed optical amplifier for pulsing the seed optical radiation, and an output optical port for outputting a pulsed optical signal produced by the pulsed optical amplifier. An optically isolating element such as an optical circulator is provided in the optical path between the optical seed source and the pulsed optical amplifier.

Abstract: By compensating polarization mode-dispersion as well chromatic dispersion in photonic crystal fiber pulse compressors, high pulse energies can be obtained from all-fiber chirped pulse amplification systems. By inducing third-order dispersion in fiber amplifiers via self-phase modulation, the third-order chromatic dispersion from bulk grating pulse compressors can be compensated and the pulse quality of hybrid fiber/bulk chirped pulse amplification systems can be improved. Finally, by amplifying positively chirped pulses in negative dispersion fiber amplifiers, a low noise wavelength tunable seed source via anti-Stokes frequency shifting can be obtained.

Abstract: An optical receiver implemented with a semiconductor amplifier (SOA) whose temperature is controlled by the automatic temperature control (ATC) circuit is disclosed. The optical receiver further includes an optical de-multiplexer, optical devices, a signal processor, and a controller. The controller monitors a temperature of the SOA and time derivatives thereof. The controller activates the optical devices and the signal processor after the time derivative of the temperature of the SOA becomes less than a reference.

Abstract: An optical amplification device which includes first and second optical amplifiers, and a controller. The first optical amplifier receives a light and amplifies the received light. The second optical amplifier receives the light amplified by the first optical amplifier, and amplifies the received light. When a level of the light received by the first optical amplifier changes by ?, the controller controls a level of the light received by the second optical amplifier to change by approximately ??. In various embodiments, the controller causes the sum of the gains of the first and second optical amplifiers to be constant. In other embodiments, the optical amplification device includes first and second optical amplifier and a gain adjustor. The gain adjustor detects a deviation in gain of the first optical amplifier from a target gain, and adjusts the gain of the second optical amplifier to compensate for the detected deviation.

Abstract: A pulsed laser system includes a variable attenuator located in a secondary optical path bounded by a target surface and one or more reflective surfaces outside of the primary laser oscillator of the laser system. The variable attenuator isolates an output optical amplifier of the laser system from light reflected from the target during time periods between laser pulses. In some embodiments, the variable attenuator is synchronously controlled with the primary laser oscillator. In some other embodiments, the variable attenuator is controlled separately from the primary laser oscillator to shape the generated laser pulses.

Abstract: Based on image data input to a display unit and an image on a display surface acquired by an acquisition unit, control is performed to decrease the difference between the input image data and the image displayed on the display surface.

Abstract: A spectrum shaping scheme for chirped pulse amplification (CPA): uses a spectrum decomposing system with CTSI construction, a spectrum synthesizing system with CTSI structure that is symmetrical to the decomposing structure, and a spectrum shaping system including an aperture and a planar reflector for spectrum shaping function design. The scheme includes the following steps: firstly decomposing the spectrum of a chirped temporal pulse laser to a spectral domain; then shaping the spectrum in the spectral domain; finally synthesizing un-shiftily this shaped spectrum in the spectral domain into a temporal chirped pulse with a designed shape. The scheme has the benefit that it can be not only utilized in a general laser spectrum shaping and spectrum modulation, but also can be utilized for a high energy and ultra-high peak-power laser system in chirped pulse amplification with a large caliber and with a chirped pulse bandwidth of a few nanometers.

Abstract: A laser amplifier includes a pump source and an optically active fiber having an input portion configured to receive a signal source and an output portion. The pump source is optically coupled to the optically active fiber. The laser amplifier also includes an output fiber optically coupled to the output portion of the optically active fiber. The output fiber includes a rare-earth element. The laser amplifier further includes a beam expansion section joined to the output fiber.

Abstract: A method of implementing a high-power coherent laser beam combining system in which the output of a master oscillator laser having a linewidth broader than the Stimulated Brillouin Scattering linewidth of the laser signal is split into N signals and fed into an array of N optical fibers. This is a modification of the self-synchronous LOCSET and self-referenced LOCSET phase matching systems in which the optical path length of each optical fiber is matched to less than the signal coherence length of the master oscillator by using a path length matching signal processor to modulate temperature controlled segments of each optical fiber.

Abstract: Methods and apparatuses for controlling a bias point voltage for an external optical modulator are provided. A control loop is used to adjust a bias signal applied to an external modulator by determining unwanted signals at a predetermined frequency received by an optical receiver of the control loop and accounting for these unwanted signals when determining the bias point voltage.

Abstract: By compensating polarization mode-dispersion as well chromatic dispersion in photonic crystal fiber pulse compressors, high pulse energies can be obtained from all-fiber chirped pulse amplification systems. By inducing third-order dispersion in fiber amplifiers via self-phase modulation, the third-order chromatic dispersion from bulk grating pulse compressors can be compensated and the pulse quality of hybrid fiber/bulk chirped pulse amplification systems can be improved. Finally, by amplifying positively chirped pulses in negative dispersion fiber amplifiers, low noise wavelength tunable seed source via anti-Stokes frequency shifting can be obtained.

Abstract: A method provides and/or controls an optical signal, wherein a control signal and at least one data signal are optically processed into a combined signal of substantially constant optical power. The level of the at least one data signal is substantially maintained within the combined signal. In addition, an according device is provided. Suitable for compensation of Raman tilt in WDM communication systems.

Abstract: A laser and amplifier combination delivers a sequence of optical pulses. Pulses from the laser are temporally stretched by a pulse stretcher before amplification and temporally compressed by a pulse compressed after amplification. The pulse stretcher includes a diffraction grating on which pulses being compressed are incident. An arrangement is provided for measuring the carrier-envelope phase of the pulses and adjusting the incidence angle of pulses on the grating cooperative with the measurement such that the carrier envelope phase of the pulses in the sequence is about constant.

Abstract: An example method includes receiving power measurements for a plurality of optical channels. Deviation measurements representing a difference between respective power measurements and corresponding power targets for the plurality of optical channels are created. Correctable deviations for the plurality of optical channels are determined based on the deviation measurements. The correctable deviations may be determined by projecting the measured deviations into a space that defines Raman gain profiles achievable with a set of channels and pumps. Pump settings for a plurality of pumps are determining based upon the correctable deviations for each channel by solving an optimization problem. The pump setting so determined may be applied to the plurality of pumps.

Abstract: An optical dispersion compensator including a first optical device in which light inputted from a first port is outputted from a second port and light inputted from the second port is outputted from a third port, an optical filter type dispersion compensation device that receives light from the second port of the first optical device and compensates wavelength dispersion with respect to the received light, and a second optical device that includes a fourth port to which light is inputted from the optical filter type dispersion compensation device, and in which the light inputted from the fourth port is outputted from a fifth port and light inputted from a sixth port is outputted from the fourth port.