Abstract: An apparatus may include a diode-pumped solid-state laser oscillator configured to output a pulsed laser beam, a modulator configured to modify an energy and a temporal profile of the pulsed laser beam, and an amplifier configured to amplify an energy of the pulse laser beam. A modified and amplified beam to laser peen a target part may have an energy of about 5 J to about 10 J, an average power (defined as energy (J)×frequency (Hz)) of from about 25 W to about 200 W, with a flattop beam uniformity of less than about 0.2. The diode-pumped solid-state oscillator may be configured to output a beam having both a single longitudinal mode and a single transverse mode, and to produce and output beams at a frequency of about 20 Hz.

Abstract: A device comprises first, second and third elements fabricated on a common substrate. The first element comprises an active waveguide structure comprising electrically pumped optical source supporting a first optical mode. The second element comprises a passive waveguide structure supporting a second optical mode in at least part of the second element. The third element, at least partly butt-coupled to the first element, comprises an intermediate waveguide structure supporting intermediate optical modes. At least part of the second element supports at least one optical mode that interacts with rare-earth dopants. A tapered waveguide structure in at least one of the second and the third elements facilitates efficient adiabatic transformation between the second optical mode and at least one of the intermediate optical modes. No adiabatic transformation occurs between any of the intermediate optical modes and the first optical mode.

Abstract: A lidar system comprising with a light source, an optical link, and a sensor head. The light source can include a seed laser to produce pulses of light and an optical preamplifier to amplify the pulses of light. The optical link can convey amplified pulses of light to the sensor head remotely located from the light source. The sensor head can include an optical booster amplifier, a scanner to scan amplified output pulses of light across a field of regard, and a receiver to detect pulses of light scattered by a target located a distance from the sensor head.

Abstract: An optical module includes a first base member, a second base member disposed spatially away from the first base member, a first laser disposed on the first base member and configured to emit red light, a second laser disposed on the second base member and configured to emit light with a color other than red, and a first electronic cooling module disposed in contact with the first base member and configured to adjust a temperature of the first laser.

Abstract: A device includes a substrate, a micro-electro-mechanical system (MEMS) device disposed on the substrate, a controller disposed on the substrate, a heating element, and an enclosure. The heating element is configured to generate heat in response to a signal generated by the controller. The enclosure encloses the MEMS sensor device, the controller, and the heating element. The controller is configured to generate the signal responsive to temperature measurements within the enclosure. The signal causes the heating element to generate heat and maintain a predetermined temperature within the enclosure.

Abstract: In one embodiment, a fiber-optic amplifier includes an optical gain fiber configured to amplify input light received from a seed laser. The optical gain fiber includes a first gain section configured to: receive the seed-laser input light and co-propagating pump light; and amplify the seed-laser input light as it propagates along the first gain section. The seed-laser input light and the co-propagating pump light propagate along the first gain section in a same direction. The optical gain fiber also includes a second gain section configured to: receive the amplified input light from the first gain section; receive counter-propagating pump light; and further amplify the amplified input light as it propagates along the second gain section. The amplified input light and the counter-propagating pump light propagate along the second gain section in opposite directions. The fiber-optic amplifier also includes a first pump laser diode and a second pump laser diode.

Abstract: Aspects of the present disclosure describe systems, methods, and structures for providing C-band and L-band transmission exhibiting increased power efficiency by diverting a portion of C-band optical energy to an input of L-band optical amplifiers (C-seeding) while optionally employing circulators to eliminate the need for optical isolators.

Abstract: The invention relates to a pulsed light source capable of effectively utilizing optical power and selecting the pulse width of output pulsed light. A pulsed light source has a MOPA structure, and comprises a seed light source and an optical fiber amplifier. The seed light source includes a semiconductor laser outputting pulsed light. In the optical fiber amplifier, an optical filter branches pulsed light amplified by a YbDF into a first wavelength component including the peak wavelength and the remaining second wavelength component. An optical switch outputs one of the pulsed light of the first wavelength component and the pulsed light of the second wavelength component which are inputted. Another YbDF amplifies the pulsed light outputted from the optical switch.

Abstract: A method includes transmitting a first set of transmission signals over an operating frequency band. The method includes detecting if a second set of transmission signals are transmitted adjacent the operating frequency band and reducing power to a subset of the first set of transmission signals when the second set of transmission signals are detected.

Abstract: An optical amplification control apparatus is provided with: a first branch unit for branching an optical signal to which an additional optical signal with a predetermined wavelength has been added in a self node or a nearest node; a first filter unit for extracting the additional optical signal from one optical signal into which the first branch unit has branched; an amplification unit for amplifying the other optical signal into which the first branch unit has branched; a second branch unit for branching the optical signal amplified by the amplification unit; a second filter unit for extracting the additional optical signal from one optical signal into which the second branch unit has branched; and a first control unit for performing automatic gain control of the amplification unit based on the additional optical signal extracted by the first filter unit, and the additional optical signal extracted by the second filter unit.

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: A spatial filter includes a first filter element and a second filter element overlapping with the first filter element. The first filter element includes a first pair of cylindrical lenses separated by a first distance. Each of the first pair of cylindrical lenses has a first focal length. The first filter element also includes a first longitudinal slit filter positioned between the first pair of cylindrical lenses. The second filter element includes a second pair of cylindrical lenses separated by a second distance. Each of the second pair of cylindrical lenses has a second focal length. The second filter element also includes a second longitudinal slit filter positioned between the second pair of cylindrical lenses.

Abstract: In the method for processing a signal light from free-space by amplifying said signal for free-space optical communications. wherein the improvement includes the steps of (a) pre-amplifying said signal light with low noise; and (b) coupling said signal light into a multimode filter which reduces coupling hisses compared to single mode filters.

Abstract: In the method for processing a signal light from free-space by amplifying said signal for free-space optical communications, wherein the improvement includes the steps of (a) pre-amplifying said signal light with low noise; and (b) coupling said signal light into a multimode filter which reduces coupling losses compared to single mode filters.

Abstract: In at least one embodiment of the wavelength-tunable light source (1), it comprises an output source (2), which is capable in operation of generating electromagnetic radiation (R). Furthermore, the light source (1) has a wavelength-selective first filter element (5), which is situated downstream from the output source (2). Moreover, the light source (1) contains a first amplifier medium (3), which is situated downstream from the first filter element (5) and is capable of at least partial amplification of the radiation (R) emitted by the output source (2). The light source (1) further comprises at least one wavelength-selective second filter element (6), which is situated downstream from the first amplifier medium (3), the second filter element (6) having an optical spacing (L) to the first filter element (5). The first filter element (5) and the at least one second filter element (6) are tunable via a control unit (11), which the light source (1) has.

Abstract: An optical amplifier amplifies signal light and includes a pump light source that outputs pump light of a wavelength different from that of the signal light; a combining unit that combines the signal light and the pump light output by the pump light source, to output combined light; an amplifying unit that has non-linear optical media that transmit the combined light to amplify the signal light, the amplifying unit further removing, in the non-linear optical media, idler light generated from the signal light and the pump light, and outputting light that results; and an extraction filter that extracts the signal light from the light output by the amplifying unit.

Abstract: An optimized Yb: doped fiber mode-locked oscillator and fiber amplifier system for seeding Nd: or Yb: doped regenerative amplifiers. The pulses are generated in the Yb: or Nd: doped fiber mode-locked oscillator, and may undergo spectral narrowing or broadening, wavelength converting, temporal pulse compression or stretching, pulse attenuation and/or lowering the repetition rate of the pulse train. The conditioned pulses are subsequently coupled into an Yb: or Nd: fiber amplifier. The amplified pulses are stretched before amplification in the regenerative amplifier that is based on an Nd: or Yb: doped solid-state laser material, and then recompressed for output.

Abstract: The present invention discloses a multi-wavelength light source apparatus. The multi-wavelength light source apparatus includes: a pump light source, configured to provide pump light; an erbium-doped optical fiber, configured to absorb energy of the pump light and emit wide-spectrum laser light; and an optical fiber, configured to filter the wide-spectrum laser light and output a multi-wavelength optical signal in a free spectral range of the optical filter, where the multi-wavelength optical signal is incident on the erbium-doped optical fiber, and the erbium-doped optical fiber is further configured to re-amplify and output the incident multi-wavelength optical signal. In the multi-wavelength light source apparatus in the embodiments of the present invention, a wavelength of output light can be selected, spectral energy of the output light is concentrated, and power of the output light is high.

Abstract: A relative intensity noise (RIN)-suppressed light source is provided that includes a light source that produces an incoming light. A semiconductor optical amplifier (SOA) arrangement receives the incoming light and provides a significant reduction in the RIN as its output. The SOA arrangement includes one or more SOAs in saturation that behave like a high pass filter for the amplitude of the incoming light.

Abstract: A device is described herein which may comprise an optical amplifier having a gain band including wavelengths ?1 and ?2, with ?1??2; a pre-pulse seed laser having a tuning module for tuning a pre-pulse output to wavelength ?1; a main pulse seed laser generating a laser output having wavelength, ?2; and a beam combiner for directing the pre-pulse output and the main pulse output on a common path through the optical 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: An optical amplifier includes: a rare-earth doped fiber configured to amplify signal light to thereby produce a amplified signal light; a gain control circuit configured to control an optical gain of the rare-earth doped fiber; a photodetector configured to detect intensities of different wavelength of light obtained from the amplified signal light; and an abnormality detection circuit configured to detect an abnormality of the signal light in accordance with a ratio or a difference between the intensities of the different wavelength.

Abstract: The present invention relates to a wavelength conversion laser system and provides a wavelength conversion laser system including a semiconductor optical amplifier, an optical condenser that condenses light emitted from the optical amplifier, a diffraction grating plate that induces wavelength components of the light having passed through the optical condenser in different directions, and an optical very large scale integration (VLSI) processor.

Abstract: A method of manufacturing a variable wavelength interference filter includes forming an electrostatic gap forming groove, a wiring forming groove extending from the electrostatic gap forming groove to an outer peripheral edge of the chip region, and an air communication groove through which the wiring groove forming groove communicates with the outside of the first substrate, in a chip region of a first substrate.

Abstract: System, method, and apparatus for smoothing of edges in images to remove irregularities are disclosed. In one aspect of the present disclosure, a method of image processing includes, identifying an edge in an image having an associated set of edge characteristics, determining the associated set of edge characteristics, and applying a low pass filter to a pixel of the edge based on the associated set of edge characteristics to generate a second image based on the image, wherein the edge in the image is smoothed in the second image. The method further includes generating a third image which is a blend of the original image and the second (edge-smoothed) image based on the associated set of edge characteristics.

Abstract: An optical amplifier includes an optical fiber which includes a core in which the signal light is propagated and with which a rare-earth element is doped; a laser that is optically coupled to an end of the optical fiber, providing the optical fiber with an excitation light; and a filter which is formed in the optical fiber and removes a light within a wavelength range, from the core, among lights propagated in the core, wherein the filter comprises a first filter that is arranged at a stage of the optical fiber and removes a first light in a first wavelength range, and a second filter that is arranged at a subsequent stage of the optical fiber and removes a second light in a second wavelength range, wherein a wavelength of the second light is longer than a wavelength of the first light.

Abstract: A system and method for filtering and enhancing signals from a noise background based on the nonlinear interaction of waves. The system and method amplify low-level signals, hide information in the signals, and then nonlinearly recover the signals. With the present invention, this can be performed for both spatial beams and temporal pulses. The signal self-filters and self-amplifies at the expense of the surrounding noise via the nonlinear medium.

Abstract: In at least one embodiment of the wavelength-tunable light source, it comprises an output source, which is capable in operation of generating electromagnetic radiation. Furthermore, the light source has a wavelength-selective first filter element, which is situated downstream from the output source. Moreover, the light source contains a first amplifier medium, which is situated downstream from the first filter element and is capable of at least partial amplification of the radiation emitted by the output source. The light source further comprises at least one wavelength-selective second filter element, which is situated downstream from the first amplifier medium, the second filter element having an optical spacing to the first filter element. The first filter element and the at least one second filter element are tunable via a control unit, which the light source has.

Abstract: A light generation and amplification system includes a length of laser-active filter fiber having a refractive index profile that suppresses unwanted Stokes orders at wavelengths longer than a target wavelength and that has normal dispersion over its operating wavelength. A nested series of reflectors is provided at the fiber's input and output ends, and are configured to provide a nested series of Raman cavities, separated in wavelength by approximately the respective Stokes shifts. The first cavity in the series is a combined cavity that provides laser oscillation due to a combination of ionic gain and feedback at a selected first wavelength and that provides Raman gain to light at the first Stokes shift of the first wavelength when light at the first wavelength has an energy exceeding a Raman scattering threshold. The Raman cavities provide a stepwise transition between the first wavelength and the target wavelength.

Abstract: An optical amplifier comprises at least two gain regions, an intermediate region situated between the gain regions, and a transition region situated between the intermediate region and each gain region. The aforesaid regions have claddings that collectively form a path for pump radiation propagating from at least one of the gain regions to the other gain region, and cores that collectively form a path for signal radiation propagating from at least one of the gain regions to the other gain region. The cores in the gain regions support multiple propagating optical modes, including at least one signal mode and at least one non-signal mode. The intermediate region, however, supports fewer propagating core modes than are supported by the gain regions. The transition regions are conformed such that when radiation in propagating non-signal core modes passes from the gain regions into the intermediate region, it is at least partly coupled into cladding modes of the intermediate region.

Abstract: Described are Gain Flattening Filters (GFFs) implemented using mechanical translating assemblies to move selected thin film Gain Attenuating Filters (GAFs), and combinations of selected GAFs, into or out of the output path from an optical amplifier. The GAFs may be used singly, or in combinations that synthesize many target filter characteristics. The GFF is primarily adapted for WDM systems operating with a wavelength range of approximately 1520 nm to 1620 nm. Several embodiments are shown for effectively combining different GAFs to provide multiple GFF curves.

Abstract: Embodiments of laser systems advantageously use pulsed optical fiber-based laser source (12) output, the temporal pulse profile of which may be programmed to assume a range of pulse shapes. Pulsed fiber lasers are subject to peak power limits to prevent an onset of undesirable nonlinear effects; therefore, the laser output power of these devices is subsequently amplified in a diode-pumped solid state photonic power amplifier (DPSS-PA) (16). The DPSS PA provides for amplification of the desirable low peak power output of a pulsed fiber master oscillator power amplifier (14) to much higher peak power levels and thereby also effectively increases the available energy per pulse at a specified pulse repetition frequency. The combination of the pulsed fiber master oscillator power amplifier and the diode-pumped solid state power amplifier is referred to as a tandem solid state photonic amplifier (10).

Abstract: An agent sensing system may comprise an emitter optical resonator, a functionalized optical resonator, and a reference optical resonator. The emitter optical resonator may be configured to emit light at one or more system peak wavelengths. The functionalized optical resonator may be optically coupled to the emitter optical resonator and configured to propagate the emitted light in the absence of a particular agent, and filter the emitted light in the presence of the particular agent. The reference optical resonator may be optically coupled to at least one of the emitter optical resonator and the functionalized optical resonator such that an intensity of light propagated by the reference optical resonator is based at least on whether light emitted by the emitter optical resonator is filtered or propagated by the functionalized optical resonator.

Abstract: A pulse laser apparatus includes a laser configured to generate a pulse of a laser beam, a fiber amplifier, and a pulse compressor. The fiber amplifier includes a rare-earth doped fiber that exhibits normal dispersion at a wavelength of the laser beam generated from the laser. The pulse laser apparatus further includes a unit configured to give a loss to energy portions in a wavelength region corresponding to a zero-dispersion wavelength of the rare-earth doped fiber and/or a wavelength region longer than the zero-dispersion wavelength within a wavelength spectrum of the laser beam having been chirped in the fiber amplifier.

Abstract: A device representing a reflector, for example an evanescent reflector or a multilayer interference reflector, with at least one reflectivity stopband is disclosed. A medium with means of generating optical gain is introduced into the layer or several layers of the reflector. The optical gain spectrum preferably overlaps with the spectral range of the reflectivity stopband. This reflector is attached to multilayer passive cavity structure made of semiconducting, and/or dielectric, and/or metallic materials with the inserted tools of achieving wavelength selection of the optical modes. For example, volume Bragg gratings, distributed feedback gratings or patterns, using of vertical optical cavities surrounded by multilayer Bragg reflectors can be applied. The optical modes of the passive optical cavity partially penetrate into the gain region of the reflector.

Abstract: A spatial filter includes a first filter element and a second filter element overlapping with the first filter element. The first filter element includes a first pair of cylindrical lenses separated by a first distance. Each of the first pair of cylindrical lenses has a first focal length. The first filter element also includes a first longitudinal slit filter positioned between the first pair of cylindrical lenses. The second filter element includes a second pair of cylindrical lenses separated by a second distance. Each of the second pair of cylindrical lenses has a second focal length. The second filter element also includes a second longitudinal slit filter positioned between the second pair of cylindrical lenses.

Abstract: Embodiments of laser systems advantageously use pulsed optical fiber-based laser source (12) output, the temporal pulse profile of which may be programmed to assume a range of pulse shapes. Pulsed fiber lasers are subject to peak power limits to prevent an onset of undesirable nonlinear effects; therefore, the laser output power of these devices is subsequently amplified in a diode-pumped solid state photonic power amplifier (DPSS-PA) (16). The DPSS PA provides for amplification of the desirable low peak power output of a pulsed fiber master oscillator power amplifier (14) to much higher peak power levels and thereby also effectively increases the available energy per pulse at a specified pulse repetition frequency. The combination of the pulsed fiber master oscillator power amplifier and the diode-pumped solid state power amplifier is referred to as a tandem solid state photonic amplifier (10).

Abstract: In at least one embodiment of the wavelength-tunable light source, it comprises an output source, which is capable in operation of generating electromagnetic radiation. Furthermore, the light source has a wavelength-selective first filter element, which is situated downstream from the output source. Moreover, the light source contains a first amplifier medium, which is situated downstream from the first filter element and is capable of at least partial amplification of the radiation emitted by the output source. The light source further comprises at least one wavelength-selective second filter element, which is situated downstream from the first amplifier medium, the second filter element having an optical spacing to the first filter element. The first filter element and the at least one second filter element are tunable via a control unit, which the light source has.

Abstract: Techniques and devices for producing short laser pulses based on chirped pulse amplification.

Abstract: The present invention relates to an optical fiber amplifying module equipped with a structure for stably attaining a high gain even when amplifying light having a low duty cycle. The optical fiber amplifying module comprises at least three amplification optical fibers successively arranged from an input connector to an output collimator. A bandpass filter is arranged between the first- and second-stage amplification optical fibers. Control means having a structure constituted by optically passive components alone or a feedback structure functions so as to render an upper limit to a gain for input light in the first-stage amplification optical fiber, thereby preventing the deterioration in performances such as destruction of the bandpass filter from occurring in optical components positioned on the upstream side of the final-stage amplification optical fiber.

Abstract: A tunable laser includes an optical gain medium, a first resonator, a periodically tunable optical filter, and a second resonator in which light of a laser wavelength exhibits a round trip time T. The optical filter is arranged between the first resonator and the second resonator and is tuned with a period t. The period t is governed by t=(n/m) T, where n and m are integers and m/n is not an integer.

Abstract: In an optical transmission system, a controller acquires a noise light loss value, which indicates a loss that noise light output from an upstream-side optical amplifier undergoes during propagation to a downstream-side optical amplifier through an optical loss medium, and a signal beam loss value, which indicates a loss that a signal beam output from the upstream-side optical amplifier undergoes during propagation to the downstream-side optical amplifier through the optical loss medium, obtains, as a loss difference, a difference between the noise light loss value and the signal beam loss value and, when setting up the downstream-side optical amplifier, determines the gain of the downstream-side optical amplifier by compensating the loss difference.

Abstract: A device is described herein which may comprise an optical amplifier having a gain band including wavelengths ?1 and ?2, with ?1??2; a pre-pulse seed laser having a tuning module for tuning a pre-pulse output to wavelength ?1; a main pulse seed laser generating a laser output having wavelength, ?2; and a beam combiner for directing the pre-pulse output and the main pulse output on a common path through the optical amplifier.

Abstract: The invention relates to a light source apparatus having a structure for effectively suppressing a negative effect due to a nonlinear effect generated in propagation of an amplifying light, and realizing a stable operation. In the light source apparatus, light amplified in an optical amplifier fiber is emitted to the outside of the apparatus through an optical output fiber whose one end is connected to an output connecter. At this time, a part of Raman scattered light, generated in the optical output fiber, propagates toward an pumping light source through the optical amplifier fiber from the optical output fiber. An optical component having an insertion loss spectrum that attenuates the Raman scattered light but allows pumping light or light to be amplified to transmit therethrough, is provided on a propagation path of the Raman scattered light, due to the light component, the intensity of the Roman scattered light reaching the pumping light source is effectively reduced.

Abstract: It is an object of the present invention to provide an optical amplifier using optical amplification mediums each doped with a rare earth element for increasing amplification efficiency of signal light in S-band and the like. To this end, the optical amplifier is constituted such that, when performing optical amplification for S-band and the like in which a center wavelength of a gain peak in the optical amplification medium is located at an outside of a signal band, a gain coefficient of when a pumping condition of the optical amplification medium is maximum is set so that a parameter ? obtained by dividing a minimum value of the gain coefficient in the signal band by a maximum value of the gain coefficient outside of the signal band becomes a previously set value or more, wherein, for example, the parameter ? can be increased by controlling a temperature of each of a plurality of EDFs between which gain equalizers are disposed.

Abstract: The invention relates to optical fibers for use in optical amplification of light, such as in optical fiber amplifiers and lasers and for use in delivery of high power light, in particular to a scheme for reducing amplified spontaneous emission at undesired wavelengths. The invention further relates to articles, methods and use. An object of the invention is achieved by a micro-structured optical fiber, which is adapted to guide light by the photonic bandgap effect and to have one or more pass bands and at least one stop-band over a wavelength range from ?stop1 to ?stop2. In an aspect of the invention, the at least one stop-band provides filter functions that suppress nonlinear effects.

Abstract: A pulse laser apparatus includes a laser configured to generate a pulse of a laser beam, a fiber amplifier, and a pulse compressor. The fiber amplifier includes a rare-earth doped fiber that exhibits normal dispersion at a wavelength of the laser beam generated from the laser. The pulse laser apparatus further includes a unit configured to give a loss to energy portions in a wavelength region corresponding to a zero-dispersion wavelength of the rare-earth doped fiber and/or a wavelength region longer than the zero-dispersion wavelength within a wavelength spectrum of the laser beam having been chirped in the fiber amplifier.

Abstract: A MO-PA type optical amplifier is provided which includes an oscillator and an amplifier including a fiber for optical amplification, including: a reflected-light wavelength conversion fiber which is provided on an optical path between the oscillator and the amplifier and which converts a wavelength of reflected-light traveling toward the oscillator due to Stimulated Raman Scattering; and a filter which is provided on the optical path between the oscillator and the amplifier and which eliminates the wavelength-converted light.

Abstract: A first wavelength converter of a wavelength-conversion device includes: an optical amplifier amplifying an incident light beam; a first dispersion flat fiber spreading the wavelength spectrum width of the amplified beam; and a first wavelength filter transmitting a predetermined wavelength bandwidth of the first fiber output beam. A center wavelength of the first wavelength converted beam is shifted by ??1 from that of the incident light beam. A second wavelength converter of the device does not include an optical amplifier and includes: a second dispersion flat fiber spreading the wavelength spectrum width of the first wavelength converted beam; and a second wavelength filter transmitting a predetermined wavelength bandwidth of the second fiber output beam. A center wavelength of the second wavelength converted beam is shifted by ??2 from that of the first wavelength converted beam. The ??1 and ??2 satisfy ??1+??2=??, ??1×??2<0, and |??1|<|??2|.

Abstract: A pulse laser apparatus includes a laser configured to generate a pulse of a laser beam, a fiber amplifier, and a pulse compressor. The fiber amplifier includes a rare-earth doped fiber that exhibits normal dispersion at a wavelength of the laser beam generated from the laser. The pulse laser apparatus further includes a unit configured to give a loss to energy portions in a wavelength region corresponding to a zero-dispersion wavelength of the rare-earth doped fiber and/or a wavelength region longer than the zero-dispersion wavelength within a wavelength spectrum of the laser beam having been chirped in the fiber amplifier.