Abstract: An apparatus for suppressing optical power transients includes a variable optical attenuator receiving an input optical signal and outputting an output optical signal; an optical power sensing element coupled to the input optical signal and sensing a portion of the input optical signal; and a feedforward loop controller coupled to the variable optical attenuator and to the optical power sensing element; the feedforward control loop providing feedforward control of the variable optical attenuator to reduce optical power transients of the input optical signal and maintain a substantially constant output power based on the input optical power and a reference value; the variable optical attenuator having a default opaque state in which the input optical signal is substantially attenuated when power is not being supplied to said variable optical attenuator. Variations include feedback loop controllers and a combination feedback and feedforward loop controllers.

Abstract: A cladding-pumped gain optical fiber is provided. The cladding-pumped gain optical fiber includes a core transmitting a signal light; a first cladding covering the core and having an optical-gain dopant; a second cladding covering the first cladding for transmitting a pumping light; and a third cladding covering the second cladding for reflecting the pumping light.

Abstract: A doped superfluorescent fiber source (SFS) has an enhanced mean wavelength stability. A method stabilizes the mean wavelength of a SFS. The method includes pumping the SFS with pump light from a pump source having a wavelength dependent on the temperature of the pump source and dependent on the power of the pump light. The length of the fiber is selected to compromise between reduction of the dependence of the mean wavelength on the pump light power and reduction of the contribution of the forward amplified spantaneous emission light produced by the fiber to the output light.

Abstract: It is an object of the present invention to provide a rare earth doped fiber whose transient response is suppressed and an optical amplifier for optical packet communication having a good characteristic even if there is little traffic. The above-mentioned problem is solved by an optical amplifier for optical packet communication comprising a first rare earth doped fiber (EDFA) having an active region whose diameter is between 3.4 ?m and 10 ?m, inclusive, an intermediate gain equalizing filter, and a second EDF, wherein the first EDFA is shorter than the second EDFA, and wherein the intermediate gain equalizing filter adjusts the intensity of each wavelength channel so as to equalize the light intensity of each wavelength channel having transmitted through the second EDF.

Abstract: The present invention relates to an assembly of multiple waveguides which includes a substrate and a plurality of waveguides positioned on said substrate at locations effective to suppress cross-talk between different waveguides. The plurality of waveguides each comprise an elongate array of quantum dots extending between sets of first and second locations on the substrate. The waveguides are positioned to receive: (1) pumped light uniformly applied to the array to produce electron-hole pairs and to enable optical gain and (2) signal light at the first location to trigger an emission from the quantum dot at the first location and transmission of photons along the array to the second location. A light transmission system which includes this assembly as well as methods of making and using the assembly are also disclosed.

Abstract: Systems and devices enabling a highly compact design for a fiber-based lasing and/or amplifying system are disclosed. In some instances, a tightly-coiled active optical fiber may be coupled with a seed source and a pump source for optical amplification and other applications. Such systems can be disposed in a small footprint package such as a butterfly package or a high heat load package. In some instances, the tightly-wound active optical fiber may further include a fiber Bragg grating adapted to accommodate bends in the active optical fiber. The active optical fiber may further utilize a cladding shaped to maintain an orientation of the active optical fiber in relation to a bend in the fiber.

Abstract: A method and apparatus for automatic shut-down and start-up of optical amplifiers in wavelength division multiplexed (WDM) optical networks include use of an optical channel monitor (OCM) to monitor loss and return of an input signal. By using the OCM to separately monitor the power level of each individual channel, it is possible to detect loss of all channels or return of a single channel even in the presence of ASE at the amplifier input. The OCM receives a fraction of the input power to the amplifier via an optical tap at the amplifier input, and provides an electrical output to a control unit corresponding to the optical power level of each individual WDM channel. Based on this electrical output, the control sends a shut-down or start-up signal to the pump unit within the amplifier.

Abstract: There is provided a parabolic pulse amplifier for amplifying a pulse light signal. The amplifier comprises an ytterbium-doped amplification waveguide pumped using a pump source with a pump central wavelength substantially offset from the absorption transition peak wavelength. The pump wavelength is selected such that the absorption coefficient of pump light and the gain coefficient of the signal are substantially equal in the amplification waveguide such that the amplification gain is distributed substantially uniformly along the amplification waveguide.

Abstract: An optical signal amplifier for use in optical networks operating in a ring configuration comprising a first doped optical fibre loop pumped by a first laser and a second optical fibre loop pumped by a second laser.

Abstract: A large-mode-area (LMA) optical fiber (10) that operates as a single-mode optical fiber. The optical fiber includes a core region (20) surrounded by an inner cladding (32), which in turn is surrounded by an outer cladding (40). The inner cladding includes at least one up-doped ring region (32R1). The ring region is configured to form a large attenuation differential between the higher-order modes and the fundamental mode so only that the fundamental mode remains traveling in the optical fiber. If necessary, the optical fiber can include a bend (10B) having a select “resonant” bend diameter (DB) that increases the relative attenuation of the fundamental and higher-order modes. The optical fiber supports an effective mode field diameter (MFD) of up to 40 ?m to 50 ?m. As a result, detrimental non-linear effects are suppressed, which allows the optical fiber to carry substantially more optical power than conventional LMA optical fibers.

Abstract: A modular ultrafast pulse laser system is constructed of individually pre-tested components manufactured as modules. The individual modules include an oscillator, pre-amplifier and power amplifier stages, a non-linear amplifier, and a stretcher and compressor. The individual modules can typically be connected by means of simple fiber splices.

Abstract: An optical fibre arrangement has at least two optical fibre sections, each optical fibre section defining an outside longitudinally extending surface. The outside longitudinally extending surfaces are in optical contact with each other. The invention further provides for an amplifying optical device have an optical fibre arrangement as just described, and a pump source. The amplifying optical device is configured such that the pump source illuminates the amplifying optical fibre. A amplifying arrangement is also disclosed. The amplifying arrangement includes a plurality of amplifying optical devices as just described, and each amplifier also has at least one input fibre and a first multiplexer connected to the input fibre. Each amplifier is configured such that at least one of the amplifying optical fibres is connected to the first multiplexer. The amplifying arrangement also has a second multiplexer connected to each of the first multiplexers.

Abstract: The present invention relates to an optical module having a structure for reducing adverse contingencies such as increased number of fusion splicing points, drops in output, and higher costs associated with a greater number of optical components. The optical module comprises an amplification optical fiber, a transmission optical fiber, and a fusion splicing structure that fusion-splices the amplification optical fiber to the transmission optical fiber, in a state where a cover layer is removed at the tip portions, including the end faces, of these optical fibers. The fusion splicing structure includes a pumping light removing resin that covers directly the tip portions of the amplification optical fiber and the transmission optical fiber from which the cover layer is removed. The pumping light removing resin has a higher refractive index than a first cladding of the amplification optical fiber.

Abstract: The present invention relates to an optical amplifier with a structure for more effectively suppressing the over/undershoot in transient responses in high-speed AGC. This optical amplifier is an optical device for amplifying signal light inputted therein, and comprises a rare-earth-element-doped optical fiber, an optical coupler, a light-receiving section, a pumping light source, and a control section. In particular, as a typical structure of the optical amplifier, the rare-earth-element-doped optical fiber has a cutoff wavelength ?c set longer than the pumping light wavelength ?p but shorter than the signal light wavelength ?s, and mainly allows a pumping light component in a fundamental mode to propagate therethrough.

Abstract: System and method for dispersion compensation tuning for a WDM optical transmission system. A tunable dispersion compensation module (4) is located at or substantially close to a transmitting end of the optical transmission line (2) and at least one distributed Raman amplifier having an Raman pump (1) is coupled to the transmission line 2. The dispersion compensation is controlled by means of a signal derived from the Raman pump (1) which is fed through a control loop (3) to the tunable dispersion compensation module (4).

Abstract: An optical communication apparatus includes an erbium-doped optical fiber amplifier for amplifying a modulated optical signal, wherein a light which is not modulated is inputted to the erbium-doped optical fiber amplifier together with the optical signal.

Abstract: The invention is directed to a high power short optical pulse source 10 comprising a master oscillator 12 and a Ytterbium doped fibre amplifier (YDFA) preamplifier 14, a pump light source 16, an optical head 18, high power optical fibre amplifier means 20, an optical signal delivery fibre 22, and a pump light delivery fibre 24. The master oscillator 12, preamplifier 14, and pump laser 16, together with their associated drive and control electronics, and cooling systems, are provided within a first enclosure 28 at a first location. The high power fibre amplifier means 20 comprises a Ytterbium doped amplifier fibre and a pump signal combiner. The high power fibre amplifier means 20 is provided within the optical head 18, which is located at a second location, remote from the first location. The optical head 18 has a small footprint and can be positioned at the intended target of the optical pulses.

Abstract: Embodiments of optical fiber may include cladding features that include a material (e.g., fluorine-doped silica glass) that may produce a very low relative refractive index difference with respect to cladding material in which the cladding features are disposed. This relative refractive index difference may be characterized by (n1-n2)/n1, where n1 is the index of refraction of the cladding material in which the cladding features are included, and n2 is the index of refraction of the cladding features. In certain embodiments, the relative refractive index difference may be less than about 4.5×10?3.

Abstract: A multi-band hybrid amplifier is disclosed for use in optical fiber systems. The amplifier uses Raman laser pumps and semiconductor optical amplifiers in series to produce a relatively level gain across the frequency range of interest. Multiple Raman pumps are multiplexed before coupling into the fiber. The Raman amplified optical signal may be demultiplexed and separately amplified by the SOAs before re-multiplexing. Gain profiles of the Raman pumps and the SOAs are selected to compensate for gain tilt and to alleviate the power penalty due to cross-gain modulation in the SOAs. The disclosed hybrid amplifier is especially useful in coarse wavelength division multiplexing (CWDM) systems.

Abstract: An optical system adapted to amplify an input signal includes an optical pump supporting the input signal and an optical pump beam. The optical pump includes an input port, a first active medium coupled to the input port, and a pump output coupled to the first active medium. The optical amplifier includes an amplifier input optically coupled to the pump output and adapted to receive the input signal after passing through the optical pump, a second active medium coupled to the amplifier input, and an amplifier output adapted to output the amplified input signal.

Abstract: An optical fiber includes: a first core portion doped with rare earth ions; a second core portion having a lower refractive index than that of the first core portion, provided along an outer circumference of the first core portion, and doped with the rare earth ions; and a clad portion having a lower refractive index than that of the second core portion and provided along an outer circumference of the second core portion, and is configured such that a concentration of the rare earth ions added to the second core portion is higher than that to the first core portion. With this configuration, it is possible to suppress an amount of FWM crosstalk in an optical amplification by decreasing the length of a fiber while alleviating efficiency deterioration due to concentration quenching.

Abstract: An optical module for supplying pump light for amplifying to-be-amplified light includes an pump light source, optical coupling means, and an optical guide section. The optical guide section optically connects the pump light source and the optical coupling means, and propagates the pump light from the pump light source, in multi-transverse-mode. The optical coupling means output the pump light from the optical guide section in multi-transverse-mode, and at least one of (i) at least one of end faces where the optical guide section and the optical coupling means are connected, (ii) an area between the end faces, and (iii) the optical guide section, has a loss medium of which transmission loss is greater in a wavelength of the to-be-amplified light than in a wavelength of the pump light. By this, an optical module which can stably supply the pump light to the optical amplification fiber can be provided.

Abstract: A method and apparatus for improved efficiency in optical fiber lasers. The system increases the efficiency of cladding pumped optical fiber amplifiers through a seeding technique which includes pumping an erbium/ytterbium doped fiber amplifier with pump energy, directing an optical signal through the erbium/ytterbium doped fiber amplifier, and seeding the optical signal with seed energy. The seed energy may have a higher energy level than the optical signal and a lower energy level than the pump energy, and the seed energy may be initially amplified in the amplifier and subsequently attenuated while amplifying the optical signal in the amplifier.

Abstract: A multi-core fiber for an optical pumping device is provided. The multi-core fiber includes a plurality of optical fibers that are inserted into holes of an alignment member. The optical fibers and the alignment member are integrated by heating. The alignment member includes a material that has a lower softening temperature than a softening temperature of the optical fibers.

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: The present invention relates to an optical module which is capable of amplifying light to be amplified to high power and which has a structure for effectively reducing influences of damage to other optical parts, and heat generation. The optical module includes a fiber unit constituted by an optical coupler, an amplification optical fiber, and an absorption optical fiber. Each of the amplification optical fiber and the absorption optical fiber has a core, a first cladding, a second cladding, and a third cladding. Further, each of the fibers allows the light to be amplified to propagate in a single mode in each of the cores, and allows pumping light to propagate in a multimode in the core, the first cladding, and the second cladding. The core of the amplification optical fiber is doped with an amplification dopant for amplifying the light to be amplified. The second cladding of the absorption optical fiber is doped with an absorption dopant for absorbing the pumping light.

Abstract: An optical system comprising a frequency modulated laser source adapted to produce a frequency modulated optical beam, an optical spectrum reshaper (OSR) adapted to receive the frequency modulated optical beam from the laser source and convert it into an amplitude modulated optical beam, a focusing lens adapted to receive the amplitude modulated optical beam from the OSR and focus the same, and an optical fiber adapted to receive the amplitude modulated optical beam from the focusing lens and transmit an optical signal; characterized in that the OSR has a central axis, the focusing lens has a central axis, and the optical fiber has a central axis, with the central axis of the optical fiber being laterally offset from at least one of the central axis of the OSR and the central axis of the focusing lens so as to effect spatial filtering and thereby generate the desired optical transmission characteristics for the resulting optical signal in the optical fiber.

Abstract: An optical parametric oscillator (OPO) is described that efficiently converts a near-infrared laser beam to tunable mid-infrared wavelength output. In some embodiments, the OPO includes an optical resonator containing a nonlinear crystal, such as periodically-poled lithium niobate. The OPO is pumped by a continuous-wave fiber-laser source having a low-power oscillator and a high-power amplifier, or using just a power oscillator. The fiber oscillator produces a single-frequency output defined by a distributed-feedback (DFB) structure of the fiber. The DFB-fiber-laser output is amplified to a pump level consistent with exceeding an oscillation threshold in the OPO in which only one of two generated waves (“signal” and “idler”) is resonant within the optical cavity.

Abstract: Multi-clad optical fibers and fiber amplifiers are disclosed. Various embodiments include multi-clad, large core fiber amplifiers. In various implementations mixing of pump modes is enhanced relative to that obtainable with conventional double-clad fibers. In some embodiments end terminations are provided with increased length of end-cap fiber. In at least one embodiment a multi-clad fiber is provided, with a pump cladding formed by stacking a layer of low index rods in the preform. Various embodiments include a multi-clad fiber amplifier system. The system includes a pump source to pump said fiber amplifier. The system also includes an optical fiber having a core and a cladding, wherein the cladding includes a pump cladding having a corrugated boundary. In various embodiments the pump cladding is formed by rods in a preform, which are disposed to mix the pump modes and/or scatter or reflect pump energy into the core.

Abstract: At an optical transmission system that uses plural light sources for Raman amplification, even when a failure occurred in a pumping light source in one of the light sources for Raman amplification, the signal light output level and its wavelength characteristic are not deteriorated at the final stage, and the number of components in the system is not made to be large and the cost of the system is not made to be high. This optical transmission system is provided. At an optical transmission system using “n” light sources for Raman amplification, a first to “n?1”th light sources for Raman amplification do not provide spare pumping light sources, and an “n”th light source for Raman amplification provides the spare pumping light sources. When a pumping light source in one of the “n” light sources for Raman amplification had a failure, the spare pumping light source in the “n”th light source for Raman amplification corresponding to the failure occurred pumping light source is worked.

Abstract: A Raman pump module for generating pump radiation having a pump wavelength (?p) for coupling into a transmission fiber of an optical wavelength division multiplex (WDM) communication system to provide Raman amplification of WDM radiation counter propagating therethrough is disclosed. The pump module is for use in a communications system in which the WDM radiation has a transmission waveband (?s) and wherein the transmission fiber has a zero dispersion wavelength (?m) lying midway between the transmission waveband and the pump wavelength. The module comprises a Raman pump laser for generating the pump radiation and a de-correlator for de-correlating the longitudinal modes of the pump radiation before it is coupled into the transmission fiber.

Abstract: A Raman amplifier according to the present invention comprises a plurality of pumping means using semiconductor lasers of Fabry-Perot, DFB, or DBR type or MOPAs, and pumping lights outputted from the pumping means have different central wavelengths, and interval between the adjacent central wavelength is greater than 6 nm and smaller than 35 nm. An optical repeater according to the present invention comprises the above-mentioned Raman amplifier and adapted to compensate loss in an optical fiber transmission line by the Raman amplifier. In a Raman amplification method according to the present invention, the shorter the central wavelength of the pumping light the higher light power of said pumping light.

Abstract: An electronic circuit for controlling a laser system consisting of a pulse source and high power fiber amplifier is disclosed. The circuit is used to control the gain of the high power fiber amplifier system so that the amplified output pulses have predetermined pulse energy as the pulse width and repetition rate of the oscillator are varied. This includes keeping the pulse energy constant when the pulse train is turned on. The circuitry is also used to control the temperature of the high power fiber amplifier pump diode such that the wavelength of the pump diode is held at the optimum absorption wavelength of the fiber amplifier as the diode current is varied. The circuitry also provides a means of protecting the high power fiber amplifier from damage due to a loss of signal from the pulse source or from a pulse-source signal of insufficient injection energy.

Abstract: A terahertz wave generating apparatus includes an excitation light source for outputting an excitation light at a predetermined wavelength, an optical crystal being excited by an irradiation with the excitation light in order to generate a terahertz wave and terahertz wave amplifying means for repeatedly performing an optical parametric amplification for the terahertz wave by use of the excitation light, wherein the terahertz wave amplifying means includes an optical waveguide having the optical crystal serving as a core and a medium serving as a clad whose refractive index is smaller than a refractive index of the optical crystal, and the inputted excitation light is propagated within the optical waveguide with fulfilling a condition for a total reflection.

Abstract: A method of operating an amplifier system includes providing a pump signal at a pump wavelength. The pump signal is a function of a pump power. The method also includes providing an input signal at a signal wavelength and coupling the pump signal and the input signal to an optical amplifier. The optical amplifier includes a gain medium characterized by a gain value at the signal wavelength. The method further includes amplifying the input signal to provide an output signal, detecting a feedback signal related to the gain value, and modifying the pump power based on the detected feedback signal.

Abstract: The present disclosure provides an approach to more efficiently amplify signals by matching either the gain materials or the pump profile with the signal profile for a higher-order mode (HOM) signal. By doing so, more efficient energy extraction is achieved.

Abstract: The invention consists in an amplifying optical fiber comprising a core containing a dopant and a cladding, wherein said core comprises a monomode core intended to propagate an optical signal, quantum dots of a semiconductor material being disposed in or near said monomode core, and a multimode core surrounding the monomode core, intended to receive a pumping signal.

Abstract: A laser radar system and a method for use in a laser radar system are disclosed. More particularly, the laser radar system includes a fiber laser capable of generating a laser signal; a first optical path through which the generated laser signal may be transmitted; a second optical path through which a reflection of the transmitted laser signal may be received; and a detector capable of detecting the received reflection. The method includes generating a laser signal from a fiber laser; transmitting the laser signal; receiving a reflection of the transmitted laser signal; and detecting the reflection.

Abstract: An optical amplifier configuration for WDM (wavelength division multiplex) systems uses a common pump source connected to an input of an optical splitter deploying pump light via variable optical attenuators to a plurality of optical amplifiers. Control circuits determine individually the output powers of the amplifiers by varying the attenuations of the variable optical attenuators. Amplifier units based on PLC technology are implemented to reduce the size.

Abstract: An optical fiber device converts an input optical pulse having a predetermined center wavelength into an optical pulse having a wavelength bandwidth broader than that of the input optical pulse. The optical fiber device includes a plurality of optical fibers connected in a cascaded manner each having negative wavelength dispersion at the center wavelength. The optical fibers have different relative refractive index differences between a core region and a cladding region from each other. The optical fibers are connected such that wavelength dispersions of adjacent optical fibers at the center wavelength are different from each other.

Abstract: An apparatus that may be used as part of an optical amplifier or laser includes a pump fiber carrying pump light from a pump source and a clad gain fiber which includes a number of coils arranged with the pump fiber to form a pump coupler. The pump coupler includes (i) a coupling section of the pump fiber, (ii) a coupling section of each of the coils of the gain fiber arranged adjacent to the coupling section of the pump fiber, (iii) an index- matching material disposed between the coupling section of the pump fiber and the coupling sections of the gain fiber to provide a high degree of coupling of the pump light from the pump fiber to the gain fiber, and (iv) a low-index material at outward-facing surfaces of the coupling sections of the gain fiber. The coupling sections of the pump fiber and of the coils of the gain fiber along with the index-matching material form a waveguide exhibiting an oscillating characteristic of coupling efficiency versus coupling length.

Abstract: A multi-band hybrid amplifier is disclosed for use in optical fiber systems. The amplifier uses Raman laser pumps and semiconductor optical amplifiers in series to produce a relatively level gain across the frequency range of interest. Multiple Raman pumps are multiplexed before coupling into the fiber. The Raman amplified optical signal may be demultiplexed and separately amplified by the SOAs before remultiplexing. Gain profiles of the Raman pumps and the SOAs are selected to compensate for gain tilt and to alleviate the power penalty due to cross-gain modulation in the SOAs. The disclosed hybrid amplifier is especially useful in coarse wavelength division multiplexing (CWDM) systems.

Abstract: An integrated optical-amplification module includes a housing member, a first input optical terminal configured to receive an optical signal, a second input, optical terminal that can receive a pump light, and an output optical terminal that can output a combined optical signal comprising at least a portion of the optical signal and a portion of the pump light. The integrated optical-amplification module also includes an optical combiner fixedly installed relative to the housing member. The optical combiner can receive the pump light and the optical signal and an optical prism fixedly installed relative to the housing member. The optical combiner can merge the pump light and the optical signal to form the combined optical signal. The optical prism can direct at least a portion of the optical signal through free space to the optical combiner.

Abstract: Optical apparatus including a pump-guiding fiber (30) including a fiber cladding (31), a fiber core (32) and an attachment section (33), the attachment section (33) including a straight core section (34) and a tapered core section (35), the pump-guiding fiber (30) being optically attached at one end thereof to a pump source (29) and an opposite end of the pump-guiding fiber (30) being attached to an inner clad (42) of a receiving fiber (40) through an attachment section (50), the attachment section (50) including both the straight core section (34) and the tapered core section (35) of the pump-guiding fiber (30), characterized in that both the straight core section (34) and the tapered core section (35) of the pump-guiding fiber (30) are attached to the receiving fiber (40) with an intermediate sol-gel material (51).

Abstract: The present invention relates to an optical amplifier module, or the like, having a structure for enabling effective suppression of photodarkening and efficient optical amplification. The optical amplifier module comprises a first optical amplification waveguide which is comprised of a phosphate glass as a main component and includes a ytterbium-doped first optical waveguide region, a second optical amplification waveguide which is optically coupled to the first optical amplification waveguide and includes a ytterbium-doped second optical waveguide region which is co-doped with aluminum, and pumping light source units which supply pumping light respectively to the first optical amplification waveguide and the second optical amplification waveguide. The light to be amplified, having inputted to the first optical amplification waveguide, is amplified only once by means of the pumping light, in each of the first optical amplification waveguide and the second optical amplification waveguide.

Abstract: An optical amplifier apparatus capable of dealing with different wavelength bands and capable of outputting an amplified light with reduced noise for any one of the wavelength bands. In a case of amplifying a light of C-band, terminals (51,52) of an optical switch (50) are connected to each other. An incident light is amplified by a first front-end optical fiber amplifier (12) and a first back-end optical fiber amplifier (18). The amplified light passes via the terminals (51,52) and through a back-end WDM coupler (36) and goes out of the optical amplifier apparatus (1). In a case of amplifying a light of L-band, terminals (51,54) of the optical switch (50) are connected to each other, while terminals (52,53) thereof are connected to each other.

Abstract: An optical fiber amplifier apparatus and optical signal amplification method are provided. In one example, the amplifier apparatus comprises an optical combiner that is configured to receive an input optical signal to be amplified and a pump light beam. The optical combiner combines for output the input optical signal and the pump light beam. A first cladding pumped optical fiber in which Erbium is the only optically active dopant is coupled to the optical combiner to receive the pump light beam and the input optical signal. The first cladding pumped optical fiber pre-amplifies the input optical signal and passes the pre-amplified input optical signal and power of the pump light beam not absorbed by the first cladding pumped optical fiber. A second cladding pumped optical fiber is provided that is coupled to the first cladding pumped optical fiber. Erbium and Ytterbium are optically active dopants in the second cladding pumped optical fiber.

Abstract: An optical fibre laser or amplifier device is disclosed, comprising: a rare-earth-doped multi-clad optical fibre having at least three cladding layers, one or more multimode pump laser diodes, and a means of multiplexing a laser signal and the pumping radiation, adapted so that a fraction of the stray signal light originating within the device is captured by one of the intermediate cladding layers of the rare-earth-doped fibre and guided out of the laser structure through the multiplexing system resulting in a reduction in the amount of stray signal radiation impinging upon the pump laser diodes.

Abstract: A composite optic fibre for laser includes a core surrounded with a pump guiding sheath in contact with the core, sheath being a photonic structure formed by a substantially regular matrix assembly of coaxial capillaries, spaced apart and arranged parallel to the core, the core being a material with doping elements which may be brought into at least one excited electronic state by absorbing the energy from a pump optical signal of a first determined wavelength running through the core and capable of giving-back the former by de-energization in the form of an optical signal of a second determined wavelength, the core having a determined diameter and the sheath having a determined diameter. The diameter of the guiding sheath is greater than the core diameter and smaller than or equal to four times the core diameter, the core diameter being greater than or equal to 35 micrometers.

Abstract: Embodiments of parametric chirped pulse amplifiers seeded with a single pulse source which is subsequently split into a signal arm and a pump arm with appropriate signal and pump conditioning stages are disclosed, which advantageously improve the utility of high average power and/or high energy ultrafast amplification systems. In various embodiments, at least one of the signal or the pump conditioning stages is non-linear, allowing for a great range of seed sources to be utilized. Chirped pulse amplification in the pump conditioning stage may be used to simplify the parametric amplification of pulses with pulse widths of the order of 10 fs. The parametric pump can include coherently combined fiber arrays, hybrid fiber solid-state amplifiers, and/or cryogenically cooled solid-state amplifiers to increase or optimize the energy extraction of high average powers.