3130 results about "Fiber laser" patented technology

An ytterbium-doped optical fiber of the present invention includes: a core which contains ytterbium, aluminum, and phosphorus and does not contain germanium; and a cladding which surrounds this core. The ytterbium concentration in the core in terms of ytterbium oxide is 0.09 to 0.68 mole percent. The molar ratio between the phosphorus concentration in the core in terms of diphosphorus pentoxide and the above ytterbium concentration in terms of ytterbium oxide is 3 to 30. The molar ratio between the aluminum concentration in the core in terms of aluminum oxide and the above ytterbium concentration in terms of ytterbium oxide is 3 to 32. The molar ratio between the above aluminum concentration in terms of aluminum oxide and the above phosphorus concentration in terms of diphosphorus pentoxide is 1 to 2.5.

The invention describes classes of robust fiber laser systems usable as pulse sources for Nd: or Yb: based regenerative amplifiers intended for industrial settings. The invention modifies adapts and incorporates several recent advances in FCPA systems to use as the input source for this new class of regenerative amplifier.

A large core photonic crystal fiber for transmitting radiation having a core comprising a substantially transparent core material and having a core diameter of at least 5 mu. The fiber also comprises a cladding region surrounding the length of core material, wherein the cladding region comprises a first substantially transparent cladding material, having a first refractive index, and wherein the first substantially transparent cladding material has embedded along its length a substantially periodic array of holes, wherein the holes are filled with a second cladding material having a second refractive index less than the first refractive index, such that radiation input to the optical fiber is transmitted along the length of the core material in a single mode of propagation. In a preferred embodiment, the core diameter may be at least 20 mu, and may be as large as 50 mu. The fiber is capable of transmitting higher power radiation than conventional fibres, whilst maintaining propagation in a single mode. The core material may be doped with a material capable of providing amplification under the action of pump radiation input to the fiber. The invention also relates to a fiber amplifier and a fiber laser comprising a doped large core photonic crystal fiber. The fiber may also be used in a system for transmitting radiation comprising a plurality of lengths of large core photonic crystal fiber, separated by large core photonic crystal fiber amplifiers, such that the power of radiation transmitted through the system is maintained above a predetermined threshold power.

Various embodiments may be used for laser-based modification of target material of a workpiece while advantageously achieving improvements in processing throughput and / or quality. Embodiments of a method of processing may include focusing and directing laser pulses to a region of the workpiece at a pulse repetition rate sufficiently high so that material is efficiently removed from the region and a quantity of unwanted material within the region, proximate to the region, or both is reduced relative to a quantity obtainable at a lower repetition rate. In at least one embodiment, an ultrashort pulse laser system may include at least one of a fiber amplifier or fiber laser. Various embodiments are suitable for at least one of dicing, cutting, scribing, and forming features on or within a semiconductor substrate. Workpiece materials may also include metals, inorganic or organic dielectrics, or any material to be micromachined with femtosecond and / or picosecond pulses, and in some embodiments with pulse widths up to a few nanoseconds.

A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

An optical spectroscopy apparatus determines the concentration of analyte in a specimen that utilizes a single radiation source which is hybrid laser comprising a semiconductor pump laser and small-cavity rare earth fiber laser where laser cavities of both lasers are butt coupled or otherwise optically coupled to form a plurality of laser cavities that produce a plurality of emission wavelengths, one which may be the pump laser emission wavelength at the output of the fiber laser thereby forming a multi-wavelength combined output where the wavelengths substantially match distinguishing spectral characteristic features along at least a portion of a characteristic optical spectrum of the analyte under examination. In lieu of complex data analysis of these wavelengths to determine values representing the concentration of the analyte in an examined specimen, the semiconductor pump laser or lasers are modulated as a plurality of tone frequencies, where at least a first of the modulation frequencies is below the maximum frequency response of the fiber laser so that the first modulation effectively modulates the pump emission wavelength and a first emission wavelength of the fiber laser in the hybrid laser combined output, and at least a second of modulation frequencies is above the maximum frequency response of the fiber laser so that the second modulation effectively modulates the pump emission wavelength but not the first emission wavelength of the fiber laser in the hybrid laser combined output. Further, one or more additional modulation frequencies may be applied to the pump laser which are intermediate of the first and second modulation frequencies where it is at least responsive to at least one further emission wavelength of the fiber laser and also provided in the hybrid laser combined output.

A pulsed laser comprises an oscillator and amplifier. An attenuator and / or pre-compressor may be disposed between the oscillator and amplifier to improve performance and possibly the quality of pulses output from the laser. Such pre-compression may be implemented with spectral filters and / or dispersive elements between the oscillator and amplifier. The pulsed laser may have a modular design comprising modular devices that may have Telcordia-graded quality and reliability. Fiber pigtails extending from the device modules can be spliced together to form laser system. In one embodiment, a laser system operating at approximately 1050 nm comprises an oscillator having a spectral bandwidth of approximately 19 nm. This oscillator signal can be manipulated to generate a pulse having a width below approximately 90 fs.

A fiber laser with a fiber for laser light generation having an entrance end and an exit end comprises a pump light source for generating pump light to be coupled via the entrance side into the fiber. At the exit end of the fiber a first resonator mirror is provided which is highly reflecting for the laser light to be generated in the wavelength range with the smallest light amplification and to the light of the pump light source. Spaced from the first resonator mirror a second resonator mirror is provided via which light of further wavelength ranges can be fed back into the fiber with the aid of a collimating lens.

An optical fiber loop has a gain medium having a gain at an oscillation wavelength and optical circulators 13 and 14. Collimate lenses 22 and 24 enlarge light bean taken from the optical circulators 13 and 14. A polygon mirror 25 is provided on the light axis, and is rotated. A diffraction grating 27 is provided at the receiving position of the light reflected by the polygon mirror 25, and is of a Littrow configuration which reflects the light in the same direction as the incident light. A selected wavelength changes according to an incident angle to the diffraction grating 27, resulting in increase of selectivity owing to twice incident, thereby permitting to change an oscillation wavelength with narrow band even when changing the selected wavelength by rotating the polygon mirror 25 at high speed.

A hybrid laser source including a solid state laser driven by an array of fiber laser amplifiers, the inputs of which are controllable in phase and polarization, to compensate for distortions that arise in the solid state laser, or to achieve desired output beam properties relating to direction or focus. The output beam is sampled and compared with a reference beam to obtain phase and polarization difference signals across the output beam cross section, at spatial positions corresponding with the positions of the fiber laser amplifiers providing input to the solid state laser. Therefore, phase and polarization properties of the output beam may be independently controlled by predistortion of these properties in the fiber laser amplifier inputs.

The invention relates to an orbital welding device for mobile use in order to join a first pipe (1) and a second pipe end (2) along a circumferential joint (3) by at least one weld seam (4), particularly for producing a pipeline (5) to be placed on land. The inventive device includes a guide ring (6), which can be oriented toward the first pipe end (1) and the circumferential joint (3), and an orbital carriage (7) that can be motor-displaced along the guide ring (6) via an advancing device (8). On the orbital carriage (7), a laser welding head (12) for directing a laser beam (10) into a laser welding zone (13) is mounted in a manner that enables it to be oriented toward the circumferential joint (3) whereby enabling the production of the weld seam (4) along the circumferential joint (3) by displacing the orbital carriage (7). The laser beam (10) is produced by a high-power fiber laser beam source (9) located, in particular, on a mobile transport vehicle (35) while being situated at a distance from the orbital carriage (7), is guided by light guide (11) passing through a tube bundle (50) to the orbital carriage (7) and then supplied to the welding head (12). A significant advantage of the invention resides in the fact that the joining of two pipe ends by only one single welding process during a short period of time is made possible in the field with autonomous operation.

The present invention relates in general to coupling of light from one or more input waveguides to an output waveguide or output section of a waveguide having other physical dimensions and / or optical properties than the input waveguide or waveguides. The invention relates to an optical component in the form of a photonic crystal fibre for coupling light from one component / system with a given numerical aperture to another component / system with another numerical aperture. The invention further relates to methods of producing the optical component, and articles comprising the optical component, and to the use of the optical component. The invention further relates to an optical component comprising a bundle of input fibres that are tapered and fused together to form an input coupler e.g. for coupling light from several light sources into a single waveguide. The invention still further relates to the control of the spatial extension of a guided mode (e.g. a mode-field diameter) of an optical beam in an optical fibre. The invention relates to a tapered longitudinally extending optical waveguide having a relatively larger cross section that over a certain longitudinal distance is tapered down to a relatively smaller cross section wherein the spatial extent of the guided mode is substantially constant or expanding from the relatively larger to the relatively smaller waveguide cross section. The invention may e.g. be useful in applications such as fibre lasers or amplifiers, where light must be coupled efficiently from pump sources to a double clad fibre.

Various embodiments may be used for laser-based modification of target material of a workpiece while advantageously achieving improvements in processing throughput and / or quality. Embodiments of a method of processing may include focusing and directing laser pulses to a region of the workpiece at a pulse width sufficiently short so that material is efficiently removed by nonlinear optical absorption from the region and a quantity of heat affected zone and thermal stress on the material within the region, proximate to the region, or both is reduced relative to a quantity obtainable using a laser with longer pulses. In at least one embodiment, an ultrashort pulse laser system may include at least one of a fiber amplifier or fiber laser. Various embodiments are suitable for at least one of dicing, cutting, scribing, and forming features on or within a composite material.

A color laser display apparatus which contains a laser light source which emits ultraviolet laser light, a modulation unit which modulates the ultraviolet laser light, a display unit which includes a fluorescent screen, and a scanning unit which two-dimensionally scans the fluorescent screen with the ultraviolet laser light. The fluorescent screen includes, for each pixel, red fluorescent material which emits red light in response to the ultraviolet laser light, green fluorescent material which emits green light in response to the ultraviolet laser light, and blue fluorescent material which emits blue light in response to the ultraviolet laser light. The laser light source may be, for example, a semiconductor laser or a fiber laser.

A color laser display apparatus which contains a laser light source which emits ultraviolet laser light, a modulation unit which modulates the ultraviolet laser light, a display unit which includes a fluorescent screen, and a scanning unit which two-dimensionally scans the fluorescent screen with the ultraviolet laser light. The fluorescent screen includes, for each pixel, red fluorescent material which emits red light in response to the ultraviolet laser light, green fluorescent material which emits green light in response to the ultraviolet laser light, and blue fluorescent material which emits blue light in response to the ultraviolet laser light. The laser light source may be, for example, a semiconductor laser or a fiber laser.

A fiber-laser-based implementation of a Terahertz source through difference frequency generation (DFG) by nonlinear optical (NLO) crystals is compact, tunable and scalable. A pair of fiber lasers (Q-switched, CW or mode-locked) generate single-frequency outputs at frequencies ω1 and ω2. A fiber beam combiner combines the laser outputs and routes the combined output to a THz generator head where a nonlinear interaction process in the NLO crystal generates THz radiation.

The invention discloses a multi-channel fiber Bragg grating (FBG) demodulator, which adopts a scanning fiber laser as a light source. The scanning fiber laser is on the basis of a micro-mechanical structural filter with temperature control, and belongs to a narrow-linewidth and high-coherent light source which is calibrated accurately. The calibration is implemented by a thermostable FP etalon with a wavelength label. A gain matching fiber amplifier amplifies the power of the output of a laser and achieves the power flatness of scanning laser spectroscopy. A fiber Bragg grating reflected signal enters a data acquiring and processing system after passing through a photoelectric detector and an AD converter processing module. A data acquiring and processing and peak detection system is implemented by adopting an FPGA-based all-digital scheme, and simultaneously utilizes a synchronous signal of a direct numerical frequency synthesis module to obtain a control voltage of the micro-mechanical structural filter. By combining with other equipment, the scanning fiber laser, the etalon and the FPGA realize the multichannel, high-precision, high-stability, high-repeatability, and serial-parallel structure detection of a grating sensor network signal.

A modelocked linear fiber laser cavity with enhanced pulse-width control includes concatenated sections of both polarization-maintaining and non-polarization-maintaining fibers. Apodized fiber Bragg gratings and integrated fiber polarizers are included in the cavity to assist in linearly polarizing the output of the cavity. Very short pulses with a large optical bandwidth are obtained by matching the dispersion value of the fiber Bragg grating to the inverse of the dispersion of the intra-cavity fiber.

Fiber lasers and methods for constructing and using fiber lasers for micro- / nano-machining with output beams including stacked pulses and combinations of continuous wave, pseudo-continuous wave and pulse sequence components.

Optical fiber lasers and components for optical fiber laser. An optical fiber laser can comprise a fiber laser cavity having a wavelength of operation at which the cavity provides output light, the cavity including optical fiber that guides light having the wavelength of operation, the fiber having first and second lengths, the first length having a core having a V-number at the wavelength of operation and a numerical aperture, the second length having a core that is multimode at the wavelength of operation and that has a V-number that is greater than the V-number of the core of the first length optical fiber at the wavelength of operation and a numerical aperture that is less than the numerical aperture of the core of the first length of optical fiber. At least one of the lengths comprises an active material that can provide light having the wavelength of operation via stimulated emission responsive to the optical fiber receiving pump light. Components include a mode field adapter and optical fiber interconnection apparatus, which can be used to couple the first and second lengths of optical fiber, or can couple the fiber laser to an optical fiber power amplifier, which can be a multimode or single mode amplifier.

The invention relates to a DFB fiber laser sensor (1). A measurement quantity makes it possible to induce a linear birefringence between mode pairs of the laser-amplifying fiber (2) and to measure an associated beat frequency (Δν1, Δν2, Δν3). According to the invention, the laser-amplifying fiber (2) has a nonrotationally symmetrical structure, so that it is possible to detect isotropic pressures p, acoustic waves or chemical substances that can be added radially to the laser-amplifying fiber (2). In a second aspect of the invention, an emission wavelength range and parameters (a, b, ΔN) of the laser-amplifying fiber (2) and also a grating period L of the fiber Bragg grating resonator (3) are coordinated with one another such that at least two different spatial modes (LP01, LP11even, LP11odd, LP21even) are propagatable and it is possible to measure beat frequencies (Δν1, Δν2, Δν3) between oscillatory longitudinal laser modes assigned to them. Exemplary embodiments relate to: rotationally asymmetrical fiber types, a choice of special spatial modes (LP11odd, LP21even) and / or multiple fiber Bragg gratings (3) for reducing the beat frequencies (Δν1, Δν2, Δν3) below 100 GHz; and elimination of temperature influences e.g. by the detection of a plurality of beat frequencies (Δνa, Δνb, Δνc, Δνd) between different pairs of spatial modes (LP01, LP11even, LP11odd, LP21even) and / or polarization modes (X, Y).

A system for pulsed synchronized laser cutting of stents and / or other medical products includes a numerical controller and a machine for moving a tube of material during cutting. A pulsed fiber laser is configured to cut the tube into, for example, a stent, the numerical controller being in communication with the machine and configured to send movement control information to the machine. The numerical controller may also receive movement speed information from the machine. The numerical controller is also in communication with the pulsed fiber laser and is configured to send pulse control information to the pulsed fiber laser. The numerical controller is configured to cause average laser power to decrease by decreasing frequency of laser pulses as stent cutting speed decreases, and to cause average laser power to increase by increasing frequency of laser pulses as stent cutting speed increases.

Apparatus and method for generating controlled-linewidth laser-seed-signals for high-powered fiber-laser amplifier systems. In some embodiments, the natural chirp (frequency change of laser light over a short start-up time) of a DBR laser diode when driven by pulsed current is used to broaden the linewidth of the laser output, while adjusting the peak current and / or the pulse duration to obtain the desired linewidth.

An optically-active air-clad fiber (30) includes a core (34, 84) that facilitates doping with an ion optically excitable and having a three-level optical transition when pumped at a first end (28) of an optical cavity (46) by a multimode pump source (72) at a pump wavelength (64) for lasing at a signal wavelength (66) different than the pump wavelength (64) at a second end (29) of the optical cavity (46), the core (34, 84) having a refractive index, wherein the core (34, 84) is transformed from the first end to proximate the second end (29) thereof such that the optically-active fiber (30) is multimode at the pump wavelength proximate to the first end (28), and is single-mode at the signal wavelength proximate to the second end (29). An air-clad (36, 86) surrounds at least one portion of the core (34, 84) and has a lower effective refractive index than the refractive index of the core (34, 84).

A low-noise laser diode module comprises a laser diode for emitting light with a wavelength in the range from UV to IR, a drive circuit for injecting electrical current into said diode, and an automatic power control circuit for monitoring and adjusting laser output power using front-facet photodiode external to the laser assembly and a feedback loop. Said drive circuit produces injection current modulated by an RF signal with variable degrees, depending on the wavelength to be stabilized, the desired spectral bandwidths of the laser output, and / or other applications. Said RF signal can be a sine wave, a distorted sine wave, a rectified sine wave, a non-sine wave, a series of narrow pulses, or repetitive shunt. The present invention encompasses a method for producing stable, broadband, and low-coherent laser. The present invention also encompasses a method for producing stable narrowband or single longitudinal mode laser. The present invention further encompasses a compact light source applicable to DPSS lasers, fiber lasers, optical parametric oscillators, low-speckle laser display systems, and seeders, with or without nonlinear frequency conversion processes.

A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

High power optical pulses generating methods and laser oscillators are provided. A light generating module generates seed optical pulses having predetermined optical characteristics. A spectrum tailoring module is then used to tailor the spectral profile of the optical pulses. The spectral tailoring module includes a phase modulator which imposes a time-dependent phase variation on the optical pulses. The activation of the phase modulator is synchronized with the passage of the optical pulse therethough, thereby efficiently reducing the RF power necessary to operate the device.

A system and method for selectively process material on a processing surface of a printing form to create a fine structure or pattern for images or text. At least one fiber laser comprising a pump source and a laser fiber is provided. A laser gun is mounted adjacent the printing form and has at least a focusing optics. The fiber laser outputs a laser beam which is diffraction-limited to permit the focusing optics to focus the laser beam onto the processing surface of the printing form as a spot having a spot size sufficiently small to process the processing surface to create the fine structure or pattern images or text.

A large diameter optical waveguide, grating, and laser includes a waveguide 10 having at least one core 12 surrounded by a cladding 14, the core propagating light in substantially a few transverse spatial modes; and having an outer waveguide dimension d2 of said waveguide being greater than about 0.3 mm. At least one Bragg grating 16 may be impressed in the waveguide 10. The waveguide 10 may be axially compressed which causes the length L of the waveguide 10 to decrease without buckling. The waveguide 10 may be used for any application where a waveguide needs to be compression tuned, e.g., compression-tuned fiber gratings and lasers or other applications. Also, the waveguide 10 exhibits lower mode coupling from the core 12 to the cladding 14 and allows for higher optical power to be used when writing gratings 16 without damaging the waveguide 10. The shape of the waveguide 10 may have other geometries (e.g., a “dogbone” shape) and / or more than one grating or pair of gratings may be used and more than one core may be used. The core and / or cladding 12,14 may be doped with a rare-earth dopant and / or may be photosensitive. At least a portion of the core 12 may be doped between a pair of gratings 50,52 to form a fiber laser or the grating 16 or may be constructed as a tunable DFB fiber laser or an interactive fiber laser within the waveguide 10. The waveguide may resemble a short “block” or a longer “cane” type, depending on the application and dimensions used.