Abstract: A high power fiber laser system includes a booster winch is configured as a fiber amplifier extending over free space, pump source and laser head including a reflective element which receives pump light and reflects toward the output end of the booster in a counter signal-propagating direction. The booster is configured with concentric and coextending frustoconically shaped (“MM”) core and cladding around the core. The core includes a mode transition region expanding between small diameter SM input and large diameter MM output core ends and configured so that amplification of high order modes is substantially suppressed as a single mode (“SM”) signal light propagates from the input to output core ends. The laser head receives output ends of respective pump light delivery fibers and signal fiber, respectively. The pump source is structured with a plurality of independent sub pumps arranged around the booster.

Abstract: An optical active fiber is configured with an asymmetrically-shaped core having at least one long axis and a shortest axis which extends transversely to the long axis. The outmost cladding of the active fiber is configured with a marking indicating the orientation of the short axis. The marking allows for bending the fiber so that the shortest axis extends along and lies in the plane of the bend thereby minimizing distortion of a mode which is guided by the asymmetrically-shaped core as light propagates along the bend.

Abstract: The present invention is a method and system for reducing contamination in the resulting plasma of a weld produced by a fiber laser. The invention establishes the fiber laser in an optimal configuration for applying a high density beam to a weld material that eliminates spectral interference. The beam is applied in a narrow bandwidth of 1064 nm+/?0.5 nm in one operative condition using an inert shielding gas, preferably argon, in a cross-flow or controlled environment around the welding region to prevent contamination of the plasma forming in the weld region. The method is optimized by determining and avoiding the emission spectrum for the fiber laser and the cover gas or gasses as well as any particular excitation spectra for the weld material. The system can utilize a single laser input, or can utilize multiple lasers joined by coupling means and utilizing a switch to select one or more of the fiber lasers.

Abstract: A high power (HP) fiber circulator is configured with a case enclosing a plurality of optical components which are arranged so as to define multiple ports. The fiber circulator further includes a plurality of launching and receiving fiber components each of which has spliced delivery and pigtailed passive fibers selectively coupling a HP input signal into and receiving a HP output signal from respective input and output ports. The passive fibers of each fiber component have respective protective coatings spaced from one another and each covering the cladding of the fibers. A light stripper, extending between the protective coatings, is operative to substantially remove cladding-supported light from one of the passive fibers before it reaches the protective coating of the other passive fiber.

Abstract: The present invention relates to a head assembly for a laser processing system, preferably a fiber laser processing system. An assembly system allows a secure and a slidingly focusing displacement of a focusing lens assembly relative to a beam path in a laser processing system. The assembly system provides easy replacement of desired focusing lens assemblies. Adaptive modifications are operative to provide computerized processor control of the focusing displacement and detection of an installed optical assembly and position thereof.

Abstract: A fiber block is configured with a fiber block including a Nd-doped active fiber and a pump-light delivery fiber which has a stretch extending along the active fiber in a side-to-side configuration so as to lunch pump light into the Nd-doped core of the active fiber. The core of the active fiber is surrounded by at least one or more claddings which, like the core, have a double bottleneck cross-section with a relatively large-area central region and relatively small input and output regions. The pump light delivery fiber is structured to have a substantially dumbbell cross-section with a relatively small-area central region coextending with the central region of the active fibers. The active fiber is dimensioned so that the overall length of the active fiber is configured to provide for the maximal amplification of the laser signal in a 900 nm range while limiting amplification in the 1060 nm range to the preset threshold.

Abstract: A method for contactless laser welding of a plurality of sheets of material stacked upon one another includes simultaneously delivering a laser beam and a stream of fluid through a laser head and further through an end cap which is removably mounted to the laser head. The end cap is configured with a stationary cylinder, which is coupled to the laser head, and a piston movable relative the cylinder. The piston moves in response to a pressure differential generated by the fluid in chambers above and below the piston. Once the pressure equilibrium is reached between the chambers, the pressure in the chamber below the piston is sufficient to reliably press the sheets of material against one another during a laser welding operation.

Abstract: A system for recording multiple volume Bragg gratings (VBGs) in a photo thermo-refractive material is configured to implement a method which provides for irradiating the material by a coherent light through a phase mask. The system has a plurality of actuators operative to displace the light source, phase mask and material relative to one another so as to mass produce multiple units of the material each having one or more uniformly configured VBGs.

Abstract: A fiber laser system is configured with a nonlinear resonator cavity which includes a plurality of mirrors. One of the mirrors is a piezoelectric mirror capable of being displaced between multiple positions in response to a control signal generated by a digital controller. The generation of the control signal is caused by mismatch between a fundamental frequency, imputed into the resonant cavity and further split by a nonlinear crystal into resonant and harmonic frequencies, and the resonant frequency. The positions of the piezoelectric mirror and time interval the piezoelectric mirror may occupy these position are controlled so that the output radiation at the harmonic may be periodically interrupted which results in a pulsed output radiation.

Abstract: An ultra-high power fiber laser system includes a multimode combiner which is configured with a plurality of low mode fibers bundled together and tapering toward its downstream end. The system further includes a clad mode absorber extending along the tapered downstream end of the combiner and extending over a portion of the combiner's output fiber. The absorber is configured with sequentially located zones which are provided with respective refractive indices. In a forward propagating direction of light signal, the upstream zone includes polymeric material with the refractive index higher than that of the cladding of the combiner end fiber. This zone is configured to remove the back reflected core guided light bled into the cladding of the combiner through a splice between combiner end and output fibers.

Abstract: A high power pump ultra bright low-noise source is configured with a multimode (“MM”) seed source outputting a MM smooth, low-noise signal light at a desired wavelength in a wavelength range between about 974 and 1030 nm, a MM Yb fiber wavelength converter operative to convert emission of a plurality of high power (“HP”) semiconductor laser diodes at a sub-pump wavelength ? sp to a pump output at the desired wavelength ??, wherein ??=????sp<0/1?sp. The Yb-doped MM wavelength converter is configured with noise levels substantially identical to those of the low-noise signal light, brightness (“B”) substantially equal to ?×B, wherein n is a number HP semiconductor laser diodes, and B is brightness of each HP laser diode, and output power (“Po”) substantially equal to nPd, wherein Pd is a power of each HP laser diode, and n is the number thereof.

Abstract: The invention relates to a machine for material processing with a laser beam, in particular laser welding. It is comprised of a machine guided protective housing with an outlet opening surrounding the laser beam that is pointed at the material during processing. To create a machine for laser beam welding which ensures improved operator and personal safety without completely enclosing the machine, it is suggested that the protective housing contains at least one sensor which measures certain chemical or physical properties. The sensor is connected to the machines control unit which compares the current values with reference values for a measure and, depending on current/reference value comparison, interrupts the laser beam or prevents laser beam activation. In addition a method and arrangement for improved operator and personal safety for operation of such a machine is presented.

Abstract: Thermal processing is performed by transmission of mid infra-red laser light through a substrate such as a semiconductor substrate with a limited mid infra-red transmission range. The laser light is generated by a rare-earth-doped fiber laser and is directed through the substrate such that the transmitted power is capable of altering a target material at a back side region of the substrate, for example, on or spaced from the substrate. The substrate may be sufficiently transparent to allow the transmitted mid infra-red laser light to alter the target material without altering the material of the substrate. In one example, the rare-earth-doped fiber laser is a high average power thulium fiber laser operating in a continuous wave (CW) mode and in a 2 ?m spectral region.

Abstract: A monolithic fiber has a double bottleneck-shaped core configured with opposite uniformly configured end regions, frustoconical transformer regions which run inwards from the respective end regions, and a central uniformly-dimensioned region which bridges the transformer regions. The core is configured as a multimode core or single-mode core and capable of guiding a single transverse mode between the end regions without splice losses.

Abstract: The present invention relates to a fiber laser system for processing materials involving a system of interconnected operational components for combining and optionally distributing beams from multiple beam emitters. More particularly, the present invention provides a system for combining and distributing fiber laser beams having different wavelengths and a method for operating the system thereof. Multiple beam combiners may be optionally linked with a beam distribution system. In exemplary use, multiple fiber laser sources generating different wavelength outputs are combined in a single beam incident of a work piece comprising multiple layers.

Abstract: A high power pulsed laser system is configured with at least two gain blocks and with at least one saturable absorber (SA) coupled to the output and input of the respective gain blocks. The SA is configured so that Qsat_sa<Qsat_gb, wherein Qsat_sa is a saturation energy of the SA, and Qsat_gb is a saturation energy of the gain blocks. The SA is further configured with a recovery time ?<1/f providing for the substantially closed state of the SA, wherein the f is a pulse repetition rate, and with the recovery time ? smaller than a round trip time Tround_trip=2*(L1+L2)*n/c, where L1, L2—lengths of the respective gains gain blocks, n—a refractive index of active media, c—a speed of light in vacuum.

Abstract: A welding tool is configured with a housing enclosing a fiber laser system which is operative to produce a weld seam for connecting two workpieces. The fiber laser system includes a focusing optic configured to focus the output beam of the system so that it propagates through an elongated slit formed in the bottom of the housing. The fiber laser system is capable to move along a predetermined path extending parallel to the longitudinal direction of the slit and limited by the perimeter thereof. The output beam is generated only when the slit sits upon at least one of the workpieces.

Abstract: A unit for measuring a power of randomly polarized light beam is configured with spaced first and second beam splitters having respective reflective surfaces which face one another and configured to sequentially reflect a fraction of randomly polarized beam which is incident upon the first splitter. The beam splitters are dimensioned and shaped so that an output beam, reflected from the second beam splitter, has a power independent from the state of polarization of the randomly polarized beam.

Abstract: A power supply for laser systems is configured with a DC power source having an output source voltage, an energy accumulator operatively connected to the output of the DC power source, and a pump. Coupled between the accumulator and source is a first DC to DC stage with at least one switched-mode power converter which is operative to charge the accumulator with voltage. The charged voltage may be same or different from the source voltage. The power supply further includes a second DC to DC stage with at least one switched-mode power converter coupled between the accumulator and pump and operative to discharge accumulator to the same or different output voltage. The DC to DC converters are configured so that current pulses at the input of the pump each have a peak value greater than the power source current.

Abstract: The present disclosure is a system for the protection of a fiber within a laser system. The system has a water-cooled housing supporting a termination block, which is operative to shield a protective layer of a delivery fiber from back-reflected beams of light. The termination block is manufactured from quartz and is frustconical in configuration and fuseable to the delivery fiber. The delivery fiber has a polymeric protective layer with an acceptance end and a delivery end, and passes through a washer contained within the housing; the washer has a dielectric reflective coating. The system has at least one terminal block connector which further comprises a cone termination block, a reflector, and a set of light guards. The cone termination block is spliced to an output end of the delivery fiber and produces an angle ? so as to reduce propagation of back-reflected light. The reflector is positioned so as to block additional back-reflected light from the protective layer of the delivery fiber.