A fiber structure includes a covering part, the covering part having an optical fiber strand and a coating covering the optical fiber strand; a strand exposed part adjacent to the covering part, the strand exposed part including an exposed optical fiber strand, and a sealing part covering a boundary between the covering part and the strand exposed part. The sealing part including a fluororesin having a structure represented by formula (1):

##STR00001##

where R represents a divalent organic fluorine compound group, and n represents an integer of 1 or more.

An electrodeless laser-driven light source includes a laser that generates a CW sustaining light. A pump laser generates pump light. A Q-switched laser crystal receives the pump light generated by the pump laser and generates pulsed laser light at an output in response to the generated pump light. A first optical element projects the pulsed laser light along a first axis to a breakdown region in a gas-filled bulb comprising an ionizing gas. A second optical element projects the CW sustaining light along a second axis to a CW plasma region in the gas-filled bulb comprising the ionizing gas. A detector detects plasma light generated by a CW plasma and generates a detection signal at an output. A controller generates control signals that control the pump light to the Q-switched laser crystal so as to extinguish the pulsed laser light within a time delay after the detection signal exceeds a threshold level.

An optical material including: a silica host; and a Praseodymium dopant; wherein the Praseodymium atoms are configured to form nanoclusters in the silica host. In addition, the optical material may include an Ytterbium co-dopant. The nanoclusters include Ge, Te, Ta, Lu and/or F, Cl to minimize multi-phonon quenching. Moreover, the nanoclusters may be encapsulated in a low phonon energy shell to minimize energy transfer to the host matrix.

An optical element includes an optical material including a first edge and an opposing second edge. The optical element further includes a plurality of micro-channels arranged within the optical material. Each of the micro-channels of the plurality of micro-channels extends from the first edge to the second edge of the optical material.

A laser system for the generation of ultrashort optical pulses of light including an oscillator emitting low power and negatively chirped optical pulses with a spectral bandwidth W1, a dispersive connecting segment to maintain the sign of the chirp of the pulses of the oscillator, an optical amplifier for amplifying the optical light pulses and a negative group velocity dispersion segment for compensating phase contributions of the whole propagation process. During the propagation from the output of the oscillator to the end of the optical amplifier, the chirp of the light pulses will change once from negative to positive chirp. After a final compression stage ultrashort optical pulses can be generated.

Multi-clad optical fiber cladding light stripper (CLS) comprising an inner cladding with one or more recessed surface regions to remove light propagating within the inner cladding. A CLS may comprise such recessed surface regions along two or more azimuthal angles about the fiber axis, for example to improve stripping efficiency. One or more dimensions, or spatial distribution, of the recessed surface regions may be randomized, for example to improve stripping uniformity across a multiplicity of modes propagating within a cladding. Adjacent recessed surface regions may abut, for example, end-to-end, as segments of a recess that occupies a majority, or even an entirety, of the length of a fiber surrounded by a heat sink. One or more dimensions, or angular position, of individual ones of the abutted recessed surface regions may vary, according to a regular or irregular pattern.

To provide a mode-locked pulse photoproduction filter for easily realizing self-starting mode-locking, and a laser device for generating a picosecond or femtosecond-pulse laser light by including such filter, the laser device including an amplifying unit for amplifying and outputting a light inside a resonator, and the mode-locked pulse photoproduction filter having a first filter part for selectively outputting a first wavelength component that is a wavelength component of an oscillation band inside the resonator, and a second filter part for selectively outputting a second wavelength component that is a wavelength component different from the oscillation band inside the resonator.

A laser cutting head includes a controllable collimator with movable collimator lenses for controlling beam diameter and/or focal point location. The laser cutting head may be used in a laser cutting system with a control system for controlling the position of the movable collimator lenses. The lenses may be moved, for example, to adjust the beam spot size for cutting different types of material or material thicknesses. The lenses may also be moved to adjust a focal point back to the workpiece after changing the distance of the laser cutting head relative to the workpiece.

The present invention makes it possible to improve excitation efficiency in a fiber laser device provided with a TFB having an injection optical fiber not connected to an excitation light source. This fiber laser device is provided with: a plurality of excitation light sources, at least one fiber bundle that injects excitation light from the plurality of excitation light sources from a plurality of injection optical fibers and couples the excitation light to one optical fiber; and a cavity that introduces the excitation light coupled by the fiber bundle and amplifies and emits laser light. The number of the plurality of injection optical fibers of the fiber bundle is larger than the number of the plurality of excitation light sources, and a loop part is configured by connecting surplus injection optical fibers to which the excitation light is not injected among the plurality of injection optical fibers of the fiber bundle.

A class of erbium-doped silicate crystals have a general chemical formula of (Er.sub.xYb.sub.yCe.sub.zA.sub.(1-x-y-z)).sub.3RM.sub.3Si.sub.2O.sub.14, in which the range of x is 0.002 to 0.02, y is 0.005 to 0.1, and z is 0 to 0.15; A is one, two or three elements selected from Ca, Sr, or Ba; R is one or two elements selected from Nb or Ta; M is one or two elements selected from Al or Ga. Using one of such crystals as a gain medium and a diode laser at 940 nm or 980 nm as a pumping source, a 1.5 μm continuous-wave solid-state laser with high output power and high efficiency, as well as a pulse solid-state laser with high energy and narrow width can be obtained.