A fiber amplifier is provided, including a pump laser (202), a pump and signal combiner (203), and a few-mode doped fiber (204). The pump laser (202) is configured to output pump light. The pump and signal combiner (203) is configured to couple input few-mode signal light and the pump light into the few-mode doped fiber (204). Refractive indexes of a fiber core of the few-mode doped fiber (204) are distributed to be gradient along a radial direction of a cross section, the fiber core is etched with periodic gratings along an axial direction, and periods of the gratings satisfy a phase matching condition. The fiber amplifier achieves strong coupling and co-amplification between optical signal modes, thereby reducing a differential gain between mode groups.

An object is to provide an optical amplifier with a cladding pumped configuration that improves amplification efficiency. The optical amplifier according to the present invention includes a pump light conversion fiber 11 that converts first pump light L1 with a first wavelength propagating in a cladding into second pump light L2 with a second wavelength, an amplification fiber 13 that is connected to the pump light conversion fiber 11 and optically amplifies signal light Ls with the second pump light L2 supplied to the cladding from the pump light conversion fiber 11, and an oscillator 12 that causes the second pump light L2 to be reflected on two reflectors 15 and to reciprocate within the claddings of the pump light conversion fiber 11 and the amplification fiber 13 to cause laser oscillation of the second pump light L2.

A radial polarization disk laser, including a pumping source, a collimator lens, a focusing lens, a laser gain medium, a Brewster axial cone, and a output lens, which are sequentially arranged along a laser light path. An angle formed between the conical surface and the bottom surface of said Brewster axial cone is a Brewster's angle. Said laser gain medium is bonded with said bottom surface; said laser gain medium and said output lens form a laser harmonic oscillator cavity therebetween. The pumped laser light emitted by said pumping source passes through said collimator lens and said focusing lens, then is focused on the laser gain medium, and. the generated photons oscillate in said laser harmonic oscillator cavity, and then a radial polarized laser beam is finally output by said output lens.

A laser system includes a beam shaping unit, a random phase plate, and a collimating optical system in an optical path between a solid-state laser device and an excimer amplifier. When a traveling direction of a laser beam entering the excimer amplifier is a Z direction, a discharge direction of a pair of discharge electrodes is a V direction, a direction orthogonal to the V and Z directions is an H direction, a shaping direction of the beam shaping unit corresponding to the V direction is a first direction, a shaping direction of the beam shaping unit corresponding to the H direction is a second direction, an expansion rate in the first direction is E1, and an expansion rate in the second direction is E2, the beam shaping unit expands a beam section of the laser beam such that an expansion ratio defined by E2/E1 is higher than 1.

The present disclosure relates to a fiber encapsulation mechanism for energy dissipation in a fiber amplifying system. One example embodiment includes an optical fiber amplifier. The optical fiber amplifier includes an optical fiber that includes a gain medium, as well as a polymer layer that at least partially surrounds the optical fiber. The polymer layer is optically transparent. In addition, the optical fiber amplifier includes a pump source. Optical pumping by the pump source amplifies optical signals in the optical fiber and generates excess heat and excess photons. The optical fiber amplifier additionally includes a heatsink layer disposed adjacent to the polymer layer. The heatsink layer conducts the excess heat away from the optical fiber. Further, the optical fiber amplifier includes an optically transparent layer disposed adjacent to the polymer layer. The optically transparent layer transmits the excess photons away from the optical fiber.

A vertical external cavity surface emitting laser (VECSEL) based system in a linear single cavity configuration is configured to deliver light in higher-order Hermite-Gaussian transverse modes with Watt-level output power. Simultaneous and independent lasing of spatially-restructurable multiple high-order transverse modes that are collinearly-propagating at the output of such laser cavity is facilitated with the use of an optical pumping scheme devised to control positions of location at which the gain medium of the system is pumped (e.g., locations of focal spots of multiple pump beams on the gain-medium chip). An external astigmatic mode converter is utilized to convert such high-order Hermite-Gaussian modes into corresponding Laguerre-Gaussian modes.

An active element added-optical fiber includes a core, having a radius d and including a first region and a second region, and a cladding that surrounds an outer peripheral surface of the core without a gap and propagates light in a few mode. The first region is a region from a central axis of the core to a radius ra and contains ytterbium as an active element. The second region is a region to the radius d that surrounds the first region without a gap and contains a plurality of dopants, one of which is germanium. The active element is not added to a region within the second region from a radius rc to the radius d. The germanium is not added to a region within the first region from the central axis to a radius rb, and a concentration of the germanium is highest among the plurality of dopants.

A laser device for generating an optical wave including at least two frequencies, such laser device including: a first element including a gain region, a second mirror, distinct from the first element, and arranged so as to form with a first mirror an optical cavity including the gain region; means for pumping the gain region so as to generate the optical wave; means for shaping the light intensity of the optical wave arranged for selecting at least two transverse modes of the optical wave; and means for shaping the longitudinal and/or transversal phase profile of the optical wave and arranged for adjusting at least two transverse modes of the optical wave.

In an optical fiber device having a configuration in which an optical fiber is joined to a side surface of another optical fiber, a joint portion is suppressed from reaching a high temperature. The optical fiber device includes a first fluoride fiber, a second fluoride fiber, and a heat dissipation member. The first fluoride fiber guides light. The second fluoride fiber has a first end on or from which light is incident or output and a second end at which an end surface of the second fluoride fiber is obliquely joined to a side surface of the first fluoride fiber.

A vertical external cavity surface emitting laser (VECSEL) based system in a linear single cavity configuration is configured to deliver light in higher-order Hermite-Gaussian transverse modes with Watt-level output power. Simultaneous and independent lasing of spatially-restructurable multiple high-order transverse modes that are collinearly-propagating at the output of such laser cavity is facilitated with the use of an optical pumping scheme devised to control positions of location at which the gain medium of the system is pumped (e.g., locations of focal spots of multiple pump beams on the gain-medium chip). An external astigmatic mode converter is utilized to convert such high-order Hermite-Gaussian modes into corresponding Laguerre-Gaussian modes.