A diode-pumped solid-state laser has been invented that provides long Q-switched pulses at high repetition rate with high stability. The laser incorporates Nd:YVO4 as the gain medium.

Long pulse vanadate laser

Broadband emission from Er-contained yttrium orthophosphate and orthovanadate nanopowders excited by near infrared radiation

An efficient laser diode module for EDFA pumping

Rectangular core multimode fibers with core dimensions of (10 - 22) micrometers X (170 - 200) micrometers and numerical aperture of 0.15 have been designed for high power diode lasers coupling with maximum preservation of laser radiation power density and laser radiation linear state of polarization.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Rectangular core fibers for high-power diode laser applications

A diode-pumped microchip laser based on an Nd3+:GdVO4 crystal was investigated. A maximum output power of about 4 W with a differential efficiency of 22% was obtained.

Microchip laser based on an Nd3+; GdVO4 crystal

A single-mode Nd3+ : GdVO4 laser (? = 1.06 ?m) with diode pumping (? = 10.81 ?m) and fibre input was constructed. It could be operated in the cw regime and in a regime of passive Q switching of the cavity. A technology was developed for coupling the radiation of laser diodes into fibre waveguides with an efficiency up to 93%. Without focusing of the pump radiation (of 175 mW power), the output power and the lasing threshold obtained for a hemispherical cavity 10 cm long were 38 and 15 mW, respectively. When the laser was passively Q switched by an LiF : crystal, the output was pulse-periodic: the pulse duration was 15?100 ns, the repetition frequency was 5?200 kHz, and the peak power was 10 W.

Diode pumped Nd3+ : GdVO4 laser with fibre input

asymmetric output mode and depolarisation of the output. As shown in Fig. 2c, the thermal lens can be compensated for by using a flat HR mirror, but the birefringence effects in the output mode are still present. However, the output energy and beam quality are almost the same as in Fig. 2a. Additional examples for a number of resonators and for different pulse rates will be given in the presentation. 1.

http://ieeexplore.ieee.org/iel3/5030/13794/00636752.pdf

Diode-pumped Nd:GdVO, laser with highefficient fiber-optic module

Radial nonsymmetrical fiber endface microlenses original fabrication technique has been used for high efficient pump laser diode radiation coupling (up to 93% without AR coating) into the standard optical fibers and for the form of a pump power diagram at the output fiber endfaces. Nd:GdVO 4 laser (2.5 mm crystals length) parameters with semiconfocal (output mirror curvature radius 10 cm) and monolith plane mirrors cavities have been measured for different pump diagrams formed by plane endfaces, spherical microlenses, and Selfoc lenses. Compact diode-pumped solid state lasers may be used in optical communications, optical storage, medicine, and other applications. Diode laser (DL)-optical fiber coupling gives several advantages for these pumping systems -- a possibility to combine several DLs radiation, a remote DLs mounting, small size and electrical safety of the laser heads, simple schemes of active crystals cooling, axial symmetry of the pumping beam for longitudinal geometry. In general, high coupling efficiency between a semiconductor light source and optical fiber may be achieved by the use of microlens, formed on the endface of the fiber. In this case bulk optical components between DL and optical fiber are not needed. In addition, the only reflection surface exists in this coupling technique. Different techniques for producing microlenses on a fiber endface have been developed. For example, tapered hemispherical lenses, melted, etched, and polished lenses are commonly used for this coupling. However, all types of such techniques produce in general radial symmetry lenses: therefore, they do not provide efficient coupling between a round fiber core and a nonsymmetrical DL's radiation. In this paper we demonstrate the fabrication technique of fiber endface radial nonsymmetrical microlenses with radii curvature from few micrometers to few tens micrometers by grinding/polishing process. This process may be used for producing different nonspherical microlenses (cylindrical, elliptical, hyperbolic, etc.) to efficient coupling DL's radiation into single-mode or multimode optical fibers and for producing microlenses (including spherical) on the output fiber endface to form a diagram of a pumping power.

Fiber optic systems for diode-pumped solid state lasers

New technique for high efficient laser diode - optical fiber coupling (up to 93%) has been developed and used in a cw and passive Q-switching of diode - pumped single transverse mode Nd:GdVO4 laser.

Nd:GdVO4 Laser with High Efficient Laser Diode - Optical Fiber Coupling

Passive Q-switching of optical fiber-diode-pumped Nd:GdVO4 laser by special developed LiF:F2- crystals have beenrealized. Pulse duration of 15-100 ns and pulse repetition rate of 5-200 kHz have been obtained. 1. INTRODUCTION The development of cmpact and efficient pulse-periodical diode-pumped solid-state lasers with high peak power andhigh pulse repetition rate oflaser oscillation is actual problem for many applications.Laser diode (LD) - optical fiber coupling has several advantages in pumping systems of the solid-state lasers -sufficientlyhigh coupling efficiency, a possibility to combine powers of several LDs, a remote LDs mounting, small size and electrical safetyofthe laser heads, more simple schemes for cooling ofthe crystals, axial symmetry ofthe pumping beam.Nd:GdVO4 crystals are most ofthe perspective laser active materials for diode-pumping regime. The properties ofthe Ndions in the GdVO4 matrix such as high absorption coefficient - up to 70 cm' in 808 rim spectral range, high efficiency of lasing -54% of differential efficiency make them suitable for diode pumping scheme. The spectroscopic properties of the Nd:GdVO4demonstrate wide absoiption band -

Oleg A. Vlasenko

Papers

Diode pumped Nd3+ : GdVO4 laser with fibre input

Diode-pumped Nd:GdVO, laser with highefficient fiber-optic module

Fiber optic systems for diode-pumped solid state lasers

Nd:GdVO4 Laser with High Efficient Laser Diode - Optical Fiber Coupling

Passive Q-switching of a fiber optic module-pumped Nd:GdVO laser with LiF:F crystals