state compact high repetition rate ked Cr 4 + : YAG laser

operated stably after more than 500h. In conclusion, we obtained a nearly round FFP in the 650nm band wavelength using the S3-laser. The laser had good I-L characteristics and good reliability at lOmW and 60°C. We consider that the laser could be of use as a light source in optical disk systems. and TERAMOTO, I.: 'Novel technology for formation of a narrow active layer in buried heterostructure lasers by single-step MOCVD', IEEE J. and YAMAMOTO, s.: '780nm laser diode fabricated by single step MBE'. FURUYA, A., and TANAHASHI, T.: 'One-step-metalorganic-vapor-phase-epitaxy-grown AlGaInp visible laser using simultaneous impurity doping', Appl. (41 l)A-like micro-facets on nonplanar substrate'. The authors report a compact, high repetition rate, all-solid-state Kerr-lens modelocked CP+:YAG laser, pumped by either a diode-pumped NdYV04 laser or a diode-pumped Yb-doped fibre laser. Femtosecond pulses have been obtained, tunable from 1.505 to 1.550p11, with single beam modelocked average output powers as high as 2XOmW at repetition rates of up to 1 GHz. Since the first report of room temperature CW lasing of Cr"+:YAG [l] from 1.34 to 158pn, much work has been carried out on the development of ultrafast CP+:YAG lasers for telecom-munication test sources, spectroscopy and other applications [2-51. Unfortunately, the strong thermal lensing of the Cr:YAG laser medium makes alignment of these lasers difficult. In this Letter, we report a very compact, high-repetition rate, Kerr-lens mode-locked CF+.YAG laser which uses a three mirror cavity [6] which is simple to align and which may be pumped by either a Nd:WO., laser or a diode-pumped Yb-doped fibre laser operating at 1. 0 6 ~. The laser cavity is shown in Fig. 1. The laser rod was a plane-Brewster angled 2 0 " long Ci4+:YAG cylindrical crystal, of nominally 2% CF+-doping, which was mounted in a copper block cooled to-20°C. The plane surface of the rod was coated for high transmssion at the pump wavelength and high reflection (HR) at the laser wavelength. This high reflector (Ml) formed one end of the laser cavity, which was completed by a 75" radius of curvature spherical HR mirror (M2) and a plane-Brewster angled BK7 substrate (M3), which was HR coated on the plane surface. This cavity configuration produces negative group velocity dispersion (GVD) which is a function of the length of the cavity arm (M2 to M3 [6].) Precise adjustment of the net GVD of the laser cavity is achieved by translation of M3 perpendicular to …