Passively modelocked diode-pumped erbium-ytterbiumglass laser using a semiconductor saturable absorber mirror

Abstract

3 +:Yb 3+ :glass are used as gain material for pulsed bulk lasers around 1.5 μ m. Cr 4+ :YAG has been passively modelocked by Kerr lens modelocking (KLM) (4) or by semiconductor saturable absorber mirrors (2). However, this laser requires a high-brightness multi-Watt pump because of its weak absorption and high laser threshold. Er 3+ :Yb 3+ :glass is a quasi-three- level gain material which can easily be diode-pumped, because co- doping with ytterbium facilitates an efficient pump process around 980nm without increasing the reabsorption losses (3). Actively mod- elocked operation of a bulk Er 3+ :Yb 3+ :glass laser has been demon- strated (4) producing 9.6ps at 3mW output power. Passively modelocked erbium-doped fiber lasers have been shown to produce sub-picosecond pulses with nanojoule pulse energies using different approaches (5, 6). However, the pulses of the side- and cladding-pumped erbium laser (6) show large wings, which con- tain a significant amount of the energy. The additive-pulse-mode- locking approach using the rejection port for output coupling (5) shows better pulse quality but depends on a rather sophisticated and expensive master-oscillator/power amplifier pump source. In this Letter we report the first demonstration of a passively CW mode- locked diode-pumped bulk Er 3+ :Yb 3+ :glass laser yielding good sta- bility and pulse quality.