Abstract

High-power, low-jitter optical pulse sources are critical for high-data-rate communication systems and optical sampling systems used for highspeed analog-to-digital conversion.¹ Planar waveguide lasers based on Er/Yb co-doped phosphate glass can produce continuous-wave output powers that exceed 170 mW.² These same lasers have the potential for producing similarly high average powers when mode locked. We present mode locking results using Er/Yb co-doped glass and semiconductor saturable absorber mirrors (SESAMs) that demonstrate improvements in output power over earlier work.’ A typical laser configuration is shown in Fig. 1. Through coupling optics, a Ti:Sapphire laser pumps a 2 cm long waveguide positioned at one end of the laser cavity. The waveguide is fabricated in Er/Yb co-doped phosphate glass.⁴ A partially reflecting mirror is butted to one facet of the waveguide with index-matching fluid and serves as an output coupler. The other facet is cut and polished at Brewster’s angle to minimize intracavity reflections in the extended cavity setup. A microscope objective collimates the light from the waveguide, and this beam is focused down onto the SESAM with a second lens. Eocal lengths for this lens range from 6.24 mm to 25.4 mm. Cavity lengths range from 40 cm to 2 m. Turning mirrors minimize the space required for the laser and reduce the intensity of the pump light that reaches the SESAM. A dichroic beamsplitter passes the 977 nm pump light and couples the 1534 nm laser output into an optical fiber.

© 2001 Optical Society of America