Abstract

Novel compact and efficient laser sources in the visible have important applications in spectroscopy, data storage, and colour displays. A promising and versatile example is the Pr³⁺/Yb³⁺-doped ZBLAN fibre laser. The excitation scheme of this up-conversion laser is shown in Fig. 1. The principal emission bands are around 717, 635, 604, 535, 520, and 490nm. So far, this fibre has been pumped by a Ti:sapphire laser that limits its versatility. We have demonstrated efficient pumping by diode-laser light as required for overall miniaturization. The fibre of 1.7 µm core diameter is doped by 0.1% Pr and 1% Yb, resulting in a low threshold. One diode laser at 850nm suffices as the pump source. Visible laser emission has been observed around 717, 635, 604, and 520nm with 10% peak efficiency so far. Fig. 2 shows the output power υs the pump power absorbed in the fibre. The smallest threshold, 3mW, was observed with 635nm output; the largest tuning range is 10nm, and the observed emission bandwidth with no frequency-selective elements is 1nm.

© 1996 IEEE