Gain switching of an erbium-doped silica-based planar waveguide laser

The gain switching of an erbium-doped waveguide laser is investigated both theoretically and experimentally. We analyze the lasing characteristics of gain-switched laser based on coupled rate equations, taking ground state absorption and the saturation effect into account. The analyzed theory indicates that the repetition rate, pulse width, and peak power vary when the pump conditions are changed. Gain-switched optical pulses are experimentally generated in the erbium-doped waveguide laser with intensity modulated optical pumping at 651 nm using a dye laser and an acousto-optic modulator. The pulses are controlled with widths of 660–2600 ns and peak powers of 1.0–6.5 mW at repetition rates of 18–60 kHz by changing the average pump rate between 2.0 and 7.0. These experimental results agree with theoretical calculations of the pulse width, peak power, and repetition rate against the pump rate.