Gain distribution measurement of an erbium-doped silica-based waveguide amplifier using a complex OLCR

We have measured the gain distributions of a 38-cm-long erbium-doped silica-based waveguide amplifier with different pump powers by using a complex optical low coherence reflectometer. The spatial resolution is /spl sim/5 mm and the noise level is /spl plusmn/1 dB. The measured distributions agree well with those derived from rate equations. We can estimate such amplifier parameters as the stimulated emission coefficient and the optimum waveguide length enabling us to achieve the maximum gain for any pump power.