ERBIUM-DOPED SINGLE-PASS AND DOUBLE-PASS TILINBO3 WAVE-GUIDE AMPLIFIERS

Single-pass and double-pass Er-diffused Z- and X- cut Ti:LiNbO3 waveguide amplifiers, optically pumped at lambda(p) almost-equal-to 1484 nm, have been investigated. With a 48 mm long Z-cut amplifier device, Er-diffusion doped at 1100-degrees-C, 6.7 dB (coupled pump power P(p,c) = 170 mW) and 14.7 dB (P(p,c) = 90 mW) net small-signal gain have been achieved with a single-pass and a double-pass configuration, respectively, at the signal wavelength lambda(s) = 1531 nm. A Z-cut sample doped at 1135-degrees-C showed a considerably improved behavior. 11.3 dB single-pass net small-signal gain has been obtained (P(p,c) = 170 mW; sample length 5.7 cm). Theoretical calculations predict gain figures up to 20 dB in single-pass and 40 dB in double-pass Er:Ti:LiNbO3 amplifiers with increased (realistic) lengths of 10 cm.