Erbium-doped single- and double-pass Ti:LiNbO/sub 3/ waveguide amplifiers

Single-pass and double-pass Er-diffused Z- and X-cut Ti:LiNbO/sub 3/ waveguide amplifiers, optically pumped at /spl lambda//sub p//spl ap/1484 nm, have been investigated. With a 48 mm long Z-cut amplifier device, Er-diffusion doped at 1100/spl deg/C, 6.7 dB (coupled pump power P/sub p,c/=170 mW) and 14.7 dB (P/sub 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 /spl lambda//sub s/=1531 nm. A Z-cut sample doped at 1135/spl deg/C showed a considerably improved behavior. 11.3 dB single-pass net small-signal gain has been obtained (P/sub 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:LiNbO/sub 3/ amplifiers with increased (realistic) lengths of 10 cm.<
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