Fabrication and Performance Evaluation of Active Er:Ti:LiNbO3 Waveguides

The excellent performance of Erbium doped fiber amplifiers and lasers in the 1550 nm wavelength region has stimulated increased interest in Erbium doped integrated optic planar waveguide devices (particularly LiNbO3). This work describes the measurement techniques and the performance evaluation of Er-doped, X-cut and Z-cut Ti:LiNbO3 waveguides. Waveguide losses have been measured in the 1300 nm and 1550 nm wavelength regions, in both TE and TM polarization states, using the low finesse Fabry-Perot technique. The resonance phenomena has been obtained with two different methods, the thermal cavity tuning and the sweeping in wavelength using a tunable semiconductor laser. The results obtained in this second case are in good agreement with those obtained by the temperature tuning. The second method has also the advantage of avoiding the coupling stability problems inherent to the thermal tuning. Absorption spectra have been evaluated using a white spectral lamp and a semiconductor LED; spontaneous emission spectra have been evaluated pumping with semiconductor laser. A strong absorption was observed around the value of 1530 nm for TE and TM polarization. Using the spectral lamp significant absorption around 980 nm was observed.