A family of narrow linewidth integrated optical distributed Bragg jeflector- (DBR-), distributed feedback- (DFB-), and DBR-IDFB-coupled cavity lasers with Er-doped LiNbO3 single-mode waveguide is reviewed. They have one or two photorefractive gratings in Fe-doped waveguide sections. Two types of DBR-lasers have been developed. The first type has a cavity consisting of one Bragg-grating in a Ti:Fe:LiNbO3 waveguide, a gain section with Ti:Er:LiNbO3 waveguide, and a multi-layer dielectric mirror deposited on one polished end face. The second DBR-cavity consists of two gratings in Ti:Fe:LiNbO3 on both sides of the Er-doped waveguide. Their power characteristics and spectral properties were investigated. Single-frequency operation could be achieved in the latter case at various wavelengths in the Er-band (1530nm < lambda < 1575nm) with up to 1.12mW output power. A DFB-laser with two lowest-order modes has been demonstrated with a photorefractive grating in a Ti:Fe:Er:LiNbO3 waveguide; it is combined with an integrated optical amplifier on the same substrate. Moreover, an attractive DBR/DFB coupled cavity laser has been developed and investigated. Its cavity consists of a photorefractive Bragg grating in the Ti:Fe:Er:LiNbO3 waveguide section close to one end face of the sample, a Ti:Er:LiNbO3 gain section and a broadband dielectric multi-layer mirror of high reflectivity on the other end face.

This paper reviews the latest developments of diode-pumped Ti,Er:LiNbO/sub 3/ waveguide lasers emitting at wavelengths around 1.5 /spl mu/m. In particular, harmonically mode-locked lasers, Q-switched lasers, distributed Bragg reflector (DBR)-lasers, and self-frequency doubling lasers are discussed in detail. Supermode stabilized mode-locked lasers have been realized using a coupled cavity concept; a side mode suppression ratio of 55 dB has been achieved at 10-GHz pulse repetition rate with almost transform limited pulses. Q-switched lasers with a high extinction ratio (>25 dB) intracavity electrooptic switch emitted pulses with a peak power level up to 2.5 kW and a pulsewidth down to 2.1 ns at 1-kHz repetition frequency. Numerical simulations for both lasers are in a good, almost quantitative agreement with experimental results. A DBR-laser of narrow linewidth (/spl ap/3 GHz) with a permanent (fixed) photorefractive grating and 5 mW output power has been realized. Self frequency doubling lasers have been fabricated with a periodic microdomain structure inside an Er-doped laser cavity; simultaneous emission at the fundamental wavelength, 1531 nm, and at the second harmonic wavelength, 765 nm, has been obtained.