Ti:Tm:LiNbO3 waveguides were fabricated by diffusion doping. Their properties were carefully investigated by a variety of experimental methods. The parameters thus found and those calculated by the McCumber theory enabled a thorough theoretical modeling of optical amplifiers and lasers. Experimentally, broadband optical amplification in the wavelength range 1750 nm - 1900 nm was achieved for the first time by in-band pumping (lambda p = 1650 nm). Fabry-Perot type lasers (operating at 1890 nm and 1850 nm) were fabricated by depositing specially designed mirrors on the end faces of waveguide amplifiers; their emission wavelength is 1890 nm (high Q resonator) and 1850 nm (low Q resonator), respectively. The laser threshold (1890 nm) is 4 mW coupled pump power; the slope efficiency is 13.3%.