Waveguide lasers and amplifiers in rare-earth-doped lithium niobate and silicate glasses.

The design, fabrication, and characterization of active waveguide devices in lithium niobate (LiNbO$\sb3$) and silicate glasses is described. Devices demonstrated include a neodymium doped LiNbO$\sb3$ waveguide laser, the first waveguide amplifier doped by high temperature indiffusion of chromium in LiNbO$\sb3$, and the first erbium-ytterbium waveguide laser in phosphate-free silicate glass fabricated by potassium ion exchange. The LiNbO$\sb3$ waveguide laser was fabricated in a x-cut neodymium-MgO codoped substrate using the annealed proton exchange (APE) method. The laser produced 8.0mW at 1085nm when pumped with 39mW at 814nm and the threshold was 6.1mW and the slope efficiency was 21.6%. The APE waveguide amplifier was fabricated in a x-cut MgO doped LiNbO$\sb3$ substrate. Doping was achieved by high temperature indiffusion of a chromium thin film. The device produce a net gain of 1.64dB at 838nm. The APE waveguides were fabricated using a new technique. This technique uses an e-beam evaporated sapphire layer, standard photo-lithography and acetone lift-off to produce diffusion masks for adipic acid proton exchange. This method is simple, repeatable and utilizes non-toxic, non-corrosive chemicals. Lasers in erbium-ytterbium codoped, phosphorus-free silicate glasses are analyzed and demonstrated. The erbium-ytterbium laser is analyzed in detail using a population rate equation approach. Key material parameters are measured and reported. Simple equations were developed to predict the performance of erbium-ytterbium codoped devices. The laser device reported produced 0.95mW at 1534.6nm when pumped with 30mW at 967nm and had a threshold of 14.8mW and a slope efficiency of 5.5%. A theoretical analysis of an intra-cavity modulation technique referred to as push-pull phase modulation (PPPM) is analyzed. Spatial hole burning, caused by the spatial interference of oppositely directed beams in a cavity, can lead to multi-mode operation even in homogeneously broadened gain media. PPPM produces single longitudinal mode operation while fully utilizing all of the available gain by rapidly moving the standing wave pattern relative to the gain medium. Approximate formula are developed which relate the cavity intensity, the pumping rate, and the PPPM amplitude. Conditions under which single longitudinal mode operation is obtained are also derived.PhDApplied SciencesCondensed matter physicsElectrical engineeringOpticsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/130151/2/9712113.pd