Experimental and theoretical studies of distributed feedback waveguide lasers

As an effective compact coherent light source, distributed feedback (DFB) waveguide laser has attracted much attention recently. Sol-gel Mass synthesized at low temperatures is a very useful optical material. DFB waveguide lasers based on sol-gel glasses were experimentally and theoretically investigated in this thesis. In addition, microring lasers based on a conjugated polymer, which is emerging as an important class of laser material, were also studied in this thesis.; Titania zirconia organically modified silicate (TiO2-ZrO 2-ORMOSIL) DFB waveguide lasers were demonstrated. The output polarization and output wavelength of TiO2-ZrO2-ORMOSIL DFB waveguide lasers were found to be dependent on the polarization of the crossing pump beams from a frequency-doubled Nd:YAG laser. Up to sixteen Output wavelengths corresponding to eight pairs of polarized output from eight propagation modes were observed simultaneously for a planar waveguide with a thickness of 6.7 mum.; DFB lasing characteristics of various dyes in zirconia waveguides and in solutions were investigated. Intensity modulation and polarization modulation were used to generate the laser action. The laser output showed different polarization characteristics and threshold energy variation when the feedback mechanism was changed from intensity modulation to polarization modulation. In addition, near infrared (NIR) wide-band tuning DFB lasing operation was achieved in NIR dve-doped sol-gel waveguides by using intensity modulation.; Theoretical expressions for the angle-dependent coupling coefficients of DFB lasers were derived to explain the polarization properties of the DFB lasers. The coupling and gain coefficients of the two orthogonal polarization components of DFB lasers are strongly dependent on the intersection angle and the polarization states of the two crossing pump heams. The experimental results of DFB lasing in dye solutions have verified our theoretical predictions.; Two-photon-pumped DFB lasing action with a narrow linewidth output was demonstrated in zirconia waveguides doped with trans-4-[p-( N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium p-toluene sulfonate a compound that shows strong two-photon upconverted emission around 620 nm. Transient gratings for coherent scattering were generated in the waveguides by crossing two 1.06 mum beams. DFB laser emission with the linewidth as narrow as 60 pm was observed. Operating at the third-order Bragg condition, tunable TE mode laser emission was achieved from 618 to 640 nm. TM output modes from the DFB laser were observed when the crossing beams were changed from s-polarized to p-polarized.; Microring cavities were fabricated by depositing poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene) (MEH-PPV) on glass fibers by a dip coating method. Laser emissions in whispering gallery modes using microring cavities were observed by pumping with a frequency-doubled Nd:YAG laser. The threshold energy of the MEH-PPV microring laser was as low as 10 nJ per pulse. The polarization characteristics of the microring lasers were studied and a polarization model was developed to explain the observed phenomena.