Title :
Ionization-induced refractive index and polarization effects in LiNbO3:Ti directional coupler waveguides
Author :
Taylor, Edward W.
Author_Institution :
Weapons Lab., Kirtland AFB, NM, USA
fDate :
3/1/1991 12:00:00 AM
Abstract :
Exposure of an LiNbO3:Ti directional coupler to pulsed 16-MeV electrons was observed to nonequivalently affect the transverse electric-transverse magnetic (TE-TM) polarized transmission of a continuous wave 1300-nm optical signal through the channel waveguides. Two distinct ionization-induced attenuation responses were observed to depend on the magnitude of the optical power in the guides and on the polarization states. An hypothesis for these phenomena is advanced based on the presence of localized space charge fields arising from ionization-induced transient color centers, free carriers within or near the light guiding regions, and polarization conversion initiated through decreased mode confinement and scattering. Transient space charge fields causing localized changes to the refractive indexes in and near the guiding regions are believed to have caused both the loss of guiding and the onset of photorefractive-like processes
Keywords :
directional couplers; electron impact; integrated optics; ionisation of solids; light polarisation; lithium compounds; optical couplers; optical waveguides; refractive index; space charge; titanium; 1300 nm; 16 MeV; CW optical signal; LiNbO3:Ti directional coupler waveguides; TE polarised transmission; TM polarised transmission; channel waveguides; electron beam irradiation; free carriers; guiding losses; ionization-induced attenuation; ionization-induced transient color centers; light guiding regions; localized space charge fields; mode confinement; mode scattering; optical power; photorefractive-like processes; polarization conversion; polarization effects; polarization states; refractive index; Directional couplers; Electron optics; Optical attenuators; Optical polarization; Optical refraction; Optical scattering; Optical variables control; Optical waveguides; Refractive index; Space charge;
Journal_Title :
Lightwave Technology, Journal of
