Subject(s)
Anastomotic Leak/therapy , Bile Ducts/surgery , Drainage , Jejunum/surgery , Pancreatic Ducts/surgery , Aged , Anastomosis, Surgical/adverse effects , Endoscopy, Gastrointestinal , Humans , Pancreaticoduodenectomy/adverse effects , Peritonitis/etiology , Peritonitis/therapy , Reoperation , Surgical Sponges , VacuumABSTRACT
An analytic model of a Ti:LiNbO3 channel waveguide has been developed to predict conveniently the coupling coefficient of directional couplers based on near-field intensity measurements. This model is compared to experimental results at wavelengths of 0.63 and 0.81 microm and indicates an accuracy of predicting coupling coefficients within a factor of 2 without prior knowledge of the fabrication parameters.
ABSTRACT
Experimental results on the photorefractive effect in Ti-indiffused LiNbO3 directional couplers at GaAs and He-Ne wavelengths are presented. The photorefractive effect has been observed as drift in the switching state of this device at GaAs wavelengths (0.81 and 0.85 microm) for intensities (powers) as low as 32 W/cm2 (3.2 microW). Analysis of this effect indicates refractive-index changes as large as 8 x 10(-4) may be occurring. Measurements also suggest the possibility of two time constants in the relaxation of the photorefractive effect in these devices.
