Characterization of defects in waveguides formed by electron irradiation of silica-on-silicon

Absorption spectroscopy and electron spin resonance are used to characterize optical waveguides formed by electron irradiation of plasma-enhanced chemical vapor deposition (PECVD) silica-on-silicon. Nonbridging oxygen hole centers and E/sub /spl gamma///sup ´/ defect centers are positively identified in undoped films. Evidence for peroxy radical and phosphorus oxygen hole centers is also found in phosphorus-doped samples. This is the first time that defects have been unambiguously identified in such guides. The charge-dose dependence of the E´ center density follows a saturating exponential curve well correlated with refractive index changes previously reported, implying that a single first order process is responsible for both effects.