Glenn Eric Kohnke

Photosensitization of optical fiber by UV exposure of hydrogen loaded fiber

We report a photosensitization process in standard hydrogen loaded optical fiber. A persistent photosensitivity is produced by exposure to UV light that can be uniform or spatially tailored along the fiber length.

Integrated platform for silicon photonic crystal devices at near-infrared wavelengths

We demonstrate an integrated fiber-photonic crystal system with a uniform band gap of around 1550 nm with insertion loss as low as 3.5 dB. One-dimensional photonic crystals fabricated on this platform exhibit a higher-order photonic band gap with over 30 dB suppression of transmission from 1400 to 1700 nm that is consistent with simulation. These results may lead to true integration of photonic crystals into optical fiber communication systems as optical switches and routers.

Fiber Bragg gratings for dispersion compensation

The group delay of a chromatic dispersion compensation grating module was measured using the phase-shift method and the system performance was predicted using a Fourier transform algorithm. Good agreement was obtained between the system simulation and the measured eye-diagram. This numerical prediction is accurate only with a proper choice of the wavelength resolution used for the group delay measurement.

Fluence-dependent transmission in CaF2 including correlation with thermally stimulated current

Calcium fluoride exhibits a fluence dependent transmission behavior at the 193 nm excimer laser wavelength of interest for photolithography applications. The transmission as a function of fluence is determined using a 193 nm excimer laser based transmission measurement system. Different transmission decay rate and saturation level is observed and correlated with structural defects and impurities. Thermally stimulated current measurements are applied to identify defects and correlate the relative concentration of mobile anion vacancies with fluence dependent transmission.