Tatsuo Izawa

Optical waveguide formed by electrically induced migration of ions in glass plates

Low‐loss waveguides for integrated optical devices are formed by electrically induced migration of ions in glass plates. The guiding region is located beneath the substrate glass. The transmission loss of the waveguides is estimated to be less than 0.1 dB/cm.

Deposited silica waveguide for intergrated optical circuits

Embedded single and multimode waveguides on fused quartz substrates have been fabricated by high‐speed silica deposition and accurate reactive sputter etching by a C2F6 gas plasma. These waveguides have rectangular cross sections with an aspect ratio close to unity. Total waveguide loss was approximately 5 dB/cm, and absorption loss measured by laser calorimetry at 637‐nm wavelength was less than 0.1 dB/cm.

Nd‐glass laser with three‐dimensional optical waveguide

Room‐temperature laser operation in a three‐dimensional Nd‐glass waveguide is reported. The waveguide was fabricated by a double‐diffusion process with ion migration. A Nd‐glass laser, 4 mm in length, was end‐pumped at 590‐nm wavelength with a pulsed Rhodamine 6G dye laser. The threshold power for the Nd‐glass waveguide laser was about 18 μJ, which was nearly one‐half of that for a conventional Nd‐glass laser without guiding structure. The measured value of the threshold for a waveguide laser agrees with the theoretical calculation.

INFRARED HOLOGRAPHY WITH ORGANIC PHOTOCHROMIC FILMS

A hologram is made by a CO2–N2–He laser utilizing the thermal bleaching of organic photochromic films and is reconstructed by a 6328 A He–Ne laser beam. These films are made of photochromic spiropirans dissolved into plastics.