Accession Number : ADP008131

Title :   Blue Second-Harmonic Generation in Waveguides,

Corporate Author : SONY CORP RESEARCH CENTER YOKOHAMA (JAPAN)

Personal Author(s) : Tamada, Hitoshi

Report Date : APR 1992

Pagination or Media Count : 2

Abstract : Blue second-harmonic generation (SHG) in waveguides has been investigated intensively over the past five years and has progressed significantly. Now it is thought one of the most promising candidates for a compact blue laser that is necessary for higher density optical disk systems. Cerenkov radiation SHG from a proton exchanged LiNbO 3 waveguide opened up such research stream in 1987. Although it demonstrated a mW-level blue output using a laser diode, it unfortunately had a serious drawback of poor focusing characteristics because of its large(16 deg) Cerenkov angle. Then quasi-phase matching (QPM) SHG from a LiNbO 3 waveguide followed. The QPM SHG has progressed very rapidly with the improvement in the fabrication process for a periodic domain inversion structure. In particular, a segmented KTiOPO waveguide and a proton exchanged LiTaO 3 waveguide reported >lOmW 4 blue output with the normalized efficiency of around 100%/Wcm2 . LiNbO 3 might catch up soon since various methods to fabricate a periodic domain inversion structure with a large aspect ratio have been investigated However, the small tolerances in temperature (2-3 deg Ccm) and a fundamental wavelength (0.1-0.2nmcm) are serious problems for a mass production of SHG using a laser diode. In this respect, a Cerenkov radiation SHG is still very attractive because of its large tolerances owing to automatic phase-matching characteristics.

Descriptors :   *OPTICAL WAVEGUIDES, ASPECT RATIO, AUTOMATIC, BLUE(COLOR), CERENKOV RADIATION, DENSITY, DIODES, DISKS, EFFICIENCY, FABRICATION, FOCUSING, HARMONICS, INVERSION, LASERS, MASS, MATCHING, OUTPUT, PHASE, PRODUCTION, PROTONS, RADIATION, RATIOS, STRUCTURES, TEMPERATURE, TOLERANCE, FREQUENCY MULTIPLIERS, LITHIUM NIOBATES.

Subject Categories : Radiofrequency Wave Propagation
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE