Blue Second-Harmonic Generation in Waveguides,
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1992
- Accession Number
- ADP008131
Entities
People
- Hitoshi Tamada
Organizations
- Sony Group