title: Design, fabrication, and evaluation of crystal-cored fibers for efficient second-harmonic generation based on Cerenkov-radiation-type phase matching.
abstract: A formulation for calculating the optical second-harmonic power based on the Cerenkov-radiation-type phase matching is derived for a crystal-cored fiber. The prerequisite condition for high efficiency is expressed by a simple relation by use of the refractive indices of a core crystal, a core radius, and a fundamental wavelength. An organic crystal-cored fiber is designed and practically fabricated by the guiding principle derived here. A blue second-harmonic wave of 1.4 mW is obtained from a 1-mm-long fiber by use of a 60-mW semiconductor laser, and the second-harmonic intensity agrees well with the prediction. Degradation of the organic core crystal caused by the generated blue wave is observed, and the lifetime of the device is evaluated.
authors.affiliation: Corporate Research and Development Laboratory, Pioneer Corporation, 6-1-1 Fujimi, Tsurugashima, Saitama 350-2288, Japan. vyc03054@nifty.com
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Chikuma
authors.forename: Sota
authors.initials: S
authors.lastname: Okamoto
authors.forename: Naota
authors.initials: N
authors.lastname: Uenishi
authors.forename: Takafumi
authors.initials: T
authors.lastname: Uemiya
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Umegaki