[OPTICAL REVIEW Vol. 18, No. 1 (2011) 166-170]
© 2011 The Japan Society of Applied Physics

Optical Properties of a Waveguide Written Inside a LiTaO3 Crystal by Irradiation with Focused Femtosecond Laser Pulses

Makoto KUMATORIYA*, Miki NAKABAYASHI1, Masaaki SAKAKURA2, Yasuhiko SHIMOTSUMA2, Kiyotaka MIURA1, Takashi FUJII, and Kazuyuki HIRAO1

Technology and Business Development Unit, Murata Manufacturing Co., Ltd., Nagaokakyo, Kyoto 615-8555, Japan
1Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8520, Japan
2Innovate Collaboration Center, Kyoto University, Kyoto 615-8520, Japan

(Received June 1, 2010; Revised October 15, 2010; Accepted October 21, 2010)

Optical waveguides were fabricated by modifying the optical properties inside a LiTaO3 crystal by irradiation with femtosecond laser pulses, and the performance and optical properties of the waveguide were investigated. On the basis of near-field pattern of the light guided through the waveguides, the optimum writing conditions such as the pulse energy and the pulse duration were determined. The waveguide written inside a LiTaO3 crystal had a strong polarization dependence of guided light. Observation by a polarized microscope suggested that the stress distribution around the photoexcited region should be responsible for the polarization dependence of guided light. In addition, the second harmonic generation from a laser beam passing through the waveguide was observed, which suggests that the ferroelectric properties of LiTaO3 were preserved after the photoexcitation.

Key words: femtosecond pulse laser, LiTaO3, refractive index, near-field pattern, optical waveguide, photoexcitation

*E-mail address: kumatry@murata.co.jp