Hiroshi MURATA^1*, Keita FURUSHO¹, Kazuhisa YAMAMOTO², and Yasuyuki OKAMURA¹

¹Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
²Photon Pioneers Center, Osaka University, Suita, Osaka 565-0871, Japan

(Received June 1, 2012; Accepted August 20, 2012)

We propose a new technique for reducing speckle noise in laser displays utilizing a high-speed optical phase modulator for expanding the laser beam spectrum. By adopting standing-wave resonant electrodes and polarization-reversed structures to LiTaO₃ electro-optic modulators, high-efficiency phase modulation with a large modulation index at high microwave frequency ranges is obtainable for different color laser beams at the same time. This enables us to expand laser spectra to over 100 GHz and reduce speckle noise. The device design, fabrication, and experimental demonstration for speckle control are reported.

Key words: speckle noise, laser display, optical modulation, optical integrated circuit

^*E-mail address: murata@ee.es.osaka-u.ac.jp