Kaori NISHIMAKI¹, Atsushi OKAMOTO¹, Atsushi SHIBUKAWA¹, Masanori TAKABAYASHI², Akihisa TOMITA¹, and Yoshihisa TAKAYAMA³

¹Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan
²Department of Systems Design and Informatics, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan
³National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan

(Received October 15, 2013; Accepted January 7, 2014)

A double phase conjugate mirror (DPCM), created by two mutually incoherent beams entering photorefractive nonlinear materials, can generate a phase conjugate beam whose reflectivity may be greater than 100%. Even though the conditions of the incident beams are changed, the DPCM can be dynamically reconfigured by using a Sn₂P₂S₆ crystal with a high response speed. These features of the DPCM are advantageous, particularly in an optical inter-satellite communication system. In particular, use of the phase conjugate beam from the DPCM offers wavefront compensation and amplification in satellite communication. In addition, the dynamically reconfigurable DPCM using a Sn₂P₂S₆ crystal relaxes the acquisition accuracy of the signal beam in the system. In this study, the temporal and spatial operating characteristics of the DPCM using a Sn₂P₂S₆ crystal were first clarified. Next, an inter-satellite system based on the DPCM was proposed, and it was demonstrated that our system significantly improves the tolerance of the acquisition accuracy and tracking time.

Key words: optical inter-satellite communication, photorefractive effect, Sn₂P₂S₆ crystal, dynamically reconfigurable device, double phase conjugate mirror