This paper presents research and development trends for deep space laser communications. In particular, JAXA and NICT have initiated the collaborative research work for cislunar optical communications. Our research work aims to accomplish 2.5 Gbit/s high-speed optical communication from the Moon to the Earth. We have proposed system configuration of deep space optical links applying Geostationary Earth Orbit (GEO) data relay satellite. In view of this, we have been developing the bread board model (BBM) of key optical components onboard laser communication terminal (LCT) of the GEO data relay satellite. Our key optical components utilize high-sensitivity digital coherent optical receiver, large-aperture optical antenna, and space-grade adaptive optics (AO) module.