The optical inter-orbit communication test satellite (OICETS) has been developed by NASDA (National Space Development Agency of Japan) in order to perform the inter-satellite optical link experiment with a GEO-satellite of ESA (European Space Agency) named "ARTEMIS (Advanced Relay and Technology Mission Satellite)". OICETS will be launched into a circular low earth orbit in 2005. In this paper, the overview of OICETS and the optical terminal "LUCE(Laser Utilizing Communications Equipment)" boarded on OICETS is introduced. The objective of OICETS and the optical terminal "LUCE(Laser Utilizing Communications Equipment)" boarded on OICETS is introduced. The objective of OICETS is to perform on-orbit demonstrations of pointing, acquisition and tracking technologies, and other key technology elements for optical inter-orbit communications. The data rates for forward (ARTEMIS to OICETS) and return (OICETS to ARTEMIS) links correspond to 2 and 50 Mbps at the optical wavelength of $0.8mum$, respectively. The proto-flight tests of the OICETS flight model was finished in January 2002. In addition, results of an optical compatibility test between LUCE and the optical terminal of ARTEMIS in geo-stationary orbit at $21.5^{circ}$ East is described. The engineering model (EM) of LUCE is placed at ESAs Optical Ground Station (OGS) in Tenerife, Canary Island. The aim of the test is to verify the end-to-end optical interfaces such as intensity, wavelength, polarization, modulation scheme of optical signals and also acquisition sequences between both optical terminals.