In recent years, optical technology has been incorporated into mechatronic systems at an accelerated rate, and as a result, a great number of machines/systems with smart optical components have been introduced. This integrated technology is termed "optomechatronics." This paper introduces the fundamental concept, definition, and characteristics of the technology by analyzing the characteristics of a variety of practical optomechatronic systems. The introduction describes how optical and mechatronic components are physically coupled to each other to form optomechatronic integration. With this observation, we describe the nature and integration concept of the technology, from which we can derive the technology-driven fundamental functionalities in some detail. Based upon the knowledge on basic optomechatronic integration and functions, we analyze optomechatronic systems in general from the viewpoint of system configuration and design and, thus, the roles of optical technology in overall system performance being learned and the synergistic effects due to its fusion with mechatronics being understood.