On efficiency of optical modulations for optical channel with noise
Noboru Watanabe · Electronics and Communications in Japan (Part I Communications) · 1993
Abstract Recently, in parallel with the advancement of lightwave technology, there has been a considerable amount of research and development work in the system engineering aspects of optical communication, including important basic research. Various types of modulation have now been applied in real optical communication systems. In this paper we introduce a scale that can be used to measure the efficiency of optical modulation in terms of the quantum entropy. With the aid of this scale, we then discuss the efficiency of information transmission in various types of optical pulse modulation (PAM, PPM, PWM) for particular photon number states of the input system and for an optical channel with noise.