Technical research on crosstalk-free polarization control devices used for blue-green light band

Abstract

In modern optical communication systems, signal light polarization state control technology can not only realize highspeed and large-capacity communication, but is also an indispensable part in the design of photonic integrated circuits. So far, the polarization extinction ratio (PER) is the main factor limiting the bandwidth of polarization control devices and it causes additional polarization loss in the whole communication system. Additionally, with the development of optical wireless communication technology in free space and underwater environment, the research on high-performance polarization control devices that suitable for visible light band has not been widely concerned. In this paper, a design concept for cross-talk free polarization control devices based on coupled mode theory has been illustrated, and several devices (including polarization splitters, polarization converters) have been given. Moreover, the design scheme and technical difficulties of polarization control devices in blue and green light band have also been evaluated.