A novel polarization-insensitive loop circulator with multiport

Presented in this paper is the design and fabrication of a novel polarization-insensitive optical circulator with multiport. For an optical circulator with n ports, it guides the signal from port I into port 2, port 2 into port 3, and so on, till port n into port 1. As a result, the circulator provides further chromatic dispersion compensation and routing function, etc. In this paper, two designs of circulators concerning with odd and even port compact are presented. The port number regarding to each scheme can be arbitrarily designed according to system requirement. Experiments have been conducted to show the performance of our designs on a 3-port and 4-port loop circulators. Key parameters of each scheme are also presented, including the insertion loss (IL), the polarization dependence (PDL), the isolation performance (IS), return loss (RL) and the crosstalk within its working wavelength. Results from the experiments show that the fabricated circulator provides an excellent performance for each set of system parameters. This circulator provides a new possibility for developing compact nonreciprocal devices in the field of optical communications.