Elimination of a back-reflected TE mode in a TM-mode optical isolator with a Mach-Zehnder interferometer.
Eimination of a back-reflected TE mode traveling in a TM-mode optical isolator was investigated. The optical isolator had a Mach-Zehnder interferometer that included a polarization-dependent reciprocal phase shifter in one of the arms. The reciprocal phase shift was achieved by an optical path difference between the two arms. By adjustment of the length of the reciprocal phase shifter, the interferometer prevented the back-reflected TE mode from coupling into an input port of the isolator. An extinction ratio of more than 18 dB was obtained against the back-reflected TE mode at a wavelength of 1.55 microm.
Yokoi
Hideki
H
Department of Electrical and Electronic Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan. yokoi@wave.pe.titech.ac.jp
Mizumoto
Tetsuya
T
Kuroda
Shinpei
S
Ohtsuka
Takafumi
T
Nakano
Yoshiaki
Y