An interferometric optical isolator that employs a nonreciprocal phase shift was studied. The optical isolator consisted of an interferometer with distinct layer structures. A traveling light wave underwent distinct nonreciprocal phase shifts such that the optical isolator could be operated in a unidirectional magnetic field. The optical isolator, in which the waveguide had a HfO<sub>2</sub> cladding layer in one of the arms, was designed at a wavelength of 1.55 μm. The propagation distance of the nonreciprocal phase shifter required for the isolator’s operation was less than 1.5 mm. The device’s total length was less than 2 mm. An optical isolator with distinct layer structures was fabricated and evaluated. An isolation ratio of approximately 9.9 dB was obtained in the unidirectional magnetic field.
© 2004 Optical Society of America
Hideki Yokoi, Yuya Shoji, Etsu Shin, and Tetsuya Mizumoto, "Interferometric Optical Isolator Employing a Nonreciprocal Phase Shift Operated in a Unidirectional Magnetic Field," Appl. Opt. 43, 4745-4752 (2004)