Development of plasmonic isolator for integration into photonic integrated circuits (Presentation Recording)

Abstract

An optical isolator is an important component of an optical network. At present, there is a significant commercial demand for an optical isolator, which can be integrated into the Photonic Integrated Circuits (PIC). A new design of an integrated optical isolator, which utilizes unique non-reciprocal properties of surface plasmons, has been proposed [1]. The main obstacle for a practical realization of the proposed design is a substantial propagation loss of the surface plasmons in structures containing a ferromagnetic metal. The reduction of the propagation loss of a surface plasmon is the key to make the plasmonic isolator competitive with other designs of the integrated isolator. We studied experimentally optical and magneto-optical properties of a Fe plasmonic waveguide integrated with an AlGaAs rib waveguides and a Co plasmonic waveguide integrated with Si nanowire waveguides. It was demonstrated experimentally that by utilizing a double-dielectric plasmonic waveguide it is possible to reduce significantly the optical loss in a plasmonic waveguide. For Fe/SiO2/AlGaAs double-dielectric plasmonic waveguide the low optical loss of 0.03 dB/um is obtained. As far as we know at present it is a lowest optical loss demonstrated for a plasmon propagating at a surface of a ferromagnetic metal. For Co/Ti2O3/SiO2 double-dielectric plasmonic waveguide integrated with a Si nanowire waveguide on a Si substrate the optical loss of 0.7 dB/um was demonstrated. The designs of the plasmonic isolator utilizing a ring resonator or a non-reciprocal coupler were studied. [1] V. Zayets, H. Saito, S. Yuasa, and K. Ando,, Materials 5, 857 (2012).