Mode converter based on ring resonator for integrated photonics

In this paper we propose design of the mode converter for implementing in photonic integrated circuits. Mode converter consists of single-mode ring resonator, single-mode access waveguide and multimode access waveguide, and we propose using of vertical coupling, i.e. locating waveguides under the ring with little gap. Using finite difference time domain simulation we showed high efficiency of proposed device design. We showed dependence of the device performance on the shape of multimode waveguide coupler: straight waveguide provide low level of mode crosstalk, “pulley coupling” scheme with small arc angle (about 13 degrees) provide strong wavelength selectivity. Devices with proposed design is suitable for SDM-WDM systems.