LiTaO3 Directional Coupler Switch with Enhanced Extinction Ratio and Low Insertion Loss

Abstract A novel design of optical directional coupler switch with S-bend waveguides on LiTaO3 platform has been designed with R-Soft CAD tool and the same is simulated by Beam propagation method (BPM) for light propagation analysis. The simulation results of the optical directional coupler (ODC) switch is reported. We observed that the directional coupler (DC) switch has lower insertion losses and higher extinction ratios for a certain values that are discussed in the paper. This was studied by variation in waveguide parameters such as, wavelength, waveguide gap, and length of the device. Simulation results designate that the switching efficiency for TE and TM modes with extinction ratio about 3dB when the waveguide gap is 3.5μm for both the polarization modes and insertion loss is 13dB with same waveguide gap in TE mode and 16dB in TM mode at 1550nm wavelength.