Theoretical and experimental comparison of an adjustable Y-junction switch

An optical switch using an adjustable Y-junction structure has been designed, fabricated, measured, and analyzed. Both the experimental performance and theoretical prediction of the switch are presented. The switching section of the device consists of three arrow-shaped, field-induced waveguides that overlap in the propagation direction such that input light from the middle guide can be transferred to either of the output guides. A cross talk of less than −18 dB is measured at a wavelength of 1.06 μm in a device with a transition length of 400 μm and a branching angle of 4°. Numerical simulations using the finite difference beam propagation method show that a cross talk of less than −22 dB may be achievable for these device dimensions.