Low-loss intersecting grooved waveguides with low Δ for a self-holding optical matrix switch

Our method using low /spl Delta/ waveguides decreases the insertion loss of intersecting optical waveguides with grooves. Theoretical analysis by the beam propagation method or the plane wave expansion method shows the benefit of decreasing the insertion loss. Experimental measurements on a trial matrix (21/spl times/21) showed that the transmission loss greatly decreased with decreasing /spl Delta/. The reflection loss was less sensitive to the positional deviation of the groove than that of conventional /spl Delta/ waveguides. The experimental results were used to calculate the total insertion loss. It decreased from 5.72 to 3.28 dB, when /spl Delta/ decreased from 0.31 to 0.15% for a matrix scale of 50/spl times/50.>