Wide-angle 1 x 3 optical power divider in LiNbO3 for variable power splitting

A new wide-angle 1/spl times/3 optical power divider with variable power splitting using substrate microprisms and two waveguide expanders is experimentally demonstrated by nickel diffusion in LiNbO/sub 3/. The produced substrate microprism with a graded-index profile and a depth-varied size is proved to be effective to produce phase-front tilt and field modification when in operation with two waveguide expanders. Experimental results show that the tuning range of the power splitting ratio can be 0.25/spl sim/1.69 and 0.18/spl sim/>1.09 with low insertion loss for branching angle /spl theta/=3/spl deg/ and 4/spl deg/, respectively. The fabricated devices have the features of low insertion loss, large branching angle, wide power tuning range, and easy fabrication.