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

A new wide-angle 1 x 3 optical power divider with variable power splitting using substrate microprisms and two waveguide expanders is experimentally demonstrated by nickel diffusion in LiNbO3. 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 similar to 1.69 and 0.18 similar to >1.09 with low insertion loss for branching angle theta = 3degrees and 4degrees, respectively. The fabricated devices have the features of low insertion loss, large branching angle, wide power tuning range, and easy fabrication.