Fabrication of wavelength-insensitive 8*8 star coupler

The fabrication and performance of a wavelength-insensitive 8*8 star coupler is described. The integrated-optic star coupler consists of two fan-shaped channel waveguide arrays facing each other and a slab waveguide region located in between. The wavelength-insensitive light splitting was realized by properly tailoring the mode coupling in the input array region. The coupler exhibits low-average excess losses of alpha =1.4 dB (standard deviation sigma =0.40 dB) at lambda =1.3 mu m and alpha =1.7 dB ( sigma =0.44 dB) at lambda = 1.55 mu m, respectively.>