Two-dimensional 45/spl deg/ surface-normal microcoupler array for guided-wave optical clock distribution

Abstract

Surface-normal couplers are indispensable parts of a guided-wave optoelectronic interconnects for the coupling of optical signals into and out of the waveguides while facilitating the packaging. In this paper, integration of the 45/spl deg/ surface-normal couplers at each fanout end of the H-tree waveguide structure is described. An optical clock signal distribution system is under development using polyimide based H-tree waveguide structure. The coupler is a 45/spl deg/ slanted end surface of the polyimide waveguide. The coupler works for a wide range of wavelength. The experimentally estimated output coupling efficiency is nearly 100%. To determine the optimized size and shape of the photodetector, near and far field diffraction patterns are evaluated. Experimental results conclude that the phenomenon is dominated by the fundamental mode of the highly multimode waveguide.