Improved fabrication of 4 /spl times/ 4 polarisation insensitive switch matrices on InP by introduction of an etch stop layer

The first polarization insensitive to 4 /spl times/ 4 switch matrix on InP with digital optical switches (DOS) has been recently presented (J-F. Vinchant et al., 1992). The authors report processing and performance improvements of this matrix by introduction of an etch stop layer in the structure grown by gas source molecular beam epitaxy (GSMBE). Several heterostructures grown on 2-inch wafers by GSMBE in a Virian reactor have been processed. This epitaxial technique allows high homogeneity of layers' thickness and doping. The optical characterization of the matrices has been done by using a 1.54 /spl mu/m wavelength laser for both transverse electric (TE) and transverse magnetic (TM) polarization. The results are reported.<>