Zero holding power digital optical switches

An optical switch, comprising:

• an input branch including a ridge waveguide heterostructure for receiving an optical signal;
• a first output branch optically coupled to the input branch and having a ridge waveguide heterostructurea refractive index;
• a second output branch optically coupled to the input branch, having an electrode disposed thereon for energizing said second output branch, and having a refractive index in an unbiased state which is different than the refractive index of said first output branch;
• wherein the refractive index of said second output optical waveguide means is selectively modified, responsive to said electrode, for switching said optical signal between the first output branch and the second output branch, and
• wherein the respective ridge waveguide heterostructures of said input branch, first output branch, and second output branch each comprise:
• an InP substrate;
• an InP buffer layer disposed on the substrate;
• an InGaAsP guiding layer disposed on the buffer layer and having a propagation wavelength of lambda=1.13 .mu.m;
• an InP cladding layer disposed on the guiding layer;
• an InGaAsP etch stop layer disposed on the cladding layer;
• and
• an InP cladding layer disposed on the etch stop layer.