pg 6 depicted in model 1 of fig8 and in accordance with the principles of the present invention comprises a single transmitting waveguide 10 and a single receiving waveguide 12 arranged in an axially adjacent relationship each waveguide 10 12 has an end surface 14 16 respectively positioned parallel and spaced from a surface referenced as the x axis by a distance y the index of refraction for the transmitting waveguide 10 is n 1 and for the external medium is n 2 representative paths of transmitted light are further illustrated as u03b8 n u03b8 3 db and u03b8 10 db and it should be noted that n 1 the 3 decibel loss angle u03b8 3 db and the 10 decibel loss angle u03b8 10 db are all parameters of the waveguide chosen for the waveguide selected as an example it will be recognized from fig8 that as light travels through the end surface 14 of the transmitting waveguide 10 refraction occurs bending the non normal u03b8 3 db u03b8 10 db paths toward the receiving waveguide interface 17 according to snell 39 s law the relationship between the angle u03b8 of light approaching the end surface 14 and the angle u03b8 34 of light leaving the end surface 14 is described by the equation equ1 if x is the distance from the waveguide interface on the receiving waveguide and y is the distance to the x axis surface set at 0 01 inches than a statement of x in terms of y would be x y tan u03b8 34 and x n 0 x 3 db 0 0026 and x 10 db 0 0064 that is.