Back reflection insensitive electro-optical interface and a method of coupling the same to a waveguide

A method of coupling an optical signal source to a waveguide, the method comprising the steps of:

• providing a semiconductor laser having a cavity;
• said cavity being sized and shaped to produce signals within the telecommunications band;
• forming a second or higher order grating within the cavity, thereby inducing surface emissions;
• operatively positioning said semiconductor laser adjacent to a waveguide, and
• coupling the surface emissions to the waveguide without an intervening optical isolator and,
• controlling size, shape and position of the cavity so that a radiation field for said cavity is not a mode discrimination mechanism, such that receiving back reflection in the cavity affects a coupling coefficient to the radiation field without affecting any fundamental modes of oscillation of said cavity.

An electro-optical coupler comprising:

• a base,
• a substrate mounted onto said base;
• a semiconductor laser telecommunication signal source mounted onto said substrate, said semiconductor signal source comprising a surface emitting semiconductor laser having a second order grating within a laser cavity oriented perpendicular to said surface emission such that any back reflections only affects a coupling coefficient of a radiation field in the cavity without substantially affecting the fundamental modes of oscillation of said cavity;
• a positioner to position a waveguide in a connection space to hold the waveguide in an operative relationship with said semiconductor laser;
• and
• a fiber waveguide inserted into said connection space and operatively positioned by said positioner adjacent to said signal source wherein signals from said signal source are coupled to said fiber waveguide in the absence of a back reflection signal isolator.