WAVEGUIDE TYPE OPTICAL ISOLATOR

摘要

PURPOSE: To attenuate one of optical waves in the cavity of a ring laser without attenuating the opposite optical wave, by placing an optical output port at one end of a waveguide stem of a branch type waveguide coupler, placing optical input port at one end of two branches, and coupling an optical absorber with the other end. CONSTITUTION: An isolator 121 has an asymmetric multi-mode branch type waveguide coupler 56 having a tapered waveguide section 55 having an aperture angleα. A first branch 57 of this coupler 56 is coupled with an optical absorber 54. The terminal end of a second branch 58 is coupled with an input port 95. A third end of the coupler 56, i.e., the end of a waveguide stem 60 is coupled with an output port 96 of the isolator 121. All these elements are integrated on the same substrate 59.