On-chip miniature optical isolator

An optical isolator comprising:

• a bus structure that receives as input an optical signal;
• a microring structure that is resonantly coupled to the bus structure;
• and
• an optical structure positioned on/around the microring structure, the optical structure generates nonreciprocal loss so as to allow the microring structure to achieve a particular optical isolation and insertion, the optical structure comprises a cladding layer and a magneto-optical layer positioned on the cladding layer, the magneto-optical layer achieves nonreciprocity with application of an external magnetic field so as to produce a nonreciprocal index resulting in a nonreciprocal coupling induced loss in the microring structure.

A method for producing nonreciprocity in an optical structure comprising:

• providing a cladding layer;
• providing an external magnetic field;
• and
• positioning a magneto-optical layer on the cladding layer, the magneto-optical layer achieves nonreciprocity with application of the external magnetic field so as to produce a nonreciprocal index resulting in a nonreciprocal coupling induced loss in a neighboring waveguide in proximity to the magneto-optical layer.