Radiolytic method for trimming planar waveguide couplers

摘要

A method is provided of trimming the optical coupling ratio of an optical coupler to a prescribed value. The optical coupler is formed from a plurality of waveguides which each include a core and cladding. In accordance with the method, an irradiation energy is selected that is absorbed by portions of the waveguides located in a coupling region. A dosage of radiation is applied to the waveguide portions at least sufficient to adjust the optical coupling ratio to the prescribed value. The radiation, which may be absorbed by the cladding and/or the core of the waveguides, causes a change in the refractive index difference between the core and cladding of the waveguides. This change in the refractive index difference will result in a change in the optical coupling ratio of the device.