GRATING AND METHOD AND APPARATUS FOR FORMING SAME

摘要

A grating formation method comprises the steps of acceleratingions; causing the accelerated ions to pass through a mask having a shapecorresponding to the grating; and implanting the ions, which have passedthrough the mask, into the core, to form refractive index-variation portionsfor the grating in the core. The other formation method comprises thesteps of accelerating ions, converging an ion beam formed of theaccelerated ions, to make a beam diameter identical with or smaller than awidth of refractive index-variation portions in a direction of the centralaxisof the optical waveguide so as to provide a converged ion beam; andintermittently irradiating the converged ion beam to the core, while movingan irradiation position in the direction of the central axis, to implant theions into the core so as to form the refractive index-variation portions inthe core.