Hybrid solgel Bragg grating loaded waveguide by soft-lithography and its potential use as optical sensor

Preliminary tests on the sensibility to external environment of an optical waveguide filter operating in the near infrared region are reported. Device consists of a hybrid sol–gel based grating loaded channel waveguide. Several techniques were implemented to obtain the final device. A hard master with gratings produced by Electron Beam Lithography was employed to fabricate a transparent soft mold. UV-nanoimprinting technique, exploiting the soft stamp, was used to reproduce on the hybrid photosensitive sol–gel film the planar grating. Optical lithography was finally applied to manufacture the grating loaded channel waveguide which is our final integrated sensor. The device was optically characterized by transmission measurements in the range 1,450–1,590 nm and its sensibility to external environment was tested in air and water.