A novel integrated optical chemical sensor based on a surface-relief Bragg grating in a waveguide with a curved input edge, and coated with a chemically sensitive polysiloxane cladding, is described. The curved edge provides a mechanism within the device fabrication that allows for alignment of the input beam to the grating to achieve Bragg scattering. As proof of principle, a low-parts-in-10<sup>6</sup> toluene-vapor sensor with a fast response time is demonstrated.
© 1999 Optical Society of America
(050.2770) Diffraction and gratings : Gratings
(130.0130) Integrated optics : Integrated optics
(130.3120) Integrated optics : Integrated optics devices
(130.6010) Integrated optics : Sensors
(230.7390) Optical devices : Waveguides, planar
Thomas M. Butler, Eishi Igata, Steve J. Sheard, and Neil Blackie, "Integrated optical Bragg-grating-based chemical sensor on a curved input edge waveguide structure," Opt. Lett. 24, 525-527 (1999)