| 摘要 |
<p>A device comprising an optical waveguide incorporating a long period grating and a thin film overlay material is described. The wavelength transmission spectrum of the device is fonctionally dependent upon the optical properties and thickness of the overlay material. If the overlay material has a refractive index higher than that of the cladding material surrounding the guiding layer of the waveguide, appropriate choice of thickness allows the sensitivity of the transmission spectrum of the device to changes in the optical properties of the overlay material to be enhanced. Appropriate choice of material thus allows voltage or optical or chemical or thermal, or any combination thereof, control over the transmission spectrum. The device may be used to form a tunable spectral filter, sensor or optical switch.</p> |
