Abstract: A photonic crystal (PC) based structure is proposed for sensing exceptionally small refractive index changes of a medium. In a typical photonic crystal, the location of the band edges and the defect modes if present are very sensitive to the dielectric contrast of the structure. Hence, a propagating electromagnetic wave at a particular frequency gains significant phase shift due to the index changes and when this phase shift is measured interferometrically, it could be possible to infer the refractive index changes as small as 10?11 per lattice distance. Furthermore any other effect that changes the band edge positions (dispersion diagram) of the photonics crystal structure such as binding an analyte to surface of photonic crystal structure will cause detectable phase change in the output wave which will indicate the amount of the analyte. This method can be used to sense biological, biochemical, chemical and refractive index sensing of gases and liquids.

Abstract: A configurable wavelength multiplexing device having first, second, and third reflectors. The first reflector has a first state in which it transmits incoming light (having first and second wavelengths) along a first transmitted path and a second state in which it reflects the light along a first reflected path. The second reflector reflects the first wavelength and transmits the second wavelength. The third reflector reflects the first wavelength. The first, second, and third reflectors are oriented so that when the incoming light is transmitted along the first transmitted path, the first wavelength is reflected by the second and third reflectors to travel along second and third reflected paths, the third reflected path intersects the first reflector at an angle such that the first wavelength is transmitted by the first reflector and continues on the first reflected path, and the second wavelength is transmitted by the second reflector.

Abstract: An optically responsive electronic lock is disclosed comprising an optical fiber serving as a key and having Bragg gratings placed therein. Further, an identification system is disclosed which has the optical fiber serving as means for tagging and identifying an object. The key or tagged object is inserted into a respective receptacle and the Bragg gratings cause the optical fiber to reflect a predetermined frequency spectra pattern of incident light which is detected by a decoder and compared against a predetermined spectrum to determine if an electrical signal is generated to either operate the lock or light a display of an authentification panel.