Abstract: An optical waveguide environmental sensor is provided that is capable of detecting a target gas or liquid in the ambient environment in an advantageously short period of time. The waveguide is preferably in the form of an optical fiber having a cladding that contains a photonic band gap structure which in turn envelopes a light conducting, hollow core portion. The cladding further includes at least one elongated side opening that preferably extends the entire length of the fiber and exposes said hollow core portion to the ambient environment, which provides broad and nearly immediate access of the core portion to gases and liquids in the ambient environment, thereby minimizing sensor response time. The ambient gases or liquids filling the hollow core portion and elongated opening function as a ridge and slab, respectively, of an optical ridge waveguide that effectively supports at least one bound optical mode.

Abstract: An optical waveguide environmental sensor is provided that is capable of detecting a target gas or liquid in the ambient environment in an advantageously short period of time. The waveguide is preferably in the form of an optical fiber having a cladding that contains a photonic band gap structure which in turn envelopes a light conducting, hollow core portion. The cladding further includes at least one elongated side opening that preferably extends the entire length of the fiber and exposes said hollow core portion to the ambient environment, which provides broad and nearly immediate access of the core portion to gases and liquids in the ambient environment, thereby minimizing sensor response time. The ambient gases or liquids filling the hollow core portion and elongated opening function as a ridge and slab, respectively, of an optical ridge waveguide that effectively supports at least one bound optical mode.

Abstract: A low-loss photonic waveguide in the form of a Bragg optical fiber is provided that includes a dielectric core region extending along a waveguide axis that is characterized by a low amount of Rayleigh scattering, and a dielectric confinement region surrounding the dielectric core region that includes alternating layers of different glass compositions having relative refractive index differences that are at least 0.10, and preferably at least 0.30. The core region may be formed from air. The confinement region includes alternating high and low index glass layers wherein the high index layers are substantially pure silica mixed with index raising dopants that form enough % of the high index glass layers by weight to achieve the aforementioned 0.10 difference in indices of refraction, while the low index glass layers may be either substantially pure silica, or silica mixed with index lowering dopants to increase the index contrast between the layers.

Abstract: According to an exemplary embodiment of the present invention, an optical apparatus compensates for chromatic dispersion and/or dispersion in an optical signal includes a plurality of serially coupled optical waveguides each of which introduces chromatic dispersion and/or dispersion slope to the optical signal that traverses the optical waveguides.

Abstract: Disclosed is an optical waveguide fiber preform which is an assembly of one or more core rods surrounded by a plurality of clad rods. The clad rods have a central portion and a surrounding layer, in which the refractive index of the central portion is lower than that of the surrounding layer. The preform is drawn into an optical waveguide fiber that has a two component clad layer. Proper choice of the central portion and surrounding layer provide a waveguide fiber that is endlessly single mode. Alternative embodiments include fibers containing dopants that enhance fiber photosensitivity or which provide stress-induced or asymmetric-refractive-index-induced birefringence in the waveguide fiber.