An optical fiber includes a cladding, a first core, and a second core. At least one of the first core and the second core is hollow and is substantially surrounded by the cladding.
A method for utilizing an optical resonator, the method comprising: providing an optical resonator comprising a reflective element and an optical fiber positioned relative to the reflective element such that light emitted from the optical fiber is reflected by the reflective e
An optical sensor includes an optical coupler. The optical sensor further includes a photonic bandgap fiber having a hollow core and an inner cladding generally surrounding the core. The photonic bandgap fiber is in optical communication with the optical coupler.