High-speed optical CDMA code generator method using super structured long period fiber gratings

摘要

PURPOSE: A method for generating a very high speed OCDMA(Optical Code Division Multiple Access) code using an arrayed long period fiber grating is provided to reduce the noise through a multiple reflection by using a time delay generated due to a path difference between a core mode and a cladding mode. CONSTITUTION: An optical pulse is projected into an optical fiber core(11). When the optical pulse reaches an LPFG(Long Period Fiber Grating)(13), an optical power of the optical pulse is divided to the optical fiber core(11) and a cladding(12). The divided optical pulses propagate in a core mode and a cladding mode. Owing to the difference of an effective refractive index between the optical fiber core(11) and the cladding(12), the divided optical pulses have a time delay defined by = L(Ncore-Nclad)/c. An LPFG(14) combines and branches the divided optical pulses.