Patent Number: 6,310,702

Title: Testing device for multistage multi-branch optical network

Abstract: A testing device performs testing on a multistage multi-branch opticalnetwork, which contains optical lines (such as optical fibers) that areconnected together at connection points (e.g., optical couplers) in amultistage multi-branch manner. An OTDR measurement device uses softwareto perform fault determination with respect to the multistage multi-branchoptical network. Herein, optical pulses are input to an input end of themultistage multi-branch optical network, wherein they are reflected atcertain portions of the optical lines and the connection points whilepropagating through the optical lines. Then, reflected beams are returnedto the input end and are mixed together as response light, which ismeasured by the OTDR measurement device. The response light is convertedto a plurality of digital waveform data representing a measured waveform,which is then divided into multiple ranges on the basis of the Fresnelreflection points and connection points. Separative analysis is performedon the digital waveform data belonging to each of the ranges of themeasured waveform. The separative analysis is repeated at measuring times,which are determined in advance. So, the fault determination is made bycomparing results of the separative analysis, which are obtained at themeasuring times respectively. By the fault determination, it is possibleto determine a fault line and a fault location (or fault distance) as wellas a fault time.

Inventors: Minami; Takao (Tokyo, JP), Takeuchi; Nobuaki (Tokyo, JP), Nozaki; Naoyuki (Osaka, JP), Shinozaki; Koichi (Osaka, JP), Genji; Takamu (Osaka, JP)


International Classification:

Expiration Date: 10/32013