To provide the optical transmission of small skewness generated among plural multiple optical fibers and to accelerate a speed at the time of data transmission, that is a communication speed, by providing respective multi- channel waveguides with a length adjusted based on a transmission time difference among the multi-channel waveguides in the optical transmission line for performing optical parallel transmission by the plural multi-channel waveguides.
A phase difference among the multiple (12-core, for instance) optical fibers F1...F4 is detected (S3). Thus, the transmission time difference among the multiple optical fibers F1...F4 whose reference is the optical fiber of a 12th core of the multiple optical fiber F4 is calculated (S4). Based on the calculated transmission time difference, conversion to the transmission time difference for which the optical fiber of the 12th core of the multiple optical fiber F4 is the same reference is performed (S5). Based on the transmission time difference, the length to be adjusted of the respective multiple optical fibers F1...F4 is obtained (S7). Then, based on the calculated cutting length, the respective multiple optical fibers F1...F4 are cut (S8).
ISONO YOSHIYA
WATANABE TSUTOMU
MATSUURA NOBUAKI
ANDO YASUHIRO
NIPPON TELEGRAPH & TELEPHONE