OPTICAL FIBER COMMUNICATION SYSTEM

摘要

PURPOSE: To extend a spectrum reduced compared to a polarization switching while a polarization diversity restores the half of transmitted power by continuously changing the polarized state of a modulation carrier at least in one code period prior to the transmission of the modulation carrier to a fiber. CONSTITUTION: A signal transmitted from a modulator 12 and a signal sent along a route 11b are sent to polarization maintaining fiber trunks 14a and 14b. The fiber trunk 14b placed on a supporting body which can be rotated by 90 degrees at the end part as shown by an arrow F, and a device 3 scrambles a polarize wave. Thus, a linear method can be executed on time. A phase is modulated by 180 degrees on the route 11a in the code period and a vector showing the polarized state is completely rotated (360 degrees). The modulator 12 modulates the phase which is directly proportional to applied voltage and therefore a generator 13 is set to be a sawtooth voltage generator whose period is equal to the code period or equal to the two-fold code period preferably.