| 摘要 |
PURPOSE:To relax the restriction of the number of distributions and to prevent a crosstalk characteristic from deteriorating by connecting a semiconductor laser and an exciting light source and cascading an optical fiber, an optical filter, and an optical receiver to respective output ports of an optical star coupler. CONSTITUTION:At least (n) semiconductor laser LD1 - LDn with an optical isolator and exciting light sources 21 and 22 are connected to input ports of the optical start coupler 4R which have at least P input ports and output ports respectively. Here, n < P. Optical fibers 100 - 10(n+2) including optical fibers to which a rare earth element is added, optical filters 51 - 5(n+2) for exciting light suppression, and optical receivers 71 - 7(n+2) are cascaded to output ports of the optical star coupler 4R. Information signals 11 - 1n of (n) channels are superposed on light signals of the semiconductor lasers LD1 - LDn, multiplexed and distributed by the optical star coupler 4R, and sent to respective subscribers. Consequently, tens of optical distributions are obtained, and the crosstalk characteristic is prevented from deteriorating. |
