| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical fiber transmission line capable of sufficiently shutting off fiber fusion using a simple configuration. <P>SOLUTION: In the optical fiber transmission line 1, a graded index fiber (GIF) 3 is inserted between single mode fibers (SMF) 2a and 2b for transmission. The GIF 3 is so formed that its mode field diameter (MFD) becomes greater gradually, from the light incident side and is made largest in the MFD at a point the length reaches a quarter pitch. The length of the GIF 3a arranged on the light incident side and that of the GIF 3b on the light exit side, where the MFD decreases gradually, are set respectively at the quarter pitch, and these are connected to set the length of the GIF 3 to a half pitch. As a result, since a portion of a large MFD is inserted into the middle of the optical fiber transmission line, even if the spread of the fire is started due to the occurrence of the fiber fusion, fusion of the fiber can be shut off at the portion of the large MFD. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
