| 摘要 |
PROBLEM TO BE SOLVED: To suppress the occurrence of an accident, such as increase of transmission loss by change in the housing state, such as swallowing, by fixing an optical fiber unit to the inlet of a pipe at the point of the time when the optical fiber unit is led into the pipe by necessary extra length. SOLUTION: The optical fiber unit 18 is pneumatically fed (b) up to the mid-way of the pipe 20 and the front end from the outlet 200 of the pipe 20 is slightly projected (c). At the point of the time when the front end of the optical fiber unit 18 emerges about 1.5m from the outlet 200, the optical fiber unit 18 is fixed near to the outlet 200 as shown by a fixing part 22. At this time, this outlet 200 is previously so formed as to allow the outflow of compressed air 14 without being closed (d). The optical fiber unit is thereafter led in by about 0.1 to 0.2% (for example, 1 to 2m if the pipe 20 is assumed to be 10000m) as the necessary extra length part (e) and the optical fiber unit 18 is fixed to the inlet of the outlet 200 as shown in the fixing part 24. The compressed air 14 is simultaneously stopped (f). |
