摘要 |
<p>The turns of an optical fiber paid out from a canister are counted, and the signature of the optical fiber is measured, by monitoring the electromagnetic field of the charge on the optical fiber as it moves past an antenna. The optical fiber follows a helical path as it is paid out. A stationary antenna located transversely proximate the payout region detects a periodic repeating variation of the bound and/or free electrical charge associated with the optical fiber, as the optical fiber periodically moves closer to and farther from the antenna along the helical path. Each period of the variation corresponds to one turn of optical fiber paid out from the canister.</p> |