光时域反射仪 - OTDR（Optical Time Domain Reflectometer），广泛的运用于光纤网路的施工及维护，能找出光纤误点定位、光纤线缆长度和光纤的传输损耗。检验的方式是由打进光突波（光脉冲）的同一侧接收光讯号，因打入的讯号遇到不同折射率介质会散射及反射回来，反射回来的光讯号强度会被测量到，且为时间的函数，并能换算成光纤的长度。光纤损耗的数值对于施工人员是非常重要的数据，损耗的数值会影响光纤传输并造成干扰。使用OTDR可以检测损耗并且快速定位故障区域，使得维修更加方便，减少光纤网路传输的问题。一般常见的OTDR都能经由USB与电脑连接，以便在测试过程中数值能被传输到电脑中用于分析和储存。

OTDR产品特性：
￭ 运用于光纤网路的施工及维护
￭ 检测出光纤误点定位、光纤线缆长度和光纤的传输损耗
￭ OTDR运算使用瑞利散射和菲涅尔反射原理
￭ USB介面资料传输至电脑中，便于分析储存资料

OTDR has been used in fiber optic network installation and troubleshooting. It is an optoelectronic instrument used to characterize an optic fiber. OTDR is a test instrument not only can identify the fault location and the length of optical fiber cable, but also can measure the loss of optical power. It also extracts, from the same end of the fiber light that is scattered or reflected back from points along the fiber. The loss of optical power cause interference of optical transmission, it’s the most concerned point from optical maintenance and troubleshooting. OTDRs are able to upload data to PC in order for engineer to analyze test result.

OTDR features:

￭ OTDR has been used in fiber optic network installation and troubleshooting.It is an optoeletronic instrument used to characterize an optical fiber.
￭ Not only can identify the fault location and the length of optical fiber cable, but also can measure the loss of optical power.
￭ It’s using Rayleigh scattering and Huygens–Fresnel principle
￭ Able to upload data to PC to analyze test result