OTDR: Quality Inspection of Optical Fiber Surface

A number of types of optical connectors are used to interface communication systems with optical networks. If the end surface of an optical fiber is contaminated, it can cause a communication network failure. In fact, more than 50% of communication network failures are caused by connector surface conditions. In addition, defects on the connector surface greatly affect Optical Time Domain Reflectometer (OTDR) measurement results.

Fig. 1 shows the measurement trace resulting from a dirty end face while Fig. 2 shows the trace with the same connector after its end face has been cleaned. In the trace for the contaminated connector surface, a slope appearing after the reflection becomes larger. Since an attenuation dead zone also becomes longer, an event cannot be detected correctly. On a high power communication path such as WDM or PON, connector burn out can result from contamination such as sebum and dust or scratches. Cleaning connector surfaces is crucial for the installation and maintenance of optical fibers. Thus, the quality assurance inspection using a fiber inspection probe with judgment criteria that conforms to a global standard becomes a critical tool to avoid costly consequences.

By connecting a fiber probe*, inspection of the fiber end is available with the AQ7280 and AQ1210. The fiber surface inspection function included in the these OTDRs (/FST option) automatically performs pass/fail judgment on contamination and scratches on the fiber surface. This is based on the IEC 61300-3-35 standard or user-defined criteria. The judgment result can be saved and added to a PDF report as an effective evidence after installation is complete.

*Please check each product page for verified models.


Fig. 1: Incorrect measurement trace due to an end face with scratches and stains.

Fig. 1: Incorrect measurement trace due to an end face with scratches and stains.


Fig. 2: Correct measurement trace for a clean end face.

Fig. 2: Correct measurement trace for a clean end face.


Pass/fail judgment display

Related Industries

Related Products & Solutions

AQ1210 Series Optical Time Domain Reflectometer

  • Yokogawa AQ1210 series OTDR
  • Fast and precise 
  • Optical time domain reflectometer delivers high reliability
  • Harsh field conditions
  • Multi-touch touchscreen, automatic measurement

AQ7280 Modular Optical Time Domain Reflectometer

  • Yokogawa AQ7280 Optical Time Domain Reflectometer (OTDR)
  • Fast and precise measurements with confidence
  • Satisfies broad range of test and measurement needs
  • Analyzing optical networks from access to core

Optical Test Equipment

  • Yokogawa optical test equipment solutions to measure optical components/systems
  • Serves demand for high capacity fiber lines and new component technologies

Optical Time Domain Reflectometer

  • Optical time domain reflectometer precision instrument for access network optical fiber installation and maintenance
  • Locate events or faults along fiber link during OTDR testing procedure

Precision Making