Low-cost embedded OTDR monitoring for direct modulation analog radio over fiber

Abstract

We present a low-cost embedded Optical Time Domain Reflectometer (OTDR) solution for link monitoring of direct modulation analog Radio over Fiber (a-RoF) systems transporting Long Term Evolution Advance (LTE-A) signals. Experimental results show that monitoring can be performed in-service and offline in order to detect fiber faults and quantify losses. A trade-off between the OTDR peak power and the data transmission power has been identified; nevertheless, it is proven that with proper configuration of the system, the required values of Error Vector Magnitude (EVM) for different modulation formats are not surpassed. Offline monitoring using this configuration setup showed a Dynamic Range of ∼24 dB with 10 meters spatial resolution.