RF over Fiber (RoF) Basics

This page describes RF over Fiber (RoF) basics and lists RF over fiber component manufacturers. It also covers RF over fiber connectors, such as FC-APC (Angle Polished Connectors) and SC-APC.

The following are the merits of an RF over fiber system that have contributed to its popularity:

• As we know, RF loss increases with increasing frequency and/or length in conventional coaxial cables. Due to this, fiber optic cables are used for the transmission and reception of radio frequency (RF) signals.
• Fiber optic cables neither couple nor leak the signal and are therefore ideal under noisy RF channel conditions.
• Fiber optic cable assemblies are smaller and lighter.
• They offer wider bandwidth as well as higher frequency transmission.
• Lower cost of the fiber.
• Single-mode fiber cable is used as an RF carrier.

Figure-1 depicts a simple 1-way RF over fiber system. As shown, the RF Transmitter part is interfaced with the FO TX part. The RF signal is carried over the fiber cable to the other end. At the receiver, FO RX converts the signal into its original RF form. In this system, FO TX is referred to as the ‘head end,’ while FO RX is referred to as the ‘remote end.’

Figure-2 depicts a 2-Way RF over fiber (RoF) system. As shown, a directional coupler is used to couple the signal into two parts: RF Antenna and Base station system. A duplexer is used between the fiber optic transceiver and the coupler.

At the receiver, the signal is amplified and fed to the duplexer, and then provided for necessary RF processing. In a 2-Way fiber system, two optical frequencies are used, one for the transmit direction and the other for the receive direction. For example, 1330 nm and 1510 nm.

The duplexer functions as a Wavelength Division Multiplexer and Demultiplexer for these signals. It is also known by the term RFoG or RF over Glass Fiber.

RF over Fiber Component Manufacturers

FC-APC and SC-APC are used as fiber cable connectors. Following are the RF over fiber (RoF) component manufacturers.

• Finisar Corporation
• Photonic Systems Inc.
• RFOptic Ltd.
• EMCORE Corporation
• Foxcom (provides RF-2-Fiber solutions)
• Optical Zonu Corporation
• Pulse Power & Measurement