What is RF over fiber technology and what are the benefits?
RF over fiber (RFoF) is the method of converting a radio wave (RF) into light by modulating the intensity of the light source (typically a laser) with RF signal. This is an analog process and no digitisation is used. The light signal is then transmitted over a fiber optic cable, which replaces and exceeds the capabilities of traditional copper coax cable. RFoF is not distance-limited like coax, which only goes to 300 ft (approx.).
The benefits of RFoF are:
- Very low signal loss (less than 0.5dB/km) allowing for connections of several kilometers without the need for amplification (see graph comparing RFoF to coax over frequency).
- Flat frequency response across the entire frequency band, meaning there is no need for slope compensation
- Immunity to EMI and RFI due to fiber being a non-conductive medium
- Security against signal interception
- Flexible and lightweight for ease of deployment
- Low maintenance – install and forget technology
- Simple installation
- Cost effective compared to high end, low loss coax cable and slope compensation amplifiers.
Additional benefits of ViaLite’s RFoF include:
- Widest dynamic range
- 99.999% reliability
- Longest product warranty (5 years)
- Focused expertise in RFoF
- Full design and support service
- Long distance DWDM link systems to 600km+.
A typical RFoF system will consist of three main elements:
- Optical transmitter
- Fiber optic cable
- Optical receiver (to convert back to RF).
The system is defined in terms of normal RF parameters, i.e. gain, noise figure, linearity etc., and can be treated as an RF black box by a systems designer.
RFoF is used to connect antennas to transmission and receiving equipment.
Typical applications include:
- Satcom ground segment equipment – such as teleports, broadcast facilities, VSAT gateways, etc.
- Broadcast Production – including wireless cameras, microphones, IFBs and Talkback
- GPS for timing – timeservers, base stations and re-radiating
- Maritime – GPS and Satcom
- Government and Defense – secure communications, Satcom, SIGINT
- Cellular and timing – GPS, re-broadcasting and distribution
- Mining and Public Safety – timing and communications
- Telemetry – Satellite, missiles and spacecraft.