Beyond Fiber

Fiber Links for RF & Microwave Communications

September 01, 2020

Berkshire Photonics has a long history of supplying fiber optic products for transmitting satellite, phased array, and other RF/microwave signals in the government, aerospace, and defense markets as well as wireless and CATV applications for the commercial market.   

Precise time delays are required where system timing is critical, in applications such as satellite site diversity, phased array antennas, and phased array calibration. Fiber chromatic dispersion affects the timing in wide band applications and when transmitter wavelength drifts. The chromatic dispersion in fiber optic delay lines constructed of conventional non-dispersion-shifted single-mode fiber (NDSF) can be fully compensated by incorporating corresponding lengths of negative-dispersion fiber into the system. However, long delays can lead to high optical losses. Typical Dispersion Compensation Modules (DCM) increase the total fiber length by as much as 65%, increasing the gain of erbium-doped fiber amplifier (EDFA) modules needed to compensate for the high optical losses in common negative-dispersion fiber.

Berkshire makes custom Dispersion Compensation Modules with precisely controlled time delays. Our DCMs use a highly-efficient high-dispersion fiber that only increases the total fiber length of the system by approximately 13%. These modules lessen the requirements on the EDFA modules. The DCMs work with a wide range of fiber optic transport products for satellite and microwave communications in all bands, and can be used to construct transparent inter- and intra-facility links from 1 meter to >200 km. They can be used in RF and microwave signal transport, antenna remoting, video transport, electronic warfare systems, and other high-dynamic-range applications.