The intrinsic characteristics of the optical fiber allow multiplying the performances of current RF technology, not only taking into account the signal processing, but also its generation. This performance has transformed photonic technology into the heart of the new-generation radiotelescopes (ALMA and SKA, among others), which need RF signals until 125 GHz and a great spectral purity.
The wide extensions occupied by the new last-generation radiotelescopes (formed by arrayed antennas) made necessary the distribution of synchronism signals between different antennas, assuring his functionality as a whole. In some cases, these harnessing distributions can get 15km. The transmitted high frequencies and the high stability requirements of the signals have caused the rejection of electrical harnessing, which would be even more expensive.
Synchronism systems which are needed to guarantee the global operation of current radiotelescopes formed by arrayed antennas require the use of high-precision clock signals. These signals, up to now generated by local RF oscillators, are suffering a growth in the operating frequency due to the evolution of new ADCs.