Optical-fibre LNBs
LNBs for fibre satellite distribution systems operate in a similar way to conventional electrical LNBs, except that all four of the sub-bands in the entire Ku Band spectrum of 11.70 GHz-12.75 GHz across two signal polarisations are simultaneously block-downconverted (as in a Quattro LNB). The fours sub-bands’ IFs are stacked to create one IF with a range of 0.95 GHz-5.45 GHz (a bandwidth of 4500 MHz), which is modulated on an optical signal using a semiconductor laser, to send down the fibre cable.
At the receiver, the optical signal is converted back to the traditional electrical signal to “appear” to the receiver as a conventional LNB.
Read more about this topic: Low-noise Block Downconverter