RF to Fiber Optics Conversion
Any limitation in your fibre will be inconsequential compared to those in your optical modulation/demodulation processes.

You will have to look critically at the characteristics of your incoming signal to decide what sort of optical modulation scheme will best preserve the parameters you want to keep, and which you can allow to degrade.

If it's a data signal, you may want to throw away weak carriers. If it's a spectrum scan, you may want to keep weak ones, and ensure that strong nearby signals generate don't obscure them with intermodulation.

The most conceptually straightforward way to encode an RF signal onto optics is to analogue AM modulate a subcarrier, which has a frequency of several times your bandwidth. However, the linearity of this could vary between bad and very bad, which would affect your EVM slightly, and your co-channel hugely, if such things are of consequence in your original signal.

An ideal route would be to fully demodulate your signal, assuming it to be data, and ship the data along the fibre, using a standard data format and end-point chipsets.

There is not enough use-case information in your question to answer more than very generally at the moment. Depending on your field of employment, you may not be able to give out use case information!