Origin of link gain fluctuations in analog radio over single-mode fiber systems

• The Radio Frequency gain of analog Radio over Single Mode Fiber links can present undesired fluctuations.
• In many applications the level of such fluctuations (fractions of dB) cannot a priori be regarded as negligible.
• Their origin is identified in the combined effect of optical back reflection and temperature variations.
• Cost effective measures aimed to keep the impact of the phenomenon under control are discussed.

In analog Radio over Fiber systems based on single mode fibers, the possible presence of unexpected fluctuating behaviors of the received radiofrequency signal in front of monotonic environmental temperature variations, is analyzed experimentally and simulated theoretically. The possibility to understand all the aspects of this behavior allows to keep it in the right account, particularly when these systems have to be realized with stringent requirements in terms of cost and performance.