RF transmission over multimode fibers using VCSELs - Comparing standard and high-bandwidth multimode fibers

Fiber-optic radio-frequency links have been assembled using oxide-confined vertical-cavity surface-emitting lasers (VCSELs) and multimode fibers. Links with single and multimode VCSELs and with standard and high-bandwidth fibers have been evaluated and compared in the frequency range of 0.1-10 GHz. The best results were obtained for links with a multimode VCSEL and a high-bandwidth fiber. For a 500-m-long link, a spurious free dynamic range of 104 dB. HZ(2/3) at 2 GHz and 100 dB (.) Hz(2/3) at 5, GHz were obtained while allowing for a VCSEL-fiber misalignment of +/-12 mum. Corresponding numbers for the intrinsic link gain and noise figure are -29 and -33 dB, and 39 and 42 dB at 2 and 5 GHz, respectively. Inferior performance Was observed for the standard fiber link due to a larger variation in modal group velocities. This paper also presents a detailed link analysis to identify performance limitations and to suggest modifications for improved performance.