Bit-rate and distance limitations of subcarrier multiplexing on multimode fiber

It has been demonstrated experimentally [l] that subcarrier multiplexed (SCM) transmission in multimode fiber, at frequencies above the intermodal bandwidth limit, may be used to obtain bit rates and distances of interest in LAN applications. This paper addresses limits on the performance of such systems. The fiber is modeled as having a basband impulse response containing N, randomly chosen delays with a spread ( AT ) corresponding to the intermodal dispersion. Figure 1 indicates three such responses for N, = 100 and AT = 10 ns. At high frequency there are many bandpass regions with a total available bandwidth much larger than the intermodal bandwidth (&). It was shown in [2] that the average value of these passband regions depends mainly on N,, decreasing as N,-*”. The bandwidth of the individual subcamer channels is limited by B,. ”------I