Splice loss requirements in multi-mode fiber mode-division-multiplex transmission links

Abstract

We investigate numerically the influence of fiber splices and fiber connectors to the statistics of mode dependent loss (MDL) and multiple-input multiple-output (MIMO) outage capacity in mode multiplexed multi-mode fiber links. Our results indicate required splice losses much lower than currently feasible to achieve a reasonable outage capacity in long-haul transmission systems. Splice losses as low as 0.03dB may effectively lead to an outage of MIMO channels after only a few hundred kilometers transmission length. In a first approximation, the relative capacity solely depends on the accumulated splice loss and should be less than ≈ 2dB to ensure a relative capacity of 90%. We also show that discrete mode permutation (mixing) within the transmission line may effectively increase the maximum transmission distance by a factor of 5 for conventional splice losses.

Reach Improvement of Mode Division Multiplexed Systems Using Fiber Splices

“…However, given that current experimental FMFs present weak distributed XT (dXT) (reported value of -18 dB after 33 km [1], [4]), the XT accumulated along transmission can be increased using discrete XT, introduced at specific points. In [5] it has been shown that ideal discrete mode permutation, without mode dependent losses (MDL), within the transmission line may effectively increase the maximum distance reach by a factor of 5. However, such conclusion was based on the statistics of multiple-input-multiple-output (MIMO) outage capacity, ignoring DMD and optical signal-to-noise ratio (OSNR).…”

Capacity Enhancement of Few-Mode Fiber Transmission Systems Impaired by Mode-Dependent Loss

“…Nonetheless misaligned fiber splices also lead to an important end-to-end accumulated MDL [6]. In our work, we focus on distributed MDL arising from fiber splices and micro-bends.…”

“…In our work we fix λ and N A and we increase r c to allow the propagation of higher order modes. In Table 1, we report the parameters of the GI-FMFs [6]. Table 1.…”

“…In the case of using OFDM modulation format, the size of the cyclic prefix should be longer enough to absorb the DMGD. Non-unitary modal coupling due to fiber misalignments at a splice point is given by an M × M coupling matrix C k , with entries computed using an overlap integral of the electrical fields of propagating modes at fiber cross sections as in [6]:…”

“…MDL arising from the fiber line is due to manufacturing imperfections such as splices or micro-bends. Accumulated splice losses as low as 0.03 dB may lead to system outage after only a few hundred of kilometers [6]. Another source of MDL comes from optical components such as multiplexers/de-multiplexers (MUX/DEMUX) [7,8] and few-mode optical amplifiers [9,10].…”