Multimode EDFA performance in mode-division multiplexed transmission systems

Abstract

Abstract:We report a detailed study on the system performance of a two-mode group EDFA. In particular we quantify how the gain spectrum and BER performance are affected by input signal and pump power as required in the execution of our ongoing MDM transmission experiments.OCIS codes: (060.0060) Fiber optics and optical communications; (060.2320) Fiber optics amplifiers and oscillators. IntroductionTo date single mode fibers (SMFs) have been used as the transmission medium of choice in long-haul telecommunication systems, with the use of multimode fibers (MMFs) restricted to short distance (e.g. local area) networks due to their severe modal dispersion which grossly limits the transmission bandwidth. However, driven by fears of a future "capacity crunch", major interest is developing in the potential use of "mode division multiplexing (MDM)" in which selective mode excitation and detection schemes are used to define distinguishable information channels within a few mode fiber (FMF) [1][2][3]. Since the modes are orthogonal, it is in principle possible to increase the capacity in accordance with the number of modes supported by the FMF. Digital signal processing can be utilized to mitigate transmission impairments caused by mode-coupling in the MDM systems and thereby to substantially increase the achievable transmission distance. However, in order to be useful in long-haul systems a practical, high performance FMF amplifier is essential. In our recent work [4], we successfully demonstrated a multimode (two-mode group) erbium-doped fiber amplifier (MM-EDFA) for MDM applications providing simultaneous modal gains of ~20dB for different pair-wise combinations of spatial and polarization modes. However, in order to reliably use this device in full data transmission experiments a far more detailed understanding of how the amplifier performs under more fully loaded conditions (both in terms of DWDM channels across the Cband and the full set of supported modes) is required. In this paper, we report a detailed characterization of how the input signal power and pump power levels affect the spectral gain flatness and bit error rate (BER) performance and the optimum condition required to obtain the minimum power penalty are discussed. Note that the following characterization of the MM-EDFA was successfully used in the 96-channel, 73.7 Tbit/s MDM transmission experiments reported in our recent ECOC 2012 postdeadline paper [2].

Ultra-high-density spatial division multiplexing with a few-mode multicore fibre

“…However, for FM-MCFs, both intracore (between LP modes) and intercore crosstalk are to be considered 20 . In relation to intracore crosstalk, it is inevitable that strong modal interactions occur due to perturbations, splice points and multi-mode components, along a realistic transmission link [22][23][24][25] . Accordingly, when designing and fabricating FM-MCFs, suppressing intercore crosstalk is critical.…”

Optimal power allocation in nonlinear MDM‐WDM systems using Gaussian noise model

“…For calculating the EDFA gain profile in Figure 2b, we consider that the 21 WDM channels occupy the wavelength-range 1548-1552 nm along which a 0.5 dB EDFA gain tilt should be considered based on [42,52,53]. Moreover, it is shown in [44,[54][55][56] that the EDFA gain tilt between LP01 and LP11a/b modes is 0.8 dB. The EDFA gain ripples are randomly selected within [−0.05, 0.05] dB [42].…”