Two mode transmission at 2x100Gb/s, over 40km-long prototype few-mode fiber, using LCOS-based programmable mode multiplexer and demultiplexer

Abstract

We present a novel optical transmission system to experimentally demonstrate the possibility of mode division multiplexing. Its key components are mode multiplexer and demultiplexer based on a programmable liquid crystal on silicon panel, a prototype few-mode fiber, and a 4×4 multiple input multiple output algorithm processing the information of two polarization diversity coherent receivers. Using this system, we transmit two 100 Gb/s PDM-QPSK data streams modulated on two different modes of the prototype few-mode fiber. After 40 km, we obtain Q(2)-factors about 1 dB above the limit for forward error correction.

Performance of Direct-Detection Mode-Group-Division Multiplexing Using Fused Fiber Couplers

“…As stated for the multiplexer, no loss is introduced by the proposed concatenation of selective couplers, with the exception of the 3-dB penalty associated to the 2×1 combiner required for outputs 2 and 3. In summary, the multiplexer and demultiplexer described in this section demonstrate losses much lower than for devices implemented in free-space optics [5], [8,9]. Our concern continues to be the crosstalk occurring between the mode LP 21 and the output channel 4 (matched to the LP 02 mode), in this case happening in the first individual coupler of Fig.…”

“…This paper pursues the latter approach, with the goal of reducing cost and power consumption for short-range links in local-area networks, data-center interconnects, or access networks SDM in multiple spatial modes was firstly proposed using conventional MMFs with core diameters of 50-62.5 μm [3], which pose challenges in mode coupling and crosstalk because of the large number of propagating modes. Subsequently designed few-mode fibers (FMF) supporting a smaller number of modes enable greater control of modal profiles, dispersion and coupling, leading to more stable transmission performance [4,5]. In coherent long-haul systems, the FMF must be optimized to yield a low differential group delay (DGD) between modes, in order to reduce the memory length requirements for MIMO processing.…”

“…One common approach uses free-space optics, selecting modes using either fixed selective glass phase masks [4] or programmable Liquid Crystal on Silicon (LCOS) spatial light modulators (SLM) [5], [8,9]. The main disadvantage of free-space optics schemes are high losses, which scale as order 1/N at both the multiplexer and demultiplexer, where N is the number of data channels.…”

Wavelength-Selective Switches for Mode-Division Multiplexing: Scaling and Performance Analysis

“…At each frequency, the mode-clipping model (4) can be generalized to compute a frequency-dependent coupling coefficient from mode (q, m) to mode (p, n): LG Due to symmetry of the LG modes in (1), sine and cosine modes do not couple to each other in (5). Sine and cosine modes are symmetric and anti-symmetric along the y-axis, respectively, and the integration of (5) between cosine and sine modes yields zero.…”

“…which includes diagonal and off-diagonal elements of the mode-coupling matrix described by (5). Figure 6 shows the equal-weight mode-averaged transmission coefficient magnitude (8) to that in Figs.…”