1 λ × 144 Tb/s free-space IM-DD transmission employing OAM multiplexing and PDM

Abstract

We report the experimental demonstration of single wavelength terabit free-space intensity modulation direct detection (IM-DD) system employing both orbital angular momentum (OAM) multiplexing and polarization division multiplexing (PDM). In our experiment, 12 OAM modes with two orthogonal polarization states are used to generate 24 channels for transmission. Each channel carries 30 Gbaud Nyquist PAM-4 signal. Therefore an aggregate gross capacity record of 1.44 Tb/s (12 × 2 × 30 × 2 Gb/s) is acheived with a modulation efficiency of 48 bits/symbol. After 0.8m free-space transmission, the bit error rates (BERs) of all the channels are below the 20% hard-decision forward error correction (HD-FEC) threshold of 1.5 × 10(-2). After applying the decision directed recursive least square (DD-RLS) based filter and post filter, the BERs of two polarizations can be reduced from 5.3 × 10(-3) and 7.3 × 10(-3) to 2.2 × 10(-3) and 3.4 × 10(-3), respectively.

Structured Light in Turbulence

“…There has been significant progress and several impressive demonstrations in using structured light for multiplexing [19], [122][123][124][125][126][127]. To date, the fastest MDM demonstration has sustained a data rate of 1.036 Pbps over a lab-bench using 26 OAM modes together with wavelength and polarisation [128].…”

Radio-over-free space optical space division multiplexing system using 3-core photonic crystal fiber mode group multiplexers

“…In [35], researchers have modulated information over FSO transmission link of 143km by multiplexing of ℓ= ±1, ±2 and ±3 orbital angular momentum (OAM) modes at various relative phases to connect two islands. In [36], SDM in conjunction with polarization division multiplexing (PDM) was adopted for experimental transmission of 1.44 Tbps data over FSO link of 1.8m using 24 OAM modes. In another experiment [37], two OAM modes (ℓ=±3) were used in transmitting 40Gbps 16 QAM data over FSO link of 260m.…”

Structured Light in Turbulence

“…Nevertheless, there has been significant progress and several impressive demonstrations in using structured light for multiplexing [16], [103][104][105][106][107][108]. To date, the fastest MDM demonstration has sustained a data rate of 1.036 Pbps over a lab-bench using 26 OAM modes together with wavelength and polarisation [109].…”