Raffaele Corsini

3.4 Gbit/s visible optical wireless transmission based on RGB LED.

In this paper, we experimentally realized a gigabit-class indoor visible light communication system using commercially available RGB White LED and exploiting an optimized DMT modulation. We achieved data rate of 1.5 Gbit/s with single channel and 3.4 Gbit/s by implementing WDM transmission at standard illumination levels. In both experiments, the resulting bit error ratios were below the FEC limit. To the best of our knowledge, these values are the highest ever achieved in VLC systems.

1-Gb/s Transmission Over a Phosphorescent White LED by Using Rate-Adaptive Discrete Multitone Modulation

Light-emitting diodes (LEDs), which will be increasingly used in lighting technology, will also allow for distribution of broadband optical wireless signals. Visible-light communication (VLC) using white LEDs offers several advantages over the RF-based wireless systems, i.e., license-free spectrum, low power consumption, and higher privacy. Mostly, optical wireless can provide much higher data rates. In this paper, we demonstrate a VLC system based on a white LED for indoor broadband wireless access. After investigating the nonlinear effects of the LED and the power amplifier, a data rate of 1 Gb/s has been achieved at the standard illuminance level, by using an optimized discrete multitone modulation technique and adaptive bit- and power-loading algorithms. The bit-error ratio of the received data was

Experimental demonstration of high speed underwater visible light communications

1.5\cdot 10^{-3}

All DFB-Based Coherent UDWDM PON With 6.25 GHz Spacing and a

, which is within the limit of common forward error correction (FEC) coding. These results twice the highest capacity that had been previously obtained.

{>}{\rm 40}~{\rm dB}

We experimentally prove high-speed underwater optical wireless transmission over 2.5 m distance, using different bit rates and modulation schemes. The system uses two low-cost Light Emitting Diodes (LEDs) arrays as optical transmitter and an avalanche photodiode module as receiver. The measurements are taken using an outdoor water tank having 3.3 m diameter, where two waterproof boxes containing the transmitter and the receiver are fixed underwater at the inner borders. We test 6.25 Mbit/s with Manchester coding, 12.5 Mbit/s with NRZ 8b/10b coding and 58 Mbit/s with Discrete Multitone modulation. Bit Error Rate measurements are collected over several hours under typical summer sunlight illumination conditions. In all the experimental conditions we achieve error free transmission.

Power Budget

We demonstrate an ultra dense WDM passive optical network based on a simplified low-cost coherent receiver and free-running DFB lasers. The proposed 1.25 Gb/s system provides a high power budget , which can be exploited to support both large splitting ratio (1 × 128) and long reach (exceeding 60 km). The homodyne receiver is significantly simplified since it does not make use of any DSP and does not require phase/frequency locking; therefore, it allows for the use of a common free-running DFB as local oscillator rather than expensive low phase noise laser. Here, the proposed system is evaluated experimentally by using 5 × 1.25 Gb/s (gross data rate) channels on a 6.25 GHz grid. In the coherent receiver, a single free-running DFB laser was able to select each individual channel by thermal tuning and showed uniform performance. A -48 dBm average sensitivity at FEC level over a 66 km reach leaves enough margin for additional 30 dB splitting losses in the optical distribution network.

A Visible Light localization aided Optical Wireless system

We report about a Line of Sight Optical Wireless Communication (LoS OWC) system aided by a simplified Visible Light localization algorithm for tracking purposes. We show experimentally that by combining the LoS OWC system with the localization algorithm it is possible to provide a gross data-rate exceeding 300 Mb/s over a 90° illumination angle by using a RGB visible-light LED at 90cm distance.

Gigabit-class optical wireless communication system at indoor distances (1.5 – 4 m)

In this paper we experimentally realized bidirectional optical wireless communication (OWC) link using four channel visible LED board exploiting wavelength division multiplexing (WDM) for the downlink and infrared LED for uplink. We achieved greater than 5 Gbit/s data rate at common indoor distance (1.5 to 4 m) for downlink and 1.5 Gbit/s for uplink using commercially available LEDs. We achieved these results after a careful choice of the LED emission wavelengths and the optical filter spectra. Moreover, we investigate the optimal LED working current and the optimal modulation depth. The bit error ratios of all the channels were maintained lower than the FEC limit (3.8·10(-3)).

High-Speed Bi-directional Optical Wireless System in Non-Directed Line-of-Sight Configuration

We propose and experimentally demonstrate the first bi-directional optical wireless link operating in non-direct line-of-sight (Nd-LOS). The system is based on visible light emitting diode (LED) for downlink and infrared LED for uplink. We achieve around 250 Mbit/s for both downstream and upstream transmission, with the ambient light noise of usual indoor illumination level (500 lx), produced by warm-white LED. 100 Mbit/s are guaranteed inside 12 m2 of a common room scenario, without LOS tracking. An optimized discrete multi-tone modulation gives bit-error-ratios always below of the common forward-error-correction threshold of 1.5 ×10-3. These results indicate that this scheme has great potential for practical VLC system implementation.

Experimental demonstration of a novel polarization-independent coherent receiver for PONs

We experimentally demonstrate a novel polarization-independent coherent receiver for low-cost PONs using intensity-modulation and low-cost components. The receiver is successfully tested in a 1.25 Gb/s long reach (66 km, 48 dB ODN loss) system.