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We experimentally demonstrate and investigate the performance of a multi-input-multiple-output (MIMO) free-space optical link employing orbital-angular-momentum multiplexing through turbulent channel. We show that turbulence effects can be mitigated by exploiting spatial diversity and MIMO equalization.
We report a cost-effective 40-Gb/s TDM-PON downstream utilizing an integrated DFB-EAM in OLT and an APD-based 3-level detection receiver in ONU, achieving a high power budget of 23.4 dB in real time operation.
A WS-TDMA optical switch fabric scalable to 1024 ports is demonstrated. Fast tunable (<200ns) transceivers using bipolar encoded transmission and coherent reception enable wavelength switching and TDMA over a passive star network for low latency packet level switching.
We demonstrate the transmission of 51.56-Gb/s OOK signals over 15 km of SSMF using a 1.55-μm DML. A receiver-side duobinary filter is used together with FFE for the compensation of the bandwidth limitation and fiber dispersion.
We report a novel single-lane 112-Gbps system based on SFP module with 10km SSMF reach employing a duobinary 4-PAM modulation. Impairment caused by electrical circuit is compensated by digital pre-distortion techniques.
An adaptive digital pre-distortion method to enable single carrier 400G DP-128QAM transmission over 328 km fiber with 30% FEC is presented. Experimental comparison in reach and spectral efficiency is made with 400G DP-64QAM.
This paper presents sub-THz interconnect for high energy-efficiency chip-to-chip communications, including a microstrip line based low-loss wideband sub-THz channel and a high energy-efficiency transceiver. The channel loss is as low as 0.06 dB/mm. The transmitter output power is 0.66 dBm with 8.8 mW of DC power consumption, and the receiver consumes 60.8 mW DC power. The interconnect achieves 9-Gb/s...
Due to the ubiquitous presence of smart mobile devices, the search for an enabling technology for indoor positioning has accelerated. Different systems have been designed for applications like asset tracking, guiding and other Location Based Services (LBS). Depending on the application, the solutions use RF-, InfraRed or ultrasound technologies as communication system between the mobile nodes and...
In free-space optical communication, aperture averaging effect can be used to optimize receiver design. A variety of factors contribute to aperture averaging effect, such as the receiving aperture, the light source, and the turbulence link. Cassegrain system is usually used as the receiver. It is technically feasible to optimally design the light source according to Cassegrain system's aperture averaging...
With an increase in demand of high data rate near field communication, Visible Light Communication (VLC) has been recognized as advanced and most promising innovation to acknowledge short-run, high speed as well as large capacity wireless communication. In this paper, a prototype of real time embedded system has been proposed, using modest financially accessible light emitting diodes (LED), which...
This paper presents the link budget analysis for free space optical (FSO) communication and the studies on how to reduce the attenuation effect to improve FSO link. The effects are primarily focused on the atmospheric attenuation on the received power. Transmission power is the main priority in link budget. The power used to transmit data is gradually decreased along the path due to attenuation effects...
We report a 2 Gb/s bidirectional real-time data transmission with bit error rate (BER) $<1\times 10^{-10}$ in a 50 m step-index polymer optical fiber link. The system is able to transmit 5 Gb/s using five channels. The system performance is tested using the most restrictive channels with the shortest and longest wavelengths in a real-time Ethernet link. The implementation takes an advantage of...
Free Space Optical FSO is a promising optical technology that has a great chance of complementing the traditional wireless communication. It offers unlicensed, higher speed, broader, unlimited bandwidth and excellent security. However, the quality of FSO links is greatly affected by weather conditions and link distance. In the tropical regions, the quality of the FSO links is affected mainly by rain...
Light-emitting diode (LED)-based optical communication is emerging as a low-power, low-cost and high-data rate alternative to acoustic communication. However, it requires a close-to-line-of-sight link between the transmitter and the receiver. Alignment for maintaining line of sight is challenging due to the constant movement of the underlying mobile platform that is caused by unwanted disturbances...
This paper proposes a 2-Phase Shift Keying (2-PSK) based modulation scheme for Image Sensor Communications. The considered communication system on a car uses a couple of LED light sources for transmitting data (either two rear light sources or two front light sources) and a typical-frame-rate camera (i.e. 30fps frame rate) which is either a global shutter camera or a rolling shutter camera for receiving...
Enormous applications which are enabled using Vehicular Ad Hoc Networks (VANETs) require a both efficient and reliable data delivery. Visible Light Communication (VLC), which has high transmission rate without using Radio Frequency (RF) spectrum, is regard as a candidate for data transmission in VANETs. Since a VLC system requires a line-of-sight communication, the position and the posture of LEDs...
We demonstrate an optical link operating in indoor ambient lighting conditions using a CMOS single photon avalanche diode (SPAD) optical receiver and a RGB light emitting diode (LED). The high sensitivity of the SPAD receiver allows the link to operate at 2 m distance at a total 60 Mb/s and bit error rate (BER) of 1×10−3 without lensing. The transmitter implements color shift keying (CSK) using a...
Image sensor communication (ISC) has appeared as one of the brand-new technologies of the recent era due to the pervasiveness of image sensor (camera) in the smartphone which operates as a receiver and light emitting device that work as a transmitter. Invisibility is a new term for ISC to adopt a communication process between light emitting device, for instance, display and image sensor (e. g: smartphone...
In an indoor multiuser bidirectional visible light communications (VLC) system, the performance of uplink VLC transmission degrades significantly due to design constraints and limited power available at uplink devices. In this paper, we propose an efficient uplink transmission scheme based on an orthogonal code division multiple access (OrCDMA) technique in a multiuser uplink transmission environment...
We describe link architectures for direct-detection mode-division multiplexing. We propose and compare three methods for estimating a multi-mode fiber channel matrix using phase retrieval.
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