Light-based Communication Research Articles

Designing a Light-Based Communication System With a Biomolecular Receiver

Designing a Light-Based Communication System With a Biomolecular Receiver

A synthetic biology tool for contact-dependent synthetic cell communication.

Cell-cell communication and signal transduction through direct cell-cell contact are found ubiquitously in biology, with examples including T-cell activation upon contact formation with antigen-presenting cell in immunological synapses and electrical signal transduction in neuronal synapses. Despite the prevalence of intercellular communication at cell-cell interfaces, it is difficult to engineer and reconstitute functional proteins at membrane-membrane interfaces. A synthetic biology tool that can recapitulate signal transduction exclusively at membrane-membrane interfaces will be useful for designing synthetic intercellular communication pathways or providing a potential replacement for damaged and malfunctional natural cell-cell communication systems. Here, we present programmable activation of a split bioluminescent protein, NanoBiT, at the membrane-membrane interface between synthetic cells. We utilize a peptide-protein pair called SpyTag and SpyCatcher as adapter proteins to mediate functional reconstitution of NanoBiT. We illustrate an example of downstream protein activation through a designed light-based communication system by using a pair of photoactivatable proteins, iLID and SspB inside synthetic cells and demonstrate iLID-SspB dimerization triggered by reconstituted NanoBiT bioluminescence.

Colloidal Quantum Dot Light Emitting Diodes at Telecom Wavelength with 18% Quantum Efficiency and Over 1MHz Bandwidth.

Developing high performance, low‐cost solid‐state light emitters in the telecom wavelength bandwidth is of paramount importance for infrared light‐based communications. Colloidal quantum dot (CQD) based light emitting diodes (LEDs) have shown tremendous advances in recent times through improvement in synthesis chemistry, surface property, and device structures. Despite the tremendous advancements of CQD based LEDs in the visible range with efficiency reaching theoretical limits, their short‐wave infrared (SWIR) counterparts mainly based on lead chalcogenide CQDs, have shown lower performance (≈8%). Here the authors report on highly efficient SWIR CQD LEDs with a recorded EQE of 11.8% enabled by the use of a binary CQD matrix comprising QD populations of different bandgaps at the emission wavelength of 1550 nm. By further optimizing the optical out‐coupling via the use of a hemispherical lens to reduce optical waveguide loss, the EQE of the LED increased to 18.6%. The CQD LED has an electrical bandwidth of 2 MHz, which motivated them to demonstrate its use in the first SWIR free‐space optical transmission link based entirely on CQD technology (photodetector and light emitter) opening a new window of applications for CQD optoelectronics.

Channel Impulse Analysis of Light Propagation for Point-to-Point Nano Communications Through Cortical Neurons

Recent Brain-Machine Interfaces have moved towards miniature devices that can be seamlessly integrated into the cortex. In this paper, we propose communication between miniature devices using light. A number of challenges exist using nanoscale light-based communication and this includes diffraction, scattering, and absorption, where these properties result from the tissue medium as well as the cell’s geometry. Under these effects, the paper analyses the propagation path loss and geometrical gain, channel impulse and frequency response through a line of neurons with different shapes. Our study found that the light attenuation depends on the propagation path loss and geometrical gain, while the channel response is highly dependent on the quantity of cells along the path. Additionally, the optical properties of the medium impact the time delay at the receiver and the width and the location of the detectors. Simulations were conducted for cells that are lined horizontally up to a distance of $450~\mu \text{m}$ using light wavelength of 456 nm and different neuron densities (men’s neocortex (25924(±15110) /mm3) and women’s (27589(±16854) /mm3)). Based on the simulations, we found that spherical cells attenuate approximately 20% of the transmitted power compared to the fusiform and pyramidal cells (35% and 65%, respectively).

Effects of a light-based communication approach as an external HMI for Automated Vehicles - a Wizard-of-Oz Study

Communication between automated vehicles (AVs) and vulnerable road users (VRUs) is highly relevant in coordinating traffic maneuvers and therefore ensuring road safety. Especially in shared spaces such as parking areas, communication is highly important. As automated driving changes the driver's role, communication between different traffic participants will also change. External human-machine interfaces (eHMIs) may enhance safety and effective communication between VRUs and AVs by providing relevant information to other traffic participants if informal communication is insufficient. Hence, a variety of information (e.g., about AVs' driving mode or future maneuvers) is recommended to be communicated to VRUs. Therefore, we investigated the effects of three different light signals, presented by a light bar placed on the test vehicle's roof, as a form of an eHMI: automation mode, starting mode and crossing mode. Moreover, two different driving conditions (i.e., a manual and a simulated automated driving condition) were implemented to investigate the effects between these conditions. Either the driver was visible in the manual condition or the vehicle appeared driverless as a seat suit covered the driver in the simulated automated condition (Wizard-of-Oz design). A total of N = 173 random pedestrians passing by were interviewed and behavioral data were collected from over 1500 pedestrians. Results indicate that participants felt significantly safer during the interaction with the vehicle when a driver was visible. Although VRUs evaluated the general approach of applying light signals as eHMIs for AVs as useful, they assessed the presented light signals as only partially trustworthy and rather unintuitive. Moreover, many participants were unsure of whether the light signals were directed towards them, thus the directedness of light signals should be considered when implementing a light-based eHMI in AVs. Further, moving light signals attracted more attention (i.e., increased pedestrians' head movements towards the vehicle) than a steady or no light signal did. Interestingly, no difference existed between the investigated steady light signal and the baseline condition (i.e., no light signal) regarding head movements towards the vehicle. The results underline the importance of implementing an appropriate eHMI design in AVs.

Two-Phase Resonant Converter to Drive High-Power LED Lamps

This paper presents the design and modeling of a two-phase resonant converter that drives a LED lamp with a high-frequency pulsed current free of instabilities and flicker effect, fulfilling the recommendations of the IEEE PAR 1789-2015, so that it enables visible light-based communication at a 10 kB/s bit rate. The dynamic study of the converter takes into consideration the effect of the reflected impedance of the output filter on the AC side. In order to evaluate the dynamic response of the converter, a Spice model is defined. A 120 W prototype intended for street lighting applications has been built to validate the analysis and modeling.

Wireless Communications for the Hospital of the Future: Requirements, Challenges and Solutions

In this conceptual paper, we discuss the concept of hospital of the future (HoF) and the requirements for its wireless connectivity. The HoF will be mostly wireless, connecting patients, healthcare professionals, sensors, computers and medical devices. Spaces of the HoF are first characterized in terms of communicational performance requirements. In order to fulfil the stringent requirements of future healthcare scenarios, such as enhanced performance, security, safety, privacy, and spectrum usage, we propose a flexible hybrid optical-radio wireless network to provide efficient, high-performance wireless connectivity for the HoF. We introduce the concept of connected HoF exploiting reconfigurable hybrid optical-radio networks. Such a network can be dynamically reconfigured to transmit and receive optical, radio or both signals, depending on the requirements of the application. We envisage that HoF will consist of numerous communication devices and hybrid optical-radio access points to transmit data using radio waves and visible light. Light-based communications exploit the idea of visible light communications (VLC), where solid-state luminaries, white light-emitting diodes (LEDs) provide both room illumination as well as optical wireless communications (OWC). The hybrid radio-optical communication system can be used in principle in every scenario of the HoF. In addition to the hybrid access, we also propose a reconfigurable optical-radio communications wireless body area network (WBAN), extending the conventional WBAN to more generic and highly flexible solution. As the radio spectrum is becoming more and more congested, hybrid wireless network approach is an attractive solution to use the spectrum more efficiently. The concept of HoF aims at enhancing healthcare while using hospital resources efficiently. The enormous surge in novel communication technologies such as internet of things (IoT) sensors and wireless medical communications devices could be undermined by spectral congestion, security, safety and privacy issues of radio networks. The considered solution, combining optical and radio transmission network could increase spectral efficiency, enhancing privacy while reducing patient exposure to radio frequency (RF). Parallel radio-optical communications can enhance reliability and security. We also discuss possible operation scenarios and applications that can be introduced in HoF as well as outline potential challenges.

Hybrid Optical/Electric Memristor for Light-Based Logic and Communication.

Light-based information processing has the potential to increase speed, security, and scalability of electronic devices if issues in the device complexity could be resolved. We here demonstrate an integrated nanoelectronic device that can combine, store, and manipulate optical and electronic information. Employing a mechanically flexible and multilayered structure, a device is realized that shows memristive behavior. Illumination is shown to control the device operation in several unique ways. First, the device produces photocurrent that allows us to read out the device state in a self-powered manner. More importantly, a varying light intensity modulates the switching transition in a proportional manner that is akin to a neuron with variable plasticity and which can be taught and queried using either light or electrical inputs. This behavior enables a multilevel light-controlled logic and teaching schemes that can be applied to light-based communication devices and provides a route toward ubiquitous and low-cost sensors for future internet of things applications.

The impact of artificial light at night on nocturnal insects: A review and synthesis.

In recent decades, advances in lighting technology have precipitated exponential increases in night sky brightness worldwide, raising concerns in the scientific community about the impact of artificial light at night (ALAN) on crepuscular and nocturnal biodiversity. Long‐term records show that insect abundance has declined significantly over this time, with worrying implications for terrestrial ecosystems. The majority of investigations into the vulnerability of nocturnal insects to artificial light have focused on the flight‐to‐light behavior exhibited by select insect families. However, ALAN can affect insects in other ways as well. This review proposes five categories of ALAN impact on nocturnal insects, highlighting past research and identifying key knowledge gaps. We conclude with a summary of relevant literature on bioluminescent fireflies, which emphasizes the unique vulnerability of terrestrial light‐based communication systems to artificial illumination. Comprehensive understanding of the ecological impacts of ALAN on diverse nocturnal insect taxa will enable researchers to seek out methods whereby fireflies, moths, and other essential members of the nocturnal ecosystem can coexist with humans on an increasingly urbanized planet.

Light-emitting diodes aided indoor localization using visible light communication technology

This paper focuses on designing and analyzing a visible light-based communication and positioning system for indoor wireless communication under light-emitting diodes (LEDs) lighting environments. The indoor positioning system uses trichromatic white LEDs, both for illumination purposes and as transmitters, and an optical processor, based on a-SiC:H technology, as a mobile receiver. An on–off keying modulation scheme is used, proving a good trade-off between system performance and implementation complexity. The relationship between the transmitted data and the received output levels is decoded. LED bulbs work as transmitters, sending information together with different identifiers, IDs, related to their physical locations. Square and diamond topologies for the unit cell are analyzed, and a two-dimensional localization design, demonstrated by a prototype implementation, is presented. Fine-grained indoor localization is tested. The received signal is used in coded multiplexing techniques for supporting communications and navigation concomitantly on the same channel. The location and motion information are found by mapping the position and estimating the location areas.

Adiabatic elimination-based coupling control in densely packed subwavelength waveguides.

The ability to control light propagation in photonic integrated circuits is at the foundation of modern light-based communication. However, the inherent crosstalk in densely packed waveguides and the lack of robust control of the coupling are a major roadblock toward ultra-high density photonic integrated circuits. As a result, the diffraction limit is often considered as the lower bound for ultra-dense silicon photonics circuits. Here we experimentally demonstrate an active control of the coupling between two closely packed waveguides via the interaction with a decoupled waveguide. This control scheme is analogous to the adiabatic elimination, a well-known procedure in atomic physics. This approach offers an attractive solution for ultra-dense integrated nanophotonics for light-based communications and integrated quantum computing.

Future Technologies and Applications of III-Nitride Materials and Devices

Nobel Prize in Physics 2014 Materials Department of the College of Engineering, University of California, Santa Barbara (UCSB), Santa Barbara CA 93106-5050, USA © The Author(s) 2015. Published by Engineering Sciences Press. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/) III-nitride light-emitting diodes (LEDs) are now used almost everywhere, due to their energy-saving capability. In the near future, the vast majority of lighting sources will undoubtedly be based on LEDs. What future technologies and applications can we expect from III-nitride-based and particularly gallium nitride (GaN)-based, materials and devices? The new generation of LED technology will be GaN-on-GaN lighting, with laser lighting following as the next opportunity. Ultraviolet A (UVA) light may play an important role in lighting, once it can be used to generate a high-quality white light source. In addition to lighting applications, ultraviolet C (UVC) light, light-based wireless communication (LiFi), laser communication, and electronic devices are the main applications of III-nitride materials and devices in the future.

Binary Quantum Communication using Squeezed Light: Theoretical and Experimental Frame Work

The aim of this paper is to develop framework to generate squeezed light for binary quantum communication. Both theoretical and experimental models to generate squeezed state  using optical parametric amplifier (OPO), which is implemented around He-Ne laser, are described in details. The results will be used as a guide line to investigate the performance of squeezed light-based quantum communication over noisy channel and this issue will be presented in accompanying paper [1]. Â

Modular Modelling in Synthetic Biology: Light-Based Communication in E. coli

Modularity – the notion that individual components can be described as self-contained units and composed in different combinations – is a concept integral to synthetic biology. In vitro, it is embodied by the notion of BioBrickTMparts: standardised DNA sequences of defined structure, function, and common interfaces that can be composed and integrated into living cells. A similar modularity in the modelling of such systems, however, has not been explored until much more recently. In the course of the 2010 International Genetically Engineered Machine (iGEM) competition, the University of Edinburgh team adopted an iterative rule-based approach to developing a BioBrick model of light-based communication in Escherichia coli. The system was modelled in the Kappa stochastic rule-based biological modelling language, allowing for the modular development and analysis of a complicated biological system. It also utilised newly developed spatial extensions to aid in the depiction of intercellular communication via light emitting and light sensing pathways, demonstrating the extensibility of the language as a whole. This paper provides a case study of modelling synthetic biology projects using the rule-based techniques outlined above, documenting the benefits of this modular iterative approach.