This study presents the design and analysis of energy-efficient visible light communication-based downlink and uplink using a thin-film corner cube retroreflector (TCCR). The uplink establishment from the user device (UD) to base station (BS) is achieved with the retroreflection of the downlink light beams using TCCR in UD. It eliminates the requirement of active optical source in the UD that reduces

The authors experimentally demonstrated the generation of mode-locked pulses from all-fibre erbium-doped fibre laser cavity by using organic material, Alq 3 , as a saturable absorber (SA). The SA film was integrated into a ring fibre laser cavity to act as a mode-locker. A mode-locking operation was achieved in three different experiments with pulse width/repetition rate of 1.26 ps/3.36 MHz, 970 fs/3

In the present paper, the bit error rate (BER) performance of hybrid power line communication (PLC) and multiple-input multiple-output (MIMO) visible light communication (VLC) system (HPMV) has been investigated using line-of-sight (LOS) and LOS plus first reflection (L-R1) signals for room size of 5 m × 5 m × 3 m (configuration A) and 7.5 m × 7.5 m × 3.5 m (configuration B). In the work, Rayleigh

Photo-current characteristics in close space sublimation processed multi-facetted Cadmium Telluride (CdTe) micro-granular films were studied under AM1.5, blue and green laser illuminations to assess the energy dependent charge transport characteristics. Photo-current under AM1.5 illumination (100 mW/cm 2 ) resulted in three times more than dark current while it was observed 2.4 and 2.5 times more in

In this study, we analyze the combined effect of TMD/Perovskite/2D Material on the performance of SPR biosensor using Kretschman configuration. In order to optimize the parameters, we compare the results of each material falls in the family of TMD/Perovskite/2D respectively and finally applied in the proposed sensor. It is observed that the combined structure based on black phosphorus, a 2D material

Here, the authors propose a new approach for realising wideband and polarisation-independent antireflection coating, based on a metamaterial composed of a subwavelength array of metallic pillars with a square cross-section. The effective impedance of the array can be duly adjusted by the size and distance of the pillars. As such, the authors design the effective impedance of the antireflection coating

This work examined the possibility of overcoming narrow band optical absorption of organic dyes in the range of 350–700   nm via surface plasmon effect mediated by RF-sputtered tungsten (W) thin film on mesoporous TiO 2 for dye-sensitised solar cells (DSSCs) application. The UV–visible spectroscopic measurement showed optical absorption of W-film in the spectral range of 350–700   nm with a dominant

This study experimentally demonstrates a Q-switched fibre laser using a new tungsten tri-oxide (WO 3 )-based saturable absorber (SA). Using the drop and casting approach, we managed to prepare a thin film that contained WO 3 powders in polyvinyl alcohol. A small bit of the film was used to form an SA which was placed in a ytterbium-doped fibre laser cavity to generate a Q-switched laser. The laser

A new device architecture of an all-optical logic inverter (AOLI) has been proposed in this study. The AOLI functions based on stimulated Raman scattering (SRS) in silicon nanocrystal embedded slotted photonic crystal waveguide (SPCW). The operating power and footprint size of the proposed device have significantly been scaled down to ∼1.5 mW and , respectively, by combining the benefits of giant SRS

A small portion of an optical fibre clad was removed and coated with methylamine hydroiodide by a slurry deposition process to develop an evanescent wave optical fibre ammonia sensor. The experiment was performed for a few volatile organic compounds in order to understand the selectivity and sensitivity. Prior to the gas sensing measurement, the methylamine hydroiodide sample was characterised using

In optical fibre communication system, improved modulation schemes have been proposed to increase capability and high bit rate transmission. One such technique is optical duobinary modulation, which can able to broadcast high-speed optical signals over bandwidth-limited channels. The conventional modulation schemes employ the non-return-to-zero modulation and return-to-zero modulation technique. These

Non-linearities introduced by power amplifiers in communication systems have been a subject of interest for industry and academia for a long time. On one hand, the search for increased range intrinsically incites operators to boost input power. On the other hand, this leads to stronger non-linear phenomena in amplifiers, which in turn increase the bit error rate. The situation led to the emergence

Evolution and accessibility of smart-phones have led to a huge demand in network bandwidth. The ubiquitous use of smart-phones in high-speed trains poses a unique challenge in delivering high-speed internet service on board. This challenge can be overcome by employing free-space optics, an alternative to radio-frequency technology. Previous coverage models for ground–train communications employed single

A novel liquid-core photonic crystal fibre (LC-PCF) based on the Zeonex substrate has been proposed for sensing the varying concentration of kerosene in petrol and diesel fuels in terahertz frequencies. Fuel sample infiltration is achieved by designing a single hexagon in the porous core region. The LC-PCF has been numerically studied using a finite element method. By filling the core hexagon with

Rich scattering of ultraviolet signals enables the non-line-of-sight outdoor wireless connectivity and eliminates the line-of-sight requirement of free-space optical links. Besides scattering losses, ultraviolet signals also suffer from the atmospheric turbulence-induced fading. One of the strong fading mitigation techniques is the spatial diversity, which has been extensively studied in the context

Radio-over-fibre (RoF) distributed antenna system (DAS) technology has been investigated for the distribution of ultra-high frequency (UHF) radio frequency identification (RFID) signals. RoF DAS allows for reduced number of readers and centralised placement of readers which facilitates easy system maintenance, but it is important to find a low-cost solution that can achieve comparable performance to

This study analysed GaN nanophosphors based white light-emitting diodes (WLEDs) with ultraviolet (UV) excitation. Graphene quantum dots (GQDs) used as a charge transfer medium to enhance the performance in terms of luminous efficacy and colour quality. The improvement in colour rendering and colour temperature has been observed with the increase in injection current. The luminous efficacy of radiation

The performance of multiple-input and multiple-output (MIMO) flip-orthogonal frequency division multiplexing (flip-OFDM) for indoor optical wireless communications (OWCs) is studied here. To improve the system performance in terms of the bit error rate (BER), the singular value decomposition (SVD)-based MIMO technique is applied together with the bit loading technique. The authors, especially, focus

A double-image asymmetric cryptosystem is proposed by using cylindrical diffraction and spectrum fusion and compression in the zigzag-scanned domain of discrete cosine transform (DCT). First, each plaintext of double image is converted into spectrum coefficients (SCs) by DCT, and the SCs are zigzag scanned. Second, the first 1/4 of SCs is resized to two low-frequency images, the second 1/4 of SCs is

A multilayer graphene-based optical modulator is proposed in this study. The structure is made of several layers of graphene on hexagonal boron nitride (hBN), working at 193 to 200 THz (1.5 to 1.55 μm) band. In this modulator, the electric field passes through graphene layers instead of passing through the silicon waveguide, causing very low insertion losses about 4 × 10 -3 dB for 40 μm long device

This study accessed the performance of the four-level Manchester coding (4-MC) and four-level modified Manchester (4-MM) technique at the bit rates of 20 and 40 Gb/s for the first-order and second-order optical equalisers. The performances were evaluated with respect to bit error rate (BER), power penalty, eye diagrams, and dispersion tolerance. Based on the results by utilising the second-order optical

Multicore fibre (MCF) has attracted considerable attention in mobile fronthaul networks as a promising solution to face the ever-increasing mobile traffic demand and to support network capacity scaling in a cost-effective manner. However, MCF-based systems suffer from the inter-core crosstalk (IC-XT) noise, which could incur severe performance degradation. In this study, we investigate for the first

A tandem solar cell including of CuIn 1-y Ga y Se 2 /Si 1-x Ge x was exhibited by integrating a CuIn 1-y Ga y Se 2 solar cell on a Si1 - xGex solar cell to achieve a conversion efficiency of about 26% by controlled current matching. Electrical analyses were used to determine the performance parameters of the bottom and top sub-cells. In this work, an experimental Si 0.73 Ge 0.27 solar cell has been

A novel InP-based metal-coated sidewall, hybrid plasmonic multimode interference (MCS-HP-MMI) power splitter has been proposed. Based on two methods of multimode interference self-imaging and finite difference time domain simulations, a 1 × 2 MCS-HP-MMI power splitter was numerically analysed and compared with an HP-MMI power splitter with the same specifications showing 70% reduction in length due

The stability of the central wavelength of the erbium-doped fibre source (EDFS) is one of the most important parameters to ensure the accurate operation of navigation systems based on high-accuracy fibre optic gyroscopes (FOGs). In this study, the method of stabilisation of the EDFS as a part of the FOG is presented. The main advantage of this method is the possibility of quick and simple matching