Iet Optoelectronics最新文献

We are delighted to present this special issue of IET Optoelectronics on ‘Towards large-scale commercialisation of Space-division multiplexing (SDM) fibres’. This issue features contributions from five speakers at the ECOC 2023 workshop ‘What Will Eventually Trigger Large-Scale Commercialisation of SDM Fibres?’, held in Glasgow on 1 October 2023.

SDM is a promising technology to effectively deal with the unabated growth of data traffic in optical fibre networks. Over the past decade, extensive research on SDM optical fibres has resulted in the development of high-quality, multicore and few-mode fibres as well as other network elements that leverage the SDM concept. Whereas large-scale commercialisation of SDM fibres is essential to meet the ever-increasing demand for higher data rates, achieving practical deployment requires more than innovative fibre designs. It also necessitates system optimisation to reduce cost per bit and standardisation to ensure interoperability. The successful commercialisation of SDM fibres also hinges on the advancement of other network elements such as optical amplifiers, multiplexers, connectors and splices. This special issue explores the challenges and opportunities associated with SDM fibre commercialisation. It aims to identify potential triggers that could accelerate the adoption of SDM technology across various applications such as submarine optical cable systems, terrestrial fibre networks and data centre interconnects.

We hope this special issue provides readers with a comprehensive overview of the latest advancements in SDM technologies and valuable insights into their large-scale deployment, paving the way for significant upgrades in optical fibre communication systems in the years ahead.

A novel refractive index (RI) plasmonic sensor is designed and simulated, which is expected to make a significant advancement in gas sensing. The sensor is composed of silver, air-filled waveguide and a square shaped cavity. In the implemented cavity, 16 silver circular nanorods (CNs) are locally placed to enhance the sensing performance. Moreover, the cavity is filled with ultraviolet-curable fluoro-siloxane (UVCFS) in order to faithfully characterise methane gas concentrations. RI sensitivity (RIS) for Peak I is 1210.12 ± 4.62 nm/RIU and for Peak II is 969.64 ± 8.56 nm/RIU as well as figure of merit (FoM) of 20.00 ± 0.08 1/RIU at Peak I and 11.82 ± 0.10 1/RIU at Peak II, respectively. Furthermore, a significant methane gas sensitivity (S_Gas) is achieved: about 4 nm/% for Peak I and about 3 nm/% for Peak II which shows that it can well determine methane gas concentrations. The introduced plasmonic-based sensor brings potential applications in gas sensing due to its high sensitivity as well accuracy in detecting methane gas concentrations.

This paper proposes and presents the first experimental demonstration of a high-precision indoor 2D and 3D visible light positioning (VLP) system using an imaging multiple-input multiple-output (MIMO) configuration with supervised artificial neural network. The proposed system utilises four distributed transmitters and receiver with four photodiodes and an imaging optics. The experiments are conducted in a typical indoor environment with transmitter separations of 300 mm and a link distance of 1400 mm. The experimental results show 2D and 3D positioning accuracies of 3.7 and 51 mm, respectively. A simulation model is also developed for the VLP system to validate the experimental results. Further optimisation of the VLP system in the simulation platform leads to improved 2D and 3D positioning accuracies of 2 and 14.7 mm, respectively. The proposed system can be seamlessly integrated with existing lighting infrastructures and is also compatible with the MIMO visible light communication system, indicating the potential for practical implementation in integrated communications and positioning applications.

The authors demonstrate the use of highly temperature insensitive dense wavelength division multiplexing filters combined with optical reflectors and optical time domain reflectometry to uniquely identify specific optical fibres beyond the optical splitter in an optical access passive optical network (PON). The very low wavelength shift (∼0.1 pm/°C) of the filters over the full industrial temperature range facilitates the future field deployment of these components in the PON without the requirement for complex and expensive wavelength tracking at the optical line terminal.

This work proposes a design of a dynamic range adjustable laser ranging chip based on element sharing, which combines single photon avalanche diodes and direct time-of-flight (dToF) to address the uncertainty of detection distance in different usage scenarios of laser ranging technology. To achieve adjustable dynamic range of the chip, an element shared control logic circuit based on external control signals is designed and integrated, which can adjust the measurement dynamic range of the chip through external control signals, making it suitable for different usage scenarios. Moreover, when the dynamic range of the chip changes, the measurement resolution of the time-to-digital converter (TDC) in the chip can remain unchanged. Through the analysis of simulation results, it is found that the laser ranging chip designed in this work can adjust the dynamic range from 3 ns to 4.29 s based on external control signals at a resolution of 125 ps, with a reference clock signal input frequency of 20 MHz. The differential non-linearity (DNL) error of TDC is −0.22 LSB to 0.19 LSB, and the integral non-linearity (INL) error is −0.82 LSB to 0.52 LSB. The dynamic range adjustable laser ranging chip based on element sharing designed in this work provides a feasible solution to address the uncertainty of detection distance in laser ranging technology.

In this paper, continuous-wave and cavity-dumped Nd:YVO4 lasers are studied. Firstly, through theoretical analysis and numerical simulation, the output characteristics of a continuous-wave laser based on the magneto-optical effect are analysed using the rate equation. The continuous adjustment of output power and pump threshold power is realised using the magneto-optical effect to rotate the polarisation direction of laser. The theoretical simulation results show that the output power of the laser could be effectively controlled under different magnetic field intensities. On this basis, the authors explore the cavity-dumped laser system based on the magneto-optical effect. By adjusting the intensity of the magnetic field and rising edge time, the pulse width and waveform could be flexibly adjusted. The relationship between the magnetic field intensity in the low Q period and the spot radius of the pump and the signal beam and the output energy and the output pulse waveform is analysed. These research results lay a foundation for further optimising the design and application of magneto-optical effect lasers.

The authors aim to build a theoretical system for calibrating the position detection of a single quadrant photodiode (QPD) attached to 2D rotators and to suppress noise using a Sugeno-type fuzzy inference system. According to the results, if the original ANFIS network (NW_o) is trained under the conditions of resolution (rs_o), traing samples (N_o), and the possibility of random noise (p_o) and presented as {original, rs_o, N_o, p_o}, with the #X testing case presented as {case #X, rs_x, N_x, p_x}, case #X is expected to be the all-pass case of the two root-mean-squared error criteria under the conditions of rs_x ≥ rs_o and p_x ≤ p_o. Thus, the measurement accuracy is improved without tracking historical data. Furthermore, the two conditions indicate the limitations of the proposed ANFIS-based method. These conditions can be employed to save time and money. If a company produces many types of QPD rotators with different values of rs, the engineers can optimise the design to train the ANFIS network with only one case with the smallest rs and a larger p for all types of QPD rotators with any value of rs and p. This demonstrates the potential industrial application of the proposed method.

The cover image is based on the Article ANFIS-based controlled spherical rotator with quadrant photodiode to improve position detection accuracy by Bing-Yuh Lu et al., https://doi.org/10.1049/ote2.12127.

The authors examine the state of submarine cable systems and conditions affecting potential widespread deployment of new spatial division multiplexing technologies, such as multicore optical fibre. The authors address areas such as cable capacity requirements, techno-economic constraints, multicore fibre characteristics, and performance and other necessary technology advances.

2-core fibre for submarine cable is becoming the first commercial application of multi-core fibre, which should enable to expand the capacity beyond the current limitation of submarine cable size. For successful commercial applications of 2-core fibre, it is important to minimise the complexities in manufacturing, splicing, and fibre handling. The 2-core fibre design for minimum complexity is reviewed.