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Experimental Demonstration of Subband Index Techniques for m-CAP in Short Range SI-POF Links
摘要： In this letter, novel spectrally-efficient subband index (SI) techniques have been developed for multiband carrierless amplitude and phase modulation (m-CAP). The subband index techniques transmit additional information bit on the index of the conventional m-CAP subbands. Experimental demonstrations are performed in a short range optical data link using step-index plastic optical fibre (SI-POF). The demonstrations show that the proposed techniques enable flexibility in design and significantly improve the power/spectral efficiency of the conventional m-CAP.
关键词： step-index plastic optical fibre (SI-POF),multiband carrierless amplitude phase modulation (m-CAP),index modulation,Optical communication
更新于2025-09-23 15:21:21
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Impact of Random Receiver Orientation on Visible Light Communications Channel
摘要： Visible Light Communications (VLC) has been studied thoroughly in recent years as an alternative or complementary technology to radio frequency communications. The reliability of VLC channels highly depends on the availability and alignment of line of sight links. In this work, we study the effect of random receiver orientation for mobile users over VLC downlink channels, which affects the existence and quality of line of sight links. Based on the statistics of the receiver location and relative orientation with respect to the transmitter LED, we develop an analytical framework to characterize the statistical distribution of VLC downlink channels, which is then utilized to obtain the outage probability and the bit error rate. Our analysis is generalized for arbitrary distributions of relative orientation and location for a single transmitter, and extended to multiple transmitter case for some certain scenarios. Extensive Monte Carlo simulations show a perfect match between the analytical and the simulation data in terms of both the statistical channel distribution and the resulting bit error rate. Our results also characterize the channel attenuation due to random receiver orientation and location for various scenarios of interest.
关键词： probability,random variables,Light-emitting diodes,optical communication,light-fidelity (Li-Fi)
更新于2025-09-23 15:21:21
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Nanoscale Light Sources for Optical Interconnects
摘要： This editorial is aimed at addressing two key aspects of nanoscale light sources: (1) low-power optical communication and (2) crystallographic defect engineering for monolithic integration with silicon. We will further discuss opportunities and challenges for nanoscale light sources for next generation, high density optical interconnect. Designing and prototyping light sources with sub light wavelength dimensions has been the topic of keen interest because of their versatility in optical communication. For example, nano light sources can operate at hundreds of GHz [1,2] which is not possible with conventional light sources [3]. In addition, power consumption in interconnects with these light sources can be reduced by omitting the modulator and using direct source modulation to encode optical data [4]. There are a number of nano light sources under investigation: (i) small photonic mode laser [5-9], (ii) plasmonic lasers [10,11] (iii) photonic-plasmonic hybrid lasers [12-15] and (iv) nanoscale LEDs [16,17]. Pros and cons of these nano light sources are discussed below.
关键词： crystallographic defect engineering,optical interconnects,low-power optical communication,Nanoscale light sources,monolithic integration
更新于2025-09-23 15:21:01
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Laser polymerized photonic wire bonds approach 1a??Tbit/s data rates
摘要： Microelectronics has solved the challenge of packaging different functional elements with integrated chips (ICs) in modern computing and communication by wire bonding. Miniaturization was a trend guided by the requirements for faster, more portable and less expensive (smaller amount of materials) solutions, where wire bonding evolved to accommodate increasingly more complex 3D architectures of chips and printed circuit boards. Even faster and more robust computing and communication can be provided by using photons rather than electrons. This was one of the underlying reasons for the fast growth of optical fiber communication, which is especially efficient over large ~1000 km distances. Data transfer in microelectronics also increasingly benefits from optical interconnects, which, however, have scaling challenges at small IC dimensions. The overall trend of optical fibers prevailing over copper wire for long-distance data transfer follows the miniaturization trend, and now, a new capability has been demonstrated on the microscale. Photonic wire bonding solves the same problem as wire bonding in microelectronics, but for optical communication on the level of chip-to-chip interconnects. In a recent study, a new milestone for data transfer over a 75 km channel at a rate of ~0.8 Tbit/s was demonstrated for Si photonic transmitters co-packaged with 1.5 μm InGaAsP lasers using photonic wire bonding. Several breakthroughs were combined to achieve the record high speed of data transfer. Optical insertion losses of only 0.7 dB were demonstrated. In addition, the required photonic wire tapering for single mode fiber operation/filtering was seamlessly achieved by direct laser writing. Most importantly, photonic wire bonding solves the stringent requirements for optical alignment between components and opens the possibility for automated packaging solutions. Si photonic platforms based on well-established complementary metal-oxide-semiconductor technologies can now be combined with other light sources and nonlinear optical components based on other platforms using photonic wire bonding. This makes hybrid photonic chip modules possible. It can be seen as a manifestation of the evolving trend in modern technology where complexity develops along with miniaturization, which has been the guiding principle established in previous decades of microelectronics.
关键词： optical communication,direct laser writing,miniaturization,photonic wire bonding,optical interconnects
更新于2025-09-23 15:21:01
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Nanofabrication of SOI-Based Photonic Waveguide Resonators for Gravimetric Molecule Detection
摘要： A silicon photonic microresonator comprising two curved vertical grating couplers and a single suspended Si nanowaveguide (NWG) is developed to investigate the giant enhanced Brillouin scattering in subwavelength NWGs caused by photon-phonon interaction. Finite element modelling based on COMSOL Multiphysics is conducted to optimize the critical device parameters (e.g., waveguide width, height, and length). As the smallest structures that need to be resolved are down to ~15 nm in size, electron-beam nanolithography is employed. In this case, dosage tests are carried out to minimize proximity charging effects during the nanopatterning of the silicon-on-insulator (SOI) surface, resulting in appropriate adaptive current area dosage distributions for the periodic gratings, couplers peripheral areas, and NWG, respectively. Furthermore, an enhanced inductively coupled plasma dry reactive ion etching (ICP-DRIE) process at a cryogenic temperature is used to realize smooth vertical sidewalls. Finally, buffered hydrofluoric acid (BHF)-based wet chemical etching is carried out to remove the buried oxide resulting in a suspended Si waveguide.
关键词： optical communication,integrated optics,silicon technology,nanowaveguide,silicon photonics
更新于2025-09-23 15:21:01
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[IEEE 2019 26th IEEE International Conference on Electronics, Circuits and Systems (ICECS) - Genoa, Italy (2019.11.27-2019.11.29)] 2019 26th IEEE International Conference on Electronics, Circuits and Systems (ICECS) - Variable-Rate FEC Decoder VLSI Architecture for 400G Rate-Adaptive Optical Communication
摘要： Optical communication systems rely on forward error correction (FEC) to decrease the error rate of the received data. Since the properties of the optical channel will vary over time, a variable FEC coding gain would be useful. For example, if the channel conditions are benign, lower code overhead can be used, effectively increasing the code rate. We introduce a variable-rate FEC decoder architecture that can operate in several different modes, where each mode is linked to code rate and decoding iterations. We demonstrate a decoder implementation that provides a net coding gain range of 9.96–10.38 dB at a post-FEC bit-error rate of 10?15. For this range, a decoder implemented in a 28-nm process technology offers throughputs in excess of 400 Gbps, decoding latencies below 53 ns and a power dissipation of less than 0.95 W (or 1.3 pJ/information bit).
关键词： variable-rate FEC decoder,high-throughput,optical communication,VLSI architecture,coding gain
更新于2025-09-23 15:21:01
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[IEEE 2018 International Conference on Radiation Effects of Electronic Devices (ICREED) - Beijing, China (2018.5.16-2018.5.18)] 2018 International Conference on Radiation Effects of Electronic Devices (ICREED) - Study on the Tracking & Pointing Accuracy Degeneration of Optical Communication System for CMOS Sensor Irradiation Damage
摘要： The CMOS sensor in space optical communication system may generate irradiation-induced noise, leading to deviation of image centroid. Based on test data, simulated defect spots have been used for calculating the value by grey-level centroid algorithm. It shows that both the amount and position of defect pixels contribute to deviation of image centroid and the accuracy decreasing.
关键词： tracking & pointing accuracy,CMOS sensor,optical communication,gray centroid algorithm,irradiation damage
更新于2025-09-23 15:21:01
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Toward the energy efficiency of multi-pulse PPM signalling for optical communication
摘要： To improve information throughput conventional single-pulse M-ary pulse-position-modulation (PPM) scheme, multi-pulse PPM has been proposed on the optical intensity-modulated and direct-detection channel. Although the multi-pulse M-ary PPM scheme significantly enhances throughput performance, nevertheless, the symbol error rate (SER) increases due to the loss of orthogonality between different pairs of symbols. In this study, the authors first derive the SER performance of general L pulses M-ary PPM scheme under Poisson channel statistic. Moreover, as the green radio is essential in future network, energy efficiency becomes the major concern. Hence, they evaluate L pulses M-ary PPM scheme by the number of reliable bits transmitted per joule of energy consumed. They analyse the trade-off between throughput and power consumption.
关键词： optical communication,symbol error rate,Poisson channel,energy efficiency,multi-pulse PPM
更新于2025-09-23 15:21:01
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Integration of FEC Channel-coding Schemes Based on the Bose-Chaudhuri-Hocquenghem (BCH) Code for WDM Fiber Optical Communication Systems
摘要： With the volumes of transmitted information growth, the task of increasing the noise immunity and reliability of data transmission networks arises. The presence of interference such as nonlinear loss, chromatic dispersion, polarization mode dispersion, and inter-channel interference decreases the performance of fiber optical communication systems. Forward Error Correction (FEC) codes are vital in optical communication systems to achieve highly efficient and highly reliable communication. The paper presents research on a simulation model where FEC channel-coding schemes based on the Bose-Chaudhuri-Hocquenghem (BCH) cycling block code are integrated with non-return-to-zero on-off-keying (NRZ-OOK) modulated wavelength division multiplexed (WDM) fiber optical communication systems. The results highlight the selection of coding parameters in the adopted FEC approach. In our paper, the BCH (255, 231), BCH (255, 223), and BCH (255,191) FEC channel-coding schemes are chosen for integration in the NRZ-OOK modulated WDM optical transmission system. The paper shows the main advantages and drawbacks of the selected FEC coding scheme and provides a comparison of the proposed schemes based on their main features, such as bit error ratio (BER), which were obtained through the simulations of 25 Gbit/s NRZ-OOK WDM fiber optical system. The dynamics of changes in BER was investigated using the Monte Carlo (MC) method for precise results. The paper shows that integration of FEC channel-coding schemes based on the BCH codes improves the noise immunity and reliability of the WDM Fiber Optical Communication Systems.
关键词： optical communication systems,BCH code,NRZ-OOK,WDM,FEC
更新于2025-09-23 15:21:01
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A Si-based InP/InGaAs nanowire array photodetector operating at telecommunication wavelength
摘要： A Si-based vertical nanowire heterostructure array photodetector is designed and studied by a coupled three-dimensional optoelectronic simulation. Each nanowire is composed of an InP/In0.53Ga0.47As/InP axial p-i-n junction, which is designed to operate at telecommunication wavelengths. The results show that the absorption of the nanowire array strongly depends on the D/P ratio and nanowire diameter. By tuning the D/P ratio and diameter simultaneously, the peak absorption wavelength could be fixed at 1550 nm. Due to the light-trapping and light-concentrating properties, the nanowire array photodetector exhibits a remarkable responsivity beyond 0.8 A/W, several times higher than its thin film counterpart with the equivalent thickness. This work suggests that the III-V nanowire array is promising for high-performance Si-based photodetectors applied in optical telecommunication systems.
关键词： Nanowire array,Light-trapping,Optical communication,Si-based,InGaAs/InP
更新于2025-09-23 15:21:01