Short Distance Data Communication Research Articles

Solution chemistry strategies to construct a stable MAPbI3 film toward high performance of amplified spontaneous emission

Lead-halide perovskites are being explored as potential light sources for short-distance data communication lasers. However, their practical applications are hindered by defects and poor stability. Ionic liquids (ILs), which are known for their environmentally friendly properties, are being investigated as alternative solvents to address these issues. In this study, methylammonium propionate (MAP), a more viscous IL solvent, was employed to regulate the crystallization process of the perovskite films through the strength of Lewis adducts. Compared with another frequently-used IL, methylammonium acetate (MAAc), the use of MAP solvent was observed to have a significant influence on the morphology and crystalline characteristics of the prepared MAPbI3 film. The findings of this comparative study provide strong evidence for the viability and preferability of using MAP solvent over MAAc in the preparation of MAPbI3 films, specifically for achieving an improved ASE performance and stability. The threshold of the MAPbI3-MAP film was only 12 μJ cm−2, which is lower than one-fourth of that observed for the MAPbI3-MAAc film (56 μJ cm−2) under nanosecond laser excitation. In addition, MAP-based devices can maintain stable ASE output emissions under harsh environments of long-term stimulation and high-humidity preservation.

Performance and complexity study of a neural network post-equalizer in a 638-nm laser transmission system through over 100-m plastic optical fiber

In recent years, plastic optical fiber (POF) has been considered as a promising cost-effective scheme for short-distance data communications, multimedia communication in cars, and in-house networks. However, due to the intrinsic nature of the relatively large numerical aperture of POF and the high attenuation rate, implementing high data rates over 100-m POF transmission length will be a significant challenge. We propose a scheme of high-speed 100-m POF transmission system based on a visible red laser and a cascaded neural network (NN) post-equalizer. To mitigate the nonlinear distortion induced by the POF, three different NNs, i.e., convolutional NN (CNN), long and short-term memory NN (LSTM), and cascaded NN structure consisting of convolutional layers and LSTM (CNN-LSTM), are employed as the post-equalizer. Experimental results show that using three different post-equalizers can significantly improve the system performance compared with the Volterra equalizer baseline. Among them, CNN-LSTM can outperform the others in terms of the bit error rate (BER) and the system Q-factor in the low nonlinear region. When the system operating in strong nonlinear region, CNN can achieve optimal performance at a lower system overhead of complexity. Finally, we successfully demonstrated a 100-m POF transmission system using 16 quadrature amplitude modulation discrete Fourier transform-spread orthogonal frequency division multiplexing modulation format at 1.8 Gbps with BER below 3.8 × 10 − 3 by utilizing CNN-LSTM.

Silicon-Germanium Avalanche Receivers With fJ/bit Energy Consumption

Fast, low-noise and sensitive avalanche photo-receivers are needed for surging short-reach photonic applications. Limitations concerning bandwidth, throughput and energy consumption should be overcome. In this work, we comprehensively study the performance opportunities provided by avalanche p-i-n photodetectors with lateral silicon-germanium-silicon heterojunctions. Our aim is to circumvent the need for chip-bonded electronic amplifiers. In particular, we demonstrate that avalanche photodetectors based on silicon-germanium-silicon heterostructures yield reliable opto-electrical performances, with high gain-bandwidth products up to 480 GHz and low effective ionization ratios down to 0.15. Moreover, they improve power sensitivities for high-speed optical signals and have a low energy dissipation of only a few fJ per received information bit. These results pave the way for high-performing receivers for energy-aware data links, in next-generation short-distance data communications.

Scalable Grid-Based Data Gathering Algorithm for Environmental Monitoring Wireless Sensor Networks

Proper utilization of the available low-power is essential to extend the lifetime of the battery-operated wireless sensor networks (WSNs) for environmental monitoring applications. It is mandatory because the batteries cannot be replaced or recharged after deployment due to impracticality. To utilize the power properly, an appropriate cluster-based data gathering algorithm is needed which reduces the overall power consumption of the network significantly. So, in this paper, a grid-based data gathering algorithm called energy-efficient structured clustering algorithm with relay (EESCA-WR) is proposed. In this algorithm, the grids have a single grid leader (GL) and multiple grid relays (GRs). The count of GRs in a grid is variable based on the geographic location of the grid with respect to the destination sink (DS). By doing this, we ensure that the reduction in power consumption is achieved because of the multi-hop short-distance data communications. Also, the GLs are rotated in the right intervals in hybrid modes to minimize the usage of control messages considerably. A hybrid GL selection policy, a threshold-based GL rotation policy, and the policy of allotting dedicated relay-clusters in every grid make the proposed algorithm unique and better for homogeneous and heterogeneous wireless sensor networks. Performance evaluation of the proposed algorithm is carried out by varying the length of the field, the node-density, the grid-count, and the initial energy. Experimental results show that EESCA-WR is extremely scalable, energy-efficient with a minimum number of control messages, and can be used for large scale WSNs.

Formation of Crystalline Si Optical Waveguides on Bulk (100) Si Substrate as a New Platform for On-Chip Interconnect Applications

Lightwave transmission is a promising candidate for data interconnections, including the short-distance data communication. The method by which photonics and electronics ought to be integrated is developing and not well resolved yet. In particular, the different requirements of buried oxide thickness for photonics and electronics hamper their integration on the same chip. In this paper, we present a crystalline Si-core waveguide as the platform of interconnection and proceed to investigate its characteristics. The Si-core of the waveguide on bulk (100) Si substrate is formed by an excimer laser system through shape reformation. The SiO2 cladding is later on created through oxidation process. Though the Si-core's shape has changed, it still preserves its monocrystalline properties, and displays a broadband transmission. This test shows several local defects along axial direction cause obvious scattering of the guided wave, and propagation loss is estimated to be about 7 dB/cm. We think the defects come from an observed wavy structure and this loss is improvable via our proposed methods. In addition, the core distance to substrate is adjustable and the sidewall roughness is good. Hence we proceed to analyze the losses theoretically. The various kinds of loss are potentially reducible to 1 dB/cm, except coupling loss on end facets, which is also improvable with the use of proper coupling devices. These demonstrate the potentiality of the platform for on-chip interconnect applications.

Research on Anti-Collision Algorithm of Short Distance Data Communication Based on Binary-Tree Disassembly

This paper puts forward adaptive anti collision algorithm based on two fork tree decomposition. New search algorithm built on the basis of binary-tree algorithm, using the uniqueness of the label EPC, to estimate the distribution of label by slot allocation, the huge and complicated two fork tree is decomposed into several simple binary-tree by search the collision slots for binary-tree, so, it can simplifies the search process. The algorithm fully considers4 important performance parameters of the reader paging times, transmission delay, energy consumption and throughput label, the simulation results show that, the improved anti-collision algorithm is obviously improved performance than other two fork tree algorithm, it is more suitable for RFID anti-collision protocols.

(Invited) Heterogeneously Integrated III-V on Silicon Lasers

Silicon photonics has generated an outstanding interest for optical telecommunications and inter/intra-chip interconnects in microelectronic systems. This platform can address a wide range of applications from very short distance data communication to long haul optical transmission. Silicon-based compounds are commonly used in commercial optical waveguide devices for applications such as passive optical interconnects and biomedical sensors. However, the integration of lasers together with Si integrated photonics-electronic circuits has proved to be much more challenging. The complexity lies in the fact that silicon is a poor light-emitting material due to its indirect energy bandgap. A particularly promising approach is based on molecular bonding of III-V materials on top of a patterned Si-on-insulator (SOI) substrate. Hybrid Si/III-V lasers are then realized following a collective fabrication procedure, enabling complex photonic integrated systems onto the silicon platform. In this communication, we describe the hybrid platform and we present the recent advances on III-V/Si lasers and transmitters.

Invited: Heterogeneously Integrated III-V on Silicon Lasers

Silicon photonics has generated an outstanding interest for optical telecommunications and inter/intra-chip interconnects in microelectronic systems. This platform can address a wide range of applications from very short distance data communication to long haul optical transmission.Recent research has focused on the realization of silicon optoelectronic integrated devices using large scale, low-cost, and highly accurate CMOS technology. While silicon is now considered as the material of choice for passive optical components due to its low-loss beyond 1.1 µm and high-index-contrast with its native oxide, it is however a very poor light-emitting material. Today, practical Si-based light sources are still missing, despite the demonstration of an electrically pumped germanium laser.Silicon-based compounds are commonly used in commercial optical waveguide devices for applications such as passive optical interconnects and biomedical sensors. However, the integration of lasers together with Si integrated photonics-electronic circuits has proved to be much more challenging. The complexity lies in the fact that silicon is a poor light-emitting material due to its indirect energy bandgap. In addition, the direct growth of standard III-V materials on Si substrates is still a major obstacle because of the mismatch in lattice constants and in thermal expansion coefficients. Although light emission from silicon is not straightforward, the development of an efficient electrically pumped laser is essential to make silicon the material of choice for monolithic optoelectronic integration.A different way consists in coupling laser beams emerging from III-V heterostructures to silicon waveguides. This so-called hybrid integration can be done using different techniques like flip-chip bonding [1] or self-assembly [2]. Both approaches present the disadvantage of requiring submicron precision alignment to enable efficient coupling between lasers and silicon waveguides. Even if the cost of a silicon photonic circuit is generally low, aligning precisely a laser chip to a planar photonic circuit is quite expensive, time consuming and unsuitable for high-volume fabrication.A particularly promising approach instead is based on molecular bonding of III-V materials on top of a patterned Si-on-Insulator (SOI) substrate. This can be performed at the die or wafer level, depending on the application needs. Then, hybrid Si/III-V lasers are realized following a collective fabrication procedure, enabling complex photonic integrated systems onto the silicon platform [3]. Using this technology, Fabry–Pérot, racetrack, distributed feedback and Bragg reflectors lasers were demonstrated [4-5].In this communication, we describe the hybrid platform and we present the recent advances on III-V/Si lasers and transmitters. References K. Kato et al., IEEE J. Sel. Tops. Quantum Electron, 6, 4-13 (2000).J. Sasaki et al., IEEE Transactions on Advanced Packaging, 24, 569-575 (2001).J.M. Fedeli et al., Advances in Optical Technologies, 2008, 412518 (2008).B. Ben Bakir et al., Opt. Exp., vol. 19, no. 11, pp. 10317–10325 (2011).A. Descos et al. Eur. Conf. Opt. Commun., Th.1.B.2, pp. 687-689, London, U.K. (2013).

Flexible thin-film polymer waveguides fabricated in an industrial roll-to-roll process

The fabrication of flexible low-loss, thin-film, foil-based polymer waveguides with grating couplers employing a high-volume industrial roll-to-roll process is demonstrated. The embossed waveguides feature propagation losses of less than 1 dB/cm (633 nm, TE polarization), bending losses of 0.4-0.8 dB/360° for bending radii as small as 2 mm, and grating coupling efficiencies of up to 25%. In addition, the waveguides possess a thermo-optic coefficient of -1.58×10(-4) 1/°C. The fabricated waveguides are promising candidates for short-distance data communication as well as for sensing applications.