Optical Decoding Research Articles

Design of $$2\times 4$$ optical decoder based on IMI plasmonic waveguide with slot

Design of $$2\times 4$$ optical decoder based on IMI plasmonic waveguide with slot

Optical decoder learning for fiber communication at the quantum limit

Optical decoder learning for fiber communication at the quantum limit

All-optical 2-bit decoder based on a silicon waveguide device for BPSK-modulated signals

Optical computing technology has gained attention as a solution to address the computational latency caused by the resistance-capacitance (RC) delay in processors based on complementary metal-oxide-semiconductor (CMOS). However, many optical computing technologies tend to rely on nonlinear effects, resulting in an increase in the device length and input light intensity to enhance nonlinear efficiency. This study proposed what we believe is a new optical decoder device based on linear effects. The device was composed of two cascaded delay-line interferometers (DLIs) made of a silicon waveguide. Targeting 2-bit binary phase-shift keying (BPSK) signals, it outputs ON state for a specific bit pattern by setting different phase conditions. The experimental results confirmed the functionality of the device, including measurements of the impulse response, evaluation of the phase-shift conditions, and successful decoding operations for a signal at 10 Gbps. The proposed decoder, which does not rely on nonlinear effects, offers advantages in terms of low latency and power consumption.

Organic High-Temperature Synaptic Phototransistors for Energy-Efficient Neuromorphic Computing.

Organic optoelectronic synaptic devices that can reliably operate in high-temperature environments (i.e., beyond 121°C) or remain stable after high-temperature treatments have significant potential in biomedical electronics and bionic robotic engineering. However, it is challenging to acquire this type of organic devices considering the thermal instability of conventional organic materials and the degradation of photoresponse mechanisms at high temperatures. Here, high-temperature synaptic phototransistors (HTSPs) based on thermally stable semiconductor polymer blends as the photosensitive layer are developed, successfully simulating fundamental optical-modulated synaptic characteristics at a wide operating temperature range from room temperature to 220°C. Robust optoelectronic performance can be observed in HTSPs even after experiencing 750 h of the double 85 testing due to the enhanced operational reliability. Using HTSPs, Morse-code optical decoding scheme and the visual object recognition capability are also verified at elevated temperatures. Furthermore, flexible HTSPs are fabricated, demonstrating an ultralow power consumption of 12.3 aJ per synaptic event at a low operating voltage of -0.05mV. Overall, the conundrum of achieving reliable optical-modulated neuromorphic applications while balancing low power consumption can be effectively addressed. This research opens up a simple but effective avenue for the development of high-temperature and energy-efficient wearable optoelectronic devices in neuromorphic computing applications.

Real-time multimodal sensory detection using widefield hippocampal calcium imaging

The hippocampus is a complex structure that has a major role in learning and memory. It also integrates information from multisensory modalities, supporting a comprehensive cognitive map for both spatial and non-spatial information. Previous studies have been limited to real-time spatial decoding, typically using electrodes. However, decoding hippocampal non-spatial information in real time has not been previously described. Here, we have constructed a real-time optical decoder driven by the calcium activity of large neuronal ensembles to decode spatial, visual, and auditory information effectively. Using advanced machine learning techniques, our rapid end-to-end decoding achieves high accuracy and provides a multisensory modality detection method. This method enables the real-time investigation of hippocampal neural coding and allows for direct neural communication with animals and patients affected by functional impairments. The ability to decode multimodal sensory inputs in real time thus forms the basis for an all-optical brain-computer interface.

Single‐mode optical fibre digital decoder based on polarization using a K‐nearest neighbour algorithm

AbstractIt is shown experimentally a new digital optical decoding scheme based on the transmission or polarized light at p polarization planes using a K‐Nearest Neighbour (KNN) algorithm through a single‐mode optical fibre at 633 nm. The optical power signal is sent at p polarization planes which constitute p classes required for signal bit recognition. Results show that it is possible to recognize 32 polarizations planes, 5 bits, using 4 features corresponding to the measurement of optical power at 4 different angles at the photodetector side with an average assertiveness of 99.02%.

Design and analysis of 1:2 line optical decoder based on linear optics

In this paper, a simple design of all-optical photonic crystal (PhC) based 1:2 line decoder has been proposed and its operating principle is based on light beam interference. The designed structure has a hexagonal arrangement of air holes in Si substrate with a finite slab height. In our proposed structure, different path lengths have been made so that the light beams should interact out of phase. Effective refractive index method has been adopted to reduce the simulation time. The Finite Difference Time Domain (FDTD) and Plane Wave Expansion (PWE) methods have been applied to evaluate the proposed structures. The required footprint area for proposed device is reported as 215 µm2. Minimum contrast ratio between the logic states of “1” and “0” is obtained as 10 dB. This device is designed based on solely linear optical phenomena in a holes-in-slab PhC structure. Therefore, mechanically stabled, ultra-compact design and simple working mechanism of the proposed optical decoder can be a potential candidate for future generation Photonic Integrated Circuits (PICs).

One-Step Preparation of Semiconductor/Dielectric Bilayer Structures for the Simulation of Flexible Bionic Photonic Synapses.

Flexible synaptic devices with information sensing, processing, and storage functions are indispensable in the development of wearable artificial intelligence electronic systems. Here, a semiconductor/dielectric bilayer structure was prepared by a one-step deposition method and used for the first time in a flexible biomimetic photonic synaptic transistor device. Specifically, poly(3-hexylthiophene)-block-poly(phenyl isocyanide) with pentafluorophenyl ester (P3HT-b-PPI(5F)) was prepared as the device active layer, where the P3HT segment served as a carrier transport channel and optical gate and the PPI(5F) segment was used for charge trapping. Various biomimetic synaptic behaviors, such as excitatory postsynaptic currents, paired-pulse facilitation, and short-term/long-term memory, were successfully simulated under green light stimulation. An ultra-low energy consumption of 1.82 fJ was achieved with a greatly reduced operating voltage. Further, the "Morse-code" optical decoding was simulated using the excellent synaptic plasticity of the device. In addition, flexible synaptic devices were prepared by a one-step deposition method and can be well-affixed to arbitrary substrates. This has promising applications in the field of wearable bionic electronics.

Tailoring neuroplasticity in flexible perovskite QDs-based optoelectronic synaptic transistors by dual modes modulation

For the achievement of robust neuromorphic computing with simple device integration and low energy consumption, the development of artificial synaptic devices incorporating multiple excitation modes has attracted wide interests. In this regard, a multi-functional and energy-efficient CsPbBr3 quantum dots-based optoelectronic synaptic transistor is designed capable of realizing required synaptic plasticity with both photonic and electric modulation modes in one device. Important synaptic behaviors, including excitatory post-synaptic current and paired-pulse facilitation, are simulated utilizing both photonic and electric stimulations. Furthermore, the transition of short-term plasticity (STP) to long-term plasticity (LTP) can also be implemented through either the adjustment of input photonic pulses or the co-modulation of photonic and electric operations. The excellent tunability between STP and LTP of the synaptic device further leads to the STP-based “Morse-code” optical decoding scheme and LTP-based simulation of visual object recognition. More significantly, the synergistic modulation of photonic and electric operations enables the implementation of logic functions. The multi-functional optoelectronic synaptic transistors are also mechanically flexible, and no distinct synaptic performance variation is observed even when the bending radius of the devices is down to 1 mm. This work suggests a new path for developing flexible and multifunctional neuromorphic electronics.

Floating-gate based PN blending optoelectronic synaptic transistor for neural machine translation

Neural machine translation, which has an encoder-decoder framework, is considered to be a feasible way for future machine translation. Nevertheless, with the fusion of multiple languages and the continuous emergence of new words, most current neural machine translation systems based on von Neumann’s architecture have seen a substantial increase in the number of devices for the decoder, resulting in high-energy consumption rate. Here, a multilevel photosensitive blending semiconductor optoelectronic synaptic transistor (MOST) with two different trapping mechanisms is firstly demonstrated, which exhibits 8 stable and well distinguishable states and synaptic behaviors such as excitatory postsynaptic current, short-term memory, and long-term memory are successfully mimicked under illumination in the wavelength range of 480–800 nm. More importantly, an optical decoder model based on MOST is successfully fabricated, which is the first application of neuromorphic device in the field of neural machine translation, significantly simplifying the structure of traditional neural machine translation system. Moreover, as a multi-level synaptic device, MOST can further reduce the number of components and simplify the structure of the codec model under light illumination. This work first applies the neuromorphic device to neural machine translation, and proposes a multi-level synaptic transistor as the based cell of decoding module, which would lay the foundation for breaking the bottleneck of machine translation.

Nonlinear optical decoder based on photonic quasi crystal ring resonator structure

Abstract Using two nonlinear photonic crystal ring resonators we proposed and designed an all optical decoder. 2D 12 fold quasicrystal was used as the core section of the resonant rings. In order to make use of advantages of nonlinear Kerr effect, we put 24 dielectric rods between the core and outer shell of the resonant ring. The linear refractive index and nonlinear Kerr coefficient of these rods are n 0 = 1.4 and n 2 = 10−14 m2/W. In the proposed structure port I was used to switch the optical beams coming from BIAS between O1 and O2 output ports. The optical intensity required for performing the switching task is about 0.1 kW/μm2.

Selective Ligand Sensitization of Lanthanide Nanoparticles for Multilevel Information Encryption with Excellent Durability.

Durable and multilevel information encryption technology has been of great importance in recent decades. Here, an inkjet printer-adaptable invisible ink was prepared with lanthanide nanoparticles, and optical decoding of information could only be achieved when specific ligand dipicolinic acid was utilized in the presence of UV illumination. In addition, the proposed protocols displayed long shelf life (>one year) and excellent durability even at harsh conditions such as in the presence of strong acids (1 M HCl) and alkalis (1 M NaOH). Meanwhile, such invisible inks could be further employed on a soft matrix via screen-printing, holding great potential for practical applications.

Photonic crystal-based optical decoders: design methods and prospective

Photonic crystal-based optical decoders: design methods and prospective

Integrating single-cell RNA-seq and imaging with SCOPE-seq2

Live cell imaging allows direct observation and monitoring of phenotypes that are difficult to infer from transcriptomics. However, existing methods for linking microscopy and single-cell RNA-seq (scRNA-seq) have limited scalability. Here, we describe an upgraded version of Single Cell Optical Phenotyping and Expression (SCOPE-seq2) for combining single-cell imaging and expression profiling, with substantial improvements in throughput, molecular capture efficiency, linking accuracy, and compatibility with standard microscopy instrumentation. We introduce improved optically decodable mRNA capture beads and implement a more scalable and simplified optical decoding process. We demonstrate the utility of SCOPE-seq2 for fluorescence, morphological, and expression profiling of individual primary cells from a human glioblastoma (GBM) surgical sample, revealing relationships between simple imaging features and cellular identity, particularly among malignantly transformed tumor cells.

Application of photonic crystal based nonlinear ring resonators for realizing all optical 3-to-8 decoder

Abstract Optical decoders are required for optical routing. In this paper we presented the design procedure and simulation results for 3-to-8 optical decoder, which was designed using nonlinear ring resonators inside two dimensional photonic crystals. The proposed structure was simulated using finite difference time domain method. Based on the simulation results the maximum delay time of the structure is about 2 ps. Also the worst transmission values for logic 0 and 1 are 10% and 78%, respectively.

Ultra-fast all optical decoder using photonic crystal based nonlinear ring resonators

Optical decoders are essential building blocks required for realizing all optical digital data processing systems. Rise and fall times are very crucial characteristics that should be considered in designing any optical devices. In this paper we are going to design an all optical 2 to 4 decoder using photonic crystal based nonlinear ring resonators. The proposed structure will be realized by cascading 3 normally closed optical switches. According to the simulation results the rise and fall times for the final structure are 1.5 ps and 0.7 ps respectively.

Improving the Performance of 2-To-4 Optical Decoders Based on Photonic Crystal Structures

In this study, a novel, two-dimensional photonic crystal-based structure for the 2-to-4 optical decoder is presented. The structure consists of 23 rows and 14 columns of chalcogenide rods that are arranged in a square lattice with a spatial periodicity of 530 nm. The bias and the optical signals are guided toward the main waveguide through the three waveguides. Two unequal powers are applied to the input ports to approach the different intensities proportional to four working states into the main waveguide. Four cavities including the nonlinear rods are in response to drop the optical waves toward the output ports. To calculate the band diagram and the spatial distribution of the electric and magnetic fields, the plane wave expansion and the finite difference time domain methods have been used. The delay time of the designed structure is obtained around 220 fs, which is less than one for the previous structures. Furthermore, the gap between the margins for logic 0 and 1 is equal to 83%, which is higher than one for other works. Besides, the area of the structure is reduced to 90 µm2 in comparison to all reported structures. Based on the mentioned results, it seems that an improvement of the performance for 2-to-4 optical decoders has been obtained in this research.

Design of Scalable Optical Decoder based on Hexagonal Plasmonic Modes induced on Topological Insulator Surface States

In the present work, optical decoder based on hexagonal plasmonic lens encrypted on topological insulator is designed. Using Finite Difference Time Domain (FDTD) simulation we have shown 2D optical lattice of scalar vortices in hexagonal plasmonic lens using surface states of topological insulator (Bi1.5Sb0.5Te1.8Se1.2). To ensure feasible and flexible physical dimensions, scaling of the optical device is proposed via increasing area density of vortices. This is numerically obtained by changing radius of hexagonal lens or decreasing incident wavelength. Using these scalable optical vortex lattices, a device scheme is proposed for storing or decoding information. Advantage of scaling in optical devices without any additional processing step shows the promise of this technology for future devices. Simulation results are further validated by detailed theoretical calculation of electric field intensity and phase distribution.

Performance Evaluation of System in Free Space Optic Utilizing Gaussian Optical Filter in Different Detection Scheme

Abstract In recent years, free space optical communication (FSO) has become a leader for its unique characteristics: large bandwidth, unlicensed spectrum, simple implementation, low power and high data rate. However, we use as a transmission medium for Spectral Amplitude Coding-Optical Code Division Multiple Access SAC OCDMA system. In this paper, we investigate the optimum received power of FSO communication system employing SAC OCDMA, by using different detection technique, such us Spectral Direct Detection SDD and Single Photodiode Detection (SPD) technique under optical Gaussian filter decoder schemes with Modified Double Weight code (MDW). In this work, the adverse effects of atmospheric channel limit the possibility of a large FSO communication, moderate turbulence and hazy weather conditions are considered. The results show that the performance of the proposed system with wavelength-division-multiplexing (WDM) multiplexer (MUX) based on Gaussian optical filter with SDP detection fares better than the system employing SDD technique.

Demonstration of PAM4-OCDM system with electrical amplitude-level pre-tuning and post-equalization for data centers applications.

A PAM4-OCDM system with optical multi-/demultiplexing and electrical pre-/post-processing is proposed for short-reach applications. We experimentally demonstrate, for the first time, a power-efficient 4 OC x 10 GSymbol/s PAM4-OCDM system. The four PSK-OCs are simultaneously generated using a single light source and a passive multiport optical encoder and received by a single optical decoder and cascaded DSP. The effectiveness of the electrical-domain amplitude level pre-tuning and post-equalizer are demonstrated, considering different values of shot and beat noises.