Simulation Of Optical Systems Research Articles

Research on optical simulation of dim target based on passive detection link analysis

In order to meet the ground calibration requirements of optical detection equipment to identify optical characteristics of dim targets, an optical simulation method of dim targets based on passive detection link analysis and bidirectional scattering distribution function model is proposed. The off-axis collimation system for long focal length, the simulated energy transmission model of dim targets and the simplified model of bidirectional scattering distribution function are established. An internal stray light suppression baffle was designed to effectively suppress secondary scattering, and an optical simulation system for dim targets was built. The experimental results show that the system can simulate +7 Mv∼+20 Mv, and the simulation accuracy is better than 0.07 Mv. At the same time, the detection ability of the camera is tested by using the +15 Mv point simulated by the system. The signal-to-noise of the star point target reaches 6.7, which meets the requirements of detection rate and false alarm rate, and realizes the ground test of the camera's detection ability of the dim target.

Surface shape error modeling in optical machining and tolerance analysis of mosaic aperture telescopes

In the simulation and tolerance analysis of mirror-based optical systems, the magnitude distribution of the surface shape error of each mirror must be established under certain values. Thus, in this study, several large-diameter meter-scale spherical mirrors were statistically processed, and a surface shape error model was constructed to control the RMS, PV, and PV/RMS of the surface shape error in Monte Carlo experiments. The findings show an improved system qualification probability from 69.2% to 99.4%. The proposed method considers the maximum evaluation of the sub-wavefront that eliminates the final co-phase adjustment for individual segments.

EDFA with power pump laser in WDM Network design of 10GBPS transmission

Wavelength Division Multiplexing (WDM) that enabled optical networks are currently widely used in current telecommunications infrastructures and are anticipated to play a significant role in next-generation networks and the future Internet, supporting a wide range of services with a wide range of bandwidth, latency, reliability, and other feature requirements. In WDM networks, the input power of an optical transmitter is crucial; as a result, this results in a good output signal at the receiver side. The purpose of this paper is to design a WDM Optical Network in terms of length and pump power. The system is simulated using Opti-System software to achieve bit error rate (BER), quality factor, and output power of EDFA through optimized fiber length and pump power. In this analysis, the BER value, Q-factor and output of the system have been evaluated between 1550 and 1552nm with 0 dBm input signal power. EDFA length of 5km, power pump value of 500mv and 980nm frequency was set as reference in this study. This system was analysed using Opti-System simulation software at 10 Gigabits per second (10GBPS) transmission system. Result have shown that, min BER value shows a very significant increase at a 9-meter length and the Q-factor was rapidly decrease. The min BER value was in range 10-11 and 10-19 and Q-factor range 6.5 to 9.1 for 200mW to 8000mW power pump.

The multi-layer secure communication system based on 2D-OCDMA coding

Abstract This paper presents a novel multi-layer secure communication system that bases 2D-OCDMA technology to enhance the security and number of users of the system. The system innovatively combines RSA encryption, polarization multiplexing, and address coding techniques to protect and transmit the data. At the transmitting end, the data is encrypted by algorithm and then encoded by address code. The encoded optical data is split into two orthogonal polarization states and sent over the same channel. At the receiving end, only the optical signals in the matching polarization state can be retrieved by the polarizer with the right angle. The retrieved data is then decoded by the address code and decrypted by the algorithm to recover the original data. This system achieves multi-layer security and capacity enhancement by processing the information at different layers. The feasibility of the system is demonstrated by joint experimental simulation using Java programming language and Optisystem simulation software. In this paper, low BER transmission of 4 code words for 8 users 50 km 1Gbit/s is realized using optical orthogonal codes (OOC) with BER around 10−30. It realizes the enhancement of 4-user to 8-user without affecting the transmission effect.

Flexible optical fiber channel modeling based on a neural network module.

Optical fiber channel modeling, which is essential in optical transmission system simulations and designs, is usually based on the split-step Fourier method (SSFM), making the simulation quite time-consuming owing to the iteration steps. Here, we train a neural network module termed NNSpan to learn the transfer function of a single fiber (G652 or G655) span with a length of 80 km and successfully emulate long-haul optical transmission systems by cascading multiple NNSpans, which gives remarkable prediction accuracy, even over a transmission distance of 1000 km. Even when trained without erbium-doped fiber amplifier (EDFA) noise, NNSpan performs quite well when emulating the systems affected by EDFA noise. An optical bandpass filter can optionally be added after EDFA, making the simulation more flexible. Comparison with the SSFM shows that NNSpan has a distinct computational advantage, with the computation time reduced by a factor of 12. This method based on NNSpan could be a supplementary option for optical transmission system simulations, thus contributing to system designs as well.

Ameliorating Uniformity and Color Conversion Efficiency in Quantum Dot-Based Micro-LED Displays through Blue-UV Hybrid Structures.

Quantum dot (QD)-based RGB micro light-emitting diode (μ-LED) technology shows immense potential for achieving full-color displays. In this study, we propose a novel structural design that combines blue and quantum well (QW)-intermixing ultraviolet (UV)-hybrid μ-LEDs to achieve high color-conversion efficiency (CCE). For the first time, the impact of various combinations of QD and TiO2 concentrations, as well as thickness variations on photoluminescence efficiency (PLQY), has been systematically examined through simulation. High-efficiency color-conversion layer (CCL) have been successfully fabricated as a result of these simulations, leading to significant savings in time and material costs. By incorporating scattering particles of TiO2 in the CCL, we successfully scatter light and disperse QDs, effectively reducing self-aggregation and greatly improving illumination uniformity. Additionally, this design significantly enhances light absorption within the QD films. To enhance device reliability, we introduce a passivation protection layer using low-temperature atomic layer deposition (ALD) technology on the CCL surface. Moreover, we achieve impressive CCE values of 96.25% and 92.91% for the red and green CCLs, respectively, by integrating a modified distributed Bragg reflector (DBR) to suppress light leakage. Our hybrid structure design, in combination with an optical simulation system, not only facilitates rapid acquisition of optimal parameters for highly uniform and efficient color conversion in μ-LED displays but also expands the color gamut to achieve 128.2% in the National Television Standards Committee (NTSC) space and 95.8% in the Rec. 2020 standard. In essence, this research outlines a promising avenue towards the development of bespoke, high-performance μ-LED displays.

Simulation of an ultrahigh capacity free space optical (FSO) communication system incorporating hybrid WDM-CPDM techniques under disturbed weather

Simulation of an ultrahigh capacity free space optical (FSO) communication system incorporating hybrid WDM-CPDM techniques under disturbed weather

P‐114: Novel Optical Simulation System for Pixel Design Optimization

OLED display quality is closely related to pixel design. Usually, in order to evaluate the effect of pixel design on display quality, we need to make panel samples and light them up, or observe killer pattern samples that putted on the back light. Either method costs a considerable amount of time and money. In this paper, we will introuce a novel optical simulation system that we established to evaluate and optimize pixel design qualitatively or quantitatively.

Design and simulation of optical chaotic-based secure hybrid optical communication system

Design and simulation of optical chaotic-based secure hybrid optical communication system

Transient optical simulation by coupling elastic multibody systems, finite elements, and ray tracing

Transient dynamical–thermoelastic–optical system simulation is an important expansion of classical ray tracing through rigid, resting lenses because the operating performance of high-precision optical systems can be influenced by dynamical excitations or thermal gradients. In this paper an approach for an integrated optical system simulation using the coupling of elastic multibody system simulations, thermoelastic finite element analysis and gradient-index ray tracing is presented. Transient mechanical rigid body motions and elastic deformations, thermally induced refraction index changes, and thermal elastic deformations can be considered simultaneously in the ray tracing using the presented method. The calculation of the dynamical and thermal disturbances, the data transfer and coupling, and the gradient index ray tracing method are introduced. Finally, the approach is applied on a transient triplet lens optical system and some investigation results are shown.

Transformer-Based Long Distance Fiber Channel Modeling for Optical OFDM Systems

The fiber channel model plays an essential role in the simulation and design of optical fiber communication systems. However, it is difficult for conventional model-driven modeling to balance accuracy and efficiency, especially in optical orthogonal frequency division multiplexing (OFDM) systems with complex and long-haul transmission. We introduce the simplified Transformer into optical OFDM systems and combine it with the feature decoupled distributed (FDD) scheme for fast and accurate fiber channel modeling. Unlike the popular Transformer architectures, we remove the Decoder part and cancel the self-attention with quadratic complexity, significantly reducing the computational cost. The modeling performance is investigated from the nonlinear fitting capability, accuracy, and generalization ability. The transmission distance ranges from 80 km to 1600 km. The highly matched four-wave mixing (FWM) power, low error vector magnitudes (EVMs), and similar signal-noise ratios (SNRs) demonstrate the high precision and robustness of the model. Furthermore, the modeling is studied under different transmission rates and is proved to be reliable over a wide transmission bandwidth. Compared to the bidirectional long short-term memory (Bi-LSTM), the Transformer performs better in accuracy and has lower computational and memory costs. For modeling under the same conditions, the required running time of the Transformer is about 60% of Bi-LSTM, less than 1% of the split-step Fourier method (SSFM). The Transformer-based method achieves high precision modeling of the fiber channel in the long-distance and high-rate optical OFDM system and makes a significant breakthrough in complexity.

Simulation of an Indoor Visible Light Communication System Using Optisystem

Visible light communication (VLC ) is an emerging research area in wireless communication. The system works the same way as optical fiber-based communication systems. However, the VLC system uses free space as its transmission medium. The invention of the light-emitting diode (LED) significantly updated the technologies used in modern communication systems. In VLC, the LED acts as a transmitter and sends data in the form of light when the receiver is in the line of sight (LOS) condition. The VLC system sends data by blinking the light at high speed, which is challenging to identify by human eyes. The detector receives the flashlight at high speed and decodes the transmitted data. One significant advantage of the VLC system over other communication systems is that it is easy to implement using an LED and a photodiode or phototransistor. The system is economical, compact, inexpensive, small, low power, prevents radio interference, and eliminates the need for broadcast rights and buried cables. In this paper, we investigate the performance of an indoor VLC system using Optisystem simulation software. We simulated an indoor VLC system using LOS and non-line-of-sight (NLOS) propagation models. Our simulation analyzes the LOS propagation model by considering the direct path with a single LED as a transmitter. The NLOS propagation model-based VLC system analyses two scenarios by considering single and dual LEDs as its transmitter. The effect of incident and irradiance angles in an LOS propagation model and an eye diagram of LOS/NLOS models are investigated to identify the signal distortion. We also analyzed the impact of the field of view (FOV) of an NLOS propagation model using a single LED as a transmitter and estimated the bitrate (Rb). Our theoretical results show that the system simulated in this paper achieved bitrates in the range of 2.1208×107 to 4.2147×107 bits/s when the FOV changes from 30∘ to 90∘. A VLC hardware design is further considered for real-time implementations. Our VLC hardware system achieved an average of 70% data recovery rate in the LOS propagation model and a 40% data recovery rate in the NLOS propagation model. This paper’s analysis shows that our simulated VLC results are technically beneficial in real-world VLC systems.

Investigation of inline optical amplifiers in 2-D time-wavelength OCDMA systems

This paper introduces the first mathematical investigation on utilizing a single inline optical amplifier in the 2-D time-spreading wavelength-hopping (TW) code division multiple access (OCDMA) system. The study adopts a non-ideal erbium-doped fiber amplifier (EDFA), where the optical gain depends on the input power of the amplifier. Three en/decoders representing different loss levels are examined. In addition, the paper highlights the significance of the power budget in the amplified TW systems to ensure the accomplishment of two concurrent conditions. First, the total input power from all users to the inline amplifier should fall within the amplifier input power range to gain sufficient amplification. Hence, the transmitted chip power from users is the key contributor. The second condition is the ordinary case where the desired received power should meet the required bit error rate (BER). The number of central splitter/combiner ports (Nsys) is an additional important system parameter, representing the upper bound of the available number of simultaneous users (K). The analysis supported by the Optisystem simulation results shows that the best location for the inline amplifier is close to the central system’s combiner. The results also reveal that, for low-user system capacities, employing a single inline optical amplifier in the 2-D TW OCDMA system is effective for the low-loss TW en/decoders but with increased code weights (w). For an 8-user system (i.e., Nsys = 8), transmitted chip power of 15 dBm, and EDFA amplification gain of 28 dB, the system can support the full-user capacity (at a BER ≤ 10-9) when w = 29. On the contrary, the performance of the higher system capacities sustains only a particular number of simultaneous users, accommodating up to 60 % of the full-user capacity when Nsys = 16.

On-ground demonstration of laser-link construction for space-based detection of gravitational waves

Laser acquisition and pointing system is subject to establish a 106km magnitude inter-satellite laser link with ultra-high pointing precision of 10 nrad/Hz (1 mHz-1 Hz) in space-based gravitational wave detection missions. For the unprecedented challenge, a dedicated laser link construction scheme with three different detectors is proposed. After initial pointing with star trackers, CMOS/CCD cameras intend to suppress the laser pointing error to 1 μrad. QPDs are subsequently used to achieve the final requirement. With various detectors and technologies, the scheme need intensive verification and study. We first design and build an on-ground laser link construction experimental system, which can simulate the whole process and recreate the actual critical working condition as realistic as possible by comprehensively considering the simulation of optical system, far field beam receiving characteristics and target precision. Results are well in agreement with the requirements and confirm the scheme under realistic conditions, which have not yet been fully tested experimentally.

Data-Driven Method for Nonlinear Optical Fiber Channel Modeling Based on Deep Neural Network

Recently, data-driven fiber channel modeling methods based on deep learning have been proposed in optical communication system simulations. We investigate a new data-driven method based on the deep neural network (DNN) to model the nonlinear fiber channel with the characteristics of attenuation, chromatic dispersion, amplified spontaneous emission noise, self-phase modulation (SPM), and cross-phase modulation (XPM). Demonstration in multiple dimensions, including constellations, optical waveforms, spectra, and the normalized mean square error, shows that DNN can approach the transfer function of the fiber channel accurately. Additionally, the DNN shows good generalization for modulation formats and wavelength schemes. Besides, the time complexity of DNN-based method for modeling nonlinear fiber channel is reduced significantly (96.5%) compared to the conventional model-driven method, which is based on the split-step Fourier method. This work demonstrates that the DNN can model accurately the nonlinear fiber channel that takes account of both SPM and XPM. Therefore, it can contribute to the application of data-driven methods in modern optical communication system simulations and designs.

A Surrogate Model Based Multi-Objective Optimization Method for Optical Imaging System

An optimization model for the optical imaging system was established in this paper. It combined the modern design of experiments (DOE) method known as Latin hypercube sampling (LHS), Kriging surrogate model training, and the multi-objective optimization algorithm NSGA-III into the optimization of a triplet optical system. Compared with the methods that rely mainly on optical system simulation, this surrogate model-based multi-objective optimization method can achieve a high-accuracy result with significantly improved optimization efficiency. Using this model, case studies were carried out for two-objective optimizations of a Cooke triplet optical system. The results showed that the weighted geometric spot diagram and the maximum field curvature were reduced 5.32% and 11.59%, respectively, in the first case. In the second case, where the initial parameters were already optimized by Code-V, this model further reduced the weighted geometric spot diagram and the maximum field curvature by another 3.53% and 4.33%, respectively. The imaging quality in both cases was considerably improved compared with the initial design, indicating that the model is suitable for the optimal design of an optical system.

ANALISIS PERFORMANCE PERANCANGAN JARINGAN FIBER OPTIC PADA RSUD WANGAYA KOTA DENPASAR DENGAN OPTISYSTEM

The hospital information system has been regulated in Law Number 44 of 2009 concerning Hospitals. The law states that every hospital is required to record and report all hospital operations in the form of a hospital management system. In this regard, the research conducted at Wangaya Regional General Hospital, Denpasar City, aims to determine the performance calculation of the fiber optic network design at the hospital so that SIMRS implementation can be carried out optimally. This research uses Optisystem 7.0 simulation to determine the performance of network design at Wangaya Regional General Hospital, Denpasar City. Optisystem simulation with MMF OM4 cable produce a power receive value greater than allowable minimum receiver sensitivity, that is -11.1 dBm. The BER value obtained from the Optisystem simulation is less than 1x10-9 which indicates that the value has met the adequacy of the standard BER value in fiber optic networks. However, the Q-factor value obtained in the simulation is greater than the optical communication standard, that is 6. This design is feasible to implement using MMF OM4 cable from the results of testing with Optisystem simulations.

Analysis of Visible Light Communication using Integrated Avalanche Photodiode

The problem with Radio Frequency (RF) communication is that it has intrusion and high remission. Moreover, RF communication requires distinct configurations for transference and reception. To overcome these problems, Visible Light Communication (VLC) is recommended, as it has a high tolerance for bandwidth and interference. The usage of LEDs instead of fluorescent lamps uplifts the use of VLC. Visible light communication is a fast-evolving LED-based illumination and data transfer method. The performance of visible light communication over Mach-Zehnder Modulation has been investigated in this paper using the Opti-system simulation tool. The opti-system simulation programme predicts the quality factor and Bit Error Rate (BER) values of various link distances. The proposed system can handle 5 Gbps data rate over a 50-meter link distance with a Quality Factor of 15.71 and no external noise. The projected VLC system performance is further tested using a simulation tool in the case of external noise effects.

Code design and interception probability of optical fibre communication system based on optical coding

Traditional optical orthogonal code has small code cardinality, which is vulnerable to the brute-force attacks by eavesdroppers. In order to improve the anti-interception performance of optical fibre communication system based on optical coding, a new family of optical code with large code cardinality is proposed. Based on information-theoretic security, the interception probability of optical fibre coding system is proposed and defined, and the expression of the interception probability is derived for the first time. The influences of extraction distance, extraction ratio, the number of interfering users and the code length on the interception probability are analysed quantitatively. The anti-interception performance of the optical coding system is investigated by numerical analysis and OptiSystem simulation. It is shown that reliability and anti-interception performance can be achieved simultaneously by selecting appropriate code parameters and the number of interfering users.

Analysis of evaluation index for the electron laminar properties in the electron optical system

In the simulation of the electron optical system of vacuum electronic devices, the evaluation of the electron laminar properties can only be judged by observing the electron trajectories. The quantitative evaluation index parameters for the electron laminar properties is lacking in the electron optical software. To achieve a quantitative analysis of the electron laminar properties in Egun simulations, the crossover rate evaluating the laminar properties of electron properties is presented in this paper. The simulation results show that the crossover rate index can accurately and quantitatively evaluate the quality of the electron laminar properties. When the crossover rate of electron properties is less than 3%, the designed electron optical system meets the engineering requirements. The crossover rate can be used as the target parameters in the automatic optimization of electron optical system.