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

2019 ◽  
Vol 41 (1) ◽  
pp. 31-36
Author(s):  
H. Djellab ◽  
A. Bouarfa ◽  
S. Bojanic
Keyword(s):  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Direct Detection ◽  
Optical Filter ◽  
Weather Conditions ◽  
Spectral Amplitude ◽  
Free Space Optical ◽  
Detection Scheme ◽  
High Data ◽  
Code Division Multiple

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.

Study of the Different Optical Filters in SAC-OCDMA System

2018 ◽  
Vol 39 (4) ◽  
pp. 381-386 ◽  
Author(s):  
H. Djellab ◽  
N. Doghmane ◽  
A. Bouarfa ◽  
M. Kandouci
Keyword(s):  
Wavelength Division Multiplexing ◽  
Local Area Network ◽  
Direct Detection ◽  
Optical Filter ◽  
Optical Filters ◽  
Local Area ◽  
Spectral Amplitude ◽  
Area Network ◽  
Code Division Multiple ◽  
The Impact

Abstract Spectral amplitude coding for optical code division multiple access (SAC-OCDMA) networks has received much attention over the last two decades. This article aims to explore the impact of encoder change on different types of optical filters, such as the Gaussian optical filter and the Bessel optical filter, for high data rates and to give an overview on importance of choosing the optimal type of optical filter according to the frequency range selected by the user is 25 and 50 GHz. SAC-OCDMA transmitter utilizes Wavelength Division Multiplexing multiplexer (WDM MUX) as an encoder, to generate a code having low cross-correlation called Random Diagonal code, and spectral direct detection as a detection technique. The change of optical filter, in WDM MUX, directly affects the performance of the system. The results show that the system for 50 GHz, with a WDM MUX, using a Gaussian optical filter has better performance compared to the optical Bessel filter and can reach a bit error rate (BER) of 10−25. SAC-OCDMA system, using a WDM MUX based on Bessel filters with a bit rate of 300Mb/s, achieves a BER of 10−28 which leads us to recommend it for second norm 25 GHz. Moreover, the power received increases by 4 dBm every 20 Km with the increase in the length of the fibre for both filters Bessel and Gaussian. Our work focuses on the two 25 and 50 GHz bands, after a study on the impact of the change of the bandwidth and the order of the different optical filters used according to the BER applied to the different networks of access, such as local area network (LAN).

Erbium/Ytterbium-Doped Waveguide Amplifier (EYDWA) for extended reach of Wavelength Division Multiplexing based free space optics system (WDM/FSO)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Bentahar Attaouia ◽  
Kandouci Malika ◽  
Ghouali Samir
Keyword(s):  
Wavelength Division Multiplexing ◽  
Free Space ◽  
Cost Effective ◽  
Weather Conditions ◽  
Free Space Optical ◽  
Wavelength Division ◽  
Space Optics ◽  
Effective Implementation ◽  
Transmission Distance ◽  
The Cost

AbstractThis work is focused to carry out the investigation of wavelength division multiplexing (WDM) approach on free space optical (FSO) transmission systems using Erbium Ytterbium Doped Waveguide Amplifier (EYDWA) integrated as post-or pre-amplifier for extending the reach to 30 Km for the cost-effective implementation of FSO system considering weather conditions. Furthermore, the performance of proposed FSO-wavelength division multiplexing (WDM) system is also evaluated on the effect of varying the FSO range and results are reported in terms of Q factor, BER, and eye diagrams. It has been found that, under clear rain the post-amplification was performed and was able to reach transmission distance over 27 Km, whereas, the FSO distance has been limited at 19.5 Km by using pre-amplification.

Effect of adverse weather conditions and pointing error on the performance of 2-D WH/TS OCDMA over FSO link

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Bithi Mitra ◽  
Md. Jahedul Islam
Keyword(s):  
Free Space ◽  
Atmospheric Condition ◽  
Optical Power ◽  
Weather Conditions ◽  
Free Space Optical ◽  
Central Wavelength ◽  
Pointing Error ◽  
Adverse Weather ◽  
Code Division Multiple ◽  
Ber Performance

AbstractIn this paper, the performance of two-dimensional (2-D) wavelength-hopping/time-spreading (WH/TS) optical code division multiple access (OCDMA) system over free space optical (FSO) channel is analyzed in the presence of pointing error and different weather conditions. Prime code scheme is employed for both wavelength-hopping and time-spreading to address user code-matrix. The operating central wavelength of 1550 nm is considered to demonstrate the bit error rate (BER) performance of the proposed system as a function of various system parameters. The required optical power of the proposed system is determined to maintain a BER value of 10−9. The numerical evaluation interprets that the BER performance is highly dependent on transmission length, transmitted power, pointing error angle as well as the number of simultaneous user. It is also observed that the 2-D OCDMA system over free space needs minimum required optical power in case of rainy atmospheric condition, but it is maximum for foggy atmospheric condition.

scholarly journals Performance Investigation of 40 GB/s DWDM over Free Space Optical Communication System Using RZ Modulation Format

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Sooraj Parkash ◽  
Anurag Sharma ◽  
Harsukhpreet Singh ◽  
Harjit Pal Singh
Keyword(s):  
Wavelength Division Multiplexing ◽  
Communication System ◽  
Free Space ◽  
Data Rate ◽  
Free Space Optical ◽  
Filter Bandwidth ◽  
Wavelength Division ◽  
High Data ◽  
Modulation Format ◽  
Space Optical Communication

We successfully demonstrate 40 GB/s 8 channels’ Dense Wavelength Division Multiplexing (DWDM) over free space optical (FSO) communication system. Each channel is transmitting 5 GB/s data rate in downstream separated by 0.8 nm (100 GHz) channel spacing with 1.8 GHz filter bandwidth. DWDM over FSO communication system is very effective in providing high data rate transmission with very low bit error rate (BER). The maximum reach of designed system is 4000 m without any compensation scheme. The simulation work reports minimum BER for Return-to-Zero (RZ) modulation format at different channels 1, 4, and 8 are found to be 2.32e-17, 1.70e-16, and 9.51e-15 at 4000 m distance, respectively. Sharp increase in BER occurs if data rate and distance increase up to 10 GB/s and 5000 m.

A Performance Analysis of Free-Space Optical Link at 1,550 nm, 850 nm, 650 nm and 532 nm Optical Wavelengths

2018 ◽  
Vol 39 (3) ◽  
pp. 335-341 ◽  
Author(s):  
Gaurav Soni
Keyword(s):  
Quality Factor ◽  
Free Space ◽  
Low Cost ◽  
Weather Conditions ◽  
Free Space Optical ◽  
Fog Water ◽  
High Data ◽  
Space Optics ◽  
Optical Wavelengths ◽  
532 Nm

Abstract Free Space Optics (FSO) communication technique is a unique method for the communication between optical transmitter and optical receiver using a free space as a medium. The advantages of FSO over other wireless communication techniques is its low power, high security, low cost infrastructure, high data rates and unlicensed spectrum. There are many atmospheric disturbances like rain, fog, water molecules particles which degrade the performance of the FSO Link. In this paper, the FSO Link is optimized at different optical wavelengths of 1550 nm, 850 nm, 650 nm and 532 nm keeping into consideration the various atmospheric challenges and weather conditions. The performance of the proposed FSO link is evaluated in terms of BER and Quality factor. Simulation results for the proposed FSO link achieve maximum link range of 1000 m at 1550 nm. The achieved values of Bit Error Rate (BER) and Quality Factor (Q) for FSO link at 1550 nm are 10e-9 and 5.58 respectively.

Performance enhancement of ultra-dense WDM over FSO hybrid optical link by incorporating MIMO technique

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Rajneesh Kumar ◽  
Love Kumar
Keyword(s):  
Wavelength Division Multiplexing ◽  
Data Transmission ◽  
Free Space ◽  
Performance Enhancement ◽  
Transmission Rate ◽  
Weather Conditions ◽  
Optical Signal ◽  
Optical Data ◽  
Free Space Optical ◽  
Modulation Formats

AbstractFree-space optical (FSO) communication is a wireless optical data transmission technology with a high data transmission rate. It has received much attention in recent years as it is cost-effective and has license free operation. It is line of sight free-space communication technique where optical signal severely degraded from atmospheric losses especially due to weather conditions; hence it restricts the link range and data carrying capacity. Therefore, a 16-channel ultra-dense wavelength division multiplexing–free space optics (UWDM–FSO) system each having each 10 Gb/s data rate is proposed to enhance the capacity and performance of FSO system. To authenticate the performance of the proposed system, investigation for different modulation formats such as nonreturn to zero (NRZ), return to zero (RZ), carrier suppressed return to zero (CSRZ) and duo binary (DB) are reported. Further, to reduce the atmospheric interference, multiple input multiple output (MIMO) technique is integrated into the proposed system. The outcomes of MIMO–UWDM–FSO link revealed a significant improvement in the bit error rate (BER), eye diagram and Q-factor, under different weather conditions. It is also observed that NRZ modulation formats perform better than RZ, CSRZ and DB formats.

scholarly journals Spectral Amplitude Coding Optical CDMA: Performance Analysis on Free Space Optical Channel

2018 ◽  
Vol 7 (4.38) ◽  
pp. 31
Author(s):  
Kehkashan A. Memon ◽  
A. W. Umrani ◽  
M. A. Unar ◽  
Wajiha Shah ◽  
B. S. Chowdhry
Keyword(s):  
Performance Analysis ◽  
Free Space ◽  
Optical Filters ◽  
Optical Cdma ◽  
Optical Channel ◽  
Spectral Amplitude ◽  
Free Space Optical ◽  
Spectral Amplitude Coding ◽  
Point To Point ◽  
Code Division Multiple

In this paper, we investigate the performance of Spectral Amplitude Coding Optical Code Division Multiple Access technique based on Free Space Optical channel. SAC OCDMA is one of the most popular multiplexing techniques since many years and FSO is gaining popularity and is very useful especially in point to point communication. The system presented in this paper utilizes Walsh Hadamard code as signature code. The coder and decoder structures are based on optical filters of fiber Bragg gratings (FBGs). This system focuses on the performance analysis of FSO based systems for subtropical regions. This paper demonstrates the error rate performance in the form of eye diagrams/BER under varying channel gain and link distances. Five cases have been taken which shows that SAC OCDMA FSO system is reliable even for distances sufficient to overcome the last mile problem.  

Performance of Hybrid OCDMA/WDM Scheme Under DPSK and QPSK Modulation Using Spectral Direct Detection Technique for Optical Communication Networks

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
N. Ahmed ◽  
M. A. Rashid
Keyword(s):  
Communication Networks ◽  
Wavelength Division Multiplexing ◽  
Optical Communication ◽  
Multiple Access ◽  
Direct Detection ◽  
Multiple Access Interference ◽  
Detection Technique ◽  
Spectral Amplitude ◽  
Modulation Formats ◽  
Code Division Multiple

AbstractThe hybrid optical code-division multiple-access over wavelength-division multiplexing (OCDMA/WDM) scheme has attractive features of supporting system reach, multi Gbps data rates, security, and robustness for optical communication networks. This paper presents the performance of such scheme under DPSK and QPSK modulation formats using spectral direct detection technique. The modified double weight (MDW) code is used as spectral amplitude coding which also acts as a signature address code for the OCDMA system. The MDW code has the advantage of reducing the multiple access interference (MAI) and enhancing the security of the proposed hybrid system. The study focuses on the comparison between the two advanced modulation techniques (DPSK, QPSK) using spectral direct detection. Simulation results show bit-error-rate (BER) ≤10–09 for up to 25 km distance at the bit rate of 1 Gbps for optical communication networks.

Comparison of Aperture Averaging and Receiver Diversity Techniques for Free Space Optical Links in Presence of Turbulence and Various Weather Conditions

2014 ◽  
Vol 35 (4) ◽  
Author(s):  
Prabhmandeep Kaur ◽  
Virander Kumar Jain ◽  
Subrat Kar
Keyword(s):  
Outage Probability ◽  
Free Space ◽  
Direct Detection ◽  
Weather Conditions ◽  
Free Space Optical ◽  
Aperture Diameter ◽  
Receiver Diversity ◽  
Optical Links ◽  
Diversity Techniques ◽  
Aperture Averaging

AbstractIn this paper, we investigate the performance of a Free Space Optic (FSO) link considering the impairments caused by the presence of various weather conditions such as very clear air, drizzle, haze, fog, etc., and turbulence in the atmosphere. Analytic expression for the outage probability is derived using the gamma-gamma distribution for turbulence and accounting the effect of weather conditions using the Beer-Lambert's law. The effect of receiver diversity schemes using aperture averaging and array receivers on the outage probability is studied and compared. As the aperture diameter is increased, the outage probability decreases irrespective of the turbulence strength (weak, moderate and strong) and weather conditions. Similar effects are observed when the number of direct detection receivers in the array are increased. However, it is seen that as the desired level of performance in terms of the outage probability decreases, array receiver becomes the preferred choice as compared to the receiver with aperture averaging.

Performance Evaluation of Hybrid FSO-SACOCDMA System under Different Weather Conditions

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Himali Sarangal ◽  
Amarpal Singh ◽  
Jyoteesh Malhotra ◽  
Simrandeep Singh Thapar
Keyword(s):  
Multiple Access ◽  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Multiple Access Interference ◽  
Weather Conditions ◽  
Spectral Amplitude ◽  
Space Optics ◽  
Spectral Amplitude Coding ◽  
Code Division Multiple ◽  
Clear Weather

AbstractSpectral amplitude coding optical code division multiple access (SACOCDMA) is a multiplexing technique, which provides faster speed, efficiency, security and unlimited bandwidth. It is widely preferred because of its ability to eliminate multiple access interference (MAI). Free space optics (FSO) provides a wireless link to transmit data securely at higher rates for last mile access. In this work, a 100 Gb/s hybrid FSO-SACOCDMA is designed using direct detection. The performance of FSO using SACOCDMA utilizing NZCC (New Zero Cross Correlation) code is evaluated under different weather conditions (clear weather, haze and fog) for ten users where each user carries 10 Gb/s. The results indicate that in clear weather FSO distance can be extended up to 13 km. Moreover, after using preamplifier in clear weather, FSO enhances the maximum distance to 35 km with acceptable signal to noise ratio and bit error rate. Using an amplifier in the link not only makes the quality of the signal better but it also increases the communication range.

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