scholarly journals Effects and Constraints of Optical Filtering on Ambient Light Suppression in LED-Based Underwater Communications

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3710 ◽  
Author(s):  
Jan Sticklus ◽  
Martin Hieronymi ◽  
Peter Hoeher
Keyword(s):  
Optical Communication ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Optical Filters ◽  
Optical Signal ◽  
High Rate ◽  
Colored Glass ◽  
Ambient Light ◽  
Ambient Conditions

Optical communication promises to be a high-rate supplement for acoustic communication in short-range underwater applications. In the photic zone of oceanic and coastal waters, underwater optical communication systems are exposed by remaining sunlight. This ambient light generates additional noise in photodetectors, thus degrading system performance. This effect can be diminished by the use of optical filters. This paper investigates light field characteristics of different water types and potential interactions with optical underwater communication. A colored glass and different thin film bandpass filters are examined as filter/detector combinations under varying light and water conditions, and their physical constraints are depicted. This is underlined by various spectral measurements as well as optical signal-to-noise ratio calculations. The importance of matching the characteristics of the light emitting diode (LED) light source, the photodetector, and the filter on the ambient conditions using wider angle of incidents is emphasized.

High-speed signal processing and wide band optical semiconductor amplifier in the optical communication systems

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hazem M. El-Hageen ◽  
Aadel M. Alatwi ◽  
Ahmed Nabih Zaki Rashed
Keyword(s):  
Optical Communication ◽  
Communication Systems ◽  
High Speed ◽  
Noise Figure ◽  
Signal To Noise Ratio ◽  
Local Area ◽  
Optical Signal ◽  
Signal To Noise ◽  
Optical Communication Systems ◽  
Noise Ratio

AbstractThis work clarifies the analysis of the theoretical study of noise and transmission gain characteristics of semiconductor optical amplifiers (SOAs), which are relevant in the novel local area optical communication systems. We investigated the effects of noise on AlGaAs/GaAs SOA transmission performance through the measurement of output power, optical gain, the optical signal-to-noise ratio, and noise figure. It was observed that noise has a dramatic effect on SOAs’ operation transmission efficiency, and the performance of the amplifier structure may be limited. If the drive current and injection power at the SOA can be changed and its active region length modified, then the variation of gain, optical signal-to-noise ratio, and noise figure at the output of the structure can be obtained.

scholarly journals Calculations of Signal to Noise Ratio (SNR) for Free Space Optical Communication Systems

2008 ◽  
Vol 5 (1) ◽  
pp. 95-100
Author(s):  
Baghdad Science Journal
Keyword(s):  
Optical Communication ◽  
Free Space ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Full Duplex ◽  
Free Space Optical ◽  
Signal To Noise ◽  
Optical Communication Systems ◽  
Space Optical Communication ◽  
Noise Ratio

In this paper, we calculate and measure the SNR theoretically and experimental for digital full duplex optical communication systems for different ranges in free space, the system consists of transmitter and receiver in each side. The semiconductor laser (pointer) was used as a carrier wave in free space with the specification is 5mW power and 650nm wavelength. The type of optical detector was used a PIN with area 1mm2 and responsively 0.4A/W for this wavelength. The results show a high quality optical communication system for different range from (300-1300)m with different bit rat (60-140)kbit/sec is achieved with best values of the signal to noise ratio (SNR).

scholarly journals A 45 nm CMOS Avalanche Photodiode with 8.4-GHz Bandwidth

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 65
Author(s):  
Wenhao Zhi ◽  
Qingxiao Quan ◽  
Pingping Yu ◽  
Yanfeng Jiang
Keyword(s):  
Optical Communication ◽  
Integrated Circuit ◽  
Communication Systems ◽  
Complementary Metal Oxide Semiconductor ◽  
Avalanche Photodiode ◽  
Cmos Technology ◽  
Optical Signal ◽  
Oxide Semiconductor ◽  
Monolithically Integrated ◽  
Process Modification

Photodiode is one of the key components in optoelectronic technology, which is used to convert optical signal into electrical ones in modern communication systems. In this paper, an avalanche photodiode (APD) is designed and fulfilled, which is compatible with Taiwan Semiconductor Manufacturing Company (TSMC) 45-nm standard complementary metal–oxide–semiconductor (CMOS) technology without any process modification. The APD based on 45 nm process is beneficial to realize a smaller and more complex monolithically integrated optoelectronic chip. The fabricated CMOS APD operates at 850 nm wavelength optical communication. Its bandwidth can be as high as 8.4 GHz with 0.56 A/W responsivity at reverse bias of 20.8 V. Its active area is designed to be 20 × 20 μm2. The Simulation Program with Integrated Circuit Emphasis (SPICE) model of the APD is also proposed and verified. The key parameters are extracted based on its electrical, optical and frequency responses by parameter fitting. The device has wide potential application for optical communication systems.

scholarly journals Optimization of system’s parameters for wavelength conversion of E-band signals

2022 ◽  
Vol 12 (2) ◽  
pp. 1659
Author(s):  
Yazan Alkhlefat ◽  
Sevia Mahdaliza Idrus Sutan Nameh ◽  
Farabi M. Iqbal
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Wavelength Conversion ◽  
Signal To Noise Ratio ◽  
Optical Amplifier ◽  
Optical Signal ◽  
Error Vector Magnitude ◽  
Wavelength Converter ◽  
High Data

Current and future wireless communication systems are designed to achieve the user’s demands such as high data rate and high speed with low latency and simultaneously to save bandwidth and spectrum. In 5G and 6G networks, a high speed of transmitting and switching is required for internet of things (IoT) applications with higher capacity. To achieve these requirements a semiconductor optical amplifier (SOA) is considered as a wavelength converter to transmit a signal with an orthogonal frequency division multiplexing with subcarrier power modulation (OFDM-SPM). It exploits the subcarrier’s power in conventional OFDM block in order to send additional bits beside the normally transmitted bits. In this paper, we optimized the SOA’s parameters to have efficient wavelength conversion process. These parameters are included the injection current (IC) of SOA, power of pump and probe signals. A 7 Gbps OFDM-SPM signal with a millimeter waves (MMW) carrier of 80 GHz is considered for signal switching. The simulation results investigated and analyzed the performance of the designed system in terms of error vector magnitude (EVM), bit error rate (BER) and optical signal-to-noise ratio (OSNR). The optimum value of IC is 0.6 A while probe power is 9.45 and 8.9 dBm for pump power. The simulation is executed by virtual photonic integrated (VPI) software.

scholarly journals Information-Bottleneck Decoding of High-Rate Irregular LDPC Codes for Optical Communication Using Message Alignment

2018 ◽  
Vol 8 (10) ◽  
pp. 1884 ◽  
Author(s):  
Maximilian Stark ◽  
Jan Lewandowsky ◽  
Gerhard Bauch
Keyword(s):  
High Precision ◽  
Optical Communication ◽  
Message Passing ◽  
Communication Systems ◽  
Belief Propagation ◽  
Ldpc Codes ◽  
High Rate ◽  
Double Precision ◽  
Information Bottleneck ◽  
Irregular Ldpc Codes

In high-throughput applications, low-complexity and low-latency channel decoders are inevitable. Hence, for low-density parity-check (LDPC) codes, message passing decoding has to be implemented with coarse quantization—that is, the exchanged beliefs are quantized with a small number of bits. This can result in a significant performance degradation with respect to decoding with high-precision messages. Recently, so-called information-bottleneck decoders were proposed which leverage a machine learning framework (i.e., the information bottleneck method) to design coarse-precision decoders with error-correction performance close to high-precision belief-propagation decoding. In these decoders, all conventional arithmetic operations are replaced by look-up operations. Irregular LDPC codes for next-generation fiber optical communication systems are characterized by high code rates and large maximum node degrees. Consequently, the implementation complexity is mainly influenced by the memory required to store the look-up tables. In this paper, we show that the complexity of information-bottleneck decoders remains manageable for irregular LDPC codes if our proposed construction approach is deployed. Furthermore, we reveal that in order to design information bottleneck decoders for arbitrary degree distributions, an intermediate construction step which we call message alignment has to be included. Exemplary numerical simulations show that incorporating message alignment in the construction yields a 4-bit information bottleneck decoder which performs only 0.15 dB worse than a double-precision belief propagation decoder and outperforms a min-sum decoder.

Performance Enhancement of Atmospheric Coherent Optical Communication Systems Using DPSK

2012 ◽  
Vol 263-266 ◽  
pp. 1081-1084
Author(s):  
Yu Peng Li ◽  
Yan Gan Zhang ◽  
Xue Guang Yuan ◽  
Jin Nan Zhang ◽  
Ming Lun Zhang ◽  
...  
Keyword(s):  
Atmospheric Turbulence ◽  
Optical Communication ◽  
Communication Systems ◽  
Performance Enhancement ◽  
Signal To Noise Ratio ◽  
Free Space Optical ◽  
Eye Diagram ◽  
Optical Communication Systems ◽  
Simulation Results ◽  
Better Than

A coherent DPSK transmission system is presented to improve the receiver sensitivity for free space optical (FSO) communication. The coherent DPSK is an effective way to overcome the atmospheric turbulence. The eye diagram and bit error rate (BER) of the system are got by the simulation. Results show that with the coherent reception method, coherent DPSK offers improved signal-to-noise ratio (SNR) performance compared to the DPSK without coherent and OOK format. And hence it can be effective to overcome the signal impairment caused by atmospheric turbulence. It is shown that the sensitivity of the system employing coherent DPSK is 3dB better than a comparable system using DPSK without coherent and 9dB better than a system using OOK.

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