Effect of Temperature and Germania on the Performance of Germania Doped Silica Fiber Raman Scattering Amplifier

The Raman gain coefficient, the attenuations at signal and pump wavelengths and the refractive indices of both core and cladding of silica doped Germania optical fiber are functions of the Germania ratio, temperature and wavelengths. The Raman amplifier gain increases with Germania ratio but it decreases with temperature. Also, Raman gain either increases or decreases with signal wavelength. As the fiber core radius increases, the Raman gain decreases. The gain distribution through the amplifier length of dual pumps with power divided ratio (S=0.5) is better than that for the forward pump amplifier and the backward pump amplifier. The forward pump has a maximized gain but the backward pump has a minimized gain, while the dual pumps have both the maximum and minimized gains. The final amplifier gain for the three kinds of pumps with the same pump power (Pp) is equally.The pump wavelength (λp=1.4553μm) gives the biggest Raman gain at the center of wideband signal wavelength (λs=1.50 to 1.60μm). With λp =1.48μm, the gain increases with λs until λs=1.57μm and after that the gain decreases with λs and so with the above three kinds of pumps, gain fluctuations over the band wavelength of signal. The threshold pump power and gain saturation are studied.

Development of a CubeSat Single Channel LoRa Receiver Module for Space-based IoT Application

CubeSat attracts many researchers due to its low production and deployment cost. One of the application is implemented in low data rate communication or machine to machine (M2M) with IoT devices in remote areas such as islands, forests, and mountains. In this study, a CubeSat receiver for IoT communication in remote areas has been developed and realized. A LoRa SX1276 chip is used for processing passband signals captured by the antenna. The device has a amplifier gain of 20.92 dB, 390 mW power consumption, and operating frequency of 923 MHz. The developed CubeSat is expected to provide a low bit rate of 5468.750 bps for SF 7 and 292.969 for SF 12 , the receiver serves as a concentrator for monitoring devices in rural areas.

Dispersion compensation FBG with optical quadrature phase shift keying (OQPSK) modulation scheme for high system capacity

The study simulated OQPSK modulation scheme-based FBG compensation for high data rates. The signal power, noise power and output power variations with the FBG length variations are clarified with fiber length of 50 km and amplifier gain of 40 dB. The max Q Factor variations with amplifier gain variations in the presence and absence of FBG device. The eye diagram analyzer for the proposed model under the same operating conditions with the previous model with/without FBG device. Besides the signal power variations is demonstrated against spectral wavelength and time variations for the proposed model with/without FGB device. Max Q and min error rate are clarified for the proposed model with 150 km length, amplifier gain pf 40 dB with FBG device length of 6 m and without FBG device.

The Design of the Emission Layer for Electron Multipliers

The electron multipliers gain is closely related to the secondary electron emission coefficient (SEE) of the emission layer materials. The SEE is closely related to the thickness of the emission layer. If the emission layer is thin, the low SEE causes the low gain of electron multipliers. If the emission layer is thick, the conductive layer can't timely supplement charge to the emission layer, the electronic amplifier gain is low too. The electron multipliers usually choose Al2O3 and MgO film as the emission layer because of the high SEE level. MgO easy deliquescence into Mg(OH)2 resulting in the lower SEE level. The SEE level of Al2O3 is lower than MgO, but Al2O3 is stable. We designed a spherical system for testing the SEE level of materials, and proposed to use lowenergy secondary electrons instead of low-energy electron beam for neutralization to measuring the SEE level of Al2O3, MgO, MgO/Al2O3, Al2O3/MgO, and precisely control the film thickness by using atomic layer deposition (ALD). We propose to compare the SEE under the adjacent incident electrons energy to partition the SEE value of the material, and obtain four empirical formula for the relationship between SEE and thickness. Through experiments and calculations, we put forward a new emission layer for electron multipliers, including 2~3 nm Al2O3 buffer layer, 9nm MgO main-body layer, 1nm protective layer or 0.3nm enhancement layer. We can apply this new emission layer to channel electron multiplier (CEM), microchannel plate (MCP), separate electron multiplier.

Modeling of Aircraft and RPAS Data Transmission via Satellites

This chapter is devoted to the modeling of aircraft data transmission via low-orbit satellites. Satellite communication channel models were designed, which allow to investigate BER dependencies on the type of signal modulation, information transfer rate, signal power, antenna diameters, and nonlinearity of a high power amplifier. Impact of a modulation type (BPSK, QPSK, 8PSK, 16QAM), Eb / N0, satellite transponder amplifier gain without and with coding on a BER was investigated. Effectiveness of error detection and correction was analyzed using classic linear block and convolutional codes. Free space path loss, AWGN, and radio frequency satellite channels were considered. MIMO 2 × 1 and 3 × 2 fading uplink/downlink channels with antenna diversity were analyzed. Results were compared with AWGN uplink/downlink channels. On the base of these models, channels integrity was investigated.

"Analytical Model of Pulse Amplification in Erbium Doped Fiber Amplifier "

"Doping a part of the optical fiber core by (Er3+ ) ions in presence of external pumping power will lead to form the erbium-doped fiber amplifier (EDFA).The performance of this optical amplifier depends on (the power and the wavelength of the pumping laser, the power and wavelength of the input signal, amplifier length, ion concentration). These parameters will affect the characteristics of EDFA such as amplifier gain, gain saturation, noise figure and output power. However, these characteristics can be determined by solving the EDFA propagation and rate equations. The solution of these equations of two-level laser medium can be done numerically. In this paper, we are proposed a novel method to solve these equations. The reconstructed results are perfectly coincided the well known numerical results.

Dissecting transcriptional amplification by MYC

Supraphysiological MYC levels are oncogenic. Originally considered a typical transcription factor recruited to E-boxes (CACGTG), another theory posits MYC a global amplifier increasing output at all active promoters. Both models rest on large-scale genome-wide ”-omics’. Because the assumptions, statistical parameter and model choice dictates the ‘-omic’ results, whether MYC is a general or specific transcription factor remains controversial. Therefore, an orthogonal series of experiments interrogated MYC’s effect on the expression of synthetic reporters. Dose-dependently, MYC increased output at minimal promoters with or without an E-box. Driving minimal promoters with exogenous (glucocorticoid receptor) or synthetic transcription factors made expression more MYC-responsive, effectively increasing MYC-amplifier gain. Mutations of conserved MYC-Box regions I and II impaired amplification, whereas MYC-box III mutations delivered higher reporter output indicating that MBIII limits over-amplification. Kinetic theory and experiments indicate that MYC activates at least two steps in the transcription-cycle to explain the non-linear amplification of transcription that is essential for global, supraphysiological transcription in cancer.