Effect of Nonlinear Dispersion Fiber Length and Input Power on Raman Scattering

2021 ◽  
Vol 19 (11) ◽  
pp. 47-65
Author(s):  
Suha Mousa Khorsheed Alawsi ◽  
Noor Mohammed Hassan ◽  
Intehaa Abdullah Mohammed Al-Juboury
Keyword(s):  
Raman Scattering ◽  
Fiber Length ◽  
Laser System ◽  
Maximum Output Power ◽  
Input Power ◽  
Raman Shift ◽  
Bragg Grating ◽  
Maximum Output ◽  
Raman Fiber Laser ◽  
Multi Wavelength

The increasing demand for information transmission makes the problem of establishing a laser system is operating in C-band (1530-1565nm) wavelength region is a significant task, which attracts a lot of researchers' attention lately. In this paper, the ability to produce signals of multi wavelengths using a single light source was adopted to employ the Raman scattering effect for establishing Raman shift configuration-based multi-wavelength fiber lasers, which is not currently addressed in available schemes. This is what prompted to simulate the performance of C-band multi-wavelength produced by Raman fiber laser that utilizing fiber Bragg grating (FBG) to amplify pumped power and also utilizing the single-mode fiber (SMF) as the nonlinear gain medium. The proposed laser system is designed by OptiSystem software. The resulted maximum output power was 22.07dB at Wavelength Division Multiplexing (WDM) of 23.01dB input power. The achieved multi-wavelength that generated by Bragg grating and SMF was containing six Stokes and anti-Stokes, they are: 1548.51nm, 1549, 31nm, 1550.116nm, 1550.91nm, 1551.72nm, and 1552.52nm, in which the resulted computed efficiency of the system was raised up to 80.23% at input power 20 dB and dispersion fiber length of 0.2 km.

scholarly journals Investigation on extreme frequency shift in silica fiber-based high-power Raman fiber laser

2018 ◽  
Vol 6 ◽  
Author(s):  
Jiaxin Song ◽  
Hanshuo Wu ◽  
Jun Ye ◽  
Hanwei Zhang ◽  
Jiangming Xu ◽  
...  
Keyword(s):  
Frequency Shift ◽  
Fiber Laser ◽  
High Power ◽  
High Efficiency ◽  
Maximum Output Power ◽  
Gain Medium ◽  
Maximum Output ◽  
Optical Efficiency ◽  
Central Wavelength ◽  
Raman Fiber Laser

In this paper, we experimentally investigated the extreme frequency shift in high-power Raman fiber laser (RFL). The RFL was developed by using a pair of fiber Bragg gratings with fixed and matched central wavelength (1120 nm) combined with a piece of 31-m-long polarization maintaining (PM) passive fiber adopted as Raman gain medium. The pump source was a homemade high-power, linearly polarized (LP) wavelength-tunable master oscillator power amplifier (MOPA) source with ${\sim}25~\text{nm}$ tunable working range (1055–1080 nm). High-power and high-efficiency RFL with extreme frequency shift between the pump and Stokes light was explored. It is found that frequency shift located within 10.6 THz and 15.2 THz can ensure efficient Raman lasing, where the conversion efficiency is more than 95% of the maximal value, 71.3%. In addition, a maximum output power of 147.1 W was obtained with an optical efficiency of 71.3%, which is the highest power ever reported in LP RFLs to the best of our knowledge.

scholarly journals D-Band Frequency Tripler Module Using Anti-Parallel Diode Pair and Waveguide Transitions

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1201
Author(s):  
Jihoon Doo ◽  
Jongyoun Kim ◽  
Jinho Jeong
Keyword(s):  
Input Signal ◽  
Low Cost ◽  
Impedance Matching ◽  
Maximum Output Power ◽  
Input Power ◽  
Maximum Output ◽  
Band Frequency ◽  
Circuit Components ◽  
Plane Probe ◽  
Harmonic Components

In this paper, D-band (110–170 GHz) frequency tripler module is presented using anti-parallel GaAs Schottky diode pair and waveguide-to-microstrip transitions. The anti-parallel diode pair is used as a nonlinear device generating harmonic components for Q-band input signal (33–50 GHz). The diode is zero-biased to eliminate the bias circuits and thus minimize the number of circuit components for low-cost hybrid fabrication. The anti-parallel connection of two identical diodes effectively suppresses DC and even harmonics in the output. Furthermore, the first and second harmonics of Q-band input signal are cut off by D-band rectangular waveguide. Input and output impedance matching networks are designed based on the optimum impedances determined by harmonic source- and load-pull simulations using the developed nonlinear diode model. Waveguide-to-microstrip transitions at Q- and D-bands are also designed using E-plane probe to package the frequency tripler in the waveguide module. The compensation circuit is added to reduce the impedance mismatches by bond-wires connecting two separate substrates. The fabricated frequency tripler module produces a maximum output power of 5.4 dBm at 123 GHz under input power of 20.5 dBm. A 3 dB bandwidth is as wide as 22.5% from 118.5 to 148.5 GHz at the input power of 15.0 dBm. This result corresponds to the excellent bandwidth performance with a conversion gain comparable to the previously reported frequency tripler operating at D-band.

Single Brillouin frequency shifted S-band multi-wavelength Brillouin-Raman fiber laser utilizing fiber Bragg grating and Raman amplifier in ring cavity

2016 ◽  
Vol 60 ◽  
pp. 38-44 ◽  
Author(s):  
A.H. Reshak ◽  
N.A.M. Ahmad Hambali ◽  
M.M. Shahimin ◽  
M.H.A. Wahid ◽  
Nur Elina Anwar ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Fiber Bragg Grating ◽  
Ring Cavity ◽  
Bragg Grating ◽  
Raman Fiber Laser ◽  
Raman Amplifier ◽  
Multi Wavelength

scholarly journals Extended Bandwidth and Increased Efficiency Quasi-Doherty Power Amplifier Design With A Revised Approach For Load Modulation

2021 ◽  
Author(s):  
Seyedehmarzieh Rouhani ◽  
Kasra Rouhi ◽  
Adib Abrishamifar ◽  
Majid Tayarani
Keyword(s):  
Power Amplifier ◽  
High Power ◽  
Maximum Output Power ◽  
Input Power ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Power Added Efficiency ◽  
Active Feedback ◽  
Doherty Power Amplifier ◽  
Load Modulation

This paper presents an approach to power added efficiency (PAE) increase for Quasi-Doherty power amplifier (Q-DPA) design. For this aim, active feedback is utilized instead of a passive quarter wavelength transmission line (TL) usage, which is conventionally used in the DPA schematic. PAE increase can be done by applying an accurate load modulation to the main amplifier (PAmain), especially for technologies in which output impedance of the main power amplifier (Zout,main) considerably varies in both low and high power regions. Because such precise modulation is still based on a modified TL, this approach suffers from the inherent narrowband behavior of that TL. As a consequence, expecting a wideband DPA may not be satisfied in all cases. To deal with this issue, active feedback is used to play a role in reaching PAmain, which is not saturated before, to its maximum efficiency at the highest level of received input power (Pin) in the high power region. Following Zout,main trajectories in power and frequency sweeps simultaneously just by a passive TL are not needed anymore. Still, for the sake of preventing total PAE degradation due to the consummated power by the feedback path’s power amplifier (PAfeedback) should be limited, analytical confinement is provided in this work. A comparison is made between GaAs pHEMT 0.25um MMIC technology-based conventional DPA and the proposed revised approach based-DPA to verify the mentioned approach. The proposed PA shows maximum output power of 33.4 dBm, maximum PAE of 41.6, fractional bandwidth of 11%. The Q-DPA works with a maximum power gain of 24.16.

Modelling and Scaling of the Impulse Turbine for Wave Power Applications

2002 ◽  
Author(s):  
Ajit Thakker ◽  
Fergal Hourigan
Keyword(s):  
Maximum Output Power ◽  
Input Power ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Operating Point ◽  
Optimum Operating ◽  
Wave Power ◽  
Maximum Output ◽  
Impulse Turbine ◽  
Optimum Operating Point

This paper addresses the dimensional analysis of experimental data for the Impulse Turbine and the use of that data to create a model to predict the performance characteristics of an arbitrarily sized turbine under arbitrary operating conditions. The model assumes that the performance of the turbine is a function of flow coefficient only. The model is used to compare the performance of different turbines at the scaled-up level and under varying conditions of axial velocity and angular velocity. Also, the model is used to identify the optimum turbine rotational speed, for maximum output power, at practical sizes over a range of input power levels. This paper clarifies issues relating to the sizing and optimum operating point of the Impulse Turbine over variable sea conditions which oblige the turbine to operate over a design range rather than at a single design point and shows how this optimum operating point may be obtained.

A Comparative Study of Determination the Spectral Characteristics of Serum Total Protein Among Laser System and Spectrophotometric: Advantage and Limitation of Suggested Methods

2019 ◽  
Vol 15 (5) ◽  
pp. 583-590 ◽  
Author(s):  
AL-Timimi Zahra
Keyword(s):  
Diode Laser ◽  
Output Power ◽  
Total Protein ◽  
Laser System ◽  
Maximum Output Power ◽  
Maximum Output ◽  
Serum Total Protein ◽  
Variable Resistance ◽  
Relative Standard ◽  
Double Beam

Background and Objective: Laser spectroscopy is becoming an increasingly paramount analytical tool. Scientists today have at their disposal many various types of laser-based analytical techniques. In this article, the possibility of using capabilities of a laser to analyze and find the concentration of Serum Total Protein (STP) was studied. Materials and Methods: The laser system includes a diode laser with 532 nm wavelength, with maximum output power being 5 mW. Laser bandwidth ranges around (524 nm – 546 nm) experimentally justified using a monochromator. A simple variable resistance with a range from zero to10Ω for obtaining a range of laser output power, detector, parallel variable resistance with the range from zero to 5 kΩ and meter for measuring the percentage of transmittance. The absorption spectroscopy of STP samples was measured by double beam spectrophotometer. Results: Maximum absorbance of STP is at the range (520-580 nm) and the peak at (500) nm. Laser system measurements included the study of absorbance of STP as a function of cuvet thickness, transmittance as a function of cuvet thickness and absorbance as a function of laser power. In order to ascertain our calculations, the results have been compared with the results of the spectrophotometer. The Relative Standard Deviation (RSD%) values are about (0.67-17.18). Conclusion: The diode laser system is a highly efficient and easy system and allows access to a range of powers. Since the divergence of the laser beam is very low. All results are in good agreement with conventional double beam spectrophotometer.

Fiber Length Optimization of Ring Cavity Multi-Wavelength Brillouin Fiber Laser Utilizing Fiber Bragg Grating

2015 ◽  
Vol 815 ◽  
pp. 343-347 ◽  
Author(s):  
A. Zakiah Malek ◽  
N.A.M. Ahmad Hambali ◽  
M.H.A. Wahid ◽  
M.A.M. Azidin ◽  
Siti Salwa Mat Isa ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Fiber Bragg Grating ◽  
Fiber Length ◽  
Brillouin Scattering ◽  
Ring Cavity ◽  
Wavelength Region ◽  
Stimulated Brillouin Scattering ◽  
Bragg Grating ◽  
Multi Wavelength ◽  
Stimulated Brillouin

In this paper, we experimentally investigated the performance of ring cavity multi-wavelength Brillouin fiber laser utilizing fiber Bragg grating which operated in the C-band wavelength region. The combination of stimulated Brillouin scattering and selective wavelengths gave a new invention in the optical fiber communication. Five different lengths of single mode fiber are used in order to get the best gain medium for stimulated Brillouin scattering effect. Up to 33 of Brillouin Stokes signals and 31 of anti-Stokes signals were obtained when 10 km fiber length was used in the laser system. The average value optical signal to noise ratio of 15 dB has been achieved. The broadening bandwidth of Brillouin Stokes signals also occurred at the center wavelength of 1550 nm based on the 3 dB bandwidth of 5 nm fiber Bragg grating.

scholarly journals Increased Efficiency of a Current Compensating Load Modulation Based MMIC Doherty Power Amplifier Design In 0.25m GaAs pHEMT Technology

2020 ◽  
Author(s):  
Seyedehmarzieh Rouhani ◽  
Kasra Rouhi ◽  
Adib Abrishamifar ◽  
Majid Tayarani
Keyword(s):  
Power Amplifier ◽  
Second Harmonic ◽  
Maximum Output Power ◽  
Input Power ◽  
Maximum Output ◽  
Modulation Equation ◽  
Gain Compression ◽  
Power Added Efficiency ◽  
Doherty Power Amplifier ◽  
Load Modulation

In this work, a premise is applied to the conventional load modulation equation of Doherty power amplifier (DPA) in 0.25 m GaAs pHEMT technology to compensate output impedance of main amplifier ( Z out,main ) variation, even in low power region. Using this modified modulation leads to the DPAs power added efficiency (PAE) increase in comparison by the case in which the load modulation revision is ignored, which is also designed in this paper. Second harmonic rejection networks are also added to both designs to play their roles as to efficiency increase. By doing so, the revised load modulation based DPA has the maximum PAE of 39.6%, maximum output power ( P out ) of 31.61dBm, at 8 GHz. Simulation results of this DPA in higher harmonics indicate the designed DPA has the minimum second and third harmonics power of -51.7 dBm and -80 dBm, respectively. For the sake of linearity evaluation, it is depicted that 1dB-power gain compression has not occurred in the input power (P in ) range in which the proposed DPA works.

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