Shaymaa R. Tahhan, Abdulla K. Abass, and Mudhafar H. Ali Laser and Optoelectronics Engineering Department, College of Engineering, Al-Nahrain University, Baghdad, Iraq Laser Engineering Branch, Laser and Optoelectronics Department, University of Technology, Baghdad, Iraq Network Engineering Department, College of Engineering, Al-Iraqia University, Baghdad, Iraq Email: shaymaa.riyadh@gmail.com; 140042@uotechnology.edu.iq; muthafarh@yahoo.com

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Characteristics of Chirped Fiber Bragg Grating Dispersion Compensator Utilizing Two Apodization Profiles

Tunable and stable multi-wavelength erbium-doped fiber laser based on a double Sagnac comb filter with polarization-maintaining fibers

Tunable multiwavelength Brillouin-Raman fiber laser in a linear cavity with spectrum reshaped by Rayleigh scattering

It is important to note that the expression for Gth contains the explicit dependence on fiber material characteristics. Results of our calculations are in reasonably good correspondence with proper measurements in silica fibres, which we have found in the literature and have done ourselves in fibre-samples without and with cavity feedback.

Threshold for stimulated Brillouin scattering in optical fibres

We propose and demonstrate a new multiwavelength Brillouin–Raman fiber laser with switchable 10 and 20 GHz spacing. This is achieved by proper adjustments of optical coupling ratios that are incorporated in the design that consists of an enhanced nonlinear amplifying fiber loop. By utilizing a 50/50 coupler, 443 flat amplitude channels with 10 GHz spacing is realized. On the other hand, a 99/1 coupler is feasible for 20 GHz spacing that yields 215 lasing lines. In both cases, the average optical signal-to-noise ratios (OSNR) are 16.5 dB (50/50 coupler) and 24 dB (99/1 coupler). Wide multiwavelength bandwidth, flexible wavelength spacing, and high number of channels with excellent OSNRs are achieved using only a single Raman pump unit through a simple construction.

Switchable Multiwavelength Brillouin–Raman Fiber Laser Utilizing an Enhanced Nonlinear Amplifying Fiber Loop Design

Broadly tunable 40 GHz Brillouin frequency spacing multiwavelength Brillouin-Erbium fiber laser for DWDM

This study demonstrates simulation and experimental validation of a wideband serial hybrid Raman/erbium-doped fiber amplifier. Two configurations are adopted; in type A, a Raman amplifier is the first stage, and in type B, an erbium-doped fiber amplifier is the first stage. At low input signal power, the average gain level is 20 dB with a flat gain bandwidth of 40 nm for both configurations. The noise figure in type B is dominated by the erbium-doped fiber amplifier and produces lower values and flatter spectra than in type A. The gain of the proposed hybrid amplifiers is affected more by the second amplification stage.

Effect of Cascading Amplification Stages on the Performance of Serial Hybrid Fiber Amplifier

A tunable multi-wavelength L-band Brillouin–Raman fiber laser with a 20-GHz channel spacing utilizing bidirectional ring cavity is proposed and experimentally investigated. The laser employs a co-pumped dispersion compensating fiber as a gain medium for both Brillouin and Raman gains. With a Raman pump of 425 mW, the laser system can generate up to 12 double-spaced Brillouin Stokes signals. This simple laser configuration provides stable Brillouin Stokes signals in the absence of self-lasing cavity modes with a tuning range exceeding 35 nm without using any filtering mechanism. The Stokes signals have more than 20 dB of optical signal-to-noise ratio.

L-Band Multi-Wavelength Brillouin–Raman Fiber Laser with 20-GHz Channel Spacing

We demonstrate a simulation of a parallel hybrid fiber amplifier in the C+L-band with a gain controlling technique. A variable optical coupler is used to control the input signal power for both EDFA and RFA branches. The gain spectra of the C+L-band are flattened by optimizing the coupling ratio of the input signal power. In order to enhance the pump conversion efficiency, the EDFA branch was pumped by the residual Raman pump power. A gain bandwidth of 60 nm from 1530 nm to 1590 nm is obtained with large input signal power less than -5 dBm. The gain variation is about 1.06 dB at a small input signal power of -30 dBm, and it is reduced to 0.77 dB at the large input signal power of -5 dBm. The experimental results show close agreement with the simulation results.

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T. F. Al-Mashhadani

Papers

Broadly tunable 40 GHz Brillouin frequency spacing multiwavelength Brillouin-Erbium fiber laser for DWDM

Effect of Cascading Amplification Stages on the Performance of Serial Hybrid Fiber Amplifier

L-Band Multi-Wavelength Brillouin–Raman Fiber Laser with 20-GHz Channel Spacing

Simulation and Experimental Validation of Gain-Control Parallel Hybrid Fiber Amplifier

Tunable multiwavelength L-band Brillouin-Erbium fiber laser utilizing passive EDF absorber section