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

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.

Design of Multiwavelength EDF-Raman Lasers Utilizing Mach-Zehnder Interferometer

This paper presents the design of multiwavelength Erbium Doped Fiber (EDF)-Raman fiber laser utilizing Mach-Zehnder Interferometer (MZI) with various cavity structures. A multiwavelength laser employing hybrid gain medium of EDF-Raman amplifier is simulated using OptiSystem software. Three cavity structures of multiwavelength laser such as unidirectional, bidirectional and ring cavity are simulated and analysed. From the simulation result, it is found that ring cavity structure produced the best performance whereas at 1000 mW pump power, up to 19 lasing lines were obtained in the ring cavity, compared to 18, and 16 lasing lines in the unidirectional and bidirectional linear cavity, respectively. All multiwavelength fiber lasers exhibit the same line spacing of 4.9 nm. In addition, at coupling coefficient of 0.9, up to 49.5 dB of side mode suppression ratio (SMSR) were achieved in the ring cavity structure, compared to 49.2 dB, and 30.3 dB of SMSR in the unidirectional and bidirectional linear cavity, respectively. However, bidirectional linear cavity exhibits the highest peak power of 2.07 dBm, compared to -17.4 dBm, and -15.5 dBm of peak power in the unidirectional linear and ring cavity, respectively.