Flattening Few Mode Fiber Laser Source Based on PMF and Loop Mirror in a Ring Cavity Resonator

Abstract: A multi-wavelength source using a hybrid amplifier comprised of a Semiconductor Optical Amplifier (SOA) and an Erbium-doped fiber amplifier (EDFA) in a ring fiber laser set up is proposed. Multi-wavelength sources are less expensive and more efficient than deploying several laser diodes at different wavelengths. They are also compact, spend low energy, and emit low heat than multiple laser diode systems. A polarization maintaining fiber (PMF) and an interference comb filter are used in conjunction with the suggested few mode fiber laser source to create higer than 14 wavelength around -28 dBm at a SOA by current near 300 mA and a 980 nm pump power of 95 mW. This source is designed by a combined of EDFA and SOA presented in this report. By altering the birefringence of the ring cavity used as a loop mirror and changing the angle of the plates of the polarization controllers, the number of wavelengths produced may be managed. The suggested fiber laser operates at room temperature and has a constant channel spacing of 0.8 nm, making it appropriate for fiber communication and sensing applications

Nonlinear fiber lasers using Bismuth based Erbium doper fiber amplifier / Sharifeh Shahi

A thorough study on Bismuth-based Erbium-doped fiber (Bi-EDF) is presented for wide-band amplifiers and multi-wavelength fiber laser applications. This fiber allows high Erbium ions concentration to be doped without a significant concentration quenching effect. The high refractive index characteristic in the Bi-EDF has broadened the emission spectrum of Erbium ions to achieve a broader gain spectrum up to extended L-band region compared to normal silica-based Erbium-doped fiber (EDF). The Bi-EDFA performances have been investigated in terms of power conversion efficiency (PCE), quantum conversion efficiency (QCE), gain and noise figure. The highest QCE and PCE for a 215 cm long of Bi-EDF are estimated to be approximately 23.7% and 25.7%, which is obtained at 1605 nm. With bi-directional pumping, the maximum gain of 34 dB is obtained at approximately 1570 nm. The operation of the bi-directional Bi-EDFA covers from C-band to the extended L-band regions. Furthermore, various configurations on the multi-wavelength fiber lasers have been proposed and demonstrated using the Bi-EDF as both the linear and nonlinear effects. Nonlinear effects such as the stimulated Brillouin scattering (SBS) and four-wave mixing (FWM) are used in the fiber lasers to generate multi-wavelength comb lines. The Brillouin Erbium fiber laser (BEFL) is able to produce a stable comb with 50 lines at extended L-band region using only a Bi-EDF as the gain medium. The multi-wavelength fiber laser has also been demonstrated for the first time based on a Bi-EDF assisted by a FWM process. The estimation of the nonlinear parameters of Bi-EDF was also proposed based on the FWM effect. With a simple ring cavity, the laser generates more than 10 lines of optical comb with a line spacing of approximately 0.41nm at 1615.5 nm region using 146 mW of 1480 nm pump power

Multi-wavelength Brillouin fiber laser using a holey fiber and a bismuth-oxide based erbium-doped fiber

Multi-wavelength Brillouin fiber laser (BFL) is demonstrated using a holey fiber and a Bismuth-oxide based erbium-doped fiber (Bi-EDF) in a simple ring resonator. The proposed BFL is able to generate up to 13 lines including anti-Stokes with a channel spacing of 0.08 nm at the 1574 nm region. The multi-wavelength BFL is stable at room temperature and also compact due to the use of only a 20 m long of holey fiber and a 215 cm long of Bi-EDF

Multi-wavelength laser generation with Bismuthbased Erbium-doped fiber

A multi-wavelength laser comb is demonstrated using a nonlinear effect in a backward pumped Bismuth-based Erbium-doped fiber (Bi-EDF) for the first time. It uses a ring cavity resonator scheme containing a 215cm long highly nonlinear Bi-EDF, optical isolators, polarisation controller and 10dB output coupler. The laser generates more than 10 lines of optical comb with a line spacing of approximately 0.41nm at 1615.5nm region using 146mW of 1480nm pump power

Bismuth erbium-doped fiber based multi-wavelength laser assisted by four-wave mixing process

We demonstrate for the first time a multi-wavelength laser based on a bismuth-based erbium-doped fiber (Bi-EDF) assisted by a four-wave mixing (FWM) process. Using a simple linear cavity resonator scheme containing a 49 cm long highly nonlinear Bi-EDF, we obtained about 8 lines of optical comb with a line spacing of approximately 0.52 nm at the maximum 1480 nm pump power of 160 mW

PCF-based Multi-wavelength Laser using Four-wave Mixing Effect

A multi- wavelength comb is demonstrated using a four-wave mixing effect in a linear cavity resonator consisting of photonics crystal fiber (PCF) and a bi-directionally pumped Bismuth-based Erbium Doped Fiber (BiEDF). The comb is generated in 1585 nm region with assistance of the pump signal from Tunable Laser Source (TLS) with a line spacing varies from 0.34 to 0.39 nm. A stable output laser comb of 14 lines is obtained using a 80/20 coupler to inject the TLS signal and a total 1480 nm pump power of 270 mW

Multi-wavelength Brillouin fiber laser using Brillouin-Rayleigh scatterings in distributed Raman amplifier

An efficient multi-wavelength Brillouin fiber laser (BFL) is demonstrated by using a self feedback mechanism of Brillouin-Rayleigh scatterings with the presence of distributed Raman gain. The balanced of these three scatterings generates a laser comb more than 27 lines with a relatively flat amplitude and constant spacing of 0.09 nm. This is realised using a piece of dispersion compensating fiber as the nonlinear gain medium, an amplified Brillouin pump and a broad-band fiber Bragg grating as a reflector

Brillouin fiber laser with a 49 cm long Bismuth-based erbium-doped fiber

Brillouin fiber laser (BFL) has been demonstrated using a 49 cm long bismuth-based erbium-doped fiber (Bi-EDF) in conjunction with a 20 m long photonic crystal fiber as gain media with a simple ring resonator. The BFL operates at 1559.09 nm, which is 0.09 nm shifted from the Brillouin pump wavelength. The BFL also has a stable output with a side mode suppression ratio of 12 dB

Compact Brillouin–erbium fiber laser

A single-wavelength Brillouin fiber laser (BFL) is demonstrated at the extended L-band region using bismuth-based erbium-doped fiber (Bi-EDF) for the first time to the best of our knowledge. A 2.15-m-long Bi-EDF is used to provide both nonlinear and linear gains to generate a stimulated Brillouin scattering (SBS) and to amplify the generated SBS, respectively. The BFL operates at 1613.93 nm, which is upshifted by 0.09 nm from the Brillouin pump with a peak power of 2 dBm and a side-mode suppression ratio of more than 22 dB. The generated BFL has a narrow linewidth and many potential applications, such as in optical communication and sensors

Evaluation of the Thermal Processes on Changing the Phenotypic Characteristics of Escherichia coli Strains from Ice Cream Compared to Non-Pasteurized Milk

Escherichia coli (E. coli) is shocked by various temperature processes in milk, which forces the organism to make proteins as a result of changes in the synthesis of enzymes that might give the strain special characteristics. The purpose of this study was to investigate the effects of the heat shock factor on changing the results of biochemical and molecular tests among E. coli strains obtained from ice cream and non-pasteurized milk when compared to a reference strain from the American-type culture collection (ATCC) in order to determine the phenotypic variation caused by the temperature conditions of the manufacturing process. Furthermore, isolates with characteristics similar to E. coli were discovered, but they were not E. coli and caused some ambiguity. To test the E. coli contamination of traditional and industrial ice cream, 82 samples were chosen at random. SDS-PAGE and 16S rDNA sequencing were carried out, as well as phenotypic testing. Isolated strains did not exactly match the reference strain. The results of biochemical testing and protein analysis revealed that the isolates were diverse. Samples E. coli phenons were classified. In the electrophoresis, the ice cream strain had two protein bands in the 20.75 and 23.59 kDa ranges that were distinct from the reference strain. These isolates appear to experience alterations in enzyme characteristics and structural proteins as a result of being exposed to various temperature conditions, such as pasteurization and frigidity. When compared to the reference strain, the calculated similarity percentage of the elicited isolate varied from 60 to 70%. The electrophoretic patterns of E. coli isolated elicited from milk samples differed from E. coli isolated obtained from the ice cream. The distinctions were in the intensity or position of the bands. The results also revealed that when isolates are subjected to thermal stresses, they exhibit a pattern similar to that of ice cream isolates. These considerations are made because a change in protein composition might result in a change in biochemical features, resulting in uncertainty in its identification. Sequences revealed that the sequences were related to E. coli 16S rDNA, despite differences in phenotypic and electrophoretic features between the isolated bacteria and the reference strain E. coli ATCC 25922. Our findings revealed that 16S rDNA could potentially be used to instantly implement an appropriate preventive measure for the purpose of identifying this type of bacteria and avoid some ambiguity