S. Shahi

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.

Bismuth-based erbium-doped fiber as a gain medium for L-band amplification and Brillouin fiber laser

Bismuth-based erbium-doped fiber (Bi-EDF) is demonstrated as an alternative medium for optical amplification and nonlinear applications. The bismuth glass host provides the opportunity to be doped heavily with erbium ions to allow a compact optical amplifier design. The bismuth-based erbium-doped fiber amplifier (Bi-EDFA) is demonstrated to operate at wavelength region from 1570 to 1620 nm using only a 215 cm long of gain medium. The maximum gain of 15.8 dB is obtained at signal wavelength of 1610 nm with the corresponding noise figure of about 6.3 dB. A multi-wavelength laser comb is also demonstrated using a stimulated Brillouin scattering in the 215 cm long Bi-EDF assisted by the 1480 nm pumping. The laser generates more than 40 lines of optical comb with a line spacing of approximately 0.08 at 1612.5 nm region using 152 mW of 1480 nm pump power.

SOA-based multi-wavelength laser using fiber Bragg gratings

We propose and experimentally demonstrate a triple-wavelength fiber ring laser using a semiconductor optical amplifier (SOA) in conjunction with a series of fiber Bragg gratings (FBGs). The three channels operate at 1554.4, 1555.3, and 1556.1 nm with a peak power above −25 dBm and optical signal-to-noise (OSNR) above 30 dB at SOA drive current of 350 mA under the room temperature. The proposed laser configuration has the advantages of a simple and compact structure, multi-wavelength operation and the system can be upgraded to generate more wavelengths by increasing the number of FBG used.

Comparisons of Multi-Wavelength Oscillations Using Sagnac Loop Mirror and Mach-Zehnder Interferometer for Ytterbium Doped Fiber Lasers

A multiwavelength Ytterbium-doped fiber ring laser operating at 1030 nm region is demonstrated using a Sagnac loop mirror and a Mach-Zehnder interferometer. We report the Performance comparisons of multi-wavelength oscillations in Yb3+ doped fiber lasers (YDFL) with typical commercial ytterbium doped silica fibers. By adjusting the polarization controller (PC), a widely tunable laser range of 22 nm from 1030 nm to 1050 nm is obtained. The Mach-Zehnder interferometer (MZI) design has exhibited simplicity in the operation for controlling the smallest wavelength spacing compared to Sagnac loop mirror method. In our observations, the smallest achieved stable wavelength spacing in Sagnac loop mirror setup and MZI setup were 2.1 nm and 0.7 nm, respectively. In case of nine-wavelength operation with a MZI setup, the stability, Full Width at Half Maximum (FWHM) and side mode suppression ratio (SMSR) of laser lines are not affected by increasing pump power, While for above four wavelength operation, the laser stability with Sagnac loop mirror becomes worse specially for higher input pump power and the power fluctuation among the wave-lengths would be also slightly larger.

BRILLOUIN FIBER LASER WITH SIGNIFICANTLY REDUCED GAIN MEDIUM LENGTH OPERATING IN L- BAND REGION

Brillouin fiber laser (BFL) is demonstrated using a piece of photonic crystal fiber (PCF) in conjunction with a Bismuth-based erbium-doped fiber (Bi-EDF) as the gain media with a simple ring resonator. The proposed BFL operates at wavelength of 1574.08 nm, which is 0.08 nm shifted from the Brillouin pump wavelength with a maximum peak power of 8dBm. The BFL has a side mode suppression ratio and 3dB bandwidth of approximately 23 dB and 0.02 nm respectively limited by the optical spectrum analyzer resolution. The BFL is also stable at room temperature and compact due to the use of only 20 m long of PCF and 215 cm long of Bi-EDF.

Multi-wavelength laser generation with Bismuth-based 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 215 cm long highly nonlinear Bi-EDF, optical isolators, polarisation controller and 10 dB output coupler. The laser generates more than 10 lines of optical comb with a line spacing of approximately 0.41 nm at 1615.5 nm region using 146 mW of 1480 nm pump power.

Compact Bi-EDF-Based Brillouin Erbium Fiber Laser Operating at the 1560-nm Region

A single-frequency Brillouin erbium fiber laser (BEFL) is demonstrated operating at the 1560-nm region using a simple ring resonator with a very short piece of bismuth-based erbium-doped fiber (Bi-EDF) for the first time. A 49-cm-long Bi-EDF is used to provide both nonlinear gain and linear gain to generate a stimulated Brillouin scattering (SBS) and to amplify the generated SBS, respectively. The BEFL operates at 1559.49 nm with a peak power of -4 dBm and a side-mode suppression ratio of 14 dB when the Brillouin pump (BP) and 1480-nm pump powers are fixed at 6 dBm and 144 mW, respectively. The BP wavelength is also tunable within a wavelength range from 1558.8 to 1560.0 nm.

L-BAND AMPLIFICATION AND MULTI-WAVELENGTH LASING WITH BISMUTH-BASED ERBIUM DOPED FIBER

Bismuth-based EDF (Bi-EDF) is comprehensively studied as an alternative medium for optical amplification. The bismuth glass host provides the opportunity to be doped heavily with erbium ions to allow a compact optical amplifier design. The gain spectrum of the Bi- EDF amplifier has a measured amplification bandwidth of 80 nm with a quantum conversion efficiency of 20% obtained using 1480 nm pumping and 215 cm long of doped fiber. A multi-wavelength laser comb is also demonstrated using a four-wave mixing effect in a backward pumped Bi-EDF. The laser generates more than 10 lines of optical comb with a line spacing of approximately 0.41 nm at 1615.5 nm region using 146 mW of 1480 nm pump power.

BRILLOUIN-RAMAN MULTI-WAVELENGTH LASER COMB GENERATION BASED ON Bi-EDF BY USING DUAL-WAVELENGTH IN DISPERSION COMPENSATING FIBER

A multi-wavelength Brillouin fiber laser (BFL) is demonstrated by using dual-wavelength fiber in a 7.7 km dispersion compensating fiber (DCF) that is incorporated in a 49 cm Bismuth erbium-doped fiber laser. The BFL operates in C-band, which is shifted by 0.08 nm and amplified by a Raman pump (RP). The threshold power for BP pumps and the Raman pump is achieved at 7 dBm and around 35 mW, respectively. The exclusive and practical benefits of using reduced high nonlinear Bismuth-erbium doped fiber (Bi-EDF) in implementing a four-wave mixing (FWM) method for multi-wavelengths Brillouin fiber laser (BFL) applications are experimentally demonstrated. Coupled interactions of Brillouin, Raman, and FWM scattering explain the unique feature of proposed configuration.

THE COMPARISON NONLINEARITY BEHAVIORS OF PHOTONIC CRYSTAL FIBER BY TWO REDUCED LENGTHS OF BI-EDF IN RING CAVITY

The nonlinearity effects of photonic crystal fiber (PCF) in a ring resonator for different lengths of Bismuth erbium-doped fiber (Bi-EDF) as the Brillouin gain medium is investigated. Bi-EDF (215 cm) itself has high stimulated Brillouin effect at 150 mW that is generated at 1480 nm pump power. The proposed Brillouin fiber laser (BFL) with PCF operates at 1559 nm for 49 cm Bi-EDF, which is upshifted by 0.08 nm from the Brillouin pump with a side-mode suppression ratio more than 12 dB. As a result of using reduced length of PCF and two long Bi-EDF, the BFL is stable at room temperature and compact in this report.