A. W. Al-Alimi

150-Channel Four Wave Mixing Based Multiwavelength Brillouin-Erbium Doped Fiber Laser

A wide band tunable multiwavelength Brillouin-erbium fiber laser (BEFL) is developed. In this structure, the laser is formed between a double pass amplification box and a highly nonlinear fiber (HNLF), which acts as a virtual mirror, results in removing the reflective physical mirror from one side of the laser structure. A large number of Stokes and anti-Stokes lines are generated through cascading stimulated Brillouin scattering and inducing four wave mixing process inside the HNLF. Due to optimizing Brillouin and erbium doped fiber (EDF) pump powers, the Rayleigh back scattering is efficiently suppressed, and the generated BEFL wavelengths are free from self lasing cavity modes over a wide tuning range. At EDF pump power and Brillouin pump power of 100 mW and 3 dBm, respectively, up to 150 Stokes lines with wavelength spacing of 0.076 nm, and a tuning range of 40 nm were achieved.

Compact Brillouin Fiber Laser Based on Highly Nonlinear Fiber With 51 Double Spacing Channels

A compact multiwavelength Brillouin fiber laser (BFL) with 51 stable double Brillouin frequency shift channels is demonstrated at room temperature. It uses a ring cavity with a 3-dB coupler for separation of odd-ordered and even-ordered Brillouin Stokes (BS) channels using a highly nonlinear fiber (HNLF) as the Brillouin gain medium. Compared with the use of a standard single-mode fiber, the HNLF-based BFL produces higher output power and a higher count of Stokes lines. At the maximum Brillouin pump (BP) power of 16.7 dBm, 36 odd channels and 15 even channels are generated with a channel spacing of 0.15 nm. The output power of the even channels is observed to be always lower than that of the odd channels as they are generated from the previous odd BS.

Stable double spacing multiwavelength Brillouin-Erbium doped fiber laser based on highly nonlinear fiber

A double frequency spaced multiwavelength Brillouin-Erbium doped fiber laser (BEDFL) with figure-of-eight cavity have been successfully developed and tested. Double frequency spacing is achieved by using a piece of 2 km of highly nonlinear fiber (HNLF) as a gain medium. Figure-of-eight configuration removes the odd order Stokes signals via a four-port circulator. Fifteen Stokes channels are simultaneously generated with a spacing of 0.154 nm that is around 20 GHz, when the Brillouin pump and 980 nm pump powers are fixed at the optimized values of 6 dBm and 40 mW, respectively. Fourteen anti stoke channels are also obtained, which are generated through four wave mixing (FWM) process in the laser cavity. The output is smooth triangular comb. The BEFL can also be tuned from 1526.5 to 1567.5 nm.

A stabilized tunable dual wavelength erbium-doped fiber laser with equal output power

Tunable dual-wavelength erbium-doped fiber laser with good stability is experimentally demonstrated. Output power of as high as +5.26 dBm is obtained in dual ring configuration. Both laser output can be tuned to as closed as 0.8 nm spacing between each other, with tuning range of 31.33 nm. The stability of both outputs was tested that results in less than ±0.8 dB and ±0.01 nm in power and wavelength fluctuation, respectively.

Efficient technique for intracavity loss optimization in a dual-wavelength erbium-doped fiber laser

An efficient technique to improve the quality of a tunable dual-wavelength fiber laser is reported. The power of both channels can be equalized with efficient intracavity loss optimization. The maximum power difference between the two wavelengths is less than ±0.37 dB and the output power is approximately flat within C-band.

Enhanced multiwavelength generation in Brillouin fiber laser with pump noise suppression technique

A new multiwavelength Brillouin fiber laser (BFL) that provides a large number of Stokes lines with improved optical signal-to-noise ratio has been proposed and demonstrated. The BFL cavity is only formed by a nonlinear fiber loop mirror (NOLM) with 500 m long highly nonlinear fiber (HNLF). The BFL with improved performance is based on the suppression of the Brillouin pump noise floor utilizing a narrow tunable bandpass filter. The generation of Stokes lines covering up to a 33.67 nm wavelength range is achieved by setting the Brillouin pump signal within the HNLFs zero dispersion wavelength and with power of 250 mW. This is owing to the combination of the stimulated Brillouin scattering and four-wave mixing effect in the NOLM structure.

Wide bandwidth and flat multiwavelength Brillouin-erbium fiber laser

A wide bandwidth and flat multiwavelength Brillouin-erbium fiber laser is demonstrated experimentally. In the proposed laser setup, the combination of a Brillouin mirror with feedback and a ring cavity with four-wave mixing assistance is realized. The efficiency of Brillouin Stokes lines generation is enhanced by the feedback-based Brillouin mirror structure. The effect of four-wave mixing in highly nonlinear fiber increases the generation of Brillouin Stokes lines in a wider bandwidth. The laser lines over 16 nm bandwidth (i.e 200 channels) within 4.65 dB power difference are obtained. The generated laser lines span from 1534 to 1550 nm with wavelength spacing of 0.08 nm and optical signal-to-noise ratio of at least 15 dB. The laser can also be freely tuned over 32 nm and is stable with power fluctuations of 0.7 dB over 1 hour duration.

Highly Nonlinear Fiber-Assisted Multiwavelength Generation in Linear Cavity Thulium-Doped Fiber Laser

We propose a multiwavelength thulium-doped fiber laser in a linear cavity stabilized by a highly nonlinear fiber (HNLF). Stable multiwavelength operation at 2 μm was obtained by introducing a 500-m HNLF within the cavity to alleviate mode competition caused by homogeneous gain broadening of the thulium gain medium. The presence of HNLF-induced spectral broadening through the FWM effect helped to increase the number of output channels, with 22 lasing lines observed within a 10-dB bandwidth and optical signal-to-noise ratio as high as 30 dB. The laser exhibited power fluctuations of less than 1.325 dB with maximum wavelength dithering of 0.12 nm. This work has demonstrated the use of simple HNLF-integrated linear cavity architecture to generate multiwavelength output without complex nonlinear-based structure.

Nonlinear Fiber Loop Mirror Optimization to Enhance the Performance of Multiwavelength Brillouin/Erbium-Doped Fiber Laser

The performance of multiwavelength BEFL based on nonlinear fiber loop mirror (NOLM) optimization has been experimentally investigated. The NOLM is optimized to act as highly reflective mirror, which results in reducing the threshold power and enhancing the number of the generated Stokes lines at low EDF pump power as well. This design presents a low threshold power of 2 mW and generates up to 26 Stokes lines at EDF pump power of 25 mW.

Widely tunable multiwavelength hybrid Brillouin-erbium fiber laser utilizing virtual mirror

Multiwavelength Brillouin erbium fiber laser (BEFL) in a new linear cavity structure have been demonstrated. The BEFL cavity was formed by a double pass amplification box on one side and a virtual mirror installed on the other side. The double pass amplification box reduces the threshold power and enhances Stokes line generation. By utilizing dispersion compensating fiber (DCF) to act as a virtual mirror, the self lasing cavity modes that limits the tuning range of the ordinary BEFL is efficiently eliminated. At Brillouin pump power of 5 dBm and EDF pump power of 90 mW, up to 14 Stokes lines and a wide tuning range of 40 nm, from 1529 nm to 1569 nm, free from the self lasing cavity modes, were obtained.