Multiwavelength Brillouin Erbium-doped Fiber Laser Research Articles

Multi-wavelength Brillouin erbium-doped fiber laser with 40 GHz frequency shift interval assisted by Sagnac loop filter

Multi-wavelength Brillouin erbium-doped fiber laser with 40 GHz frequency shift interval assisted by Sagnac loop filter

Q-switching pulse generation in multi-wavelength Brillouin Erbium-doped Fiber laser

Stimulated Brillouin scattering (SBS) was successfully used to induce Q-switching operation in a multi-wavelength Brillouin Erbium fiber laser (BEFL) operating in a long-wavelength band (L-band) regime. The SBS based self Q-switched laser used a 4.5 long highly nonlinear Erbium-doped fiber (EDF) as the hybrid gain medium to generate a multiple wavelength Q-switched pulses, which operated at the center wavelength of around 1603 nm. By changing the input pump power in a range from 59.1 mW to 162.2 mW, the repetition rate can be varied from 14.29 to 29.69 kHz and the pulse width can be grasped from 26.52 to 14.80 μs. Under 162.2 mW pump power, the maximum pulse energy was recorded at 96.0 nJ and the signal to noise ratio of the fundamental radio frequency was measured to be as high as 52.73 dB, which indicates the excellent stability of the SBS-based Q-switched laser. To the best of our knowledge, this is the first experiment of realizing a BEFL with Q-switched multi-wavelength output without any physical saturable absorber devices.

Flat Multi-Wavelength Brillouin Erbium-Doped Fiber Laser Based on a Sagnac Loop for High-Sensitivity Sensor.

We have demonstrated the use of a flat multi-wavelength Brillouin erbium-doped fiber laser (MWBEFL) based on a Sagnac loop with an unpumped erbium-doped fiber (Un-EDF) as a high-sensitivity sensor. A Sagnac loop with a Un-EDF was used as power equalizer to achieve multi-wavelength power flatness by adjusting the birefringence beat length properly. In the experiments, the best result obtained in terms of Brillouin Stokes lines and output power flatness was ±0.315 dB and the optical signal-to-noise ratio (OSNR) was 18.97 dB within a 33 nm bandwidth range from 1532.0 nm to 1565.0 nm. The flatness of the 33 nm bandwidth range varied from ±0.315 dB to ±1.38 dB and the average OSNR was about 17.51 dB. The peak power values of Brillouin Stokes lines observed under different wavelengths were extremely close and their range of fluctuation was about ±0.37 dB. These experimental results were close to our previous experimental values obtained using a passive Sagnac loop with a Un-EDF. The flat range covering almost the entire C-band has broad application prospects in high-sensitivity distributed optical fiber sensing and wavelength-division multiplexing.

Flat Multi-Wavelength Brillouin Erbium-Doped Fiber Laser Based on a Sagnac Loop with an Unpumped Erbium-Doped Fiber

Flat Multi-Wavelength Brillouin Erbium-Doped Fiber Laser Based on a Sagnac Loop with an Unpumped Erbium-Doped Fiber

Power Fluctuations and Random Lasing in Multiwavelength Brillouin Erbium-Doped Fiber Lasers

We experimentally and theoretically investigate the power fluctuations of the temporal interference signal produced by up to 5 Stokes orders generated by cascaded stimulated Brillouin scattering in a multiwavelength Brillouin erbium-doped fiber laser system with a 2.5-km-long intracavity fiber and erbium-doped fiber amplifier. Power fluctuations in such a system are due to the existence of several modes within the SBS gain bandwidth with the possibility of random hopping resulting in a chaotic temporal evolution of the pump and Stokes-wave powers and consequently the output signal power. Our simulations and statistical analyses show that at the threshold power resulting in the initial Stokes wave generation over round trips, the output signals have the maximum correlation over replicas; however, by increasing the power and producing more stokes waves, the correlation fades out leading to replica symmetry breaking and the system emits in a disordered manner and shows the signatures of a random laser.

Multi-wavelength Brillouin erbium-doped fiber laser sensor with high tunable temperature sensing coefficient

A multi-wavelength Brillouin erbium-doped fiber laser sensor is proposed and investigated experimentally. It is a linear laser cavity multi-wavelength fiber laser, formed by fixing two high-reflectivity Sangac loop mirrors at both ends. We investigate the laser system output characteristics and test the sensor performance for different temperature. Temperature/humidity and reliable linear-cavity fiber laser sensing operation were successfully achieved. Experimental results show that the temperature sensitivity is $$27.15$$ MHz/ °C and the measurement error caused by frequency drift is about $$\pm 0. 2 8 5$$ °C.

Single and Double Brillouin Frequency Spacing Multi-Wavelength Brillouin Erbium Fiber Laser With Micro-Air Gap Cavity

Single and double Brillouin frequency spacing multi-wavelength Brillouin Erbium-doped fiber laser based on micro-air gap cavity is proposed and demonstrated. A 6.90-km dispersion shifted fiber is used as Brillouin gain medium to induce stimulated Brillouin scattering in the ring cavity. The micro-air gap cavity is constructed by aligning two polished fiber facets coaxially, and induces strong Fresnel reflection to switch the Brillouin frequency spacing from a double spacing to single spacing regime. Under the Brillouin pump power of 13 dBm and the laser diode pump power of 300 mW, five Stokes with a wavelength spacing of 0.160 nm and six Stokes with a wavelength spacing of 0.084 nm are generated. The fluctuation of the Stokes for both single and double Brillouin spacing regimes in the proposed setup are less than 3 dB throughout a 1-h time span. The variation of the cavity efficiency between the single and double spacing regimes is less than 1.2 dB.

Dynamics of Stokes Waves and Pulses Generated by Stimulated Brillouin Scattering in a Resonator Including Highly Nonlinear Fiber

We experimentally and theoretically investigate the generation of Stokes waves and the dynamics of pulses produced by cascaded stimulated Brillouin scattering (SBS) in a resonator, including a highly nonlinear fiber (HNLF) and an in-cavity erbium-doped fiber amplifier (EDFA) forming a multi-wavelength Brillouin erbium-doped fiber laser system. Using coupled wave equations with the Brillouin pump, Stokes and acoustic waves, propagation in the presence of the SBS and optical Kerr effect, the modeled system simulates the evolution of participating pump and Stokes waves to verify the experimental results. The dependence of the number of generated Stokes waves on EDFA pump and Brillouin pump powers is studied showing that the proper simultaneous change (increase or decrease) of the two pump powers over few hundred of milliwatts (using the power design diagram) results in generating the same number of Stokes waves reaching steady state. Dynamics of the interference signal at the resonator output are also presented for a long HNLF (33 m) showing strong instability due to the existence of a few longitudinal modes within the SBS gain bandwidth with the possibility of random mode hopping. For a short HNLF (3 m), a single longitudinal mode operation is possible and the stability of generated pulses is expected but still depends on the phase relationships per round trip of the participating pump and Stokes waves. A good consistency between simulation and experiment is found.

A novel double-Brillouin-frequency spaced multi-wavelength Brillouin erbium-doped fiber laser based on non-linear amplified fiber loop mirror

In the paper, a ring double-Brillouin-frequency spaced multi-wavelength Brillouin erbium-doped fiber laser based on non-linear amplified fiber loop mirror filter is demonstrated, in which the non-linear amplified fiber loop mirror (AFLMF) is used as a filter. At the 980nm pump power of 10.29dBm, the tunable laser source center wavelength of 1563nm and power of −3dBm, up to 12 even output channels with 0.16nm spacing are achieved. At the same time, we study the influence of 980nm pump power, the polarization controller and the tunable laser source center wavelength on the number of Stokes light wave.

Experimental and numerical study of high order Stokes lines in Brillouin-erbium fiber laser

We experimentally study the dependences of high-order Stokes lines on the erbium-doped fiber (EDF) pump power PEDF, the Brillouin pump (BP) power PBP, and its working wavelength in a multiwavelength Brillouin erbium-doped fiber laser (MBEFL). By using the rate and propagation equations, and the coupled wave equations of stimulated Brillouin scattering, we establish a lumped model to describe the MBEFL. Numerical simulations show that the number of Stokes lines can be increased by decreasing the spacing between the BP wavelength and the EDF peak gain or PBP as long as it is larger than a critical value PBP(cr)=1.7 mW, or by increasing PEDF without reaching a saturation value PEDF(cr)=250 mW. However, when PBP and PEDF are varied beyond PBP(cr) and PEDF(cr), respectively, the number of Stokes lines is reduced, accompanied by some self-lasing cavity modes. These results by numerical simulation are consistent with experimental observations from the MBEFL.

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.

Simple multiwavelength Brillouin–Erbium-doped fiber laser structure based on short SSMF

An efficient multiwavelength Brillouin–Erbium fiber laser (BEFL) was developed by improving the feedback mechanism of Brillouin Stokes lines. The BEFL performance in terms of threshold power and wavelengths count was improved by using a new structure of double pass amplification cavity. The new structure utilized the variable optical coupler (VOA) not only as the input and output ports but also to form a fiber loop mirror that reduces the number of optical components, thus, only three optical components were needed. By optimizing the Brillouin and 1480nm pump power, up to 41 channels and 26 channels were obtained using 0.6km and 0.3km long of standard single mode fiber (SSMF), respectively.

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.

四波混频增强多波长布里渊掺铒光纤激光器的实验研究

四波混频增强多波长布里渊掺铒光纤激光器的实验研究

四波混频增强多波长布里渊掺铒光纤激光器的实验研究

四波混频增强多波长布里渊掺铒光纤激光器的实验研究

Enhancement of Brillouin stokes powers in multiwavelength fiber laser utilizing band‐pass filter

AbstractWe report an increased number of stokes when used with a band‐pass filter in multiwavelength Brillouin erbium‐doped fiber laser (BEFL). A total of 15 Stokes were achieved as compared with seven in a system without the band‐pass filter. The efficiency of generating Brillouin Stokes improved due to the suppression of out‐of‐band amplified spontaneous emission in the BEFL. The band‐pass filter provides a specific range of lasing window that coincide with the Brillouin pump signal. The flatness of the Brillouin stokes is also improved in the proposed design. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 408–410, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11395