All-fiber Superfluorescent Source Research Articles

Mid-infrared all-fiber superfluorescent source in Er3+-doped fluoride fiber

We report, to the best of our knowledge, the first mid-infrared (MIR) all-fiber superfluorescent source based on a superfluorescent seed and a single-stage amplifier. A 7.8-m-long section of highly-Er3+-doped fluoride fiber is used in the superfluorescent seed and a 4.3-m-long section of lightly-Er3+-doped fluoride fiber acts as the amplifier. Two home-made MIR pump-signal combiners based on side-pumping technology are fabricated directly on two sections of gain fiber. By direct-low-loss fusion splicing of two kinds gain fiber, the power of MIR superfluoresescence main output is amplified to 0.35 W and the power of rear output is amplified to 0.2 W. The output spectrum under maximum power spans from 2680 nm to 2880 nm with 20 dB bandwidth of 60 nm. The measured time domain and output beam profile show that this superfluorescent source keeps relatively stable in microsecond time scale without self-pulsing effect occurrence and has near single-mode gaussian characteristic. This works provides a new way for MIR superfluorescent source, which is of practical interest in a range of applications.

Mid-infrared side-pumping combiner and all-fiber superfluorescent fiber source (invited)

Mid-infrared side-pumping combiner and all-fiber superfluorescent fiber source (invited)

1.08 kW Narrowband All-Fiber Super-Fluorescent Source with Spectral-Broadening-Free Property

1.08 kW Narrowband All-Fiber Super-Fluorescent Source with Spectral-Broadening-Free Property

Optimization investigation for high-power 1034 nm all-fiber narrowband Yb-doped superfluorescent source

An optimization for all-fiber narrowband Yb-doped superfluorescent source with a central wavelength shorter than 1040 nm is conducted theoretically and then verified experimentally using steady-state rate equations. Theoretical investigation indicates that with the increase in fiber length, signal power presents one peak value, but the ratio of signal power to output power is decreasing monotonously. Moreover, a filter with high extinction ratio and a gain fiber with high absorption coefficient can have gain suppression on a long wavelength. One all-fiber superfluorescent source is built experimentally on the basis of the theoretically optimized parameters. The source achieves an output power of 214.64 W with a central wavelength of 1034.18 nm and signal–noise ratio of 30 dB. The output power of the source can have further power scaling with considerable available pump power.

Study on the power scalability of all-fiber superfluorescent source operating near 980 nm.

The high-power all-fiber superfluorescent source operating near 980 nm is studied experimentally and numerically. In experiment, an all-fiber superfluorescent source operating near 980 nm is fabricated with the distributed side-coupled cladding-pumping (DSCCP) Yb-doped fiber (YDF). By optimizing the active fiber and angle-cleaving of the output port, a recorded 17.1-W output power and 14.6% slope efficiency of 980-nm ASE are obtained. No parasitic laser oscillation is observed at the maximum output power. The power scalability of the source is also numerically investigated. A simple but effective method is present to numerically determine the threshold of parasitic laser oscillation. It is found that the output power can be scaled up to 50 W and 100 W with the optical feedback of each output port suppressed to 1.2 × 10-6 and 7 × 10-7, respectively. It is also revealed that coupling coefficient should be larger than 6 to realize more than 50% slope efficiency. These results provide significant guidance for understanding and designing the high-power superfluorescent Yb-doped source (SYFS) operating near 980 nm and other sorts of three-level fiber sources.

Experimental study on high-power all-fiber superfluorescent source operating near 980 nm

A high-power all-fiber superfluorescent source operating near 980 nm is experimentally studied with the help of a large-core distributed side-coupled cladding-pumped Yb-doped fiber. By optimizing the active fiber length and the angle cleaving of the output fiber facet, a 10 W all-fiber superfluorescent source operating near 980 nm is demonstrated for the first time, to the best of our knowledge. An 11.4 W combined 980 nm ASE power is obtained with a 9.3% slope efficiency and an 18 dB suppression of the ASE around 1030 nm. The output spectrum spans 973 nm to 982 nm with the 3 dB bandwidth around 3.5 nm. A 10.5 W output power with 13.1% slope efficiency is also obtained by changing the length of the active fiber. The variations of the output power and spectrum with the active fiber length and pump power are also investigated in the experiment.

Demonstration of multi-Watt all-fiber superfluorescent source operating near 980 nm* *Project supported by the National Natural Science Foundation of China (Grant No. 61405249).

The superfluorescent Yb-doped fiber source operating near 980 nm is studied. The design requirement is theoretically discussed aiming to suppress the amplified spontaneous emission around 1030 nm in the 980-nm superfluorescent fiber source. Based on the theoretical study, a multi-Watt, all-fiber, bi-directional, pumped, superfluorescent source operating near 980 nm is designed and experimentally demonstrated for the first time, to the best of our knowledge. The recorded 8.38-W combined output power is obtained with a 3-dB bandwidth about 3.5 nm. The power scaling of the 980-nm superfluorescent fiber source is limited by the parasitic laser oscillation.

基于高功率窄线宽掺镱全光纤超荧光源的光谱合束

基于高功率窄线宽掺镱全光纤超荧光源的光谱合束

Power scaling of narrowband high-power all-fiber superfluorescent fiber source to 1.87 kW.

We demonstrate a high-power narrowband all-fiber superfluorescent fiber source employing three-stages master oscillator power-amplifier chain. Narrowband seed light is selected from a broadband-amplified spontaneous-emission source by a spectrum filter combing with fiber circulator and fiber Bragg grating. In the main amplifier, the maximal output power is 1.87 kW with an optical-to-optical conversion efficiency of 77.4% and a full width at half-maximum (FWHM) linewidth of 1.7 nm. The corresponding power fluctuation is ±1.4% in 100 s operation, and no parasitic oscillation or self pulsation is observed. A beam quality of M(2)=1.71 is measured at 1.4 kW output power. This manuscript investigates the spectral evolution in high-power amplification. The central wavelength shifted from 1079.5 nm to 1080.7 nm, and the FWHM linewidth narrowed from 2 nm to 1.7 nm at full power, respectively. These effects could be inferred as hybrid effects of many factors, such as wavelength shifting of pump LD, nonoptimized length of gain fiber, and enhancement of temperature level of gain fiber. The narrowband-maintained characteristic in spectral domain under high-power amplification is significant for applications such as spectral beam combination, and further power scaling is available as the output power is only limited by the pump power.

High-Power Thulium-Doped All-Fiber Superfluorescent Source With Ultranarrow Linewidth

The narrow-band superfluorescent source is a promising optical source in various fields. We constructed a novel scheme for the narrow-band all-fiber thulium-doped superfluorescent source and demonstrated the power scaling based on multistage amplifiers. A stable narrow-band thulium-doped all-fiber superfluorescent seed source, a three-stage preamplifier, and a main amplifier were adopted. The maximum output power reached 228 W with the slope efficiency of 50%. The full-width at half-maximum (FWHM) was 0.19 nm, and the center wavelength was 1968.1 nm. To the best of our knowledge, this is the highest power of the narrow-band thulium-doped all-fiber superfluorescent source at 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$\mu$</tex-math></inline-formula> m, which is only limited by available pump power for the time being.

1.5 kW 近衍射极限全光纤窄带超荧光光源

1.5 kW 近衍射极限全光纤窄带超荧光光源

High-power all-fiber superfluorescent source with fused angle-polished side-pumping configuration

We report high-power operation of a broadband superfluorescent source with an all-fiber configuration. The superfluorescent source yields an amplified spontaneous emission (ASE) output of 43.2 and 25.1 W from both ends, respectively. The maximum combined ASE output is 68.3 W with a slope efficiency of 78.6%. The wavelength bandwidths (FWHM) of the counterpropagating and copropagating ASE output are 31.5 and 18.9 nm, respectively. The fused angle-polished side-pumping coupler is applied to set up the all-fiber configuration. Furthermore, the influence of reflectivity on the laser threshold of the ASE sources is studied theoretically. The experimental results agree with the theoretical analysis.

High-stability Er/sup 3+/-doped superfluorescent fiber sources

Data are presented on Er/sup 3+/-doped superfluorescent fiber sources showing the dependence of output characteristics on pump wavelength and power, fiber length, fiber temperature, and feedback. In particular, the broadband operation and mean wavelength stability required for fiber optic gyroscope applications are evaluated. Substantial improvements in the mean wavelength stability with pump power have been achieved by optimizing the fiber length. An all-fiber superfluorescent fiber source utilizing a fiber-pigtailed 980-nm diode pump laser is demonstrated, with a 1-h mean wavelength stability better than 0.9 ppm RMS and /spl les/8 ppm drift over 20 h. The intrinsic mean wavelength variation versus fiber temperature is measured, with values of 4.8 and 3.0 ppm//spl deg/PC obtained for fiber lengths of 23 and 78 m, respectively. >