Experimental Research on Erbium-doped Superfluorescent Fiber Source

The effects of the variations in fiber length,fiber mirror reflectance on efficiency and output power are experimentally investigated for erbium-doped double pass backward superfluorescent fiber sources (SFSs).The influence of fiber length on mean wavelength stability (MWS) has also been demonstrated.By incorporating a short section of un-pumped erbium-doped fiber (EDF) at the output port,the pump power dependent on MWS becomes independent of pumped EDF length.This is a novel phenomenon that hasn’t been reported up to now,and should be helpful to SFS fabrication and theory analysis.By using a fiber Michelson interferometer as spectrum slicing component,a multi-wavelength fiber source (MWFS) with ～20 channels (from 1 542 nm to 1 559 nm) is got.The MWFS has a channel spacing of ～0.8 nm which satisfies ITU-standard.The intensity fluctuation among channels is less than 0.5 dB,and the extinction ratio of all channels is above 14 dB.This kind of MWFS should be useful to wavelength division multiplexing systems.

Numerical Simulation on Broad-band Er-doped Superfluorescent Fiber Source Filter Using Long Period Chirped Fiber Grating

Given is an analysis of broad-band Er-doped superfluorescent fiber source(EDSFS)filter using long period chirped fiber grating by transmission matrix method.For our EDSFS attenuated amplitude demand and the flattened wavelength range demand,proposed are the key factors of designing such filters of high performances.The simulation result demonstrates that such type filters have an enough attenuation to flatten the dramatic increase in output amplified spontaneous emission(ASE)in the wavelength range of 1529nm^1535nm by choosing conformable fiber filter parameters such as chirped degree,original period,induced index change,length of the fiber filter,and then broad-band EDSFS could be achieved.

Experimental investigation of the stimulated Raman scattering effect in high-power nanosecond superfluorescent fiber source

In this work,we experimentally investigate the dependence of the stimulated Raman scattering(SRS)effect on the seed linewidth of a high-power nanosecond superfluorescent fiber source(ns-SFS).The results reveal that the SRS in the ns-SFS amplifier is significantly influenced by the full width at half maximum(FWHM)of the ns-SFS seed,and there is an optimal FWHM linewidth of 2 nm to achieve the lowest SRS in our case.The first-order SRS power ratio increases rapidly when the seed’s linewidth deviates from the optimal FWHM linewidth.By power scaling the ns-SFS seed with the optimal FWHM linewidth,a narrowband all-fiberized ns-SFS amplifier is achieved with a maximum average power of 602 W,pulse energy of 24.1 mJ and corresponding peak power of 422.5 kW.This is the highest average power and pulse energy achieved for all-fiberized ns-SFS amplifiers to the best of our knowledge.

In-band pumping avenue based high power superfluorescent fiber source with record power and near-diffraction-limited beam quality

High power superfluorescent fiber sources(SFSs), which could find wide applications in many fields such as middle infrared laser generation, Raman fiber laser pumping and spectral beam combination, have experienced a flourishing time in recent years for its unique properties, such as short coherence length and high temporal stability. The challenge for performance scalability of powerful SFS mainly lies on the physical issues including parasitic laser oscillation and modal instability(MI). In this contribution, by employing in-band pumping avenue and high-order transverse-mode management, we explore a high power SFS with record power, near-diffraction-limited beam quality and spectral manipulation flexibility. An ultimate output power of 3.14 kW can be obtained with high temporal stability and a beam quality of M^2= 1.59 for the amplified light. Furthermore, the dynamics of spectral evolutions, including redshifting of central wavelength and unsymmetrical broadening in spectral wings, of the main amplifier with different seed linewidths are investigated contrastively. Benefiting from the unique high pump brightness and high MI threshold of in-band pumping scheme, the demonstrated system also manifests promising performance scaling potential.

2-kW-level superfluorescent fiber source with flexible wavelength and linewidth tunable characteristics

The superfluorescent fiber source(SFS)with tunable optical spectrum has shown great application potential in the sensing,imaging,and spectral combination.Here,we demonstrate for the first time a 2-kW-level wavelength and linewidth tunable SFS.Based on a flexible filtered SFS seed and three stages of fiber amplifiers,the output power can be scaled from the milliwatt level to about 2 kW,with a wavelength tuning range of 1068–1092 nm and a linewidth tuning range of 2.5–9.7 nm.Moreover,a numerical simulation is conducted based on the generalized nonlinear Schr?dinger equation,and the results reveal that the wavelength tuning range is limited by the decrease of seed power and the growth of amplified spontaneous emission,whereas the linewidth tuning range is determined by the gain competition and nonlinear Kerr effects.The developed wavelength and linewidth tunable SFS may be applied to scientific research and industrial processing.

High Stability Multi-Wavelength Source by Using Synchronized Etalon Filter in Superfluorescent Fiber Source

We demonstrate a new technique to generate a high stability multi-wavelength fiber source by inserting a synchronized etalon filter in superfluorescent fiber source. Multi-wavelength source can easily be obtained over the EDF gain region with the proposed schedule. By partially feedback diffracted spontaneous emission into erbium doped fiber medium, greater output power, extinction ration and narrower linewidth for each channel than that simply using the spectrum slicing technique is easy obtained. Stab...

Demonstration of multi-Watt all-fiber superfluorescent source operating near 980 nm

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-rim 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 superlfuorescent fiber source is limited by the parasitic laser oscillation.