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.

Replacement of Forage Fiber Sources with Dried Distillers Grains with Solubles and Corn Germ Meal in Holstein Calf Diets

This study was carried out to determine the effect of replacement of forage fiber sources from alfalfa and Leymus chinensis with nonforage fiber sources（NFFS） from dried distillers grains with solubles and corn germ meal on calves growth, rumen development and blood parameters. 48 female and 12 male calves（（110.55±15.36） kg of body weight and 12 wk of age） were assigned randomly to four dietary treatments（15 calves/treatment） in a completely randomized design. Experimental diets were： 0% NFFS（control）, 9% NFFS（group 1）, 18% NFFS（group 2）, 27% NFFS（group 3）, and contained equivalent neutral detergent fiber and total digestible nutrients, respectively. The dry matter intake was similar among diets, averaging 3.33 kg d-1, and no differences were detected for body weight, withers height, body length and heart girth. In addition, the development of rumen, reticulum, omasum and abomasum also were similar among diets. Dry matter, crude protein, and neutral detergent fiber digestibilities increased with the increasing levels of NFFS in the experimental diets, but had no significant effect. Blood urea nitrogen, total protein and glubulin were not affected by the dietary treatment, but group 3 resulted in the highest（P〈0.05） concentrations of glucose and the lowest（P〈0.05） concentrations of triglycerides and albumin. In conclusion, dried distillers grains with solubles（DDGS） and corn germ meal（CGM） were available and alternative fiber sources for Holstein calf diets.

Radiation-induced attenuation self-compensating effect in super-fluorescent fiber source

The compact super-fluorescent fiber source （SFS） output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced attenuation （RIA） self-compensating effect in SFS based on photo-bleaching was found and the general mathematic model of SFS output spectra variations was made. The radiation-induced background attenuation （RIBA） at the pump wavelength was identified to be the main cause of the total output power and spectra variations and the variations can then be compensated by active control of the pump power to enhance the self-compensating effect. With closed-loop feedback control of pump current, double-pass backward （DPB） configuration and spectrum re-shaping technology, an SFS prototype was made and tested. The mean-wavelength stability of about 87.4 ppm and output power instability of less than 5% were achieved under up to 200 krad （Si） gamma-ray irradiation.

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.

Theoretical study on erbium ytterbium co-doped super-fluorescent fiber source

Erbium ytterbium co-doped super-fluorescent fiber source （EYD-SFS） has been simulated by a theoret- ical model based on rate equations and power transfer equations. The output performances of four basic structures of EYD-SFS have been expressed, and it indicated that the DPF structure is a preferable structure. The dependence of output power, mean wavelength and bandwidth stability on the pump fiber length and the concentration of Er3＋ and Yb3＋ have also been studied. The results indicated with a proper doping concentration of Er3＋ and Yb3＋ of 6.0 × 10^26 ions/m3 and 1.0 × 10^27 ions/m3, the optimal gain fiber length is 3.6 cm. In this condition, good performances of DPF structure of EYD-SFS have been achieved.

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.

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...

Experimental optimization of an erbium-doped super-fluorescent fiber source for fiber optic gyroscopes

Double-pass forward and double-pass backward erbium-doped super-fluorescent fiber sources（EDSFSs） were combined in one configuration.A 980 nm laser diode pumped the same erbium-doped fiber from both directions using a coupler as a power splitter.The double-pass configuration was achieved by coating the fiber end face.Firstly,an optimal fiber length was found to obtain a high stability of output light wavelength with pump power, and then 1530/1550 nm wavelength division multiplexing was used for spectrum planarization,which expanded the bandwidth to more than 22 nm.The final step was a test of temperature stability.The results show that the rate of the central wavelength change kept to below 3.5 ppm/℃in the range of -40 to 60℃and 1-2 ppm/℃in the range of 20-30℃.Considering all the three factors of the fiber optic gyro applications,we selected 80 mA as the pump current,in which case the central wavelength temperature instability was calculated as 2.70 ppm/℃, 3 dB bandwidth 22.85 nm,spectral flatness 0.2 dB,output power 5.17 mW and power efficiency up to 9.92%.This experimental result has a significant reference value to the selection of devices and proper design of ED-SFSs for the application of high-precision fiber optic gyroscopes.

A Temperature-Insensitive Amplified Spontaneous Emission Broadband Source Based on Er-Doped Fiber

To obtain a stable amplified spontaneous emission（ASE） source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperatures.We optimize the structure of the ASE source to flatten the ASE spectrum, and study the output characteristics in terms of output power and optical spectrum under different pump powers. Then the performance of the ASE source is investigated in the temperature range from-18.9°C to 50°C. A stable-power and flat-spectrum ASE source can be obtained by structural optimization and pump control.

Three dimensional photovoltaic fibers for wearable energy harvesting and conversion

As the development of smart electronics, self-powered sources have been attracting increasing attention.This review summarizes research progress of photovoltaic fibers and their integrated power sources with multi-stage energy conversion. Recent development of three dimensional photovoltaic fibers is glanced with special attention to structure design and materials of typical photovoltaic types（inorganic, organic,dye/quantum dot sensitized and perovskite solar cells）. The application of carbon materials in fiber energy is focused as it is a hot topic recently. The hybrid energy systems based on fiber solar cells and fiber supercapacitors, fiber batteries and fiber nanogenerators are summarized together with hybrid energy textiles. This review provides a macroscopic view of novel energy fibers and will attract research interest in flexible/wearable fiber electronics and energy textiles.

Impact of sugar beet pulp and wheat bran on serum biochemical profile,inflammatory responses and gut microbiota in sows during late gestation and lactation

Background:Sows are frequently subjected to various stresses during late gestation and lactation,which trigger inflammatory response and metabolic disorders.Dietary fiber can influence animal health by modulating gut microbiota and their by-products,with the effects depending upon the source of the dietary fiber.This study aimed to evaluate the impacts of different fiber sources on body condition,serum biochemical parameters,inflammatory responses and fecal microbiota in sows from late gestation to lactation.Methods:Forty-five multiparous sows(Yorkshire×Landrace;3–6 parity)were assigned to 1 of 3 dietary treatments from d 85 of gestation to the end of lactation(d 21 post-farrowing):a control diet(CON,a corn-soybean meal diet),a sugar beet pulp diet(SBP,20%SBP during gestation and 10%SBP during lactation),and a wheat bran diet(WB,30%WB during gestation and 15%WB during lactation).Results:Compared with CON,supplementation of SBP decreased(P<0.05)lactation BW loss,reduced(P<0.05)serum concentration of total cholesterol,non-esterified fatty acids,interleukin-6 and tumor necrosis factor-α,and increased(P<0.05)fecal water content on d 110 of gestation and d 21 of lactation,while supplementation of WB reduced(P<0.05)serum concentration of total cholesterol on d 110 of gestation,increased(P<0.05)fecal water content and decreased(P<0.05)serum interleukin-6 concentration on d 110 of gestation and d 21 of lactation.In addition,sows fed SBP had lower(P<0.01)abundance of Clostridium_sensu_stricto_1 and Terrisporobacter than those fed CON,but had greater(P<0.05)abundance of Christensenellaceae_R-7_group and Ruminococcaceae_UCG-002 than those fed the other two diets on d 110 of gestation.On d 21 of lactation,supplementation of SBP decreased(P<0.05)the abundance of Firmicutes and Lactobacillus,but enriched(P<0.05)the abundance of Christensenellaceae_R-7_group,Prevotellaceae_NK3B31_group,Ruminococcaceae_UCG-002,Prevotellaceae_UCG_001 and unclassified_f__Lachnospiraceae compared with WB.Compared with CON,sows fed SBP had greater(P<0.05)fecal concentrations of acetate,butyrate and total SCFAs during gestation and lactation,while sows fed WB only had greater(P<0.05)fecal concentration of butyrate during lactation.Conclusions:Supplementation of dietary fiber during late gestation and lactation could improve sow metabolism and gut health,and SBP was more effective than WB.

Source of fiber influences growth,immune responses,gut barrier function and microbiota in weaned piglets fed antibiotic-free diets

This study examined the impacts of different fiber sources on growth,immune status and gut health in weaned piglets fed antibiotic-free diets.Sixty piglets(BW=8.18±1.35 kg)were assigned to 3 dietary treatments based on BW and gender in a randomized complete block design(5 replicates/treatment and 4 piglets[2 barrows and 2 gilts]/replicate):(1)an antibiotic-free diet(control,CON);(2)CON+6%wheat bran(WB);(3)CON+4%sugar beet pulp(SBP).Dietary WB supplementation tended to increase ADG compared with CON from d 1 to 14(P-0.051)and from d 1 to 28(P-0.099).Supplementation of WB increased(P<0.05)G∶F compared with CON and SBP from d 1 to 14 and from d 1 to 28.Compared with CON,the addition of WB reduced(P<0.05)diarrhea rate from d 1 to 14 and tended(P=0.054)to reduce diarrhea rate from d 1 to 28.The addition of WB decreased(P<0.05)serum diamine oxidase activity on d 14,and up-regulated(P<0.05)ileal mRNA levels of occludin on d 28 when compared with CON.Piglets fed WB showed decreased(P<0.05)serum interleukin-6 levels compared to those fed SBP and decreased(P<0.05)ileal interleukin-8 levels compared to those fed CON and SBP on d 28.Supple-mentation of WB increased(P<0.05)serum levels of immunoglobulin A(IgA),IgG and IgM compared with SBP on d 14,and increased(P<0.05)the levels of serum IgA and ileal sIgA compared with CON and SBP on d 28.Piglets fed WB showed an enhanced(P<0.05)α-diversity of cecal microbiota than those fed SBP,while piglets fed SBP showed reduced(P<0.05)α-diversity of cecal microbiota than those fed CON.Compared with CON,the addition of WB elevated(P<0.05)the abundance of Lachnospira and cecal butyric acid level.Piglets fed WB also showed increased(P<0.05)abundances of Lachnospira and unclassified_f_Lachnospiraceae compared with those fed SBP.Collectively,the supplementation of WB to antibiotic-free diets improved performance,immune responses,gut barrier function and microbiota compared with the CON and SBP fed piglets.Therefore,supplementing weaned piglets with WB was more effective than SBP.