Four-wave mixing in carbon nanotube-coated optical fiber gratings
Li-Yang Shao, Michael B. Jakubinek, Tingting Sun, Benoit Simard, and Jacques Albert
Citation: Applied Physics Letters 100, 071108 (2012); doi: 10.1063/1.3687170
View online: dx.doi/10.1063/1.3687170
View Table of Contents: scitation.aip/content/aip/journal/apl/100/7?ver=pdfcov
Published by the AIP Publishing
Articles you may be interested in
Carbon nanotube coated fiber Bragg grating for photomechanical optic modulator
Rev. Sci. Instrum. 84, 095101 (2013); 10.1063/1.4819742
CO2 nsing at room temperature using carbon nanotubes coated core fiber Bragg grating
Rev. Sci. Instrum. 84, 065002 (2013); 10.1063/1.4810016
Intermodal four-wave mixing in a higher-order-mode fiber
Appl. Phys. Lett. 101, 161106 (2012); 10.1063/1.4759038
世界100强大学排名Polarization innsitive in-fiber mode-locker bad on carbon nanotube with N-methyl-2-pryrrolidone solvent filled fiber microchamber
Appl. Phys. Lett. 100, 101110 (2012); 10.1063/1.3691922
weeksSingle-walled carbon-nanotube-deposited tapered fiber for four-wave mixing bad wavelength conversion Appl. Phys. Lett. 96, 061104 (2010); 10.1063/1.3304789
Four-wave mixing in carbon nanotube-coated optical fiber gratings Li-Y ang Shao,1,a)Michael B.Jakubinek,2Tingting Sun,1Benoit Simard,2
and Jacques Albert1
1Department of Electronics,Carleton University,1125Colonel By Drive,Ottawa,Ontario,K1S5B6,Canada
2Steacie Institute for Molecular Sciences,National Rearch Council Canada,100Susx Drive,Ottawa,
Ontario K1A0R6,Canada
by no means(Received4November2011;accepted24January2012;published online16February2012)
The obrvation of four-wave mixing(FWM)in single-walled carbon nanotubes(SWCNTs) deposited around a tiltedfiber Bragg grating(TFBG)has been demonstrated.A thin,floating SWCNTfilm is manually wrapped around the outer cladding of thefiber and FWM occurs between two core-guided lar signals by TFBG-induced interaction of the core mode and cladding modes.
The effective nonlinear coefficient is calculated to be1.8Â103WÀ1KmÀ1.The wavelength of generated idlers is tunable with a range of7.8nm.[doi:10.1063/1.3687170]
Single-wall carbon nanotubes(SWCNTs)have drawn considerable interest and rearch activity due to their non-linear properties.1–3Many applications have been reported with SWCNTs as nonlinear optical materials,including pas-sively mode-locked lars,optical noi suppression,and wavelength conversion.4–7In particular,SWCNTs exhibit an extremely high third-order nonlinearity which is believed to be due to interband transitions of p-electrons.4Such effects would be desirable in guided wave configurations and much effort has been made towards devices where SWCNTs inter-act with guided light through evanescentfield coupling, including D-shapedfibers,5taperedfibers,6and cladding-removed planar waveguides.7All the devices require phys-ical modifications of the waveguiding geometry and hence the degradation of their mechanical strength(as well as incread fabrication complexity and cost per device). Recently,our group has reported on the deposition of SWCNT on standard opticalfiber claddings and investigated their ultrafast optical respon using a4 tiltedfiber Bragg grating(TFBG).The TFBG couples the launched light into cladding modes,which interact with the outer SWCNT coat-ing.8Here,we investigate four wave mixing(FWM)in a similar configuration where two core-guided pump waves generate idler waves that are recoupled into the c
ore of the fiber in the forward direction.The wavelength tunability and efficiency of the conversion process are reported for this grating-bad device.
A TFBG is a variant of the normalfiber Bragg grating (FBG)who grating planes are not perpendicular to the fiber axis.This subtle variation allows the TFBG to couple the light from the single core mode to counter-propagating cladding modes.Conquently,the grating transmission respon becomes highly structured with numerous cladding mode resonances in addition to the core mode resonance.9 Figure1demonstrates the working principle of SWCNT-coated TFBG for FWM generation.Two lar sources(k1 and k2)are launched into the TFBG and coupled out to the fiber cladding.The evanescentfields of the two lar waves reach into the SWCNT layer,where they interact with each other and generate two new wavelengths(k FWM1and k FWM2) through the high third-order nonlinearity of the SWCNT layer.Then,the FWM signals are coupled back into thefiber core by the TFBG and appear in the transmission spectrum.
In this experiment,1-cm-long TFBGs with a tilt angle of10 were inscribed in hydrogen-loaded Corning SMF-28fibers using a puld KrF excimer lar and the pha mask technique.For the wrapping deposition technique,afloating SWCNTfilm was prepared as previously described.10 Briefly,2mg of purified SWCNTs were disperd in500ml of2wt.%aqueous sodium cholate solution using sonication.
SWCNTfilms were then produced by vacuumfiltering10ml of suspension through cellulo acetatefilter membranes (Nalgene,47mm diameter,0.22l m pore size).In this ca,a rectangular mask($7mmÂ20mm)was placed beneath the filter membrane to producefilms for wrapping.Immediately afterfiltration,thefilms are detached by submerging thefil-ter membrane in a nanopure water bath.
The transmittance of such afilm,collected on a glass slide,is shown in Figure2.Thefloatingfilms were wrapped around TFBGs by lifting thefilm with the opticalfiber and rotating thefiber to wrap thefilm around the TFBG.After drying,additional SWCNTfilms can be wrapped around the first coating.Following this approach,a TFBG was wrapped with twofilms to provide a thicker coating.The int of Figure2shows a scanning electron microscopy image of the edge of a cleavedfiber wrapped with a similarfilm.The av-erage thickness SWCNTfilm ud in our experiments was measured to be60nm by atomic force
microscopy.
FIG.1.(Color online)Schematic illustration of the FWM process in a SWCNT-coated TFBG.上海国际学校排名2019
a)Author to whom correspondence should be addresd.Electronic mail:
0003-6951/2012/100(7)/071108/3/$30.00100,071108-1
APPLIED PHYSICS LETTERS100,071108(2012)
Figure 3depicts the spectra of a 10 TFBG without/with wrapped SWCNTs.The SWCNT layer attenuates the high order cladding mode resonances (at shorter wavelengths)becau of the high refractive index of SWCNTs and the small linear absorption.The maximum inrtion loss is around 5dB near 1550nm,indicating strong interaction of the guided light with the coating.The experimental tup for FWM in a SWCNT-wrapped TFBG is shown in Figure 4.
Two CW tunable lars (TLS 1and 2;k 1and k 2)rve as a pump and a probe light,respectively,which were com-bined through a 3dB coupler.The combined light is then launched into a high power erbium-doped fiber amplifier (EDFA,Amonics Ltd,HK)followed by two narrow band op-tical filters,a polarization controller (PC),and the SWCNT film-wrapped TFBG.The optical filters were employed to suppress unwanted amplified spontaneous emission (ASE)noi introduced by the EDFA.The polarization of the amplified light was adjusted by the PC to align with the TFBG.The output of the device is measured with an optical spectrum analyzer (OSA,ANDO 6137B using 0.05nm spec-tral resolution).
Figure 5shows the transmitted FWM spectrum through the SWCNT-wrapped TFBG.In the experimen
t,the first lar (k 1)is fixed at 1548.6nm and different FWM wave-lengths are obtained by tuning the other lar wavelength (k 2).The FWM conversion efficiency is defined as the ratio of the FWM signal power to the input pump lar power inside the nonlinear device.Assuming the two input lar wavelengths are clo enough,the FWM conversion effi-ciency g can be approximately expresd by 11
g ¼ðc PL eff Þ2;考研英语复试自我介绍
(1)
where L eff is the effective length of the device (shorter than the physical length of the coated TFBG becau of absorp-tion),c is the effective nonlinear coefficient,and P is the power of each pump (with equal power here).The measured pump power of the tunable lar #2incident on the SWCNT-wrapped TFBG is 160mW.From the grating length and propagation loss induced by the wrapped SWCNTs,L eff is calculated to be 0.87cm.The coupling efficiency of k FWM1is higher than that of k FWM2,which may be caud by the ASE noi.The intensity of k FWM1is higher than that of k FWM2in the ASE spectrum of EDFA,and the optical filter cannot suppress all the ASE noi out of the wanted band.g is meas-ured to be À52dB bad on k FWM2of the FWM spectrum shown in Figu
re 5.From Eq.(1),the effective coefficient of the SWCNTs wrapped TFBG is then calculated to be 1.8Â103W À1Km À1.Finally,the wavelength tunability of FWM spectrum is also investigated.Figure 6shows the rela-tionship between conversion efficiency and the input wave-length detuning of the cond pump against the fixed pump.A 3dB tuning range of around 7.8nm is
obtained.
FIG.2.Vis-NIR spectrum of a rectangular SWCNT film produced under the same conditions as the films ud for TFBG wrapping.The int depicts the SEM image of a cleaved fiber with wrapped
诱惑是什么意思
SWCNTs.
FIG. 3.(Color online)Spectra of a 10 TFBG without/with wrapped
SWCNTs.FIG.4.(Color online)Experimental tup for FWM in a SWCNT-wrapped TFBG (e text for
details).
FIG.5.(Color online)Output FWM spectrum obtained from the SWCNT-wrapped TFBG.
The efficiency obtained is remarkable considering the fact that the SWCNTs are randomly oriented(but mostly tan-gential to the surface of the cladding)and that the generated light from the thin coating must be recoupled back into the core by the grating.Furthermore,the visible and near-infrared reflectance(VIS-NIR)spectrum shows that our SWCNTs have some diameter distribution which lowers the effective nonlinearity.It will be possible to further enhance the effec-tive nonlinear coefficient by adopting CNTs with more pre-cily engineered average tube diameter(1.35nm on average here).
In conclusion,FWM generation of core-guided light in SWCNTs wrapped around the undisturbed cladding of conventional single mode transmissionfiber has been demonstrated.Up to0.2l W of wavelength converted light was produced with two pumps at160mW each,along with a 3dB wavelength tuning range of7.8nm.Further work on improving the grating design and optimizing the thickness, tube diameter distribution and alignment of the SWCNTs on fiber cladding are required to allow the enhancement of FWM efficiency but the preliminary results show the sig-nificance of the TFBG technology in ultrafast wavelength conversion with nonlinear claddings.
This work is supported by the Natural Sciences and En-gineering Rearch Council of Canada,the Canada Founda-tion for Innovation,the Canada Rearch Chairs program(J. Albert),LxDATA,the National Rearch Council Canada, and the National Natural Science Foundation of China under Grant No.61007050.
1S.Tatsuura,M.Furuki,Y.Sato,I.Iwasa,M.Tian,and H.Mitsu,Adv. Mater.15,534(2003).
beamreader
2S.Y.Set,H.Yaguchi,Y.Tanaka,and M.Jablonski,IEEE J.Sel.Top. Quantum Electron.10,137(2004).
3Y.Chen,N.Raravikar,L.Schadler,P.Ajayan,Y.Zhao,T.Lu,G.Wang, and X.Zhang,Appl.Phys.Lett.81,975(2002).
4A.Martinez,K.Zhou,I.Bennion,and S.Yamashita,Opt.Express18, 11008(2010).
5K.K.Chow and S.Yamashita,Opt.Express17,15608(2009).
6K.K.Chow,M.Tsuji,and S.Yamashita,Appl.Phys.Lett.96,061104 (2010).
7K.K.Chow,S.Yamashita,and S.Y.Set,Opt.Lett.35,2070(2010).
amg什么意思
8G.E.Villanueva,M.B.Jakubinek,B.Simard,C.J.Oton,J.Matres,L.-Y. Shao,P.Pe´rez-Milla´n,and J.Albert,Opt.Lett.36,2104(2011).
ayana
9C.-F.Chan,C.Chen,A.Jafari,A.Laronche,D.J.Thomson,and J.Albert, Appl.Opt.46,1142(2007).
10M.B.Jakubinek,M.B.Johnson,M.A.White,J.Guan,and B.Simard,J. Nanosci.Nanotechnol.10,8151(2010).
11G.P.Agrawal,Nonlinear Fiber Optics,3rd ed.(Academic,New York,
企业财务通则2001). FIG.6.FWM efficiency against detuning of one pump relative to the other.
