基于周期性矩形压力槽的可调谐长周期光纤光栅_英文_

基于周期性矩形压力槽的可调谐长周期光纤光栅_英文_ 第 38 卷第 6 期光 子 学 报 Vol . 38 No . 6 2009 年 6 月 J une 2009 A C TA P H O TO N ICA S IN ICA Tuna ble Long Period Fiber Gratings Ba sed on Periodic 3Rectangular Pressure Grooves a b aJ IA N G Mi ng2s h u n, F EN G De2j u n, SU I Qi ng2mei ( a. S c hool o f Cont rol S ci ence an d En g i nee ri n g ; b. S c hool o f I n f orm at i on S cie nce a n d En g i nee ri n g , )S h a n d on g U ni ve rs i t y , J i n a n 250061 , Chi na Abstract : Lo ng p erio d fi ber grati ng s were mecha nicall y f a bricat ed t hro ugh p erio dic rect a ngula r p re ssure groo ve s met ho d. The rect a ngula r p e rio dic p re ssure groo ve s were ma de by mecha nical μli ne p roce ssi ng t ec h nolo gy wit h t he groo ve p e rio d of 600m a nd 60 grati ng p e rio ds. The p re ssure a nd t e mp erat ure cha ract eri stic s of t he f a bricat e d L P F G we re st udied wit h diff ere nt p re ssure a nd t e mp e rat ure , re sp ectivel y. The re so na nt wa vele ngt h co ul d be a dj u st ed by tilti ng t he a ngle bet wee n t he fi ber a nd t he groo ve d p lat e . The f a bricat e d L P F G′s ma xi mu m re so na nt p ea k i s up to 15 dB a nd t he ra nge of t una ble re so na nce wavele ngt h e xceed s 12 n m by a dj u sti ng t he a ngle bet wee n fi be r a nd groo ved p lat e . Key words :L P F G ; Perio d rect a ngula r groo ve s ; Re so na nt wavele ngt h ; Ela stic2op tic eff ect () Art icle ID :100424213 2009062139724 CL CN : TN253 Document Code : A t hro ugh co mp ut e r co nt rolli ng i s mat ure no wa day s 0 Introduct ion a nd t he p ro ductio n co st i s quit e lo we r . ( ) Lo ng2p e rio d Fi ber Grati ng s L P F Gs w hic h 1 Princ iple and fa bricat ion co up le li ght f ro m t he co re mo de to diff e re nt cla ddi ng mo de s have bee n wi del y st udie d fo r it s It i s well k no w n t hat L P F G2i nduced mo de wi de app licatio n s i n op tical fi be r co mmunicatio n s co up li ng occ ur s at t he re so na nt wavele ngt h a nd se n so r s , suc h a s ba nd rejectio n filt e r s , sp ect ral de scri be d by equalize r s , op tical swit che s , et c . Thei r succe ss λ( )Λ() 1 = nco - nc1 st e ms f ro m t hei r lo w i n ser tio n lo ss a nd f le xi bilit y Λ w here i s t he grati ng p e rio d , na nd na re t he co c1 [ 1 ] i n filt er shap e de si gn. In ge ne ral , seve ral eff ective i ndice s of t he fi be r co re gui di ng mo de a nd [ 8 ] f a bricatio n met ho d s we re a dop t ed to ma ke L P F Gs , t he cla ddi ng mo de s of t he fi ber , re sp ectivel y. such a s U V bea ms e xpo sure , elect ric a rc The f a bricat ed p erio dic p re ssure groo ve s a re [ 223 ] μwit h p erio d of 600 m , 60 grati ng p e rio ds a nd 36 di scha r ge , a nd CO2 la ser e xpo sure met ho d. mm i n le ngt h . The dep t h of t he groo ve i s 1 mm . Ho wever , t he se met ho ds a re u suall y ti me The se p a ra met e r s a re cho se n i n o r der to let t he co n su mi ng a nd requi re e xp e n sive equip me nt s a nd grati ng′s t u na ble ra nge s a re u sually li mit ed o nce mo de co up li ng bet wee n fi ber co re gui di ng mo de t hey a re ma de . Th u s , it wo ul d be u sef ul to develop a nd cla ddi ng mo de occur wit hi n t he 1 550 nm a no vel alt e r native wa y t hat p ro vide s si mp le a nd ra nge . The e xp e ri me nt al set up i s sc he maticall y i ne xp e n sive L P F Gs. Beca u se t he i nde x mo dulatio n sho w n i n Fi g . 1 . It i s mai nl y co mpo se d of a p erio d i n a L P F G ca n be a s la r ge a s h undred s of rect a ngula r p re ssure groo ved p lat a nd a f lat p lat e . [ 425 ] micro met er s, it i s po ssi ble to i nduce it The p re ssure wa s app lie d o n t he groo ve d p lat e mecha nicall y by p re ssi ng fi ber bet wee n p e rio dic 2drive n de si gne d sp ri ngequall y by a sp ecial [ 627 ] p re ssure groo ve s a nd a f lat p lat e. ( app a rat u s. A ge neral si ngle mo de fi be r Co r ni ng Mecha nical L i ne Proce ssi ng Tech nolo gy ( ) ML P T wa s a dop t ed to f a bricat e t he p e rio dic groo ve s. Thi s t ech nolo gy w hich ca n ma ke t he ( μ)groo ve s ve r y acc urat e p reci sio n wit hi n 10 m 3 Suppo rted by Shando ng Pro vince Nat ural Science ( ) Fo undatio n Z2006 G06 a nd The Excellent Yo ut h Scienti st Awar d Fo undatio n of Sha ndo ng Pro vince () 2006B S01001 Fig. 1 Experimental set up fo r t he mecha nically induced Tel :0531288392231 Email :jiangmi ngshun @to m. co m L P F G a nd dimensio ns of t he groo ved plate Received date :2008203227 μμκ SM F228 , 8 . 3 m co re dia met er , 125 m cla ddi ng i s t he co up li ng co efficie nt a nd L i s t he w here [ 10 ] κ) le ngt h of t he grati ng. The co up li ng coefficie nt dia met er , a nd 0 . 11 nume rical ap e rt ure wit h jac ket i s p laced under t he groo ved p lat e st rai ghtl y . i s p ropo r tio nal to t he a mo unt of i nde x va riatio n The t ra n smi ssio n sp ect r um of t he L P F G i s i nduced by t he mec ha nical p re ssure . Th u s , a s t he ( mo nito red by a n op tical sp ect r um a nal yze r A NDO p re ssure i ncrea se s , t he mo de co up li ng reache s t he ) κπ) ( A Q 6331a nd a co mme rcial gai n f lat t e ned Er bi u m2 ma xi mum at =/ 2 L a nd t he n decrea se s wit h c κκ>, w hic h mea n s t he cla ddi ng mo de co up le s dop ed fi be r a mp lifie r s i s u se d a s t he broa dba nd c back to t he fi ber co re gui di ng mo de . Ce r t ai nl y , li ght so urce . κ κwit h la r ge r p re ssure co r re spo ndi ng to µ , t he c mo 2 Experimental Results and Anal ysis de co up li ng to t he cla ddi ng mo de occ ur s a [ 11 ] 2 . 1 Pressure experiment an d analysis gai n. J u st a s sho w n i n Fi g. 2 , f ro m cur ve P1 to Whe n a p re ssure i s app lie d o n t he groo ve d P7 , t he re so na nt p ea k i ncrea se s wit h t he i ncrea si ng p lat e , t he re will i nduce a p erio dical st rai n i n t he p re ssure a nd t he ma xi mum t una ble ra nge of re so na nt p ea k i s up to 15 dB i n o ur e xp e ri me nt . A s fi ber . Thro ugh t he ela stic2op tic eff ect , t he st rai n t he p re ssure i ncrea se s a bo ve o ne cer t ai n li mit , t he will ca u se p erio dical i nde x c ha nge s bo t h i n t he fi ber [ 12 ] ( o ver co up li ng p he no me no n will occ ur see cur ve co re a nd i n t he cla ddi ng , t h u s fo r mi ng a L P F G ) P8 i n Fi g. 2. eff ect i n t he fi be r co re . The i nf l ue nce of i ncrea si ng 2 . 2 Eff ect ive period a djusting experiment p re ssure i s sho w n i n Fi g . 2 . The p re ssure A n a dva nt a geo u s f eat ure of t hi s device i s t hat gra dually i ncrea se s f ro m Pto P.1 8 o ne ca n a dj u st t he le ngt h of fi be r unde r p re ssure a nd t he grati ng p erio d by cha ngi ng t he a ngle bet wee n t he fi ber a nd t he groo ve s , w hich will mai nl y aff ect t he re so na nt wavele ngt h of t he grati ng. O n t he o t her ha nd , o ne ca n t u ne t he re so na nt p ea k lo ss by a dj u sti ng t he p re ssure . Co n seque nt l y , a wi de ra nge of filt er sp ect ra ca n be ge nerat ed wit h t he sa me groo ve d p lat e a nd fi ber . In e xp eri me nt , t he relative locatio n a s sho w n i n Fig. 3 and transmission spect ra as displayed in Fig. 4. Fig. 2 Mea sured t ra nsmi ssio n spect ra of a L P F G wit h Λμ = 600 m under diff erent p ressure λ The re so na nt wa vele ngt h at w hic h re so na nt [ 9 ]co up li ng occ ur s ca n be w rit t e n a s (δδ) ( λΛ) n- nd/ dco cl re s ()λλ2 1 + ?re s2 ( ) n - nco cl λδw here i s wa vele ngt h , n t he i nitial re so na nt re s co δa nd na re t he avera ge i nde x c ha nge s i n t he co re cl a nd t he cla ddi ng , re sp ectively . Si nce Yo ung′s mo dul u s a nd t he ref ractive i ndice s of t he fi ber co re a nd cla ddi ng a re al mo st equivale nt , t he va riatio n δδbet wee n na nd ni s small , t herefo re , le ss co cl wa vele ngt h shif t s a re o b ser ve d i n t hi s mecha nicall y i nduce d L P F G t ha n t he co nve ntio nal p ho to2 i nduce d. A s ill u st rat ed i n Fi g. 2 , t here a re o nl y le ss t ha n 2 nm wavele ngt h shif t fo r t he i nitial re so na nt p ea k . The ma xi mum t ra n smi ssio n f ro m fi be r co re gui di ng mo de to cla ddi ng mo de s ca n be e xp re sse d a s 2 (κ)()3 T? si nL 6 期 J IA N G Mingshun ,et al : Tunable Lo ng Perio d Fiber Gratings Ba sed o n Perio dic Recta ngular Pressure Groo ves1399 O bvio u sl y , wit h t he a ngle bet wee n t he fi ber a nd t he groo ve s i ncrea si ng , t he eff ective p erio d of L P F G will get lo nge r . Acco r di ng to t he p ha se ) Λλ( mat chi ng co nditio n = n nc1 , t he re so na nt- co wa vele ngt h will i ncrea se . The t una ble re so na nt wa vele ngt h e xcee ds 12 nm wit hi n t he a ngle ra nge of 16?. 2 . 3 Temperature experiment and analysis While t he t e mp erat ure c ha nge s , t he va riet y of Λ t he grati ng p e rio d ca u sed by t her mal e xp a n sio n i s a s follo w s ()ΛαΛ4 d/ d T =? αw here i s t he t he r mal e xp a n sio n coefficie nt . So we ca n get t he diff e re ntial fo r m of equatio n () 1. λ nΛd d nco c1 dd ) Λ( ) ()( - n 5 = -+ nco c1 d T d T d T d T Th u s , t he va riet y of re so na nt wa vele ngt h Λ dep e nds o n t he va riet y of grati ng p erio d ca u se d by t he r mal e xp a n sio n a nd t he va riet y of eff ective ref ractive i nde x ca u se d by p ho to2t her mal eff ect . Acco r di ng to co up le d2mo de t heo r y a nd a bo ve st at e me nt s , we ca n deduce t he t e mp erat ure se n sitivit y of t he re so na nt p ea kA . κ( κ) d A L si n 2L 9 I 9 I ( (ξ ξ ) ) co c1 = - [ +]+9 n 9 nd T co c1 I λ9 I I d ) ( ()- 6 λ λ 9d T w here Ii s t he o ve rlap i nt egral of fi be r co re gui di ng ξmo de s , i s t he p ho to2 mo de a nd t he cla ddi ng co t her mal coefficie nt of fi ber co re f unda me nt al mo de , ξi s t he p ho to2t he r mal co efficie nt of t he cla ddi ng c1 [ 13 ] mo de s. So t he L P F G′s t e mp e rat ure se n sitivit y ξξof re so na nt p ea k d A / d T i s relat e d to I ,,, co c1 t e 3 Concl usions λmp erat ure se n sitivit y of re so na nt wa vele ngt h d/ d T A n efficie nt a nd mecha nicall y2i nduced t u na ble κa nd L . L P F G device wa s f a bricat ed ba se d o n p e rio dic Fi g . 5 sho w s t he mea sured t ra n smi ssio n p re ssure groo ve s t ech nolo gy . Thro ugh sp ect ra fo r L P F G wit h diff ere nt t e mp erat ure . e xp eri me nt s , we ca n co ncl ude t hat t he ma xi mum () Cur ve ai n Fi g. 6 sho w s t he relatio n ship bet wee n t una ble ra nge of re so na nt p ea k i s up to 15 dB , t he t e mp erat ure a nd re so na nt p ea k . The re so na nt p ea k t una ble ra nge of re so na nt wa vele ngt h e xceeds 12 decrea se s gra duall y wit h t he t e mp erat ure nm. Co mp a re d wit h o t her f a bricatio n met ho ds , t he i ncrea si ng , sho wi ng a n app ro xi mat e li nea r L P F G ma de by t hi s t ec h nolo gy i s ea sy to be t une d ( )relatio n . A nd c ur ve b e xp re sse s t he relatio n ship o ver a relative broa d wavele ngt h ra nge a nd t he bet wee n t e mp e rat ure a nd re so na nt wavele ngt h . grati ng i s era sa ble . Wit h suit a ble p acki ng ,it ca n be The re so na nt wa vele ngt h shif t ed to lo nger a n u sef ul la bo rato r y device . wa vele ngt h wit h t he t e mp e rat ure i ncrea si ng , Ref erences sho wi ng a n app ro xi mat e p a ra bola relatio n . All [ 1 ] J IA N G Li , ZHA N G Do ng2sheng , YU A N Shu2zho ng , et al . Co nt rol of L P G′s sp ect ral st r uct ure a nd it s applicatio n i n t he se e xp e ri me nt al re sult s co ul d be e xp lai ne d by ED FA gai n2flat t eni ng equalizer [ J ] . A ct a P hot oni ca S i nica , t he a bo ve t heo retical a nal ysi s qualit ativel y. The ( ) 2004 , 33 7: 8102813 . qua ntit ative co mp a ri so n bet wee n t he t heo r y a nd VON B IB RA M L , ROB ER TS A . Fa bricatio n of lo ng2perio d [ 2 ] e xp eri me nt will be ca r ried o ut i n o ur f ut ure wo r k . op tical fi ber grati ng by use of focused io n2bea m i r radiatio n [J ] . O p t L et t , 2001 , 26 : 7652767 . [ 3 ] RAO Y J , RA N Z L , Z H U T. No vel fi ber2op tic sen so r s ba sed 2dop ed silica2co re fi ber s[J ] . O FC ,1998 : 2792280 . nit ro gen [ 9 ] o n lo ng2p erio d fi ber grati ngs writ t en by hi gh2f requency CO2 C H EN K , S H EN G Q Q ,DO N G X Y. A new met ho d fo r filt er 2 ( ) design ba sed o n lo ng2perio d fi ber grati ng [ J ] . Chi nese P h y sics la ser p ul se s [ J ] . L i g ht w ave T ec g nol o g y , 2003 , 52 6 : 14322 ( ) L et t e rs , 2004 , 21 2: 3322334 . 1437 . SO N G Ni ng , GU O Xiao2ji n , YIN Zo ng2mi n . A nal ysi s a nd WU En2bao , YA N G Ro u2chi ng , SA N Kuo2chi ng. 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Fa bricatio n a nd anal ysi s of lo ng perio d fi ber grati ngs u si ng co upled2mo de [ 12 ] ( ) reso na nce wavelengt h adj ust ment of lo ng p erio d fi ber grati ngs t heo r y [J ] . A ct a Phot onica S i nica ,2002 , 31 10:120521208 . [ C ] . S P I E , 2004 , 5644 : 1722178 . SA V IN S , D I GO N N E T M , KINO G S , et al . Tuna ble [ 7 ] C H EN K , S H EN G Q Q , DO N G X Y. Ba nd rejectio n a nd [ 13 ] mecha niacall y i nduced lo ng2p erio d fi ber grati ngs[ J ] . O p t L et t , ( ) ba nd2p a ss fil t er s ba sed o n mecha nnicall y i nduced lo ng2perio d 2000 , 25 10:7102712 . ( ) fi ber grati ngs[J ] . M ic ro O p t Tec h nol L et t , 2004 , 42 7:1532 KA R POV V I , GR E KOV M V , et al . Mo de2fiel d co nvert er s [ 8 ] 155 . and lo ng2perio d grati ngs f a bricat ed by t her mo diff u sio n i n 基于周期性矩形压力槽的可调谐长周期光纤光栅 a b a姜明顺,冯德军,隋青美 () 山东大学 a . 控制科学与工程学院 ; b. 信息科学与工程学院 ,济南 250100 收稿日期 :2008203227 摘μ 要 :利用机械线加工技术矩形压力槽制作了周期为 600 m ,周期数为 60 的长周期光纤光栅. 实验 研究了所制作长周期光纤光栅的温度和压力特性 ,并通过调整光纤和压力槽之间的角度改变长周期光纤光 栅的谐振波长. 采用此技术制作的长周期光纤光栅最大谐振峰值可达 15 dB ,通过调整光纤与压力槽之间的 角度可使谐振波长变化超过 12 nm . 关键词 :长周期光纤光栅 ; 周期性矩形槽 ;谐振波长 ;弹光效应 J IANG Ming2shun wa s bo r n i n 1981 . He receive d hi s M . S. degree f ro m Sha ndo ng U niver sit y , i n 2007 . No w , he i s p ur sui ng hi s Ph . D . de gree at Sha ndo ng U niver sit y ,a nd hi s re sea rc h i nt ere st s focu s o n op tical fi ber grati ngs a nd p ho to2elect ro nic s.