Transmission of high power sensor system and DWDM data system in one optical fiber

T ansmission o High Powe Senso Sys em and DWDM Da a Sys em in One Op ical Fibe Milan Cucka, Pe Muns e , Lukas Koci, Tomas Ho a h, Milosla Filka, and Jose Voj ech Abs ac —This a icle deals wi h he possibili y o employing phase sensi i e OTDR (Op ical Time Domain Re lec ome y) in o ibe s wi h ac i e da a ansmission DWDM (Dense Wa eleng h Di ision Mul iplex). Due o he low backsca e ed signal o phase sensi i e OTDR is equi ed o gene a e pulses wi h a high in en- si y and sho ime du a ion. These high powe pulses can cause deg ada ion o he da a ansmission. By using VPIpho onics so wa e we pe o med he simula ions in es iga ing he in luence o phase sensi i e OTDR o quali y DWDM connec ions and we a e also in e es ed in he wa eleng h spacing be ween senso ic sys em and da a sys em. In ou a icle i was e i ied ha phase sensi i e OTDR and da a ansmission can be ac i e oge he in one op ical ibe . I bo h sys ems wo k e y close o each o he i will lead o deg ada ion o da a ansmission. We ha e e i ied ha da a ansmission may be a ec ed i powe o pulses exceed 13 dBm. Index Te ms—DWDM, Phi-OTDR, Pulse gene a ion, Backsca - e ed signal, Simula ions, VPIpho onics. I. INTRODUCTION Nowadays op ical senso s a e used hanks o hei abili ies o sense high empe a u es, ib a ions and mechanical ension. One big ad an age is accu acy o measu emen and compac po able ins umen packages. Fo example, ib a ion senso s a e pu on al eady exis ing ou es and a e used o ack any mo emen a ound he ou e. Ano he commonly used ype o op ical senso s a e senso s o empe a u e sensing due o hei abili y o measu e high empe a u es. These ypes o senso s can o e noncon ac measu emen . Op ical senso s can be di ided in o wo g oups. The i s g oup includes ex insic senso s wi h sensing ou side he ibe and he second g oup is in insic ha means ha sensing akes place wi hin he ibe i sel . This a icle ocuces on he in lu- ence o φ–OTDR (Op ical Time Domain Re lec ome y) senso and hei lase o he BER (Bi E o Ra e) o he DWDM (Dense Wa eleng h Di ision Mul iplex) sys em. Using same op ical ibe s o pa allel ansmission o a da a and a sensing signals simul aneously is new and inno a i e idea. The es o his pape is s uc u ed as ollows. Sec ion I sho ly in oduce ibe op ics senso s and new ends. Sec ion II Manusc ip ecei ed No embe 30, 2015; e ised No embe 7, 2016 and No embe 22, 2016. Resea ch desc ibed in his pape was inanced by he Na ional Sus ainabil- i y P og am unde g an LO1401, and SIX CZ.1.05/2.1.00/03.0072. Fo he esea ch, in as uc u e o he SIX Cen e was used. Au ho s a e wi h he Depa men o Telecommunica ions, B no Uni- e si y o Technology, B no, Czech Republic and om CESNET, z.s.p.o., P aha, Czech Republic (E-mails: [email p o ec ed].cz, [email p o ec ed].cz, [email p o ec ed].cz, ho [email p o ec ed].cz, [email p o ec ed].cz, [email p o ec ed]). desc ibes ela ed wo k in φ–OTDR senso s. Sec ion III gi es an o e iew abou DWDM sys em and in oduces unc ion o φ–OTDR senso . Sec ion IV and sec ion V desc ibes ou simula ion se up in VPIpho onics and discusses he esul s achie ed in he simula ion. Sec ion VI concludes he pape and desc ibes u u e wo k. II. RELATED WORKS Op ical senso s based on φ-OTDR we e i s in oduced in 2003 by Juan Ca los Jua ez. He published his esea ch wo k abou op ical senso s in [8]. Fu he , φ-OTDR senso s a e widely used as senso s o mechanical ib a ions o moni o ing and secu ing na ional bo de s, oil and gaspipelines, mili a y ins alla ions, s uc u al heal h e c. Many sys ems use an ex emely na ow lase and EDFAs (E bium Doped Fib e Ampli ie ). This sys em wo ks on a 4 km long op ical ibe wi h esolu ion o 50 m. A e de ec ion da a a e p ocessed in Ma lab en i onmen . I is neccessa y o il e he ecei ed signal. [9] desc ibes he issues bu does no desc ibe using one op ical ibe o he de ec ion and o da a ansmission. Nex issue o φ–OTDR is p ocessing o ecei ed signal due o di icul il e ing and analyzing. Fea u e ex ac ion o ime domain signals in hese sys ems is ime-consuming and may lead o inaccu acies due o noise dis u bances. The ecogni ion and speed o φ–OTDR sys ems canno be used o online ib a ion moni o ing sys ems. The wo k which is called Recogni ion o a Phase-Sensi i i y OTDR Sensing Sys em Based on Mo phologic Fea u e Ex- ac ion be e desc ibes his p oblem bu does no deal wi h any simula ion o use φ–OTDR sys ems on elecommunica ion ou es [10]. Ou a icle ocuses on simula ions in VPIpho onics so wa e. The au ho s in [11] desc ibe ampli ica ion o he φ–OTDR sys ems, epe i ion a e and wid h o he pulses. They use a simple me hod using he holding beam o ampli ying o pulses wi h low epe i ion a e by s anda d elecommunica ion EDFA boos e . The e a e desc ibed h ee me hods o φ– OTDR signals ampli ica ion and hei e i ica ion by measu e- men . These a icles [12], [13], [14], [15], and [16] deal wi h he same opics, pulse wid h, du a ion, epe i ion equency and il e ing o he ecei ed signal. In compa ison wi h o he a icles, ou pape looks a simula ion o φ–OTDR wi h DWDM sys em on one op ical ibe . 190 JOURNAL OF COMMUNICATIONS SOFTWARE AND SYSTEMS, VOL. 12, NO. 4, DECEMBER 2016 1845-6421/12/8416 © 2016 CCIS O iginal scien i ic pape III. OVERVIEW OF THE SYSTEM A. Dense wa eleng h di ision mul iplex sys em T ansmission sys ems based on DWDM a e now o en used o inc ease he ansmission capaci y o op ical ibe o bi- di ec ional communica ion. I is a combina ion o se e al wa eleng hs which ansmi mul iple lase s. A ansmi e which ansmi s in o ma ion is modula ed on each ca ie equency. A mul iplexo combines each op ical channel wi h he op ical ibe . Fo n-channels con- nec ion one mul iplexo /demul iplexo and also one modula- o /demodula o a e needed. Each channel needs ligh sou ce on speci ic wa eleng h. DWDM echnology uses DFB (Dis ibu ed Feedback) lase wi h ex emely na ow spec al line and highly selec i e spec- al il e s. These de ices a e e y sensi i e o equency and he mal s abili y. This is one eason why he echnology is expensi e. The s anda d ITU-T G.694.1 speci ies he indi id- ual ansmission channels a he wa eleng h in he ange om 1490 nm (200.95 THz) o 1620 nm (186.00 THz) called S, C, and L band. DWDM g id is based on a no malized pilo equency 193.1 Thz. The minimum spacing o each wa eleng h may be 0.1 nm, which uses ul a na ow DWDM. To main ain he s anda d i is necessa y o ha e a spacing o 0.2 nm. To ensu e p ope unc ioning wa eleng h di ision mul iplexing i is bes o choose a spacing o 0.8 nm. B. Φ–OTDR op ical senso Commonly used op ical ibe ib a ion sensing sys ems use phase sensi i e op ical ime domain e lec ome e . Φ–OTDR sys ems can de ec and loca e ib a ion signals by measu ing he backsca e ligh ac oss op ical spec um. Senso ic sys- em commonly wo ks wi h Rayleigh and B illouin sca e ing. Phase sensi i e OTDR uses basic single mode op ical ibe which is also used o ansmission. This ype o senso has been used o moni o ing and sa e y condi ion o building s uc u es, gas o oil pipeline s uc u es. Measu ing can be eal- ime. Sou ce o op ical adia ion sends beam o he ibe , i is sho ime and high powe ed pulse which can p opaga e in op ical ibe . Then he pa o ligh is con inuously backsca e ed because o Rayleigh o B illouin sca e ing. This beam is measu ed by p ocessing he backsca e ed signal. Cap u ing and p ocessing o he signal is he mos used echnique. This signal is sensed by he op ical ime domain e lec ome y. Re lec ome ic sensing is e y use ul o de ec ion ib a ions and hei localiza ion. Many dis ibu ed senso s use φ–OTDR. Senso ic sys ems based on φ–OTDR can be used o moni o mo e han one ib a ion sou ce along he op ical ibe . This ype o sensing needs special pulses, because he backsca e ed signal is e y low. The backsca e powe may be desc ibed as [11]: PR( ) = Pi·SγR ·W0·υg·exp−γ· g · 2=PR(0) ·expγ· g · , (1) whe e γis he a enua ion coe icien and is equal o 1/20 h o he g adien o a plo o Rayleigh backsca e a enua ion in dB, Piis he inpu powe , γR is he Rayleigh sca e ing coe icien . The ac ion o cap u ed op ical powe is de ined o s ep index ibe s as [11]: S=NA2 4n2,(2) whe e NA is nume ical ape u e and n is he ibe e ac i e index. A e his we can simpli ied he i s equa ion as [11]: PR( )=7.8·Ep·exp−γ· g · = 7.8·Ep·exp−2γ· g · ,(3) whe e we use γ= 4.6·10−5, NA = 0.12, n = 1.46. ¿F om hese equa ions we can see ha backsca e ed powe is lowe han inpu powe . Fo a e age powe o 150 mW and pulse du a ion o 200 ns. The le el o he backsca e ed signal is abou 52 dB lowe compa ed o he inpu . S anda d elecommunica ion op ical ibe has an a enua ion a ound 0.2 dB/km. The pulse epe i ion a e is dependen on he maximal leng h o he op ical ibe , pulse epe ion a e can be exp essed as [9]: τ=2·L υ=2·L c/n (s)(4) o ou measu e sys em du a ion o he pulse is [9]: τ=2·L c/n =2·40 ·103 3·108/1.46 = 3.89 ·10−4(s)(5) whe e epe i ion a e can be calcula ed as [9]: =1 τ=1 3.89 ·104= 2.57(kHz).(6) IV. SYSTEM DESCRIPTION Ou sys em desc ip ion can be di ided in o wo pa s. The i s pa ocuses on dense wa eleng h di ision mul iplex, hei unc ion and se ings. The second pa ocuses on φ–OTDR sys em. Ou designed sys em is depic ed in Fig.1. Recei ing pa T ansmi ing pa Senso ic sys em pulses 130 ns, epe i ion a e 2.57 kHz, –30 dBm – +20 dBm DWDM sys em DWDM sys em Senso ic sys em M U X D E M U X Op ical ibe 40 km, G.652.D Fig. 1. Block schema ic o sys em In ou sys em we use ou DFB lase s o DWDM sys em and one DFB lase o ibe op ics senso . Lase o op ic senso has wa eleng hs s a ing a 1550.5nm; 1551.0nm; 1551.5nm; 1552.0nm; 1552.5nm; and powe pe o mance is a iable. These wa eleng hs a e used o in luence he i s channel o DWDM. Senso ic sys em is shi ed om DWDM sys em abou 0.5 nm and he ange o wa eleng h o senso ic M. CUCKA e al.: TRANSMISSION OF HIGH POWER SENSOR SYSTEM AND DWDM DATA SYSTEM 191 sys em is inc eased in compa ison wi h DWDM. Cohe en leng h o used lase o φ–OTDR is abou 750 Hz. This leng h is used o 40 km op ical ibe . Lase s o DWDM ha e wa eleng h o 1550 nm, 1550.8 nm, 1551.6 nm, 1552.4 nm and powe 3 dBm. Da a sys em ansmi s da a 10 Gbi /s wi h BER (Bi E o Ra e) abou 1.91E−40. Fi s o all, we simula e he op ical pa h wi h 40 km op ical ibe wi hou ampli ie s. We use s anda d elecommunica ion ibe G.652.D wi h a enua ion 0.2 dB/km. In op ical ib es, he a enua ion is mainly caused by wo physical ac o s, abso p ion and sca e ing losses. Abso p ion is caused by ib e ma e ial and sca e ing due o s uc u al impe ec ions wi hin he ib e. Mic obending o op ical ib e also con ibu es o he a enua ion o signal. Ou simula ion con ains CD (Ch oma ic Dispe sion) and PMD (Pola iza ion Mode Dispe sion) which a ec ing he shape and cou se o he ansmi ed signal. I we ake in o accoun hese e ec s, ou DWDM sys em has clea eye o he decision. A ansmi ing pa o DWDM sys em in VPIpho onics is depic ed in Fig. 2. I is a module which gene a es pseudo andom da a sequence. A ano he block gene a es a sampled NRZ (Non Re u n o Ze o) coded signal de ined by a sequence o bi s a i s inpu . The signal is edi ed by Gaussian il e ha ans o ms elec ical inpu pulses in o smoo he ou pu pulses. In ou ansmi e we use Mach-Zehnde modula o which modula es signal om gene a o o he DFB lase . O he blocks in Fig. 2 a e o p ope unc ion o he simula ion. Fig. 2. T ansmi ing pa o he DWDM sys em in VPIpho onics. A ecei ing pa o he sys em consis s o wo ypes o il e s, Lo en zian and Bessel (op ical and elec ical). These ypes o he il e s a e con igu ed by ecei ing wa eleng h. Ou simula ion ocuses on unc ion o DWDM sys em, we do no conside o wa ch he BER o senso sys em. In ou simula ion we use DMUX 4 which has ex ension a io abou 20 dB. We wan o simula e eal pa ame e s o he bo h sys ems (DWDM and φ–OTDR ). A ecei ing pa o he DWDM sys em can be seen in Fig. 3 Fig. 3. Recei ing pa o he DWDM sys em in VPI pho onics. V. SIMULATION We s a a –30 dBm powe o senso ic sys em and wa ch he BER o each channel o DWDM sys em which un a 10 Gbi /s. In ou simula ion we ha e ou channels DWDM. DWDM sys em is shi ed om senso ic sys em abou 1 nm. In his case he BER o all channels a e abou 1E−40 and eyes o he decision a e clea . When we g adually inc ease powe o he senso ic lase , we can see in all g aphs ha he BER slowly dec eases and eye o he decisions is no clea . I inc eases i he senso ic lase has he powe a ound 0 dBm. Wi h high powe o he senso ic lase (abou 13 dBm) DWDM is no able o ans e da a (1E−7). Tha means da a ansmission is unsuccess ul. In schema ic Fig. 4 we can see he simula ion se up in VPI pho onics which is desc ibed ea lie . Fig. 4. Lase and DWDM sys em con igu a ion in VPIpho onics. The i s esul s o ou simula ions a e shown in Fig. 5. I shows he in luence o he senso ic sys em o DWDM sys em shi ed o 1 nm. Wa eleng h o he DWDM sys em is 1551.6 nm which is he hi d channel o DWDM sys em. We s a wi h BER 1E−40 and inc ease he powe o senso ic sys em. Dependence shows ha he BER o he hi d channel DWDM sys em g adually dec eases wi h inc easing powe . All g aphs also include he cu e ha shows BER limi o DWDM sys em. 192 JOURNAL OF COMMUNICATIONS SOFTWARE AND SYSTEMS, VOL. 12, NO. 4, DECEMBER 2016 10−210−1 10−7 102 1011 1020 1029 1038 BER limi (W) –BER(—) 1553.4 nm 1552.4 nm Fig. 5. In luence o he φ–OTDR o he DWDM sys em (1551.6 nm). Fig. 6 depic s he dependency o high powe senso sys em (abou 27 dBm) o DWDM sys em. Dis ance be ween da a sys em and senso ic sys em is 0.5 nm. 10−210−1 10−3 104 1011 1018 1025 1032 BER limi (W) BER (-) 1550.5 nm 1551 nm Fig. 6. In luence o he high powe φ–OTDR o he DWDM sys em. Ano he impo an pa o he measu emen s is a di e ence be ween wa eleng h spacing DWDM and φ–OTDR ha can be seen in Fig. 7. I we ha e small spacing, in luence o φ–OTDR sys em on he i s channel o DWDM sys em is highe han a dis ance o mo e han 2.5 nm, when sys em is no a ec ed. Ou designed model also includes he non-linea and linea e ec s. Dis ance be ween da a sys em and senso ic sys em is a iable. We ocus on dis ance by 0.5 nm, 1 nm, 1.5 nm, 2 nm, 2.5 nm. 10−210−1 10−12 108 1028 1048 1068 1088 BER limi (W) –BER (—) 1550.5 nm 1551 nm 1551.5 nm 1552 nm 1552.5 nm Fig. 7. In luence o he φ–OTDR o he DWDM sys em wi h a iable dis ance. VI. CONCLUSION Ou simula ion sys em designed in he VPI pho onics so - wa e showed ha i is possible o use an op ical ibe o DWDM ansmission and i can be also used as an op ical senso . This da a ansmission sys em is limi ed by maximum op ical powe o he used lase o he senso sys em. Ou sim- ula ion shows ha DWDM can ansmi da a i he powe o φ–OTDR is unde 13 dBm. I was also e i ied ha a dis ance o 2.5 nm i is no possible o a ec DWDM sys em wi h φ– OTDR. Fu u e wo k aims o use ano he pulse gene a o wi h di e en ange o pulse. These gene a o can make pulses om 10 ns o 1000 ns wi h di e en epe i ion a e o he pulses. The mos impo an u u e wo k is measu emen in he unc ion o DWDM sys em. This measu emen con i ms o disapp o es ou simula ions. REFERENCES [1] T. 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Popp, Phase- sensi i e OTDR sys em based on digi al cohe en de ec ion, Op ical senso s and biopho onics III, ol. 2011, no. 8311, p. 83110, 2011. [15] Y. Zhan, Q. Yu, K. Wang, F. Yang, Y. Kong, and X. Zhao. ”A high pe o mance dis ibu ed senso sys em wi h mul i-in usions simul aneous de ec ion capabili y based on phase sensi i e OTDR,” Op o-Elec onics Re iew, ol. 23, issue 3, 2015. [16] Y. Lu, T. Zhu, X. Bao, L. Chen, W. J. Bock, and J. Albe , Vib a ion moni o ing wi h high equency esponse based on cohe en phase- sensi i e OTDR me hod, 21s In e na ional Con e ence on Op ical Fibe Senso s, ol. 2011, no. 7753, p. 77533K–77533K–4, 2011. Milan Cucka (MSc.) was bo n in Vysko , Czech Republic on Janua y 20, 1989. He ecei ed his M.Sc. deg ees in Telecommunica ions om he B no Uni e si y o Technology, B no, in 2014. His e- sea ch in e es s include dis ibu ed op ical senso s, op oelec onics, and ibe b agg g a ings. Cu en ly, he has been pos g adua e s uden a B no Uni e si y o Technology, Depa men o Telecommunica ions and his opic o disse a ion hesis is dis ibu ed ibe op ics sys ems. Pe Muns e (MSc., Ph.D) was bo n in Zlin, Czech Republic. In 2010 he g adua ed om he B no Uni e si y o Technology and ecei ed his academic i le o elec ical enginee (Ing.). His esea ch wo k ocuses on op ical communica ions, especially FTTx access ne wo ks and OTDM sys ems, and be op ic senso s. He is an au ho o co-au ho o mo e han wen y publica ions in scien ic jou nals and a in e - na ional con e ences. He is a membe o p og am commi ees o se e al con e ences. Lukas Koci (MSc.) was bo n on 29 Sep embe 1990 in B no, Czech Republic. He g adua ed om he B no Uni e si y o Technology and ecei ed aca- demic i le Ing a he Depa men o Telecommuni- ca ions. Cu en ly, he is s udying Doc o al p og am a he B no Uni e si y o Technology, Depa men o Telecommunica ions. His esea ch ocuses on op ical communica ion ne wo ks, op ical ime di ision mul- iplexing, wa eleng h di ision mul iplexing, passi e op ical ne wo ks, and especially so wa e de ined op ical ne wo ks. Tomas Ho a h (MSc.) was bo n in Ha i o , Czech Republic on Ma ch 7, 1989. He ecei ed his M.Sc. deg ees in Telecommunica ions om he B no Uni- e si y o Technology, B no, in 2013. His esea ch in e es s include passi e op ical ne wo ks (xPON), op oelec onics, and Bi To en p o ocol. Cu en ly, he has been pos g adua e s uden a he B no Uni e si y o Technology, Depa men o Telecom- munica ions and his opic o disse a ion hesis is Op imiza ion se ices in FTTx op ical access ne - wo ks. Milosla Filka p o . was bo n in 1946 in B no, Czech Republic. Since 2010 he has been a p o- esso a he Depa men o Telecommunica ions a he B no Uni e si y o Technology. He is a leade o he op ical g oup Op oLab and also a head o he Labo a o y o ansmission media and op ical ne wo ks. He is a membe o a se e al ins i u es (e.g. Ins i u e o Elec ical Elec onics Enginee es) and is also a commi ee o many con e ences (In e na ional Con e ency Telecommunica ions and Signal P o- cessing, In e na ional Con e ency New In o ma ion and Mul imedia Technologies). His cu en esea ch hemes ocus on ibe - op ic elecommunica ions, especially FTTx echnologies. Jose Voj ech (MSc., B.Sc., Ph.D) ecei ed wi h hono s M.SC. deg ee in Compu e Science, B.Sc. deg ee in Pedagogy and Ph.D. in ield o op ical ne wo king om he Czech Technical Uni e si y, P ague, in 2001, 2003 and 2009 espec i ely. Since 2003, he has been wi h esea ch Depa men o Op ical Ne wo ks, CESNET, a.l.e., which he leads now. He pa icipa ed in in e na ional p ojec s: COM- PLETE, FI-PPP XIFI, GN4, GN3+, GN3, GN2, Po a Op ica S udy, SEEFIRE. He has been also esponsible o de elopmen o open amily o pho- onic de ices. He holds 15 pa en s (including 3 US and 1EU) and u ili y models. His eco d shows Hi sch index 5 wi h mo e han 64 ci a ions. He is a membe o IEEE, OSA and SPIE. In 2007 he ecei ed he Resea ch p ize o he Czech minis e o educa ion. 194 JOURNAL OF COMMUNICATIONS SOFTWARE AND SYSTEMS, VOL. 12, NO. 4, DECEMBER 2016