100G and 200G single carrier transmission over 2880 and 320 km using an InP IQ modulator and Stokes vector receiver

Transcription

1 Vol. 4, No. 6 6 Dec 016 OPTICS EPRESS G and 00G single caie ansmission ove 880 and 0 km using an InP IQ modulao and Sokes veco eceive MOHAMMED Y. S. SOWAILEM,1,4,5 THANG M. HOANG,1,4,6 MATHIEU CHAGNON,1 MOHAMED MORSY-OSMAN,1, MENG QIU,1 STEPHANE PAQUET, CARL PAQUET, IAN WOODS, ODILE LIBOIRON-LADOUCEUR,1 1 AND DAVID V. PLANT 1 Phoonics Sysem Goup, Elecical and Compue Engineeing Depamen, McGill Univesiy, 480 Univesiy See, Moneal, QC HA 0E9, Canada Cuenly wih he Elec. Eng. Dep., Alexandia Univesiy, Alexandia, Egyp Ciena, 716 Einsein, Quebec, Canada 4 These auhos have conibued equally in his wok 5 mohammed.sowailem@mail.mcgill.ca 6 hang.hoang@mail.mcgill.ca Absac: We demonsae expeimenally he ansmission of single caie 56 Gbaud 16QAM, 8-QAM and QPSK opically modulaed signals ove 0, 960 and,880 km, especively, using a fully packaged InP IQ modulao and a Sokes veco diec deecion (SV-DD) eceive ealized using discee opics. Resuls show ha by opimizing he caieo-signal-powe aio, he oal houghpu-imes-disance poduc fo 16 QAM and QPSK ae 71,680 Gbps.km and,560 Gbps.km, especively, a bi eo ae (BER) below he had decision fowad eo coecing heshold (HD-FEC) of Opical Sociey of Ameica OCIS codes: (060.0) Fibe opics communicaions; ( ) Modulaion. Refeences and links 1. D. Rafique, Fibe nonlineaiy compensaion: commecial applicaions and complexiy analysis, J. Lighwave Technol. 4(), (016).. Opical Inenewoking Foum (OIF), OIF-FEC G Fowad Eo Coecion Whie Pape, Opical Inenewoking Foum (OIF), OIF-Tech-Opions-400G Technology opions fo 400G Implemenaion Fowad, D. H. Sim, H. Kim, and Y. C. Chung, Diec-deecion eceive fo polaizaion-division-muliplexed OOK signals, IEEE Phoonics Technol. Le. 7(1), 8 41 (015). 5. D. Che, A. Li,. Chen, Q. Hu, Y. Wang, and W. Shieh, Sokes veco diec deecion fo sho-each opical communicaion, Op. Le. 9(11), (014). 6. M. M. Osman, M. Chagnon, M. Poulin, S. Lessad, and D. V. Plan, 4-Gb/s 10-km ansmission of PDM PAM-4 a 1. μm using a single inensiy modulaed lase and a diec deecion MIMO DSP-based eceive, J. Lighwave Technol. (7), (015). 7. M. Chagnon, M. Mosy-Osman, D. Pael, V. Veeasubamanian, A. Samani, and D. Plan, Digial signal pocessing fo dual-polaizaion inensiy and ine-polaizaion phase modulaion fomas using sokes deecion, J. Lighwave Technol. 4(1), (016). 8. K. Kikuchi and S. Kawakami, Muli-level signaling in he Sokes space and is applicaion o lage-capaciy opical communicaions, Op. Expess (7), (014). 9. D. Che and W. Shieh, Polaizaion demuliplexing fo Sokes veco diec deecion, J. Lighwave Technol. 4(), (016). 10. D. Che, Q. Hu,. Chen, and W. Shieh, 1-Tb/s Sokes veco diec deecion ove 480-km SSMF ansmission, in Poc. OECC (014), pape THPDP. 11. P. Dong,. Chen, K. Kim, S. Chandasekha, Y.-K. Chen, and J. H. Sinsky, 18-Gb/s 100-km ansmission wih diec deecion using silicon phoonic Sokes veco eceive and I/Q modulao, Op. Expess 4(1), (016). 1. S. Benedeo and P. Poggiolini, Theoy of polaizaion shif keying modulaion, IEEE Tans. Commun. 40(4), (199). #74119 Jounal 016 hp://dx.doi.og/10.164/oe Received Aug 016; evised 1 Oc 016; acceped 8 Oc 016; published Dec 016

2 Vol. 4, No. 6 6 Dec 016 OPTICS EPRESS S. Bei, F. Cui, G. de Machis, and E. Iannone, Mulilevel coheen opical sysem based on Sokes paamees modulaion, J. Lighwave Technol. 8(7), (1990). 14. K. Kikuchi, Fundamenals of coheen opical fibe communicaions, J. Lighwave Technol. 4(1), (016). 15. M. Chagnon, M. Mosy-Osman, M. Poulin, C. Paque, S. Lessad, and D. V. Plan, Expeimenal paameic sudy of a silicon phoonic modulao enabled 11 Gb/s PAM ansmission sysem wih a DAC and ADC, J. Lighwave Technol. (7), (015). 16. S. Chandasekha,. Liu, P. J. Winze, J. E. Simsaian, and R. A. Giffin, Compac all-inp lase-vecomodulao fo geneaion and ansmission of 100-Gb/s PDM-QPSK and 00-Gb/s PDM-16QAM, J. Lighwave Technol. (4), (014). 17. F. Chang, K. Onohaa, and T. Mizuochi, Fowad eo coecion fo 100 G Tanspo newoks, IEEE Commun. Mag. 48(), S48 S55 (010). 18. T. Miyazaki, Linewidh-olean QPSK homodyne ansmission using a polaizaion-muliplexed pilo caie, IEEE Phoonics Technol. Le. 18(), (006). 19. P. Johannisson, M. Sjodin, M. Kalsson, E. Tipsuwannakul, and P. Andekson, Cancellaion of nonlinea phase disoion in self-homodyne coheen sysem, IEEE Phoonics Technol. Le. (11), (010). 0. M. Y. S. Sowailem, T. M. Hoang, M. Mosy-Osman, M. Chagnon, D. Pael, S. Paque, C. Paque, I. Woods, O. Liboion-Ladouceu, and D. V. Plan, 400G Single caie 500km ansmission wih an InP dual polaizaion IQ modulao, IEEE Phoonics Technol. Le. 8(11), (016). 1. P. J. Reyes-Iglesias, I. Molina-Fenández, A. Moscoso-Mái, and A. Oega-Moñux, High-pefomance monolihically inegaed 10 downconvee wih elaxed hadwae consains, Op. Expess 0(5), (01).. M. Mosy-Osman, M. Chagnon,. u, Q. Zhuge, M. Poulin, Y. Painchaud, M. Pelleie, C. Paque, and D. V. Plan, Cololess and peamplifieless ecepion using an inegaed Si-phoonic coheen eceive, IEEE Phoonics Technol. Le. 5(11), (01). 1. Inoducion Daa cene ineconnecs (DCIs) ae gowing significanly due o he massive incease in daa sevices such as cloud compuing, social media and viualizaion. This gowh is diving he demand fo fase, compac and cos-effecive opics fo DCI affic in meo applicaions [1]. Amongs he vaious soluions, coheen ansmission deploying dual-polaizaion IQ modulaos (DP-IQM) and coheen eceives is used fo 100G signal ansmission wih QPSK modulaion foma in long haul applicaions. Coheen sysems ae also used fo 00G signal ansmission wih he 16-QAM modulaion foma fo meo applicaions. These applicaions have been ecenly sandadized [, ]. Meo applicaions fo disances less han 1000 km, found in ine-daacene ineconnecs, epesen inemediae sysems beween long haul applicaions and sho each applicaions. The ansceive design fo meo newoks is umos challenging because of he need of capaciy-each, foopin and cos [1]. Nowadays, hee is a gowing inees in finding alenaive soluions fo sho each and meo applicaions using Sokes veco modulaion and deecion [4 11] ahe han unidimensional inensiy modulaion/ diec deecion (IM/DD) sysem o complex coheen sysem. Alhough he concep of a Sokes veco eceive (SVR) has been descibed in he 1990s [1, 1], SVR sysems wih advanced modulaion fomas have only been demonsaed ecenly. Fo insance, 100 Gbps pe wavelengh ove 480 km fo meo applicaions was demonsaed in [10] using a complex IQ modulaion on he polaizaion and ansmiing he caie on he ohogonal polaizaion. This modulaion scheme pesens a hybid soluion beween coheen and diec deec sysems. The Sokes veco diec deecion (SV-DD) sysem and single polaizaion coheen sysem have a simple ansmie when compaed o ha of he dual polaizaion coheen sysem. Since only one polaizaion is modulaed, he ansmie in SV-DD equies half he numbe of he eleconic and eleco-opic devices including he numbe of digial-o-analog convees (DACs), amplifies, Mach-Zehnde modulaos compaed o he dual polaizaion coheen sysem ansmie. This is a he expense of halving he specal efficiency ha can be achieved by he dual polaizaion coheen sysem. On he ohe hand, he SVR, which has seveal configuaions shown in [9], has simple eceive compaed o he single polaizaion coheen sysem. The common feaue in SVR configuaions compaed o coheen sysems is ha SVR does no employ a local oscillao (LO) lase wih is associaed hemoelecic

3 Vol. 4, No. 6 6 Dec 016 OPTICS EPRESS 0487 coole (TEC) and diving cicuiy. The deployed SVR in his demonsaion compises a 4 hybid, wo balanced phoodeecos (BPDs) and wo single-ended phoodeecos (SE-PDs) insead of wo 4 hybids and 4 BPDs in coheen deecion. I is woh noing ha he single polaizaion and he dual polaizaion coheen eceives shae he same configuaion o avoid he deploymen of a polaizaion sabilize in single polaizaion coheen eceive [14]. Moeove, SV-DD sysems equie less complex digial signal pocessing (DSP) a he eceive compaed o a coheen sysem since hee is no fequency offse emoval, lase phase noise miigaion o cycle slip deecion. In paallel o he ineess in SV-DD sysems, eseaches, designes, and manufacues use phoonic inegaed devices fabicaed on vaious plafoms such as silicon (Si) [15] o indium phosphide (InP) [16] o supply he demand fo DCI applicaions. SV-DD sysems have been demonsaed using Si phoonics modulaos in [6, 7] and using Si phoonics IQ modulao (IQM) and Si phoonics SVR in [11]. In his pape, we demonsae, using an InP IQM, a ecod-beaking single caie ansmission using a SV-DD sysem a symbol ae of 56 Gbaud wih QPSK, 8-QAM and 16- QAM modulaion fomas coesponding o payload aes of 100G, 150G and 00G, especively. The sysem opeaes below he 7% ovehead BCH had-decision fowad eo coecion (HD-FEC) heshold of [17] ove disances of 880, 960 and 0 km, especively. These modulaion schemes enable 100G ansmissions and 00G ansmissions fo long haul and meo applicaions afe emoval of he FEC and encapsulaion ovehead. To achieve his esul, we opimize he caie-o-signal-powe (CSR) aio and implemen DSP a he ansmie and he eceive including equalizaion of he ansmie fequency esponse, non-linea compensaion fo he Mach-Zehnde modulao (MZM) ansfe funcion, and chomaic dispesion (CD) pe-compensaion. The emainde of he pape is oganized as follows: Secion povides a descipion of he Sokes veco ansceive. Secion discusses he expeimenal seup and he applied DSP funcions. Secion 4 pesens he expeimenal esuls, and we finally conclude in Secion 5.. Pinciple of Sokes veco ansceive A schemaic diagam of he Sokes veco ansmission sysem is shown in Fig. 1. The ansmie in Fig. 1(a) compises a polaizaion beam splie (PBS), one IQ modulao ha pefoms complex modulaion on he elecic field of one of he wo ohogonal saes of polaizaion (SOP) oiginaing fom a single lase (-polaizaion) denoed heeafe by E The modulaed signal ( E = I + jq) is hen combined wih he opical caie (C) on he ohe SOP (Y-polaizaion) using a polaizaion beam combine (PBC). I is noed ha a SV- DD sysem shaes idenical ansmie achiecue and almos simila eceive achiecue wih a self-homodyne coheen deecion sysem ha uses a polaizaion-muliplexed pilo caie. Howeve, by adding wo single ended phoodeecos, SVR does no equie a polaizaion sabilize o sepaae he pilo one and he signal ha is essenial fo a selfhomodyne coheen deecion sysem [18, 19]. T The ansmied field can be equivalenly epesened in he Jones space J = E C o T in he Sokes space S = S0 S1 S S, whee boh epesenaions can be elaed by S0 = E + C, S1 = E C, S { * = Re E. C }, S { * = Im E. C }. T denoes a veco anspose, he supescip * sands fo he complex conjugae and Re and Im epesen he eal and imaginay pas of a complex numbe. Wihou loss of genealiy if we assume ha C = 1, we ge S0 = E + 1, S1 = E 1, S = I, S = Q. This means ha he valuable infomaion is available on S and S. Afe popagaion in he fibe, he SOP of ansmied signal is andomly oaed due o fibe biefingence. This oaion is modeled in eihe he Jones space by an unknown uniay complex valued maix ha muliplies he ansmied Jones veco J o he Sokes space by he maix muliplicaion of an unknown 4 4 eal valued maix and he ansmied Sokes veco S. Due o andom SOP oaion

4 Vol. 4, No. 6 6 Dec 016 OPTICS EPRESS 0488 along he fibe, each of he eceived elecic fields on and Y polaizaions ( E and linea combinaion of he ansmied polaizaions E and C. E Y ) is a Fig. 1. Schemaic diagam of SV-DD ansceive (a) ansmie, (b) eceive. T The eceived Sokes veco S = S0 S1 S S can be measued using he diec deecion sysem illusaed in Fig. 1(b). A PBS is iniially used o spli he eceived signal ino wo ohogonal SOPs. Each SOP is fuhe spli using 67/ polaizaion mainaining couples. This coupling aio ensues ha he sysem pefomance is independen fom he SOP of he signal befoe he PBS [6]. A he % oupu po of he couples, E and E Y ae deeced sepaaely using single-ended phoodeecos o obain he inensiy on boh polaizaions giving he ems equied fo calculaing S0 = E + EY, and S1 = E EY. A he 67% oupu pos of he couple, he wo ohogonal SOPs ae inoduced o a 90 opical hybid afe SOP alignmen using a 90 polaizaion oao on one banch. Afe balanced deecion a he oupu of he hybid, he beaing povides he eceived Sokes paamees { * S = Re E. EY }, { * S = Im E. EY }. Since S and S ae he only ansmied Sokes paamees ha ae equied o be eieved, hey can be found via he following MIMO file ha pefoms he SOP de-oaion, S. 1 S m11 m1 m1 = S S m 1 m m S whee m11,, m ae coefficiens of he invese oaion maix ha ae found adapively a he eceive via DSP, and ae used o ecove he Sokes paamees S and S which in un fully descibe he complex field of he modulaed signal.. Expeimenal seup and DSP sack.1 Expeimenal seup Figue shows he expeimenal seup deployed o demonsae he pefomance of he SV ansmission sysem. An AC-coupled 8-bi digial-o-analog convee (DAC) opeaing a 64 GSps geneaes wo 1. V pp diffeenial oupus. These wo diffeenial oupus ae amplified wih a linea amplifie. The linea dive poduces wo 5 V pp single-ended signals ha dive (1)

5 Vol. 4, No. 6 6 Dec 016 OPTICS EPRESS 0489 one half of he DP-IQM. This epesens he complex modulaion on he -Pol of he DP- IQM. The InP DP-IQM, has a 5 GHz -db bandwidh, less han 10 db of inseion loss, a V π of.5v, and less han 5 ps skew beween boh polaizaion pahs [0]. To conol he caie powe on Y-pol elaive o he fixed modulaed signal powe on he -pol, he MZM on he Q componen of Y-pol is biased a null and he bias fo he MZM on he I componen of Y-pol is swep o poduce he desied CSR. The opical souce is a 100 khz linewidh exenal caviy lase (ECL) opeaing a nm wih 15.5 dbm opical powe. Fig.. (a) Expeimenal seup (b) SVR deails (c) BB opical specum wih 0.05 nm esoluion bandwidh. Befoe ansmission, he opical signal is amplified using a boose EDFA o compensae fo subsequen swiches and couples loss used in he eciculaing loop and o enhance he signal powe level fo bee opical signal o noise aio duing ansmission. The opimizaion of he oal launched signal powe depends on he opimizaion of he CSR and launching sufficien powe fo he modulaed signal on he polaizaion accoding o he used modulaion foma o have he equied OSNR fo he achieved each. This dependency on CSR value is because of he boose which has a fixed oupu powe of dbm, so he incease in he CSR value is accompanied by a decease in he modulaed signal powe on he polaizaion. Thus, he launched signal powe is opimized using a vaiable opical aenuao (VOA) along wih he CSR fo diffeen modulaion fomas by minimizing he bi eo ae a he maximum each accoding o he used modulaion foma. The signal is hen ansmied ino a fou-span opical eciculaing loop. Each span compises 80 km of SMF- 8e + followed by an in-line ebium-doped fibe amplifie (EDFA) wih 5 db noise figue. A unable opical file is used afe he second span wih is cene wavelengh se o nm and bandwidh se o nm. The oupu signal fom he e-ciculaing loop is conneced o a 0.8 nm file followed by a pe-amplifie and a second VOA. The opimum eceived powe, as deemined expeimenally, is 16.6 dbm. This high equied eceived opical powe along wih he use of 90/10 couple insead of 67/ couple ae needed o compensae fo he lage inseion loss of all passive discee opical componens ha ae conneced on he opical bench o ealize he middle secion of a SVR. In paicula, he use of a 8 dual polaizaion opical hybid, which has a heoeical inseion loss of 9 db, insead of a 4 single polaizaion hybid o ealize a SVR (see Fig. 1(b)) accouns fo an addiional db inseion loss ha could have been avoided if a single polaizaion device is available fo he expeimen To opeae only one half, i.e. one polaizaion, of he dual polaizaion hybid, wo polaizaion conolles

6 Vol. 4, No. 6 6 Dec 016 OPTICS EPRESS 0490 (PC 1 and PC in Fig. (b)) a is inpus ae adjused such ha he wo inpu fields bea in one half of he device. A he inpu of he SVR, a PBS iniially splis he incoming signal ino wo eceived ohogonal polaizaions. Each polaizaion is hen spli using a 90/10 polaizaion mainaining couple whee he 10% po is conneced diecly o a single-ended phoodeeco o deec he inensiy on each eceived polaizaion. The 90% pos ae conneced o he hybid, wih one of is inpus oaed by 90 as shown in Fig. 1(b). A vaiable opical delay line (VODL) is used o mach he opical delay beween he wo polaizaion ibuaies of he signal befoe eneing he opical hybid o have coec signal beaing. The opical hybid is followed by balanced deecion which povides he eceived Sokes paamees. The diec deecion ems and he Sokes paamees ae hen sampled fo offline signal pocessing using a eal ime oscilloscope (RTO) having fou synchonized channels each is unning a sampling ae of 80 GSps and having an analog bandwidh of GHz.. DSP sack Figue illusaes he DSP sack used a he ansmie and eceive. The offline ansmie DSP (Tx-DSP), shown in Fig. (a), sas wih he N-QAM symbol geneaion. Nex, he geneaed symbols ae pulse shaped using a aised-cosine (RC) file having a oll-off faco of 0.1 a wo samples pe symbol. Afewads, he signal is pe-disoed fo chomaic dispesion (CD) pe-compensaion depending on he popagaion disance and fibe ype. The chomaic dispesion is fully pe-compensaed a he ansmie side which allows combining he polaizaion acking and eceive equalize in one DSP block. In his wo-dimensional SV-DD sysem wih complex modulaion, CD can also be compensaed a he eceive, eihe befoe o afe he MIMO file. Applying he CD poscompensaion can be done pefecly when he sae of polaizaion (SOP) of he inpu signal is adjused such ha he ansmied caie is on one inpu po of he hybid and he modulaed complex signal is on he ohe po. Howeve, when he SOP is andom, sevee penalies aise when aemping o do CD pos-compensaion in he pesence of he wo powe ems E and C appeaing in he S and S eceived Sokes paamees. This pevens CD poscompensaion befoe polaizaion acking o a leas will affec he pefomance consideably. Anohe mehod is o do CD-pos-compensaion afe he MIMO file which pefoms polaizaion acking. This mehod, howeve, equies he use of slow aining symbols o obain he Sokes veco MIMO de-oaion maix pio o doing CD poscompensaion, as was done in [5]. Afe CD pe-compensaion, he I and Q seams of he N-QAM symbols ae e-sampled o 64 GSps o mach he sampling ae of he subsequen DAC as shown in Fig. (a). The invese of he non-linea ansfe funcion of he MZM is hen applied o he esampled symbols such ha he consellaion poins ae equally spaced afe opical modulaion. Afewads, an expeimenally opimized FIR file is used o equalize fo he fequency esponse of he ansmie componens including he DAC, he linea dive, and he InP DP- IQM. Finally, he equalized samples ae quanized o 56 levels and uploaded o he memoy of he 8-bi DAC. Fig.. DSP sack used fo he SV ansmission: (a) Tx-DSP; (b) Rx-DSP.

7 Vol. 4, No. 6 6 Dec 016 OPTICS EPRESS 0491 The offline eceive DSP (Rx-DSP) sas by e-sampling he capued paens fom 80 GSps o wice he symbol ae because all Rx-DSP opeaes a wo samples pe symbol. Afe e-sampling, a iming ecovey o selec he appopiae sampling insance is pefomed using he same algoihm as in [0]. Afe consucing he S 1 paamee fom he wo diec deecion ems ( E and E Y ), he eal valued MIMO adapive fileing is used fo wo oles: (i) i acks he polaizaion oaion and inves i accoding o Eq. (1) o ecove he ansmied Sokes paamees S and S and (ii) i equalizes fo any esidual inesymbol inefeence (ISI). In he MIMO, aining symbol leas mean squaes (TS-LMS) algoihm is used iniially o ack he polaizaion oaion and deemine he adapive file ap coefficiens. Afe he aining symbols, decision dieced LMS (DD-LMS) eplaces TS- LMS whee symbol decisions in he seady-sae opeaion ae used o slowly adap he aps of he MIMO. Finally, he eceived symbols ae de-mapped ino bis fo BER couning. The BER couning is done ove 1,76,560 bis, 10,1,90 bis, and 6,881,80 bis, in case of 16-QAM, 8-QAM and QPSK, especively. 4. Resuls Fig. 4. BER vesus ansmission disance a he opimum CSR and he opimum launch powe fo QPSK, 16-QAM and 8-QAM modulaion fomas a 56 Gbaud using SV-DD. Figue 4 shows he BER vesus ansmied disance fo a 56 Gbaud signal a opimum CSR values fo QPSK, 8-QAM and 16-QAM fomas. The opimum launch powe, which is expeimenally found, is 5 dbm fo QPSK and 6 dbm fo 8-QAM and 16-QAM. A he opimum launch powe and CSR values, we achieve he following hee key ansmission esuls wih BER below he HD-FEC heshold using he SV-DD: i) 0 km wih 4 Gbps 16-QAM, ii) ove 1000 km wih 168 Gbps 8-QAM, and iii) 880 km wih 11 Gbps QPSK. Nex, Fig. 5 shows he CSR opimizaion esuls fo all hee modulaion fomas. Moe specifically, i depics he BER vesus CSR a he maximum each whee BER his he HD- FEC heshold fo a given foma. The CSR measuemen is done by measuing he oupu powe fom he modulao befoe and afe loading he wavefoms ino he DAC fo each foma wih coesponding CD pe-compensaion. The measued oupu powe fom he modulao gives eihe: a) he caie powe going hough he Y polaizaion of he DP-IQ modulao when he modulaing RF wavefoms of he -polaizaion ae zeo, b) he oal

8 Vol. 4, No. 6 6 Dec 016 OPTICS EPRESS 049 powe fo he signal and caie when he modulaing RF wavefoms ae loaded ino he DAC. In his SV-DD configuaion, he caie on Y polaizaion is he phase divesiy efeence fo he modulaed signal on he polaizaion, which is equivalen o he ole of he local oscillao (LO) in a coheen sysem. Thus, CSR is an impoan paamee o invesigae, simila o LO-o-Signal-Powe-Raio (LSR) a he eceive in coheen ansmission [1, ]. Fom Fig. 5, as he QAM ode inceases, he opimum CSR value deceases, giving moe powe on he signal polaizaion. This is because he oal launch powe fom he boose fo he modulaed signal and he caie is consan and inceasing he QAM ode, i.e. having a dense consellaion, equies inheenly lage OSNR fo deecing he signal iself. This means ha he equied modulaed signal launch powe inceases which esuls in a lowe opimum CSR value. Fig. 5. BER vesus CSR of vaious foma a fixed ansmied disance wih consellaions. Finally, Table 1 compaes sysem equiemens (hadwae and DSP funcions) and achieved pefomance of his cuen wok agains seveal ecen demonsaions of SV-DD sysems ageing sho each and meo applicaions [6, 7, 10] as well as a compaison wih a ecen InP IQM enabled 400G coheen sysem demonsaion fo meo applicaions [0] fo benchmaking puposes. Coheen sysems enable modulaion of fou available dimensions fo modulaion, namely he ampliude and phase of he elecic field on wo ohogonal polaizaions. Howeve, i has he highes sysem complexiy in ems of equied DSP and ansceive componens as indicaed in Table 1. On he ohe hand, hough shaing he same capaciy as SV-DD sysem, single polaizaion (SP) coheen ansmission equies eihe a polaizaion sabilize o align he andomly vaying SOP in he fibe o ha of he LO, o a polaizaion divesiy configuaion consising of a 8 dual polaizaion hybid and fou BPDs [14]. In [6], a dual polaizaion inensiy modulaion (DP-IM) sysem is demonsaed fo sho each applicaions enabling wo dimensional modulaion (D modulaion) which doubles he numbe of bis pe symbol compaed o convenional IM/DD wih one dimensional modulaion. This appoach is suiable fo sho each applicaions whee each is less han 0 km and opeaing in he O-band is essenial o avoid he effecs of CD. In [10], he auhos used an OFDM modulaion echnique in SV-DD sysem whee a single polaizaion IQ modulao (SP-IQM) is used on one polaizaion and he caie is ansmied on he ohogonal polaizaion. Thus, CD pos-compensaion can be done in such a sysem

9 Vol. 4, No. 6 6 Dec 016 OPTICS EPRESS 049 afe he polaizaion oaion is inveed following he mehod descibed in [5] which exends he each of SV-DD sysems. In ou wok, we use he same configuaion in [10] (complex modulaion on one polaizaion and caie ansmission on he ohe polaizaion), bu insead we use single caie modulaion wih CD pe-compensaion a he ansmie eplacing CD pos-compensaion. Ou SV-DD scheme shows a significan educion in ems of sysem complexiy (hadwae and DSP funcions) compaed o coheen sysems while mainaining an almos simila pefomance of a SP coheen sysem. Tx main componens Rx main componens Main use of DSP a ansmie and eceive Table 1. Schemes fo SV-DD compaed o 400G coheen sysem demonsaion (SP- IQM: single polaizaion IQ modulao, IFFT: invese fas Fouie ansfom). DP coheen sysem DP-IQM (6 MZMs) 4 DAC channels 4 RF amplifies Dual Pol. Hybid 4 BPDs 4 ADCs LO Digial Pe-emphasis complex MIMO CD pos-comp Feq. Offse Removal Phase noise miigaion SV-DD sysem (DP-IM) MZMs DAC channels RF amplifies Single Pol. Hybid SE-PDs and BPDs 4 ADCs Digial Pe-emphasis 4 eal MIMO SV-DD sysem SP-IQ modulaion SP-IQM ( MZMs) DAC channels RF amplifies Single Pol. Hybid SE-PDs and BPDs 4 ADCs OFDM synch Sokes aining (4 eal MIMO) IFFT / FFT Channel equal. CD pos-comp Ou wok SP-IQM ( MZMs) DAC channels RF amplifies Single Pol. Hybid SE-PDs and BPDs 4 ADCs ( ADCs if balanced deecion used o consuc of S 1 paamee) Digial Pe-emphasis CD pe-comp eal MIMO Modulaion foma DP-16QAM DP-PAM4 OFDM 16QAM Modulaed dimensions 4 Thoughpuimes- disance 14,60,40 48,000 71,680 (Gbps.km) Bi ae (Gbps) Reach (km) BER a specified each ~ Refeence [0] [6] [10] 5. Conclusion We demonsaed 100G and 00G Sokes-Veco ansmission using an InP DP-IQM and a SVR DD on a single caie using diffeen modulaion fomas, namely QPSK, 8-QAM and 16-QAM. Fo 56 Gbaud 16-QAM signal, he oal houghpu-imes-disance poduc is 71,680 Gbps.km a an opimized CSR value of 6 db. Fo 56 Gbaud QPSK signal, he oal houghpu-imes-disance poduc is,560 Gbps.km a an opimized CSR value of 8 db. These esuls show he viabiliy of using SVR DD and small fom faco inegaed InP IQM o mee 100G and 00G ansmission sysem equiemens fo meo applicaions.