JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 27, NO. 3, …home.eps.hw.ac.uk/~xw66/Publications_files/... · ﬁber based 1-bit delay line, a dual-pin photo detector (PD), and an OCDM Rx

JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 27, NO. 3, FEBRUARY 1, 2009 299

Field Trial of Duplex, 10 Gbps 8-UserDPSK-OCDMA System Using a Single 16 16

Multi-Port Encoder/Decoder and 16-LevelPhase-Shifted SSFBG Encoder/Decoders

Nobuyuki Kataoka, Member, IEEE, Naoya Wada, Member, IEEE, Xu Wang, Senior Member, IEEE,Gabriella Cincotti, Senior Member, IEEE, Akira Sakamoto, Yoshihiro Terada, Tetsuya Miyazaki, Member, IEEE,

and Ken-ichi Kitayama, Fellow, IEEE

Abstract—An optical code-division multiple access (OCDMA)over wavelength-division multiplexing (WDM) system could beone promising solution to the symmetric Gigabit access networkwith high spectral efficiency, cost effective, good flexibility andenhanced security. A cost-effective OCDMA/WDM system using asingle multi-port en/decoder at an optical line terminal (OLT) andsuperstructured fiber Bragg grating (SSFBG) encoder/decodersat each optical network unit (ONU) in an optical network has beenproposed and demonstrated. In this paper, we prepare 16-chip,16-level phase-shifted SSFBG encoder/decoders and developthe full-asynchronous 10 Gigabit Ethernet (10 GbE) interfaceOCDMA prototype for the first time. Field trials of duplex,fully-asynchronous, 10 Gbps 8-user DPSK-OCDMA systemover 100 km using hybrid multi-port and SSFBG encoder/decoderare demonstrated.

Index Terms—Differential phase-shift keying (DPSK), field trial,optical code-division multiple access (OCDMA), wavelength-divi-sion multiplexing (WDM).

I. INTRODUCTION

I N FUTURE access networks, a symmetric Gigabit fiber-to-the-home (FTTH) service is required to meet the needs of

future high-bit-rate applications such as uncompressed 1.2-Gb/shigh-definition (HDTV) class or even 6-Gb/s 4 K digital cinemaon a peer-to-peer basis as well as bidirectional medical appli-cations of telediagnosis and surgery [1]. Therefore, in the up-grading scenario of the FTTH services in the near future, in

Manuscript received June 29, 2008; revised October 02, 2008. Current versionpublished February 13, 2009.

N. Kataoka, N. Wada, and T. Miyazaki are with the Photonic Network Group,Research Department 1, New Generation Network Research Center, NationalInstitute of Information and Communications Technology, Tokyo 184-8795,Japan (e-mail: [email protected]; [email protected]; [email protected]).

X. Wang is with the School of Engineering and Physical Sciences, Heriot WattUniversity, Riccarton, Edinburgh, EH14 4AS, U.K. (e-mail: [email protected]).

G. Cincotti is with the Department of Applied Electronics, University RomaTre, I-00146 Rome Italy (e-mail: [email protected]).

A. Sakamoto and Y. Terada are with the Optics and Electronics Labora-tory, Fujikura Ltd., Chiba 285-8550, Japan (e-mail: [email protected];[email protected]).

K.-I. Kitayama is with the Department of Electrical, Electronic and In-formation Engineering, Osaka University, Osaka 565-0871, Japan (e-mail:[email protected]).

Color versions of one or more of the figures in this paper are available onlineat http://ieeexplore.ieee.org.

Digital Object Identifier 10.1109/JLT.2008.2009233

order to meet the users’ needs, a high bit-rate uplink is a req-uisite, leading to a novel-system concept of gigabit-symmetricFTTH.

For current passive optical network (PON) deployments, theindustry has selected time division multiplexing (TDM) PON,which achieves cost effectiveness [2]. However, the TDM-PONsystem would be difficult to simultaneously provide all thecustomers with a gigabit-class bandwidth uplink due to thenature of the timeslot-based multiple access protocol. There-fore, TDM-PON will not be a solution to the gigabit-symmetricFTTH system.

Wavelength division multiplexing (WDM-) PON is a nat-ural approach to enhance the uplink capacity. WDM-PON cre-ates point-to-point links between an optical line terminal (OLT)and each optical network unit (ONU) by uniquely assigning awavelength to the user. Coarse WDM (CWDM) with the wave-length spacing of 20 nm in the spectral range from 1270 to1610 nm has been linked with the PON architecture by Interna-tional Telecommunication Union (ITU) G.983.3 [3]. However,the number of wavelengths is only 18, which may not be suf-ficient for the future multiple access system, which accommo-dates even a moderate number of users.

Optical code division multiple access (OCDMA) is onepromising candidate for a new-generation broadband multipleaccess technique with some features such as full asynchronoustransmission, low latency access, and soft capacity on demand.In particular, enhanced security is a frequently cited benefit ofOCDMA techniques [4]. There are two different approachesfor the multi-user coherent OCDMA system: synchronous andasynchronous OCDMA. In the synchronous OCDMA, propertiming coordination is required to carefully avoid the overlapsbetween signal and interferences [5], [6]. On the other hand, theasynchronous capability is essential in practical OCDMA sys-tems [1], [7], [8]. Recently, for coherent time-spreading (TS-)OCDMA, a multi-port OCDMA encoder/decoder (E/D) has thecapability of simultaneously processing multiple time-spreadoptical codes (OCs) with a single device [9], which makes it apotential cost-effective device to be used in the central officeof an OCDMA network to reduce the number of E/Ds [7].Meanwhile, a phase-shifted superstructured fiber Bragg grating(SSFBG) E/D is another attractive TS-OCDMA E/D, whichhas the ability to process ultra-long TS-OC with polarization

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300 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 27, NO. 3, FEBRUARY 1, 2009

Fig. 1. Architecture of OCDMA/WDM network using hybrid multi-port andSSFBG E/D.

independent performance, low and code-length independentinsertion loss, compactness as well as low cost for mass pro-duction [10].

By combining OCDMA with WDM technique, high-ca-pacity transmission in access networks can be achieved, whichin prospective can enable a gigabit-symmetric fiber-to-the-home(FTTH) [1], [7]. Hybrid using different types of the E/D in anOCDMA network, which is expected to significantly improvethe system flexibility and performance, has been proposed anddemonstrated [7], [11]. Fig. 1 shows the architecture of a flex-ible and cost-effective hybrid OCDMA/WDM network usinghybrid a multi-port E/D and SSFBG E/Ds. The multi-port en-coder with periodic frequency response can be used in the OLTto process multiple OCs in multiple wavelength bands with asingle device, whose cost can be shared by all the subscribers.While at each ONU, the WDM demultiplexing and OCDMAdecoding could be simultaneously carried out by employing alow cost multi-level phase-shifted SSFBG decoder. However,the implementation is only limited to the downlink.

In this paper, we will challenge the duplex transmissionbetween the OLT and ONUs. We develop the full-asynchronous10 GbE interface OCDMA prototype for the first time anddemonstrate field trials of duplex, fully-asynchronous, 10Gbps 8-user DPSK-OCDMA system by using 16-chip,16-level phase-shifted SSFBG at each ONU. Moreover, 160Gbit/s (10 Gbps 8-OCDM 2 WDM) field trial over 100 kmis also demonstrated.

II. PERFORMANCE OF HYBRID MULTI-PORT AND SSFBGENCODER/DECODER

The work in [11] developed 16-chip, 16-level phase-shiftedSSFBGs and demonstrated the multi-user OCDMA system. In

Fig. 2. Waveforms of (a) input pulse, (b), (c) encoded signals, and (d), (e) de-coded signals with 16� 16 port and SSFBG E/Ds.

this experiment, we prepare newly developed 16-chip, 16-levelphase-shifted SSFBG E/Ds. The center wavelength are 1546and 1551 nm, chip length is mm, total length of gratingis 8.32 mm, and the 16 phase levels are generated by shifting thechip grating by a step of . The patterns for SSFBGsOC-1 to 8 correspond to the OCs generated from the 16 16port encoder with input odd ports, output port 8, respectively.The frequency deviation (channel spacing) between neigh-boring ports of 16 16 port encoder is 12.5 GHz. The gratingswere simply packaged that is 45 mm 3 mm in size withouttemperature control.

Fig. 2(a)–(c) shows waveforms of the input pulse and thegenerated OCs encoded by the 16 16 port and SSFBG en-coder, respectively. The duration of the generated OCs is

ps (chip-rate: 200 Gchip/s). The peaks of each individualchips of Fig. 2(c) generated from SSFBGs are not as clear asFig. 2(b). This is probably due to the non-ideal fabrication con-dition for these gratings. Fig. 2(d) and (e) shows waveformsof the auto-correlation with different combinations of 16 16port and SSFBG E/Ds. They are quit similar showing that the16 16 port and SSFBG E/D can work with each other.

Generally, in a coherent OCDMA, where the time-spreadingfactor is ( : length of code), the interference level is

. PCR (power contrast ratio) (dB) shows the dif-ference between auto- and cross-correlation power of decodingoutput. As an example, to support ten active users in a coherentOCDMA network with chip-rate detection, should be lowerthan dB [12]. We need OCs with[13]; but if dB, a 50-chip code can work properly,and if PCR increases up to 20 dB, 5-chip codes are sufficient.Therefore, a new method to reduce , without employing ul-tralong OC and high chip rate, is to use OCs with ultrahigh


KATAOKA et al.: FIELD TRIAL OF DUPLEX DPSK-OCDMA SYSTEM 301

Fig. 3. PCR for 16� 16 port and SSFBG decoders. (a) En: 16� 16 port; De:SSFBG. (b) En: SSFBG; De: 16� 16 port. (c) En: 16� 16 port; De: 16� 16port.

PCR. Fig. 3 show the comparison of PCR for different com-binations of E/Ds. Comparing with Fig. 3(c), a pair of 16 16port, 16 16 port encoder/SSFBG decoders has the similar per-formance. PCR of 16-chip (200 Gchip/s), 16-level phase-shiftedcodes generated by the 16 16 port encoder can be as high as

dB, and is significantly reduced. It can suppress co-herent beat noise and MAI and achieve 8 multiplexed users.However, in Fig. 3(b), the SSFBG encoder/16 16 port de-coder are dB lower. Considering that the gratingsare uniform and there was obvious imperfectness in the fabri-cation. In addition, the bandwidth of the SSFBG encoder is nar-rower than 16 16 port decoder. Therefore, the spectrum gen-erated by the SSFBG encoder is cut off. However, these perfor-mances are expected to be further improved by using nonuni-form SSFBGs [14]. These performances verify the feasibilityof hybrid multi-port and multiphase-level phase-shifted SSFBGE/D to enable flexible and cost-effective OCDMA network.

III. CONFIGURATION OF OCDMA PROTOTYPE

We develop OCDMA prototypes, which include an OCDMtransmitter (Tx) and receiver (Rx). Fig. 4 show configurations

Fig. 4. Configurations and photographs of OCDMA prototype: (a) OCDM Txand (b) OCDM Rx for ONU.

and photographs of the OCDM Tx and Rx for an ONU, re-spectively. The OCDM Tx generates 10.3125 Gbps DPSK op-tical signal for the improved receiver sensitivity; better toler-ance to beat noise and MAI noise; no need for optical thresh-olding, no need for dynamic threshold level setting; and en-hanced security compared with OOK [15]. It consists of a mode-locked laser diode (MLLD), a phase modulator (LN-PM), an erbium-doped fiber amplifier (EDFA), a SSFBG en-coder, and an OCDM Tx board, which includes a 10 Gbit/s smallform-factor pluggable (XFP) module, a DPSK pre-coder, anda clock recovery circuits. An inputted 10 GbE signal is con-verted into a 10.3125 Gbps DPSK precoding serial-data andclock. The MLLD, which is driven by the recovered clock, gen-erates ps optical pulses at the repetition rate of 10.3125GHz. The generated signal was modulated with DPSK formatby the LN-PM and amplified by the EDFA. Finally, DPSK mod-ulated signal is encoded by the SSFBG encoder. The OCDM Txis 19-inch 3 U rack in size and can be independently drivenby the inputted 10 GbE signal without another external synthe-sizer. It allows full-asynchronous operation.

The OCDM Rx mainly consists of an optical decoder, afiber based 1-bit delay line, a dual-pin photo detector (PD),and an OCDM Rx board, which has an XFP module. Theinputted OCDM signals are correlated by the optical decoder.The correlated signal is launched into the 1-bit delay line anddual-pin PD for DPSK detection. In the XFP module, DPSKdetected signal is converted into the original 10 GbE signal.The OCDM Rx is in a 19-inch 1 U sized rack.

In this experiment, each OCDM Tx in the OLT shares theoptical encoder with all the subscribers for generating multi op-tical codes. On the other hand, in the ONU, the signal generatedfrom an OCDM Tx was split into two ports only for the lackof equipments. Therefore, we also didn’t use the SSFBG in theOCDM Tx of the ONU.

IV. FIELD TRIALS

Fig. 5 shows the experimental setups of down- and up-linkfield demonstrations, respectively. We employed 4 OCDM Txs



Fig. 5. Experimental setups and results: (a) downlink and (b) uplink.

in this experiment. Each OCDM Tx was independently drivenby different signal sources: a pulse pattern generator (PPG) forthe bit error rate (BER) measurement, a network analyzer, andtwo high-definition video (HDV) streaming systems.

A. Downlink

In downlink, each OCDM Tx asynchronously generated10.3125-Gbps DPSK signal is shown in insets (i) in Fig. 5.Each OCDM Tx output was split into two branches withbalanced power by variable optical attenuators (VOAs) andlaunched into the 16 16 port encoder that can simultaneouslygenerate and multiplex 8 different coherent TS-OCs with16-chip (200 Gchip/s). We used all the odd input ports and#8 output port of the encoder for generating 8 different OCs.For investigating the system performance in the worst scenariowhere the interference becomes most serious, polarizationcontrollers (PCs) were placed to align the polarization states ofall the signals. Inset (ii) in Fig. 5 shows the waveform of thegenerated OC. The eight OCDMA signals were launched intoa field single mode fiber (SMF), which is part of the JNGIInational test bed installed in Tokyo metro area between Koganeiand Otemachi [16] in a loop back configuration with a round

trip length of 100 km, and a dispersion compensation fiber(DCF). Inset (iii) in Fig. 5 shows the waveform of 8 OCDMAsignal. The field transmission loss was 20 dB including losses atpatch cords and connectors in the laboratory. The total opticalpowers launched into each installed SMF and DCF wereand , respectively. The transmitted signals were splitinto 8 lines and launched into each ONU (OCDM Rx). Ateach ONU, the OCDMA signal was decoded by the 16-chip,16-phase-shifted SSFBG decoder. The insertion loss of theSSFBG was dB. The decoded signal was detected by afiber based 1-bit delay line and dual pin PD, which performedthe DPSK detection. For the BER measurement, the DPSKdetected signal was recovered by the clock-and-data-recovery(CDR) circuit and forwarded to the BER tester (BERT). In-sets (iv), (v), and (vi) in Fig. 5 show the eye diagrams afterthe SSFBG decoder, DPSK detector, and CDR, respectively.Fig. 6(a) and (d) shows the measured BER performances forsingle- ( ) and eight-user ( ) in case of B-to-Band field transmission, respectively. Error-free transmissionhas been achieved for all eight users. About dB powerpenalty has been observed at for OCDMAcompared with . The penalties between B-to-B and the



Fig. 6. Measured BERs. (a)–(c) Downlink in case of B-to-B. (d)–(f) Downlink after field transmission. (g) Uplink in case of B-to-B. (h) Uplink after field trans-mission without FEC. (i) Uplink with FEC.

field transmission were almost zero because of its same OSNRcondition and almost complete dispersion compensation.

Moreover, we demonstrated 160 Gbit/s (10Gbps 8-OCDM 2 WDM) downlink field trial forOCDMA/WDM network. In this demonstrattion, two asyn-chronous OCDM Txs on each wavelength were employed andthen split into four ports, respectively. The center wavelengthswere 1546 and 1551 nm. These signals were launched into asingle 16 16 port encoder and simultaneously multiplexed.The 2 WDM 8 OCDMA signals were transmitted over the100 km field SMF. At each ONU, the transmitted signalswere simultaneously demultiplexed and decoded by theSSFBG decoder. Fig. 6(b)-(c), (e)-(f) show the measuredBER performances for single- ( ) and eight-user( ) in case of B-to-B and field transmission, respectively.Error-free transmission has been achieved for all the users ofall channels. About dB power penalty has been observedat for OCDMA compared with .The penalties between B-to-B and the field transmission werealso almost zero because of its same OSNR condition andalmost completely dispersion compensation.

B. Uplink

In uplink, as well as downlink, each Tx generated 10.3125Gbps DPSK signal is shown in inset (vii) in Fig. 5. These out-puts were split into 2 branches and then launched into 8 differentSSFBG encoders, which were the same device as SSFBG de-coder used in downlink experiment, respectively. Inset (viii) in

Fig. 5 shows the waveform of the generated OC. These eightdifferent OCs were asynchronously multiplexed with the samepolarization and power in the worst scenario as well as down-link experiment, and then launched into the 100-km field SMFwith the DCF. Inset (ix) in Fig. 5 shows the waveform of theeight OCDMA signals. At the OLT, the eight OCDMA signalswere simultaneously decoded by the 16 16 port decoder. Theinsertion loss of the 16 16 port decoder was dB. The de-coded signal was detected by the same method as downlink. In-sets (x), (xi), and (xii) in Fig. 5 show the eye diagrams after the16 16 port decoder, DPSK detector, and CDR, respectively.Fig. 6(g) and (h) shows the BER performances of uplink forsingle- ( ), four- ( ), and eight-user ( ) in caseof B-to-B and field transmission, respectively. In this case, 4OCDMA has been achieved error-free transmission for all of theusers. However, in 8 OCDMA, six users have not achieved errorfree except 2 users. This is probably due to the nonideal fabri-cation condition for SSFBG gratings. Adding the forward errorcorrection (FEC) parity, which is Reed–Solomon code (RS(255,239)), to the data stream, we measured BER performance at10.71 Gbps (10 G for payload FEC overhead). Fig. 6(i)shows the BER performances of uplink with FEC. Error-freetransmission has been achieved for all of the users.

V. CONCLUSION

We have developed full-asynchronous 10 GbE interfaceOCDMA prototype for the first time. We have also conducteda field trial of duplex, fully-asynchronous, 10 Gbps, 8-user



DPSK-OCDMA system. A key enabler for cost-effective con-figuration is the multi-port en/decoder at an OLT and SSFBGen/decoder at each ONU. A promising deployment scenariowould be to overlay this duplex OCDMA system onto existingWDM PON system for the system scale-up on demand.

ACKNOWLEDGMENT

The authors would like to thank Y. Tomiyama, H. Sumimoto,and T. Hashimoto of NICT for their support in this experiment.This experiment was conducted by the field-installed fiber ofJGN2.

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[16] [Online]. Available: http://www.jgn.nict.go.jp/english/index.html

Nobuyuki Kataoka (S’03–M’06) received the B.E.,M.E., and Dr. Eng. degrees from Osaka University,Osaka, Japan, in 2001, 2003, and 2006, respectively.

In 2006, he joined the National Institute of Infor-mation and Communications Technology (NICT),Tokyo Japan. His research interests are in the area ofphotonic networks such as optical packet switching,optical add/drop multiplexing, and optical codedivision multiple access.

Dr. Kataoka is a member of the Institute of Elec-tronics, Information and Communication Engineers

(IEICE) of Japan.

Naoya Wada (M’97) received the B.E., M.E., andDr. Eng. degrees in electronics from Hokkaido Uni-versity, Sapporo, Japan, in 1991, 1993, and 1996, re-spectively.

In 1996, he joined the Communications ResearchLaboratory (CRL), Ministry of Posts and Telecom-munications, Tokyo, Japan. He is currently a SeniorResearcher with the National Institute of Informationand Communications Technology (NICT), Tokyo,Japan. Since April 2006, he has been project readerof Photonic Node Project and research manager of

the Photonic Network Group. His current research interests are in the area ofphotonic networks and optical communication technologies, such as opticalpacket switching (OPS) network, optical processing, and optical code-divisionmultiple access (OCDMA) system. He has published more than 70 papers inrefereed journals and more than 200 papers in refereed international confer-ences.

Dr. Wada is a member of IEEE Comsoc, IEEE Lasers and Electro-Optics So-ciety, the Institute of Electronics, Information and Communication Engineers(IEICE), the Japan Society of Applied Physics (JSAP), and the Optical So-ciety of Japan (OSJ). He was the recipient of the 1999 Young Engineer Awardfrom the Institute of Electronics, Information and Communication Engineers ofJapan, and the 2005 Young Researcher Award from the Ministry of Education,Culture, Sports, Science and Technology.

Xu Wang (S’91–M’98–SM’06) received the B.S. de-gree in physics from Zhejiang University, Hangzhou,China, in 1989, the M.S. degree in electronics engi-neering from the University of Electronics Scienceand Technology of China (UESTC), Chengdu, China,in 1992, and the Ph.D. degree in electronics engi-neering from the Chinese University of Hong Kong(CUHK) in 2001.

From 1992 to 1997, he was a Lecturer with theNational Key Laboratory of Fiber Optic BroadbandTransmission and Communication Networks of

UESTC. In 2001–2002, he was a Postdoctoral Research Fellow with theDepartment of Electronic Engineering, CUHK. From 2002 to 2004, he waswith the Department of Electronic and Information Systems, Osaka University,Osaka, Japan, as a TAO Research Fellow. From 2004 to 2007, he was anexpert Researcher with the Photonic Network Group, National Institute ofCommunication and Information Technology (NICT), Tokyo, Japan. He joinedthe School of Engineering and Physical Sciences, Heriot Watt University,Edinburgh, U.K., as a Senior Lecturer in July 2007. He is also serving as anInvited Advisor of NICT and Advisory Professor with Chongqing University ofPost and Telecommunication, Chongqing, China. His research interests includefiber optic communication networks, optical code-division multiplexing,optical packet switching, application of fiber gratings, microwave photonics,and fiber optic signal processing. He has filed five patents and delivered over30 invited talks in international conferences. He has published more than 110technical papers and he is the first author of over 80 among them.

Dr. Wang was awarded the Telecommunications Advancement Research Fel-lowship by the TAO of Japan in 2002 and 2003.



Gabriella Cincotti (A’01–M’03–SM’06) receivedthe Laurea (M. Sc.) degree (cum laude) in electronicengineering from “La Sapienza” University ofRome, Rome, Italy, in 1992.

She was a Project Engineer with the MicrowaveLaboratory of ALENIA, Aeritalia & Selenia S.p.A.,Rome, from 1992 to 1994. She joined the Departmentof Electronic Engineering of University “Roma Tre,”Rome, as an Assistant Professor, in October 1994. InMay 2005, she became an Associate Professor withthe Department of Applied Electronics. Her research

interests are in optical packet switching and optical code division multiple ac-cess networks and devices. She has been the Guest Editor of the JOURNAL OF

LIGHTWAVE TECHNOLOGY and Optical Signal Processing and serves as TopicalEditor of Optics Letters. She has authored about 170 papers in refereed journalsand conference proceedings, holds a Japanese and two international patents.

Prof. Cincotti is a senior member of the IEEE Lasers and Electro-OpticsSociety (LEOS) and member of the National Inter-University Consortium forTelecommunications (CNIT), the Optical Society of America (OSA), and theInter-University Consortium for Matter Science (CNISM).

Akira Sakamoto received the B.E. and M.E. de-grees in electrical engineering from Keio University,Tokyo, Japan, in 1996 and 1998, respectively.

In 1998, he joined Fujikura Ltd., Koto-ku, Tokyo,Japan, where he has been engaged in research and de-velopment of a fiber Bragg grating and other opticaldevices.

Yoshihiro Terada received the B.E. and M.E. de-grees in material engineering from Tokyo Institute ofTechnology, Tokyo, Japan, in 1996 and 1998, respec-tively.

In 2001, he joined the Fujikura Ltd., Koto-ku,Tokyo, Japan, where he has been engaged in theresearch and development of optical fibers anddevices for optical communication.

Tetsuya Miyazaki (M’03) received the B.S. degreein physics from the University of Tsukuba, Ibaraki,Japan, in 1985 and the M.S. and Dr. Eng. degrees ininformation processing from the Tokyo Institute ofTechnology, Tokyo, Japan, in 1987 and 1997, respec-tively.

From 1987 to 2002, he was with KDDI R&D Lab-oratories, where he was engaged in coherent opticalcommunications and WDM optical networks. Since2002 April, He has been with NICT where he was en-gaged in ultra-fast and multi-level modulation tech-

niques. Since 2005 January, he has been a group leader of the Photonic NetworkGroup.

Dr. Miyazaki is a member of the IEEE Laser and Electro-Optics Society(IEEE LEOS) and the Institute of Electronic, Information, and CommunicationEngineering (IEICE) of Japan.

Ken-ichi Kitayama (S’75–M’76–SM’89–F’02)received the B.E., M.E., and Dr. Eng. degrees incommunication engineering from Osaka University,Osaka, Japan, in 1974, 1976, and 1981, respectively.

In 1976, he joined the NTT Electrical Commu-nication Laboratory in 1976. During 1982–1983, hespent a year as a Research Fellow with the Univer-sity of California, Berkeley. In 1995, he joined theCommunications Research Laboratory (presentlyNational Institute of Information and Communica-tions Technology, NICT), Tokyo. Since 1999, he has

been a Professor with the Department of Electrical, Electronic and InformationEngineering, Graduate School of Engineering, Osaka University. His researchinterests are in photonic networks, optical signal processings, optical code-divi-sion multiple access (OCDMA) systems, and radio-over-fiber systems. He haspublished over 230 papers in refereed journals and holds more than 30 patents.He currently serves on the Editorial Boards of the JOURNAL OF LIGHTWAVE

TECHNOLOGY (JLT), the IEEE TRANSACTIONS ON COMMUNICATIONS, andOptical Switching and Networking as the Associate Editor. He has served as aGuest Editor for special issues, including for the Journal of the Optical Societyof America B on “Innovative Physical Approaches to the Temporal or SpectralControl of Optical Signals” in 2002, the IEEE JOURNAL OF SELECTED TOPICS

IN QUANTUM ELECTRONICS on “Optical Code in Optical Communications andNetworks” in 2007, JLT on “Convergence of optical wireless networks,” in2007, the IEEE JOURNAL OF SELECTED AREAS OF COMMUNICATIONS on “Roleof optical and electronic technologies for large capacity switches and routers”in 2008, and JLT on “Converged Optical Network Infrastructures in Support ofFuture Internet and Grid Services” in 2008.

Dr. Kitayama is a Fellow of the Institute of Electronic, Information, and Com-munication Engineering (IEICE) of Japan. He was the recipient of the 1980Young Engineer Award from the Institute of Electronic and CommunicationEngineers of Japan, the 1985 Paper Award of Optics from the Japan Societyof Applied Physics, 2004 Achievement Award of IEICE of Japan, and 2007 theShida Rinzaburoh Award.


Documents

JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 27, NO. 3, …home.eps.hw.ac.uk/~xw66/Publications_files/... · ﬁber based 1-bit delay line, a dual-pin photo detector (PD), and an OCDM Rx