november 2013 doc.: ieee 802.15-13-0653-00-0thz … · – fractional bandwidth ... • mode-locked...
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doc.: IEEE 802.15-13-0653-00-0thz
Submission
November 2013
Norihiko Sekine (NICT), et. al.Slide 1
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: 30-Gbps-class terahertz transmission using optical sub-harmonic IQ mixer for backhaul/fronthaul directly connected to optical networksDate Submitted: 10 November, 2013Source: Norihiko Sekine, Atsushi Kanno, Toshiaki Kuri, Isao Morohashi, Akifumi Kasamatsu,
Iwao Hosako and Tetsuya KawanishiNational Institute of Information and Communications Technology4-2-1, Nukuikita, Koganei, 184-8795, Tokyo, JapanVoice: +81 42 327 5848, FAX: +81 42 327 6941, E-Mail: [email protected] Yoshida and Ken’ichi Kitayama, Osaka UniversityVoice: +81 6 6879 7728, FAX: +81 6 6879 7688, E-Mail: [email protected]
Re: n/aAbstract: 30-Gbit/s-capacity transmission using multi-level modulation at 300 GHz are briefly presented as information for future 100-Gbit/s terahertz point to point link.Purpose: Informing 802.15SG100G on coherent communication technologies for fixed point-to-point linkNotice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.
doc.: IEEE 802.15-13-0653-00-0thz
Submission Norihiko Sekine (NICT), et. al.Slide 2
30-Gbps-class terahertz transmission using optical sub-harmonic IQ mixer for
backhaul/fronthaul directly connected to optical networks
Norihiko Sekine*, Atsushi Kanno*, Toshiaki Kuri*, Isao Morohashi*, Akifumi Kasamatsu*,
Iwao Hosako*, Tetsuya Kawanishi*,Yuki Yoshida** and Ken’ichi Kitayama**
*National Institute of Information and Communications Technology (NICT), Japan
**Osaka University, Japan
November 2013
doc.: IEEE 802.15-13-0653-00-0thz
Submission
Abstract
• Introduction of realization of multi-level-modulated 300-GHz signal transmission technique by optical technology.– Broad bandwidth optical modulator with bandwidth > 40 GHz.
• Optical sub-harmonic quadrature mixer (sub-harmonic IQ mixer) is configured with conventional and advanced optical fiber communication components.
• The technique is capable of the terahertz backhaul/fronthauldirectly connected to broadband optical networks.
November 2013
Norihiko Sekine (NICT), et. al.Slide 3
doc.: IEEE 802.15-13-0653-00-0thz
Submission
Bandwidth Issues on Tx and Rx Devices• Available bandwidth of conventional RF devices:
– Fractional bandwidth (FBW) of electrical amplifier and IQ mixer: ~ 10-15%
e.g. At 300 GHz, BW will be approximately 30-45 GHz.– For example, bandwidth of 30 and 45 GHz at 300-GHz carrier meets 22.5-
Gbaud and 31-Gbaud QPSK with rectangular pulse shape because identical and empirical required bandwidths for modulation are a half and 70% of available bandwidth, respectively.
• Realization of 40-Gbps and 100-Gbps capacity requires higher-order multi-level modulation such as quadrature phase-shift keying (QPSK) and quadrature amplitude modulation (QAM).
November 2013
Norihiko Sekine (NICT), et. al.Slide 4
OOK QPSK 16 QAM 64 QAM
22 Gbaud 22 Gbps 44 Gbps 88 Gbps 132 Gbps
31 Gbaud 31 Gbps 62 Gbps 124 Gbps 186 Gbps
doc.: IEEE 802.15-13-0653-00-0thz
Submission
How to Generate Multi-level Signal• Using electrical IQ modulator/sub-harmonic quadrature mixer
– Pros.: Robustness, small footprint– Cons.: Narrow bandwidth (30~40GHz at 300GHz)
• Optical IQ mixer/SHIQM configured with optical two-tone generator, IQ modulator and photomixer– Pros.: Broad bandwidth (>>40GHz), frequency tunability over the band– Cons.: Quite large footprint, complexity
November 2013
Norihiko Sekine (NICT), et. al.Slide 5
IQ mixer or SHQM(Sub-harmonic quadrature mixer)I component
Q componentLO
Terahertz signal
Optical IQ modulator Photmixer
Opt. freq.f0
Freq.f0
Terahertz signalOptical spectrum
LO
I,Q signals
Optical two-tone signal
Optical SHIQM
doc.: IEEE 802.15-13-0653-00-0thz
Submission
How to Demodulate Multi-level Signal
• To demodulate the multi-level signal, coherent detection technique is indispensable.– ex.) 3GPP Rel. 10: 20-MHz-BW OFDM-256QAM– IEEE802.11ad: 2.16-GHz-BW 16QAM
• High-speed digital signal processing technologies can be diverted from advanced optical communication technology, so-called “digital coherent detection.”– In advanced optical communication, 28-Gbaud dual-polarization
quadrature phase-shift keying (QPSK) has been already standardized in the Optical Internetworking Forum (OIF) and installed for 100-Gb/s optical transport system.
November 2013
Norihiko Sekine (NICT), et. al.Slide 6
doc.: IEEE 802.15-13-0653-00-0thz
Submission
Block Diagram of Optically-Synthesized Terahertz Signal Transmission
November 2013
Norihiko Sekine (NICT), et. al.Slide 7
300-GHz opticaltwo-tone generator
10-Gbpsbinary data(PRBS15)
Photomixer
Optical SHIQM
LO
AD
C (8
0Gsp
s)
Off-
line
DS
PSHM
IF amp.
Terahertz Rx
300-GHz radio
Optical signal generator: Developed in NICTQPSK modulator: Sumitomo Osaka Cement, T.SBXH1.5-20PD-ADCPhotomixer: NTT Electronics, IOD-PMJ-110001Horn antenna: Radiometer Physics Gmbh, FH-SG-325-25SHM: VDI, VDI-MixAMC-157IF amp.: SHF, 804TLADC: LeCroy, WaveMaster 830ZiOff-line DSP: Developed by NICT and Osaka Univ.
Horn antenna
Optical fiberCoaxial/waveguide
10-GHz LO
Optical IQModulator
Heterodyne
Diverted from optical coherent detector
doc.: IEEE 802.15-13-0653-00-0thz
Submission
300-GHz Optical Two-Tone Generator Based on Optical Frequency Comb Source
November 2013
Norihiko Sekine (NICT), et. al.Slide 8
Optical Comb Generator
Optical Filtering
Optical spectrum
Optical Two-Tone Signal
Opt. freq.
f0==n×fLO
fLO
• Mode-locked laser diode• optical modulation• …
• Arrayed waveguide grating• Fiber Bragg grating• Liquid-crystal-based optical filter• …
ex.) optical spectrum of modulator-based optical frequency comb
ex.) obtained SSB phase noise of 300 GHz signal down-converted by SHM into 15 GHz
Photomixer works as an envelop (square-low) detector to generate the RF signal f0 from the optical two-tone signal with the frequency separation f0.
n-th-order multiplier
doc.: IEEE 802.15-13-0653-00-0thz
Submission
Picture of Terahertz Transmission Section between Terahertz Converter and Rx
November 2013
Norihiko Sekine (NICT), et. al.Slide 9
Terahertz RX with 300-GHz SHMPhotomixer
300GHz radio
For proof-of-concept demonstration, short-distance transmission was performed because the output RF power of the photomixer was much less than 100 uW.=> Insertion of 300-GHz amplifier will extend the transmission distance >10 m.
doc.: IEEE 802.15-13-0653-00-0thz
Submission
Spectra of Optical Signal at Optical Tx, and Received IF Signal at Terahertz Rx
• 10-Gbaud (line rate: 20-Gbps) and 16-Gbaud (line rate: 32-Gbps) QPSK signals at 300 GHz are received successfully.
• There is no significant degradation of obtained IF spectra.
November 2013
Norihiko Sekine (NICT), et. al.Slide 10
10 Gbaud
16 Gbaud
20GHz
doc.: IEEE 802.15-13-0653-00-0thz
Submission
Observed Bit Error Rates and Constellation Maps
• Clear BERs and Constellations are shown at the receiver within a forward error correction limit of BER of 2×10-3.
– FEC: for example, RS(1023,1007)/BCH(2047,1952) super FEC code descried in ITU-T Rec. G.975.1 (2004).
November 2013
Norihiko Sekine (NICT), et. al.Slide 11
10-Gbd 20-cm
16-Gbd 20-cm
BER: 2×10-3
doc.: IEEE 802.15-13-0653-00-0thz
Submission
Power Penalties on Observed BERs
• Possible origins of power penalty corresponding to approx. 2.5 dB in each arrow, which is evaluated with conversion ratio of the photomixer, are
– Transmission distance difference betw. 15 cm and 20 cm (black arrow). Estimated propagation loss: approx. 3.0 dB using simple Friis eq.
– Difference of symbol rates of 10-Gbd and 16-Gbd (red arrow).ADC bandwidth of 30 GHz cannot fully demodulate 16-Gbaud signal.
November 2013
Norihiko Sekine (NICT), et. al.Slide 12
doc.: IEEE 802.15-13-0653-00-0thz
Submission
Channelization for 300-GHz Frequency Division Multiplexing/Frequency Division Duplexing
• Proof-of-concept demonstration with frequency-division-multiplexing (FDM) or frequency-division-duplexing (FDD)
– 5-Gbaud QPSK at 290 GHz (ch. #1), 300 GHz (ch. #2) and 310 GHz (ch. #3).
November 2013
Norihiko Sekine (NICT), et. al.Slide 13
290 GHz300 GHz310 GHz
Optical spectraIF spectra of received THz signal
doc.: IEEE 802.15-13-0653-00-0thz
Submission
Observed BERs of FDM configuration
• Power penalty of observed BERs is caused by the frequency response of a photomixer and an SHM.
November 2013
Norihiko Sekine (NICT), et. al.Slide 14
doc.: IEEE 802.15-13-0653-00-0thz
Submission
Summary and Consideration
• Coherent terahertz transmission with multi-level modulation was proposed and demonstrated by optical SHIQM and digital coherent detection with heterodyning.
• Optical SHIQM has advantages on its broad bandwidth and center frequency tunability.
• 20-Gb/s- and 30-Gb/s-class-capacity transmission over air were realized by 10- and 16-Gbaud QPSK modulation.
• As a length of an optical fiber can be extended easily, remote terahertz radio head configuration is capable of realization of terahertz backhaul/fronthaul directly connected to optical fiber networks.
November 2013
Norihiko Sekine (NICT), et. al.Slide 15
Acknowledgments: This research was conducted as part of the project entitled “Agile DeploymentCapability of Highly Resilient Optical and Radio Seamless Communication Systems” program of theCommissioned Research of the National Institute of Information and Communications Technology(NICT).