Diapositive 1 - CHIST-ERA

23/06/2015

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THz communications for next generation HD rate wireless links

TENXSYS Talk, 2015, June 17th

G. Ducournau, M. Zaknoune, P. Szriftgiser, Jean-François Lampin

G. Ducournau, CHIST-ERA TENXSYS, 2015, June 17th Lisbon

• THz communications: general issues

• THz devices for coms (Tx and Rx)

• Some Reported com links

• Some conclusions

Outline

2 G. Ducournau, CHIST-ERA TENXSYS, 2015, June 17th Lisbon





Outline

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THz coms: general issues (1/3): why?

• Context: how to place T-ray coms on the telecom map?

[P.J. Winzer; IEEE Proceedings]

- Line of Sight

- Point to point (actual)

- Single/multi-carrier?

Future fixed ‘pencil links’

Future mobile accesses

Radio comms

Marconi

Satellite comms LMDS

WPAN

60 GHz LAN

1 GHz

1 THz

1 MHz

1900 1940 2020 1980

THz

“We will use THz carrier frequencies by 2020”, a f t e r T . S . B i r d , K e y n o t e t a l k a t Asia-Pacific Microwave Conference, Melbourne, A u s t r a l i a , D e c e m b e r 2 0 1 1 .


THz coms: general issues (2/3): why?

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Changing activities…

How handle this « big » wireless data???

… Increase backhaul network capability

Some years ago…

Today…


THz coms: general issues (3/3): THz windows

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« 400 GHz » window

« 200/300 GHz » window

« 600 GHz » window

THz coms may index that range

[xxx]


Applications… indoor? (LiFi like?)

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Courtesy of SEEM service, Lille University

Has to be direct line

Wall/objects reflexions?

Advantage of Photonics:

multi-user service


Concept for optical-to-THz radio links… outdoor?






Outline

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THz devices for coms

From micro-waves…

‘THz’: 100 GHz (l = 3 mm)? 300 GHz (l = 1 mm)?

(Depend on electrical/optical point of view!)

…or optics

…to THz



• Electronic side: ‘Bench-top, waveguide based’ TX

Multiplication chains: Phase noise (driven by synthesizers) Can be powerfull (mW) but narrow band Usefull for first tests (trials, channel investigation) Can be modulated using SHM at output or vectorial THz signaling:

Cost!! Bulky

[600 GHz source, IEMN]

GaAs Schottky Technology

GaN based future?

[Electronics Letters 50 (23), 1715-1717, 2015]

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Very usefull for first links Commercially available



• Electronic side: Integrated Sources for TX

Oscillators (fundamental): - HEMT InP 35 nm -1.3 dBm @ 300 GHz - SiGe Bipolar 2.7 dBm @ 106 GHz - 130 nm CMOS -3.5 dBm @ 121 GHz Oscillators (harmonic): - 130 nm CMOS -3.5 dBm @ 256 GHz - 65 nm CMOS -1.2 dBm @ 290 GHz - 65 nm CMOS -1.5 dBm @ 288 GHz

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Major issue Integration with free space


THz photomixers

• Several structures: photo-conductors, photo-diode are most common in THz now:

• Photoconductor ‘pionners’(Auston, Grischkowski, Brown)

• Unitraveling carrier photodiodes ‘pionners’ (Ishibashi, Ito, Nagatsuma)

• Traveling wave structures, resonant structures…

UTC-PD devices: up to mW level (0 dBm) demonstrated around 300 GHz band

• Silicon photonics (Ge Photodiodes) is pushing the limits: may become a competitor?

• Less powerfull than THz UTC-PD devices BUT… level of integration due to silicon photonics processes!

• SiGe photodiodes -41.3 dBm @ 180 GHz for ex.

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[Hajimiri, IMS 2015]

Key advantage: « fiber-optic » compatible

[Song et al., IEEE MWCL (2012)]


THz photomixers: some devices

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2×UTC-PD integrated (module):

1.2 mW @ 300 GHz

(20 mA/PD @ -3.9 V)

NBUTC-PD: 0.67 mW @ 260 GHz

Flip-chip on AlN

TW-UTC: 110 µW @ 300 GHz

[Song et al., IEEE MWCL (2012)]

[Wun et al., IEEE PTL (2014)]

[Rouvalis et al., IEEE MTT (2012)]

• Advantage of PM devices: the relative bandwidth.

• 1 device = compatible with multi-carrier THz emission



• Receivers (Rx):

• Photonic devices?

- photodiodes ?

- photo-conductors? - (No really efficient material at 1.55 µm)

- At 0.8 µm OK but no telecom industry

Photonics devices for THz detection?

1.55 µm TDS systems were integrated video bandwidth is narrow.

Seems to be not appropriate for coms

Electronic devices: sub-harmonic mixers Good performances (Conv losses 8 dB around 300 GHz) Usefull for first tests (field trials, channel investigation) Can also be modulated using SHM at Tx output for vectorial THz signaling.

GaAs Schottky Technology

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Rx: maybe electronic (more efficient)



• Receivers (Rx): ‘Bench top’ Electronic devices

• Ways for THz detection: direct and heterodyne schemes using diodes

DIRECT

THz-modulated signal Data signal…

- 50 ohms loading - Lost of phase info./quadratic detection

- Phase noise not a problem - No L.O. required

THz-modulated signal

- 50 ohms loading - Phase information conserved/linear - Phase noise: high quality required - L.O. required - Very sensitive

Data signal…

HETERODYNE

+ LO

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Very usefull for first links Commercially available


Inside the Rx… the LNAs!

• Receivers (Rx): ‘Integrated’ Electronic devices / First chipsets (Tx/Rx modules)

• IAF (Germany) : mHEMT Single devices (Lg -> 20 nm), fT/fmax 660/1000 GHz

LNA MMICs: 24 dB @ 300 GHz, (NF 5 dB), 4 stages

• Sch. Electrical Engineering, Korea University/Teledyne: 0.25 µm DHBT InP Tx/Rx chip @ 300 GHz

Tx: -2.3 dBm, 18 GHz (3dB BW)

Rx: 20 GHz BW, NF > 12 dB.

• IHCT/Wuppertal SiGe chipset @ 240 GHz I/Q Tx/Rx, 65 GHz Bandwidth

• Validated in Tx/Rx transmission over 30 cm

Infineon/IHP J-Band amplifiers (220 GHz): > 20 dB

(LNA, 0.13 µm SiGe)

• Northrop Grumman 480 GHz amplifier (2010), HEMT InP sub 50 nm.

660 GHz amplifier (2012)

THz amplifier (2014)

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Future: Mixed technologies? Depend on application!

User (<< cost) or specific (Space, P2P)

[M. Schlechtweg, IMS 2015]

[U. Pfeiffer, IMS 2015]

[W. Deal, MWCL 2010]

[S. Kim et al. TTST 2015]


Other Rx/circuits or specific devices

• Receivers (Rx):

# 300 GHz Fully integrated Rx (ASK)

InP amp.

Up to 12.5 Gbps (BER = 10-9 @ -16 dBm)

0.3 m (25 dBi Tx, UTC-PD)

# 300 GHz QPSK Tx and Rx (250 nm InP HBT)

Tested on-wafer up to 50 Gbps

• Resonant Tunelling Diode (RTD) Tx for short distance THz coms (Rx = Schottky)

542 GHz, 2 Gbps / 1 cm distance / BER 2.10-8

…

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[Song, TMTT July 2013]

[Song, TMTT March 2014]

[Ishigaki Elec. Lett., 2012] … Could not be exhaustive!!!

Tested on-wafer

23/06/2015

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Outline


Some THz links reported

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References corresponding to paper: G. Ducournau et al. “THz Communications using Photonics and Electronic Devices: the Race to Data-Rate”, Journal of Infrared, Millimeter, and Terahertz Waves, February 2015, Volume 36, Issue 2, pp 198-220.

• Reported working data links used mainly III/V electronic and/or photonic devices



• First Links: 120 GHz at NTT: the ‘T-ray coms’ pionners

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Integrated dual-freq laser



• Photonics is pushing up the first tests at highest data rates

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W-band (multiplexed channels)




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Highest data rate @ 237.5 GHz Including LNA at Rx




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Highest data rate @ 300 GHz: 48 Gbit/s

Dual polarization UTC-PD




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Ultra-broadband @ 400 GHz




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Up to 625 GHz + Comparative tests IR vs THz

(Same data rates)


Data formats

• THz window for first applications (data com): seems to be 220-330 GHz (Huge BW)

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• Interests:

- Sharing bandwidth

- co-existence of THz links with observation services…

• Simple amplitude coding: easy but not efficient (0.5 bit/s/Hz of spectral data density)

• Bandwith in THz is huge but some other techniques are possible:

• High level signaling

• Multi-carrier frequencies

Basic Medium More Complex

F F

Propagation of complex THz signaling With environnemental effects???

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Fiber-to-THz bridge using Photomixing

• Key advantage of THz photonics devices: fiber-optic compatibility

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• Create a fiber-to-THz bridge?

• Only Use photonics with a

optical signal!!!

QPSK at 32 Gbit/s @ 400 GHz

[Ducournau, Elec. Lett, June 2015]

Easy Integration with coherent optical networks!


Other…

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• IEEE 802.15 THz group to study the release of a 100 Gbps standard for THz coms…

• -> 2020?

Leader: Thomas Kuerner


THz link budget

• Link budget:

• Order of magnitude of LdB

• 1 km: easy to have 150 dB!

• Large Optics (P2P): 2*50 dBi

• Still 50 dB + Margin required!

• Links: up to km range?

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THz links: will be first for Point to Point (P2P), up to km range?


Why not free space optics??

• Free space optics has been developped also…

• Devices with affordable cost / Commercially available for Gbps back-haul

• Quite simple to operate

• Weakness with envrionnemental effects compared to T-rays (wavelenght effects)

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220-330 GHz band

[Adapted from K. Miyauchi, “Millimeter-Wave

Communications”, ISBN 0-12-147709-6, 1983]






Outline


Conclude with open questions?

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• « Current state of the art ?»

• It works! Technology is very close to be fully operational in the lab.

• First ‘Out-of-the-lab tests’ ok with packages devices!

TRL achieved between 4 and 5?

depending on technologies used



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• « What your ‘vision’ of the field is in ~20 years’ time? »

• 220-330 GHz band in use for ‘operator’ needs (fixed links) or backhauls: very probable

• Every smartphone connected with THz: ??? Depend on back-haul capability !

BUT required: robust components, channel effects known and taken into account in an operational system

Still many things to develop in that field!

• Need outdoor tests, environnemental effects, weather effects,

• Field trials, mixed/hybrid technologies

• Next 10 years: complete efficient packaged systems to be used in outdoor!

• Interface with ‘fiber optic world’: could be III/V for specific purposes.

• Need channel effects modeling for indoor (multipath, signal processing…)!!!

• Silicon photonics technologies applied to THz G. Ducournau, CHIST-ERA TENXSYS, 2015, June 17th Lisbon


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Perceived challenges in Terahertz Band New-Generation Mobile Communication Systems

Demonstrate THz High Data rates links in intented environment Find a way (normalization for ex.) to make THz radio compatible with existing systems Physical layer but also MAC (Medium Access Control) Show a real gain beyond E-band coms (71-76 and 81-86 GHz) recently opened

Technology? (III-V, Photomixers, SiGe, CMOS, …): Will they all be used?

Perceived opportunities in Terahertz Band New-Generation Mobile Communication Systems It is new => so new activities, new markets, applications, usages, opportunities New frequencies: mandatory to release the saturated electromagnetic spectra! It should be used… it is only a question of time-scale!

G. Ducournau, CHIST-ERA TENXSYS, 2015, June 17th Lisbon 36

Live THz com demo!

23/06/2015

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THz coms at IEMN, Lille

1 Gbps@200 GHz

Year

Brillouin lasers for THz Narrow THz gen.

UTC-PD for THz

UWB @ 400 GHz …

THz coherent coms THz QPSK

High distance P2P links Channel effects, …

2014 2013 2011 2010 2008 2015

• THz coms are still in their infancy

• Photonics-based devices are very attractive for fiber optic compatibility and bandwidth.

• …

• Next-gen. UTC-PD devices

• Solid state InP

G. Ducournau, CHIST-ERA TENXSYS, 2015, June 17th Lisbon 38

Thank you!

Diapositive 1 - CHIST-ERA

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