Transcript ppsx - OptCom - Politecnico di Torino

HONET-ICT 2015
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Optical Communications:
from the Smoke Signals to
Gigabit Internet
Vittorio Curri
OptCom
DET, Politecnico di Torino, Torino, Italy.
[email protected]
The origin
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 Communications is a
fundamental need for
human beings
 With the growth of social
structures also
telecommunications
became fundamental
 Eyes are the longestreach human senses
 So wireless optical
communications was the
first option
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Wireless optical communications
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 For thousands of years optical wireless numerical
telecommunications has been the only choice
1793: Chappe’s optical
telegraph…
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…and its encoding table
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Telecommunications based on EM signals
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 Across 18th-19th century
theory of electricity was
developed
 The telegraph was the first
application of electricity
in telecommunications,
still numerical
transmission
 Then the telephone was
invented and the analog
age started
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1837: telegraph
1856: telephone
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The ancient WWW: telegraph network
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1866: first
transatlantic cable
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1901: telegraph
network
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1895-1901: Guglielmo Marconi went wireless
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1895-1901:
Guglielmo Marconi went
wireless
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1929: UK wireless
network
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From the analog to the digital age
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 1880-1980: The analog century
 Telephone
 Radio broadcasting
 TV broadcasting
 1980’s: The digital age starts
 Personal Computers
 Cellular phone
 Optical fiber communications
 A connected world exchanging information on the
global network
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------
INTERNET
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The optical fiber
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A tiny pipe
(125 mm diameter)
for light, made of glass
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Optical Communications history (I)
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 1977: (Bell Labs) one-million hours lifetime for diode
lasers
 1978: (NTT Lab) single-mode fiber (SMF) with 0.2
dB/km loss @ 1550 nm
 1982: MCI installs SMF from New York to Washington
carrying a single wavelength @ 400 Mbit/s
 1987: (University of Southampton) EDFA operating @
1550 nm
 1996: First unrepeated trans-Atlantic link (TAT 12/13)
single wavelength per fiber, 5 Gbit/s
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Optical Communications history (II)
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 1996 - 2000: thanks to WDM performances of optical
systems doubles steadily every nine months
 2000: long-distance links with 100 channels at 10
Gbit/s per channel (1 Tbit/s) are demonstrated over
10000 km
 2000: several trans-Atlantic and trans-Pacific systems
are being built at 160 Gbit/s (16 x 10 Gbit/s) per fiber
 2000-2005: No major advances due to the internet
bubble
 2009: Multilevel modulation formats with coherent
receiver at 100 Gbit/s per channel
 2014: 10 Tbit/s per fiber commercially available
reaching thousands of kilometres
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2015: undersea optical cables
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Optical communications: state-of-the art
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Pseudo Nyquist WDM transmission
Df
Gch 
……
Rs
Pch
Rs ……
f
Bopt  N ch Df
 Bopt = 5 THz
 Rs=32 Gbaud (25 net + 28% FEC+protocol overhead)
 Channel spacing: Df= 50 GHz  Nch = 100 ch/fiber
 Modulation format: up to 8 bit per symbol (BpS)
 Net bit rate per channel: Rb up to 8x25= 400 Gbps/ch
 Overall aggregated rate: 40 Tbps/fiber
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Optical communications: state-of-the art
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 Several fibers/cable
 Let’s assume Nf=100
 It means Nfp=50 bidirectional
fiber pairs
 Overall fiber cable bidirectional
capacity:
C  Rb  N ch  N fp  400 100  50  2 10 6 Gbit/s
2 million Gbitps !!!!!
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How many internet conections?
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 1 Gbps corresponds to 100 internet connections
at 10 Mbitps
 So, at the state of the art, a fully spectrally
populated fiber link including 100 fibers/cable
may carry up to
200 million internet
connections at 10 Mbitps
 Quite impressive, isn’t it?
 And we are far from saturation….
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What next?
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 In modern fibers the low-loss available spectral
window is roughly 30-40 THz
 We are currently exploiting only the C-band
because of amplifier bandwidth
 A realistic mid-term forecast is for Bopt=15 THz
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What next?
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 So, we can envision a more than 3-times
bandwidth extension
 We can also envision a reduction of channel
spacing down to the symbol rate  pure NyWDM
 Let’s redo some math…
 Bopt=16 THz
 Nch= 16000/32=500 channel per fiber
C  Rb  N ch  N fp  400  500  50  10 10 6 Gbit/s
1 billion internet
connections at 10 Mbitps
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The highway metaphor
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 We have - or we’ll have soon - the availability of
huge highways for IP traffic
 Outside the highways we have an increasing
dimension web of local roads
 The challenge for the future is to be able to
fill the highways!
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The internet galaxy
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 Internet is the union of back-bone
and access networks
 Back bone networks are made of
high capacity optical links
 Access technologies are a mix of
wireless and wired solutions
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How many internet users?
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Overall IP traffic
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Global IP traffic
 Global IP traffic has increased fivefold over the past five years,
and will increase threefold over the next five years. Overall, IP
traffic will grow at a compound annual growth rate (CAGR) of
23 percent from 2014 to 2019.
 Busy-hour Internet traffic is growing more rapidly than average
Internet traffic.
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Which applications?
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Global IP traffic
 The sum of all forms of IP video, which includes Internet video, IP VoD, video files
exchanged through file sharing, video-streamed gaming, and videoconferencing, will
continue to be in the range of 80 to 90 percent of total IP traffic. Globally, IP video
traffic will account for 80 percent of traffic by 2019
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Wireless vs. wired
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Global IP traffic
 Traffic from wireless and mobile devices will exceed traffic from wired devices by
2016. By 2016, wired devices will account for 47 percent of IP traffic, and Wi-Fi and
mobile devices will account for 53 percent of IP traffic. In 2014, wired devices
accounted for the majority of IP traffic, at 54 percent.
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Evolution of optical networks (I)
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 Regarding the optical back-bone networks,
solutions are incremental starting from state of
the art…
 Firm constraints of carriers regard maximal
exploitation of installed equipment
 They aim at maximizing economical returns
without replacing installed transmission
equipment
 Regarding the use of the spectrum
 Keeping fixed grid
 Migrating to flex-grid
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Evolution of optical networks (II)
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 Keeping fixed WDM grid
OFC 2014
 Introduction of transparent
wavelength routing in nodes
 Use of elastic transponder
 Improvement of amplifiers’ quality
using hybrid Raman/EDFA fiber
amplifiers
 Use of spatial division multiplexing
among the available fibers
 Extension of bandwidth per fiber
JLT invited paper, Jan 2016
 Migrating to flex-grid
 Many different options depending on
the transponder technology
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A novel approach to the network analysis
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 In modern networks based on NyWDM and multilevel
channels, lightpath QoT depends on
OSNR 
 where
PNLI
Pch
PASE  PNLI
2
2

16
   2 Rs 2 RDSf

asinh
N ch
27


 4
3

  2 2 Pch
 Leff 2

Rs

 2
 thanks to the GN-model developed by the OptCom
group
JLT best paper award 2015
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Some results…
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OFC 2016
ECOC 2015
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How to move forward?
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 Joint NUST-POLITO laboratory on Broadband Networks
 Research areas
Transmission techniques
Node/transponder structure
Energy efficiency
Flexible optical networks
Traffic modeling, including Wireless generated traffic
 Student exchange
 Faculty collaboration
 Joint research project
 Industrial partnership
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Thank you
for your
attention
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