nications
2
TDM History
TDM History
~Year
Commercial
Introduction
Key Technology
1982
135 Mb/s
Multimode fiber
1985
565 Mb/s
1310 FP laser, Singlemode fiber
1986
1 Gb/s
1550 DFB laser
1991
2.5 Gb/s
SONET
1995
10 Gb/s
Dispersion Compensation, Optical
Amplifier, LiNbO
3
modulators.
2007 ?
40 Gb/s
Phase Shift Keying
2009-10
?
100 Gb/s
Multi-level? Coherent?
Polarization Multiplexing? ©2007 Fujitsu Network Communications
3
TDM Going Forward
TDM Going Forward
ITU grid is aligned on 100 GHz spacing
50 GHz, 25 GHz sub channels are realizable.
Constrains Potential higher-rate TDM solutions
Channelized, Specified Channel Width.
New 40 Gb/s modulation formats are spectrally efficient
No excess bandwidth remaining.
100 Gb/s must either utilize more spectral bandwidth
(lower efficiency) wider band or multi-lambda, or
Provide more effective utilization of spectral bandwidth
(higher efficiency) higher order modulation: Amplitude, Phase,
Polarization, Trellis. ©2007 Fujitsu Network Communications
4
LiNbO3 Modulators for 40Gb/s
LiNbO3 Modulators for 40Gb/s
40 Gb/s low drive voltage modulators
40 Gb/s 1.8 V dual-drive with
advanced electrode design
Dual-drive for zero chirp
C- and L-band operation
40 Gb/s compact modulators for new modulation formats
New modulation formats: RZ-DPSK, RZ-DQPSK
Integration of phase- and intensity- modulators
DATA
CLOCK
DATA
CLOCK
PM
PM
PM /2
RZ-DQPSK
RZ-DPSK ©2007 Fujitsu Network Communications
5
Comparison of 40Gbit/s modulation
Formats
Comparison of 40Gbit/s modulation
Formats
Medium
Poor
Good
Poor
Medium
Medium
Good
Medium
Good
Medium
Good
Good
Good
Good
Very good
Optical nonlinear
tolerance
Optical noise tolerance
: advantage
PMD tolerance
: disadvantage
NRZ
Optical spectra
Chromatic dispersion
tolerance
MZI out
RZ-DPSK
Tx out
1

Phase= 0

Phase= 0
OADM cascadability
RZ-DQPSK
MZI out
Tx out
4 values are mapped to phase 0, /2, ,
3 /2
Good in linear
regime
Medium
Poor
Very good
Poor
Duobinary
Good
Medium
Medium
Medium
Medium
CS-RZ
Frequency (GHz)
Frequency (GHz)
Frequency (GHz)
Frequency (GHz)
Frequency (GHz)
25ps
50ps ©2007 Fujitsu Network Communications
6
WDM History
WDM History
~Year
Commercial
Introduction
Key Technology
1999
OXC
2D MEMS Optical Switch
1987
2-wavelength
1310 + 1550 coupler
1992-5 CWDM
Thin film filter
1996
DWDM
Fiber Bragg Grating (FBG) filter,
Optical Amplifier
2001
Dense DWDM
Arrayed Waveguide Grating Mux
(AWG)
2004
Re-
configurable
ROADM
Wavelength Selective Switch
(WSS) ©2007 Fujitsu Network Communications
7
Automatic Power Balancing
Automatic Power Balancing
Maintains equal channel output power in face of wavelength
assignment/rearrangement/network failure
Enables software provisionable wavelength add/drop/thru and
reconfigure
No manual adjustments anywhere
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
-2
0
2
4
6
8
time(ms)
r
e
l
a
ti
v
e
po
w
e
r
(
r
.u
.
)
40ch
1ch
Conventional AGC
technology
New technology
Fujitsu
Technology
Fujitsu
patented
technology
All wavelength power levels equal ©2007 Fujitsu Network Communications
8
40Gbps Transmission Considerations
40Gbps Transmission Considerations
Todays networks, deploying 2.5Gb/s and 10Gb/s rates
extensively. Will migrate to 40Gb/s per wavelength for ;
Higher rate client interfaces
Overall capacity growth requirements
Challenges
OSNR requirement is more stringent at 40G than 10G: 6 dB
Dispersion sensitivity increases: x 16
PMD sensitivity increases: x 4
Optical filtering effects due to OADM filters
Power cut off
distortion
OADM filter passband
40G
10G
2.5G ©2007 Fujitsu Network Communications
9
Variable Dispersion Compensation for
40Gbps
Variable Dispersion Compensation for
40Gbps
VIPA (Virtually Imaged Phased Array) based VDC
VIPA (Virtually Imaged Phased Array) based VDC
VIPA (Virtually Imaged Phased Array) based VDC
3-Dimensional
mirror
Collimating lens
Line-focusing
lens
Glass plate
Focusing
lens
Optical
circulator
X-axis
D
C
>0
D
C
<0
Chromatic dispersion in 40Gbps
systems
More severe dispersion tolerance
~ 50 ps/nm
1/16 of 10G systems
Chromatic dispersion changes with
temperature
~60 ps/nm @ 600 km, 50
°
C change
Advantages of available Variable
Dispersion Compensation
Replaces menu of fixed DCM
High tunable dispersion resolution:
1 ps/nm
Large variable dispersion range:
±
800 ps/nm
No penalty due to fiber nonlinear effect ©2007 Fujitsu Network Communications
10
Ethernet History
Ethernet History
~Year
Commercial
Introduction
Key Technology
1990
Switched
Networks
Bridge, Spanning Tree
2009 ?
100 GbE
Optical LAN Interconnect,
WAN Support on Existing Spans
2002
Ethernet WAN
Ethernet over SONET, Metro Ethernet
1983
10-Base5
Thick Cable AUI
1991
10-BaseT
Twisted Pair, Hub
1995
100-BaseT
DSP, Auto-negotiation, Switching
1998
VLANs
Routers, VLAN-switches, VLAN Trunks
1998
1 GbE
Silicon Ethernet Switches, Fabrics,
Optical Interconnects
2002
10 GbE
Low-cost standardized Optical
Interconnect (XFP et al.) ©2007 Fujitsu Network Communications
11
Ethernet Going Forward
Ethernet Going Forward
Ethernet will become pervasive
Overlays on existing optical infrastructure (EoS, EoCu)
Supporting new (eventually all?) types of services (real time, video,
etc.)
Some approaches to converge Packets and TDM in the
Metro:
Packet over Ethernet over SONET over WDM.
TDM over Circuit Emulation Services over Packet over
These are not as efficient as mapping non-native formats.
Muxponders, etc. provide efficient mapping
Resulting network topology is usually point-to-point.
Ring and multi-point are possible (but more difficult).
Ethernet switching and aggregation is ultimately a better
approach than fixed payload mappings. ©2007 Fujitsu Network Communications
12
Transponding
Transponding
DWDM
So Alien DWDM
So Alien Optical
Switch
Optical
Switch
Po Po TDM
Switch
Packet
Switch
Somewhat more
Flexible Transponding
Basic Transponding
Simple but Inflexible ©2007 Fujitsu Network Communications
13
Switching
Switching
DWDM
So PoS
Alien DWDM
Po CES
Alien Optical
Switch
Optical
Switch
Packet
Switch
TDM
Switch
TDM
Switch
Packet
Switch
Adding Packet Services
To Existing SONET Network
Adding TDM Services
To Existing Packet Network ©2007 Fujitsu Network Communications
14
Probable Future Direction
Probable Future Direction
DWDM
Native o Alien Client
Client
Optical
Switch
Dual-Mode
Switch
Most Flexible Approach,
Yet efficient Mapping ©2007 Fujitsu Network Communications
15
Channel Compatibility
Channel Compatibility
Data Service rates will continue to increase.
Existing systems are channelized.
Research and Education environment generally needs
flexibility:
New experiments, new formats, new rates alongside existing
equipment and formats.
Compatibility with carrier systems for remote-location reach (GFP /
VCAT etc.)
Maximally-flexible equipment must accommodate intermixing
of optical line formats an data rates.
Otherwise existing systems need to be replaced for rate & format
upgrades.
Alien lambda support allows transparent transport (clear channel).
Maximally-flexible equipment should accommodate both
wavelengths and packets in flexible & switched architectures. ©2007 Fujitsu Network Communications
16
Control Plane
Control Plane
A control plane allows setup and teardown of Optical and TDM
paths through a network.
GMPLS enabled network elements provide a method to simplify
the establishment of these paths.
A subset of options can be chosen for simple network topologies:
RSVP-based signaling,
Hard-state (explicit tear message required to delete a path),
Bidirectional requests
Centralized Path Computation Element (PCE) can advise on suitability of
optical path.
Well aligned for R & E environment needing path flexibility.
LDP not normally needed in optical/SONET GMPLS
Optical paths and SONET paths are very static.
Can determine (assume) label values without the need to run a
distribution protocol.
Add IP/MPLS, LDP when packet switching is integrated into NE. ©2007 Fujitsu Network Communications
17
Conclusions
Conclusions
R & E Networks
1.
Should include compatibility for forward-looking rates and
formats in todays equipment and spans.
2.
Should focus on simplification of node designs in the face of
multiple types of traffic.
3.
Should be more easily optimized for Ethernet services.
4.
Should plan for switch fabrics with multiple capabilities. ©2007 Fujitsu Network Communications
18
FLASHWAVE
®
7500 ROADM
One Platform - Three Powerful Configurations
FLASHWAVE
®
7500 ROADM
One Platform - Three Powerful Configurations
FLASHWAVE 7500 core
40 channels WSS ROADM, 8-degree Hubbing
Best-in-Class transmission performance
<= 24 nodes, <= 1000 km ring size, without OEO
Active, non-banded
Dynamic, self-tuning optical network
Common Transponders and Software
Perfect for metro & regional applications
FLASHWAVE 7500 small system
32 Channel FOADM and ROADM
19 shelf; 19 & 23 rack mounted option
<= 16 nodes, 800km ring size without OEO
Active, non-banded, self-tuning
Common Transponders and Software
Compact, low cost Metro/Edge applications
FLASHWAVE 7500 extension system
Lower-cost, smaller capacit