Download Optical Switches (Packet and Circuit

Optical Switches
(Packet and Circuit-Based)
Wong King Heng, Kenny
Wu Ka Man, Karmen
Chen Aiqin, Joanne
Tam Chi Fai, Jeffrey
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Outline
– Optical Switch
– OEO vs OOO vs OEO-O-OEO
– WDM & DWDM
– MEMS & 2D MEMS & 3D MEMS
– MPLS & GMPLS
– More about MEMS
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Optical Switch
• ‘Optical-to-Electronic-to-Optical' (OEO)
– Most lower layer networking equipment today
is still based on electronic-signals
– Core network use optical-signals
– Electrical ones to be amplified, regenerated or
switched
– Converted to optical signals
• Significant bottleneck in transmission
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OEO vs OOO vs OEO-O-OEO
Pros
OEO
OOO
Cons
- Known and mature technology
- 3R regeneration for free
- capable of bandwidth grooming
bit error rate monitoring and
statistical multiplexing
- Optical Scalability limit
- Not bit-rate transparency
- Not protocol transparency
- Expensive
- Optical Scalability
- Bit-rate transparency
- service/protocol transparency
- Emerging Technology
- not capable of bandwidth
grooming, bit error rate
monitoring and statistical
multiplexing
- Combines scalability of optics with
3R regeneration and wavelength
OEO-O- translation of electronics
OEO
- Allow Bit error rate visibility
- can choose this as an option per-port
-increased complexity over both
designs
- doesn‘t allow stat muxing or
grooming
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Wave Division Multiplexing
(WDM)
• splits light waves into different frequencies of
infrared light
• each frequency capable of transmitting data at
high speeds
• Mainly divided into Dense WDM(DWDM) and
Coarse WDM(CWDM)
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Wave Division Multiplexing
(WDM)
• CWDM
– ITU has standardized
a 20 nanometer
channel spacing grid
• DWDM
– closer spacing of the
wavelengths
– 1530 nm and 1560 nm
– wavelengths between
1310 nm ~ 1610 nm
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MEMS
• Micro-Electrical Mechanical Systems
(MEMS)
• New photonic optical switches
– Switch hundreds of wavelengths at a time
– a fraction of space & power & cost of existing
equipment
• Novel materials, not semi-conductors
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Optical MEMS
• Tiny arrays of tilting mirrors
• Adjust the angle to transmit
to desired output port
• Eliminate OEO conversion
– costly
– Save space and power
Optical MEMS Mirror
Used in an Optical Switch
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MEMS Drawbacks
• Moving parts
– Requires milliseconds to switch
– Ok for lambda provisioning or restoration
– SLOW for optical burst switching or
optical packet switching application
• Ineffective improvements
– Put a lot current into the array
– ONLY small improvement
• Solved by design change
• => Faster MEMS design
• => 2D MEMS
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2D MEMS
• single level mirrors
• adjusted only in 2D
• A x A in size
•32x32 are already available
•Rotating mirror as a 2*2 switch.
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3D MEMS
• Mirror on multiple planes
• Controls of thousands of mirrors
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3D MEMS
• Adv
– More flexible
– More scalable
• Disadv
– more complex to control thousands of mirrors
request complex software to coordinate their operations
– More costly
• typically support much larger switch core sizes
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MPLS
• Multiprotocol Label Switching (MPLS) is
a data-carrying mechanism which
emulates some properties of a circuitswitched network over a packet-switched
network
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GMPLS
• Generalized Multiprotocol Label
Switching (GMPLS)
• extension of the signaling protocols of
MPLS to lower-layer entities in the network
• enabled photonic switches allow
– automated provisioning
– and bandwidth-on-demand services
– optical virtual private networks
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GMPLS applications with MEMS
• Lower capital
expenses
• Lower cost of
ownership
• Reduce space
& power
consumption
•Local equipment connected to OEO switch
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MEMS Products
• MEMS Products:
While MEMS is an amazing technology, there are a
number of real products emerging
• Some examples of real MEMS products include
–
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Adaptive Optics for Ophthalmic Applications
Optical Cross Connects
Air Bag Accelerometers
Pressure Sensors
Mirror Arrays for Televisions and Displays
High Performance Steerable Micromirrors
RF MEMS Devices
Disposable Medical Devices
High Force, High Displacement Electrostatic Actuators
MEMS Devices for Secure Communications
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Some MEMS Images
A truly amazing
MEMS device. It is a
sophisticated MEMS
Thermal Actuator
Complex MEMS
Ratchet
Mechanism
New Torsional
Actuator.
Potentially
packing a lot
of umph into a
VERY small
space.
Incredible MEMS
Clutch
mechanism. This
is actually a
complex device
that required a
working clutch
mechanism.
Gears are 50
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microns across.
MEMS Adaptive Optics
Adaptive Optics MEMS Chip
(Pixels are 600 microns flat-to-flat)
MEMX Packaged 93 Pixel AO Array
(Package is 2 Inches Across)
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MEMS Optical Cross Connect
• MEMS mirrors
• optics module
• MEMS optical cross
connect chip
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Optical Switching Technologies
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•
•
•
•
Optical MEMS-Based Switch
Thermal Optical Switch
Electro-Optical Switch
Opto-Optical Switch
Acousto-Optical Switch
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• Optical MEMS-Based Switch
Optical MEMS are miniature devices with optical, electrical,
and mechanical functionalities at the same time, fabricated
using batch process techniques derived from microelectronic
fabrication . Optical MEMS provide intrinsic characteristics
for very low crosstalk, wavelength insensitivity, polarization
insensitivity, and scalability . Optical MEMS-based switches
are distinguished in being based on mirrors , membranes,
and planar moving waveguides.
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• Thermal Optical Switch
Thermal optical switches are based on
waveguide thermooptic effect or thermal
phenomena of materials.
• Electro-Optical Switch
Electro-optical switches realize optical
switching functions by using electro-optic
effects, which offer relatively faster switching
speed.
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• Opto-Optical Switch
Opto-optical switches realize switching
functions relying on the intensity-dependent
nonlinear optic effect (which is ultrafast) in
optical waveguides
• Acousto-Optical Switch
Acousto-optic switches are based on the
acousto-optic effect in crystals
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Commercial Products
• In this section, we will discuss our survey
in State-of-the-art Commercial Products
about Optical Switches
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http://newsroom.cisco.com/dlls/2006/prod_060206c.html
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MobiCom Deploys State-of-theArt Optical Network with Cisco
• June 2, 2006
• MobiCom, a Mongolian mobile
communications service provider
• Cisco® Internet Protocol Next-Generation
Network (IP NGN) architecture
• Cisco ONS 15454 SDH Multiservice
Provisioning Platform (MSPP)
• Converging its mobile and Internet traffic
into a unified optical transport platform
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National LambdaRail and Cisco Systems, Inc.
Extend Strategic Relationship to 2013
• The foundation of the NLR infrastructure is a dense
wave division multiplexing (DWDM)-based national
optical network using Cisco ONS 15808 and 15454
systems, with capacity of 40 and 32 wavelengths per
fiber pair respectively. Each wavelength can support
transmission at 10 billion bits (or gigabits) per second.
• Over this optical DWDM network, NLR has also
deployed nationwide a very robust switched Ethernet
network built on the Catalyst 6509 Series switches.
Rounding out NLR's unique set of capabilities and
services is the routed IP network built on the Cisco CRS1 Carrier Routing System, the core of Cisco's Internet
Protocol Next-Generation Network (IP NGN)
architecture.
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IP over DWDM
IP
IP
ATM
ATM
SONET/SDH
Optical/WDM
IP
IP
SONET/SDH
Optical/WDM
Optical/WDM
Optical/WDM
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IP over DWDM
• ATM
– Strong QoS
– High overhead
• SONET/SDH
– Protection/restoration functionality
– High equipment cost and operational costs
• Wavelength Routers (Intelligent Network)
– Can be configured to provide dynamic provisioning,
reconfiguration for optimizing network resources and
protection and restoration at the wavelength level
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IP NGN
• Multiple Transport Layer
– Router-Terminated Traffic
• Layer 3 (IP) lookup
– Pass-Through Traffic
– (~70-80%)
• SONET
• SDH
• DWDM
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ROADM
• Cisco combine the transponder in the
optical switch to reduce costly OEO
transformation
• Reconfigurable optical ADM (ROADM)
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Multi-Service
Provisioning Platform
• The ONS 15454 SDH MSPP integrates digital
cross connect functionality, add-drop
multiplexing, and multiple service interfaces in a
single network element.
• This evolutionary platform supports a broad
variety of service interfaces, including electrical
(E1, E3, and DS3), Ethernet (10/100-Mbps and
Gigabit Ethernet), optical interfaces (STM-1,
STM-4, STM-16, and STM-64), and DWDM.
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Multi-Service
Provisioning Platform
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Research efforts
• In the recent years, the demand of high
speed links strongly increases
• In the IEEE Xplore website
• Nearly 5000 articles are about Optical
Switches
• This topic is very hot in these few years
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Journal on Feb 2006
Integrated Array of 1 × N Optical Switches for WavelengthIndependent and WDM Applications
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Journal on Feb 2006
ARRAYED OPTICAL SWITCH DESIGN (AOSD)
• The optical configuration allows effective arrangement of optical
switches as an integrated array
Design
• A two-dimensional (2-D) N ×M fiber array (with attached N ×M
microlens array for individual optical beam collimation
• A cylindrical lens
• A one-dimensional (1-D) 1 ×M MEMS mirror array positioned in the
back focal plane of the cylindrical lens.
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Journal on Feb 2006
Feature:
• Independence
– a cylindrical lens focuses the light only in the
horizontal plane
– the optical switching module could be functionally
divided into M independent planar 1 × N optical
switches (“sandwiched” design).
– Each of the fiber rows has one input fiber (central
fiber) and N − 1 output fibers
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Journal on Feb 2006
What is so special?
• each of the 1 × N optical switches requires only
one MEMS mirror for its switching operation
• use of a cylindrical lens in the proposed AOSD
allows the compact arrangement of several
planar optical switches
• potentially a very cost-effective integrated optical
module
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Journal on Feb 2006
Also
• Useful when a large number of 1 × N optical
switches is required at the same network node.
• uniform performance and a mean fiber-to-fiber
insertion loss of 2.75 dB
• Switching times are better than 10 ms
Ref: JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 24, NO. 2, FEBRUARY 2006
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Latching Micromagnetic Optical Switch
• a new type of latching micromagnetic
optical switch
• a cantilever made of soft magnetic
material with a reflective surface
serving as a mirror.
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Latching Micromagnetic Optical Switch
How does it work?
• cantilever has two stable positions
• positions are controlled by magnetic field
• momentarily flowing a pulsed electrical current into the
planar coil underneath the cantilever
• in DOWN position without any power consumption
• input optical signal to the device is switched selectively
to one of the two output ports
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Latching Micromagnetic Optical Switch
Features
• large angle deflection of the cantilever can be achieved
• optical signals can be effectively manipulated
• the measured mechanical switching speed between the two states
of the prototype 3.2 ms. (fast)
• optical insertion loss 4 dB
• the energy consumption 44 mJ for each switching event
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Latching Micromagnetic Optical Switch
Problem
• Large insertion loss (the best result after
the test is still 4 dB)
– the mirror surface was not perfectly flat
– Vibration is observed for the mirror at its UP
position
Suggestion
Try to add some vibration absorbing
material
Ref: JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 15, NO. 1,
FEBRUARY 20
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• Thank you !!!
• Q&A
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