OPTICAL SWITCHING

1
OPTICAL SWITCHING
Presented by, VIVEK.S.M S7 EC ROLL NO
13083420
2
An optical communication network
3
The switching dilemma
4
Optical switching so easy?
5
Its not that easy as it looks..

• Data traffic doubles every year. Information
  demand in internet creates enormous need for
  capacity expansion.
• Simple switching techniques cannot support DWDM.
• Optical networks are regarded as the ultimate
  solution to bandwidth needs of future
  communication.

6
OEO approach
All traffic goes through O/E/O conversions.
However, as transmission speed goes higher, this
approach is neither scalable nor cost-effective
(heat, power)
7
WAVE LENGTH DIVISION MULTIPLEXING (WDM)

• A technology used to increase the information
  rate
• Here multiple signals can traverse through a
  single strand of optic fiber

8
Dense Wavelength Division Multiplex (DWDM)

• DWDM is a variation of Wavelength Division
  Multiplex (WDM) but with much higher bandwidth
  and density.
• Multiple signals are carried together as separate
  wavelengths (color) of light in a multiplexed
  signal.

9
ADVANTAGES OF DWDM

• DWDM, up to 80 separate wavelengths or channels
  of data can be multiplexed into a lightstream
  transmitted on a single optical fiber.
• Each channel can carry up to 2.5 Gbps, therefore
  up to 200 billion bits per second can be
  delivered by the optical fiber.

10
OPTICAL TRANSMISSION MEDIA

• Links between the nodes are optical fibers.
• Here packets are in the optical format.
• O-E-O conversion are required at the interface.

11
LIMITATIONS

• LIMITED PACKET PROCESSING
• SLOW OPERATION
• COST AND COMPLEXITY
• CROSS TALK
• These limitations degrades the performance
  of the system affecting the bandwidth

12
SOLUTION!

• The solution is OPTICAL PACKET SWITCHING
• The signals are being processed by means of
  OPTICAL SWITCH FABRIC

OPTICAL SWITCH FABRIC
OPTICAL SIGNALS
OPTICAL SIGNALS
13
GENERAL PACKET FORMAT

• A generic packet format consists of
• Header
• Payload
• Additional GUARD BANDS before and after payload

14
PACKET HEADER

• A packet header may comprise of following fields
• Sync- provides synchronization
• Source Label-provides source node address
• Destination Label-provides destination node
• address
• Type-type and priority of the carried payload

15

• Sequence Number Packet sequence number to
  reorder packets arriving out of order and
  guarantee in-order packet delivery.
• OAM Operation, Administration, Maintenance
• HEC Head Error Correction

16
SWITCH ARCHITECTURE

• An OPS node consists of following components
• INPUT INTERFACE
• SWITCHING MATRIX
• BUFFER
• OUTPUT INTERFACE
• 5. ELECTRONIC CONTROL UNIT
  

17
1. INPUT INTERFACE

• Wave length conversion
• -gtconversion of external to internal
  wavelengths
• -gtidentification of the beginning and end of
  the header and payload
• Provides synchronization
• Header processing

18
2. CONTROL UNIT

• Processing routing information.
• Updates header information.
• Forwards header to output interface.

19
3. SWITCHING MATRIX

• Optical switching of the payloads according to
  the commands from the control unit.

20
4. OUTPUT INTERFACE

• Provides 3R(reamplification,reshaping,retiming)
  regeneration
• Attaches updated header to corresponding optical
  payload
• Conversion of internal to external wavelength
• Resynchronization

21
CLASSIFICATION
22
MEMS(Micro-electro Mechanical Systems)

• Software in the switchs processor deicide
  where an incoming stream of photons should go.
• Sends a signal to an electrode on the chips
  surface that generates an electric field that
  tilts the mirrors.
• The wavelengths
• Bounce off the input mirrors
• Gets reflected off another mirror onto output
  mirror.
• Output mirror direct the wavelength into another
  fiber.

23
(No Transcript)
24
THERMO-OPTIC SWITCH

• Waveguides have a core and cladding made of glass
  with differing indices of refraction.
• An input light wave is split onto two separate
  waveguides.
• No heat is applied to the lower branch, the
  coupler will output the waveform on to the
  waveguide labeled output1.
• Heating element activated the output light wave
  ends upon the waveguide labeled output2 .

25
WORKING
26
BUBBLE SWITCH

• The switch consist of a silica waveguide with
  arrays of intersecting light pipes that form a
  mesh.
• A small hole sits at a point where these light
  pipes intersect.
• It contains an index-matching fluid (one whose
  index of refraction is the same as the silica).

27

• If no bubble is present at the junction, the
  light proceeds down the default waveguide path.
• If a bubble of fluid is present at the junction,
  the light is shifted onto the second output
  waveguide.

28
LIQUID CRYSTAL SWITCH

• Principle -when an electric field is applied to
  liquid crystal, the molecules line up and become
  opaque
• The molecules are so thin and straight, will
  allow light of a particular orientation to pass
  through the liquid crystal
• It consists of 2 components
• CELL
• DISPLACER

29
CELL AND DISPLACER

• CELL Formed by placing the liquid crystal
  between 2 plates of glass
• Glass is coated with oxide materials that
  conducts electricity
• The function is to REORIENT the polarized light
  entering the cell
• DISPLACER
• It is a composite crystal that directs the
  polarized light leaving the cell

30
(No Transcript)
31
CONCLUSION

• Optical packet switched networks has great
  potential and can support much higher capacities
  than may be possible with electronic packet
  switched networks.
• The new technology regarded as ULTIMATE SOLUTION
  to bandwidth needs PROVIDING
• -gtIMPROVED EFFICIENCY
• -gtLOW COSTS
• -gtUTILISE DWDM

32
THANK YOU
33
Thanks to..
Pashaura Singh
Jun-ichi Nishizawa
Father of optical communication
Father of optic fiber