ECE4043/5143 – Optical
Communications
Design Project
Arthur Lowery (based on Bill Corcoran’s work)
www.eng.monash.edu.au
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Design project
• Fibre backbone link
• Melbourne to Adelaide, 1.2 Tb/s total capacity
• Occupying no more than 1.2 THz total bandwidth
• Groups of 3 people
• DEADLINE: Last Friday of Semester 2, Week 12
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Route (potential)
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Defining what your link is
• Very general restrictions
– 1.2 Tb/s (e.g. 12 x 100 Gb/s channels) on DWDM grid
• You will need to find the simulation parameters by
using the analytical formulae in the lectures
• Find real components, take data sheet values and use
them in in simulation
– Fibre, transceiver, amplifier WDM filters, etc
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Before you start getting right into it …
• Use design rules to design your link!
– Have a look for transceiver options for 100Gb/s
channels. Different tech has different requirements
(residual CD, PMD, required OSNR …). The hardest part
will be to get from Melbourne to Adelaide.
– Draw your planned system, do the required
calculations, make sure your link fits the transceiver …
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Calculation requirements (1)
• OSNR: 58 equation
– Doesn’t need to be fully rigorous, but should give a
good indication of what OSNR you expect to see at
each node
• CD:
– Calculate the residual CD at each node
– Find the maximum tolerance to residual CD with
simulation only AND from datasheet
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Calculation requirements (2)
• PMD/DGD:
– Can often have a quoted DGD tolerance on transceiver
datasheets
– Need to find the root of the variance to get DGD
– The MATLAB does not simulate this effect, so you will
need to fully justify that your link will work by looking
at the receiver specifications.
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What do you need off the transceiver datasheet?
• Modulation format
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What do you need off the transceiver datasheet?
• PMD/DGD tolerances
– Since you are not simulating with PMD (too hard …),
you will need to prove via calculation that your
transceiver is suitable
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What do you need off the transceiver datasheet?
• What forward error correction is used?
– What is the ‘error free’ BER criterion
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Reading EDFA datasheets
• Noise figure, max. gain
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EDFA datasheets
• Look for:
– Minimum input power: does this meet your
requirements?
– PMD: some amplifiers will quote a DGD/PMD number
that they add into your system. Make sure to include
these in your calculations
– Essentially, try to make sure that there are no surprise
specs on the datasheet that would mean that the
device that you’ve chosen will not work in your system
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WDM mux/demux datasheets
• Fixed or reconfigurable?
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Picking a filter type
• Try to find spec sheets with crosstalk parameters or
filter spectra provided
– You’ll need to be able to confidently state that the
WDM mux/demux are able to be used in your system.
We’ll not be testing a full WDM system, so your design
needs to be convincing.
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Installed fibre
• Transmission fibre
– Standard single mode fibre (G.652 ITU Standard)
– You’ll have 80-km spans in the test link, so think about
match between test and real-world design in planning
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DSPstack
• We’re providing a set of scripts to run standard QPSK
DSP
– “Well commented” for dual pol. QPSK
– Information on how this DSP works is provided in the
Week 9 snapshots.
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What should I be doing this week?
• Form groups of three
• Have a look at the project specification
• Start thinking about the design of your system
• Start looking for datasheets for components you want
to use in your system
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