Gigabit Ethernet PMD
ECE135 Group 2 – Presentation 2
Andrew Meyerson February 3, 2005
Gigabit Ethernet:Progress Summary
Updated Gantt chart Made initial assignment of
group responsibilities Reviewed IEEE 802.3z
Standard regarding the PMD module
Started researching VCSELs
Test eval board Preliminary optical link
budget
Select VCSELs and PDs/ROSAs
Complete optical link budget Build practice board Revise Gantt chart Order parts?
Completed Tasks Next Week’s Tasks
Group Responsibilities
Andrew Meyerson – Administration, ordering, soldering
Clifton Kerr – Layout, design, testing Vinh Nguyen – Webpage, report writing Bryan Justice – Optical link budget, design,
testing, report writing
Gantt Chart
IEEE 802.3z PMD Initial Research
We will be building a Physical Medium Dependent (PMD) sublayer board
PMD should conform to the IEEE 802.3z specifications for type 1000BASE-SX (Short Wavelength Laser)
802.3z Standard
PMD block diagram as found in the 802.3z standard
802.3z Cont.
Transmit characteristics (from 802.3z standard)
802.3z Cont.
Receive characteristics (from 802.3z Standard)
802.3z Cont.
The standard also defines a worst case link power budget and penalties
This will probably be needed for determining the optical link budget
802.3z Cont.
The standard also specifies how to test the PMD to ensure compliance
For example, the extinction ratio must be measured with a repeating K28.7 data pattern
The standard also specifies test values corresponding to the minimum level of compliance
For example, maximum high frequency optical jitter is specified
VCSEL Research
Started looking at VCSELs Performed 4 Corner Analysis of:
– Advanced Digital Optics– Roithner Lasertechnik– Appointech– ThorLabs
Briefly examined:
Four Corners Analysis for Roithner Lasertechnik TTR-D1
Four Corners Analysis for Advanced Digital Optics HFE438x-521
Extinction Ratio (dB): 9.00000
Maximum Output Power Pmax (mW): 1.00000
Minimum Output Power Pmin (mW): 0.12589
VCSEL Model: Advanced Digital Optics HFE438x-521Cost:
VCSEL ParametersParameter: Symbol: MIN TYP MAX
Threshold Current (mA): Ith 3.50000 6.00000
Slope Efficiency (mW/mA): η 0.02000 0.04000 0.10000
VCSEL Current RequirementsIth η Imax Imin Ibias Imod
(mA) (mW/mA) (mA) (mA) (mA) (mA)3.50000 0.02000 53.50000 9.79463 31.64731 43.705373.50000 0.10000 13.50000 4.75893 9.12946 8.741076.00000 0.02000 56.00000 12.29463 34.14731 43.705376.00000 0.10000 16.00000 7.25893 11.62946 8.74107
Four Corners Analysis for Appointech 850nm VCSEL Module
Four Corner Analysis for ThorLabs VCSEL 780
Four Corner Analysis for TechLabs VCSEL 850
Other VCSEL Vendors
Lasermate– Link to datasheet for VCSEL with SC connector is
dead
Optek– Does not appear to have VCSEL model with SC
connectors
Summary of VCSELs
The Roithner Lasertechnik TTR-D1 appears to be the best VCSEL so far in performance terms– Potential problems
Delivery time Currency costs
The most affordable with good performance appears to be the ThorLabs 850 option– Is it connecterized?
PDs and ROSAs
Preliminary research has begun for selecting an appropriate PD or ROSA
Delay due to questions regarding which will be used
ROSAs are readily available online and it is just a function of finding a cheap one with the right connecters
Evaluation Board Testing
Evaluation Board Testing (cont)
Tested both PRBS7 and K285– Using the clock, found the eye diagram of both
signals with and without attenuation– Used the Bit Error Rate tester to find the BER of
the PRBS7 pattern
Evaluation Board Testing (cont)
K285 with proper attenuation (above)Triggering itself (below)
PRBS7 with attenuation (above) without (below)
Evaluation Board Testing (cont)
With attenuation, the BER of PRBS7 was measured to be 0E-9
With no attenuation, the BER of PRBS7 was measured to be 6.9E-2
Next Week
Research and select parts– Look at more VCSELs– Look at PDs/ROSAs– Call vendors for more information about price,
availability, and whether the components are connecterized
Finalize optical link budget Build evaluation board Revise Gantt chart as necessary Order parts?
References
IEEE Computer Society (2003). IEEE 802.3 Standard. New York: The Institute of Electrical and Electronics Engineers, Inc. Retrieved Thursday, January 20, 2005, from ECE 164.02 website: http://www.ee.duke.edu/~mbrooke/EE164.02/Spring_2004/group_2/index_files/8023.pdf
ECE164 Group 1 Presentations. (April 26, 2004). ECE164 Group 1 Website. Retrieved January 20, 2005 from http://www.ee.duke.edu/~mbrooke/EE164.02/Spring_2004/group_1/downloads.html
ECE164 Group 2 Presentations. (April 17, 2004). ECE164 Group 2 Website. Retrieved January 20, 2005 from http://www.ee.duke.edu/~mbrooke/EE164.02/Spring_2004/group_2/presentations.html
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