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Optical Gigabit Ethernet

Optical Gigabit Ethernet. Group 4 February 3, 2005 Ronen Adato. Progress Overview. Tested Evaluation board Continued part research Created an Optical Link Budget Began contacting part vendors. Evaluation Board Testing.

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Optical Gigabit Ethernet

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  1. Optical Gigabit Ethernet Group 4 February 3, 2005 Ronen Adato

  2. Progress Overview • Tested Evaluation board • Continued part research • Created an Optical Link Budget • Began contacting part vendors

  3. Evaluation Board Testing Setup for BER testing; the clock was fed into the BER tester, thus the oscilloscope signal was triggered on itself Setup for viewing eye diagrams; the clock was used to trigger the oscilloscope signal, producing a better eye

  4. Evaluation Board Testing Self triggered setup, signal PRBS 7 with 40 db attenuation Clock triggered setup, signal PRBS 7 with 40 db attenuation

  5. Evaluation Board Testing Signal PRBS 7, 0 db attenuation • Signal quality decreased with attenuation in general • BER remained constant • 0 db was too little attenuation

  6. VCSEL and PD Selection • 6 possible VCSEL vendors • Advanced Optical Components, Lasermate, Roithner Lasertechnik, Appointech, Oepic Inc. and TERAdian Inc. • 6 possible PD vendors • Optoway Inc., OSI Fibercomm, Appointech, Luxnet, Hamamatsu and OECA

  7. VCSEL and PD Selection

  8. VCSEL and PD Selection

  9. VCSEL and PD Selection • Equations • I = (P/η) + Ith • Imax = (Pmax/η) + Ith • Imin = (Pmin/η) + Ith • Ibias = (Imax + Imin)/2 • Imod = Imax - Imin

  10. VCSEL and PD Selection

  11. VCSEL and PD Selection • Equations • Pat PD = (Pfrom VCSEL)(10-(fiber loss/10)) • Iout = R x Pat PD

  12. VCSEL and PD Selection • Optical Link Budget • The Limiting Amplifier (MAX3264) takes 5-1200 mV • The TIA (MAX3266) has 2.26 kΩ transimpedence • So Iout from the PD must be at least 2.212μA to drive the Limiting Amplifier • The TIA also cannot take more than 4mA and operate normally

  13. VCSEL and PD Selection • Optical Link Budget • The Laser Driver (MAX3287) can only produce current modulation between 2-30 mA • Based on the necessary input current to the TIA we can determine which PDs have adequate responsivity • The output of the Laser Driver determines which VCSELs will work

  14. VCSEL and PD Selection • All the PDs have adequate responsivities and thus worst case output currents • The Advanced Optical Components HFE438x-521 VCSEL, with a worst case Imod of 43.705 is outside the range of the Laser Driver

  15. Vendor Quotes • VCSELs • Lasermate: The part is available • 1-9 units - $32.00 • 10 units - $25.00 • 10,000 units - $7.95 • Roithner Lasertechnik: The part is discontinued, they have 10 left • 25 Euros/ unit for all of them

  16. Vendor Quotes • PDs • OSI Fibercomm FCI-125G-006HR: 9 are in stock • 1-9 units - $10 • 101-500 units - $5 • OSI Fibercomm FCI-125G-010HR: 12 are in stock • 1-9 units - $10 • 101-500 units - $5

  17. Vendor Quotes • PDs • Hamamatsu S5971: none are in stock • $6.72 regardless, but a minimum order of $50

  18. Additional Concerns • The Oepic VCSEL is 10Gbps • The company gives samples, so it may fit into our budget • For the large scale budget it may be to costly • It may not work with the other parts • The rise/fall time on the Laser Driver data sheet is a minimum of 250, most of our VCSELs do not meet this requirement • The capacitances of some of our PDs are high • Lasermate also makes a SC-ROSA PD

  19. GANTT Chart

  20. Goals for Next Week • Complete Optical Link Budget and choose components • Build the test board (if the parts have come in) • Begin financial budgeting • Possibly order our VCSELs and PDs

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