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 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

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

Evaluation Board Testing Signal quality decreased with attenuation in general BER remained constant 0 db was too little attenuation BERs for signal PRBS 7 AttenuationBER 0 db1.2x db10-9 Signal PRBS 7, 0 db attenuation

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

VCSEL and PD Selection

Equations I = (P/η) + I th I max = (P max /η) + I th I min = (P min /η) + I th I bias = (I max + I min )/2 I mod = I max - I min

VCSEL and PD Selection

Equations P at PD = (P from VCSEL )(10 -(fiber loss/10) ) I out = R x P at PD

VCSEL and PD Selection Optical Link Budget The Limiting Amplifier (MAX3264) takes mV The TIA (MAX3266) has 2.26 kΩ transimpedence So I out 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

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

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 I mod of is outside the range of the Laser Driver

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

Vendor Quotes PDs OSI Fibercomm FCI-125G-006HR: 9 are in stock 1-9 units - $ units - $5 OSI Fibercomm FCI-125G-010HR: 12 are in stock 1-9 units - $ units - $5

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

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

GANTT Chart

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