Optical Gigabit Ethernet Group F.O.R.E. March 31, 2005 Ronen Adato

Progress Overview Completed Midterm Report Soldered and Tested 2 Conservative Design Boards

Eye Produced by Rx Circuit, Signal PRBS 7 Conservative Board 1 Soldered all components and tested the Rx circuit for a clear eye Errors in part selection prevented BER testing for the Rx circuit, and any Tx circuit testing Rx Circuit Test Setup Eye Produced by Rx Circuit, Signal PRBS 7

Conservative Board 1 QMAs were sent instead of SMAs We elected to attempt and use these incorrect parts A clear eye was produced by the Rx circuit, but the coaxial cables had to be held tightly into the QMAs BER testing of the Rx circuit was impossible as a consistent signal could not be achieved with the QMAs Tx circuit was not tested as this would have been very difficult with the QMAs

Board 1 With QMAs Removed Conservative Board 2 SMAs were removed from the test board to be used in the prototype The QMAs were removed from the original board Attempts to insert the SMAs into the holes occupied by the QMAs resulted in the destruction of a trace Board 1 With QMAs Removed The Destroyed Trace

The Second Conservative Board The VCSEL and ROSA were de-soldered and a new board was constructed The VCSEL was recycled while a new ROSA was used The Limiting Amplifier (MAX3264) was incorrectly placed and had to be removed and re-soldered The Second Conservative Board

Conservative Board 2 The Rx circuit failed to produce an eye It was determined that the LA (MAX3264) had been damaged Rx Circuit Waveform Measured Before LA Rx Circuit Waveform Measured After LA

Conservative Board 2 The Tx circuit was tested and does not work The VCSEL is not lasing Voltage measurements were taken throughout the circuit In general, the entire loop around the VCSEL has a 5V dc voltage Potentiometer adjustments changed nothing We suspect our VCSEL may not be functioning

GANTT Chart

Tasks for Next Week Replace the LA in the Rx circuit and retest, including BER measurements Fix and test the Tx circuit The VCSEL will probably be replaced Loop-back test the entire board Solder and test the aggressive design