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

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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. GANTT Chart

10. 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