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

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

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

Conservative Board 2 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