Optical Gigabit Ethernet

1
Optical Gigabit Ethernet

• Group F.O.R.E.
• March 31, 2005
• David Larado

2
Progress Overview

• Replaced the LA in the Rx circuit and retested,
  including BER measurements
• Tried new conservative Tx with Emcore VCSEL
• Aggressive Design was heavily tested
• Loop back test was performed with aggressive
  layout, various attenuations
• Ordered more passives, change in plans

3
New Plan

• Our aggressive design proved to be incredibly
  successful, so we have plenty of functional
  boards left. Were not going to fabricate
  another board, but instead order more VCSELs from
  Lasermate.
• We needed more passives to construct a another
  aggressive run of the full TxRx board they were
  ordered on Tuesday.

4
GANTT Chart
5
Aggressive Board, Rx

• We replaced the damaged LA, and built another Rx.
• This waveform is from the aggressive receiver
  layout with a new LA in the correct place on the
  board.

6
Aggressive Board, Tx

• Here we are soldering the aggressive transmitter
  board, joking about how great it would be if we
  plugged it in and it worked

7
Aggressive Board, Tx

• Here is the first eye we got when we connected
  the board ?

• After playing with resistance and connections, we
  got ?

8
Aggressive Board, TxRx

• Now that we had a working receiver and
  transmitter, it was time to try the loop-back
• Note We tried all future testing on the
  aggressive design, because we have many
  fabrications of it and we knew it was successful.

9
Aggressive Board, TxRx

• Loopback waveforms Initial (upper R), with BER
  turned on (lower R), and the clock waveform with
  BER turned on (lower L)

10
Aggressive Board, BER

• As seen in the previous slide, simply turning on
  the BER tester introduced noise in the signal.
  We still got a BER of less than 10-9 when the
  signal was tested.

11
Aggressive Board, TxRx

• We varied the
• attenuations with, the transceiver
• 4dB
• 7dB?
• Using different combinations of the optical
  attenuators, we were able to try these also
• ?9dB
• 12dB?

12
Success

• Potentiometers were varied and our limiting
  resistors proved themselves worthy. We will order
  more Lasermate VCSELs to test in the design
  instead of the Emcore VCSEL.

13
New Tentative Budget
14
Tasks for Next Week

• Get the new passives and build another board
• Order Lasermate VCSELs with the money saved from
  not fabricating a second board
• Starting thinking about what we want to include
  in our final paper, its due less than two weeks
  from today.