ECE 4006 Presentation on Preliminary Results

Group: G3

Member: Karen Cano, Scott Henderson, Di Qian

Overview

STEP Procedure Name VCSEL PD

1 Component Purchase Completed Mostly Completed

2 Circuit Layout Design Completed Completed

3Etched PCB Board

Design Completed Not Completed

4 Circuit Assembly for

1) RadioShack Board Completed Not Completed

2) Etched PCB Board Not Completed Not Completed

5 Circuit Testing for

1) RadioShack Board Completed Not Completed

2) Etched PCB Board Not Completed Not Completed

Circuit Layout for PD

• Optical connection on top, (SC - Light In). Electrical connections on left and right (SMA)

• R=1/(2*pi*f*CDET), where CDET = 1.5 pF (from spec. sheet). So, R = 53.1Ω.(impedance of PD).

• Capacitors were chosen based on their frequency response at 1.25 GHz. From Murata’s site: C = .01uF.

Circuit Layout for the VCSEL• Electrical connections on the left (SMA - In),

optical connections on the right (SC - Light Out).

• Constraint: Circuit’s RTOT has to be 50Ω, due to equipment requirements.

• VCSEL’s RTYPICAL=25Ω (from spec.sheet)

• So, a 25Ω resistor was placed in series with the VCSEL.

Constructing the VCSEL Board

• Radio Shack purchased “through” boards• SMA connectors, SMT components, and

VCSELs• Impracticalities of initial design• Remedy for small holes and lack of a drill• Problem: GTS-1250’s outputs are AC-

coupled• Bias-T applied and shown in new circuit

VCSEL Testing Procedure

• GTS-1250• New VCSEL

board• Old opto-board• Scope• Electrical

connections and optical loop

Testing Results

• IEEE 802.3z standard mask application

• Bit error rate settings in scope

• New VCSEL vs. old VCSEL

• Failure of complete Tx module thus far

VCSEL PCB Design

• Five components:

- SMT Resistor,

- LED,

- Power Connector, - 2K ohms Resistor,

- SMA Connector

VCSEL PCB Design (Con’t)

• SMT Resistor – 0.1 inch

• LED – Two Leads

• 2K Ohms Resistor – 0.5 inch

• Power Connector – hole 0.2 x 0.1 inch

VCSEL PCB Design (Con’t)

SMA Connector Bottom View

Conclusion (Short term goals)

• Ensure the delivery of the connectorized PD

• Making and testing the PCB for VCSEL

• Intergrating with modules from other groups.