Fri 11 Nov: Meeting (2): Minutes

1. What has been achieved since last meeting (Wed 9 Nov)

Samir:  terminology and equation of diode, typed up information with basic understanding, simple pricing (subject to change)

John: looked into materials (widths, etc.) and power output

James: terminology, different types of cables, basic pricing,

Kevlar plated loose half duplex four core graded index cable.

Natalie: types of connectors and splicing and their differences, problems that occur because of them, basic power losses associated with them

2. To do before the next meeting (Wed 16 Nov)

Everyone’s work is to be posted on the blog, and each team member should read everyone else’s sections.

Try and come up with figures for each section in order to do calculations.

Find out what is provided in the market. In particular, find out how the fibre is manufactured (1 or 2km rolls?).

3. Questions and Notes

-       Splicing and connectors:
à Connectors are cheaper
à Fusion splicing requires heating up the ends of the cables and fixing them – lowest attenuation value ~0.002dB?

-       Duplex: can send two signals at once
à not applicable to this project – all we need is one channel of data (will work with more but this is basic requirement)

-       Can buy optical fibre per km – splicing required

-       Detectors: responsiveness (how rapidly it responds to changes) and sensitivity
à Dark current – look into?

-       Question to consider: How much extra bandwidth is needed to overcome these problems?

-       2 calculations:
1. Power (dB): start with LED + cable length losses + splice losses + detectors
2. Bandwidth (Hz) – transmit at 12.5MHz: LED can flicker with ?Hz + distortions/ frequency lag + responsivity

-       Detection sets limits for other components

4. Future Ideas/ Notes

The signal when it is received is bad.

Consider: redundant bits of data, symmetry, Shannon’s law, Group theory