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I am designing an Internet of Things system with fiber optics as its transmission medium (for its immunity to various kinds of interference and inability to carry a shock from a failed high voltage interface to the controller unit, school project, don't ask)

I am here asking whether I should socket the fiber optics module (possibly using a card edge connector), or I should just build the transceiver in? I do have space constraints.

If I socket the transceiver, which should be designed to be universal to all components that can accept one, are those signals and voltages adequate:

  • +5V
  • GND
  • VDD (the system's IO voltage, some parts of the design use 5V logic, while some use 3.3V)
  • TxD
  • RxD

And what is the appropriate kind of card edge connector?

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  • \$\begingroup\$ You might want to include pins for output enable and signal detected, even if you don't implement those functions yet. \$\endgroup\$
    – The Photon
    Jul 5, 2016 at 20:25

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You could have a look at the SFP or SFP+ standard (SFF-8431). It might be grossly overpowered for your application but the physical interfaces might give some interesting hints. SFP uses an opto-to-electrical module (with a small PCB inside) which is plugged into a PCB mounted cache witch has a female cardedge connector inside. The interconnect can also be made purely electrical without fibre.

http://en.wikipedia.org/wiki/Small_form-factor_pluggable_transceiver

For some connector hints check out some of the connector manufacturers. Samtec has a couple of card edge connectors that are OK. Go "Signal Integrity"->"High speed IO" in the link below. http://www.samtec.com/picturesearch/

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  • \$\begingroup\$ That will not work for me as it is too overpowered and too expensive. I don't need the 1Gbps throughput as my system speed is capped at 9600bps which is both the speed for 1-Wire bus and SPI UART's top speed. I ended up rolling my own module with non-directional (that is, reversible) card edge connector and TOSLINK modules. Total BOM cost will be under $2. \$\endgroup\$
    – Maxthon Chan
    Oct 13, 2014 at 18:45

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