DIY USB Powered Fiber Tester
Using a cheap TP-Link media converter you too can make a portable fiber tester. The SFP cage allows you to swap optics to fit whatever fiber you’re trying to test.
This particular media converter ships with a 9 volt wall brick, but fortunately it’s happy to run the SFP cage off of a 5V usb charger; all you have to do is make a custom cable for it.