How to test if a Near Infrared Emitter and Photodiode still working?
1450 nm is far enough into the IR that most cell phone cameras won't see it. That's because the sensors are silicon CMOS or CCD sensors, and silicon sensors only respond to wavelengths below about 1.0 - 1.1 um.

You can check if your emitter is working using an IR viewer card like one of these:



The VRC2 and VRC4 models cover your wavelength. These have a flourescent coating that absorbs IR light and re-emits visible light so that you see a bright spot on the card when there is IR present. 2 mW, like your LED is rated for, should be plenty to create a bright spot on one of these cards. 

If the emitter is working, but your overall system is not, then suspect the receiver.

The easiest test is simply to replace your photodiode with a new one of the same type and see if that fixes the problem. If it doesn't then you'll need to look at your whole receiver circuit, node by node, to see where the behavior is not what you expect.