Q: Can I mix 62.5 micron multimode optical fibers with 50 micron multimode optical fibers.
A: No. In reality, they will work together in one direction, but not the other. Since multimode fibers are utilized in pairs, one strand to send (TX) and one to receive (RX) signals, you need a signal loop to send and receive data. Think of putting a garden hose into a fire hose. Flow from the garden house will easily flow into the fire hose. But if you reverse the flow, from the fire hose into the garden hose, water will spill out.