62.5 to 50um optical converter?

Going to throw this out there, I’ve already spent almost an hour looking on google and not finding anything…

Does anyone know of an optical converter/adapter to go between 62.5um multimode and 50um multimode fiber? Seems like it would be a simple thing to produce and publish the loss values.

Reason, I bought a fiber light source and a power meter. The power meter doesn’t seem to care too much on the size of the fiber and which adapters I use to get the connectors to latch. But the light source was designed with an LED and a larger aperture LED… Using 50um cable results in a very large loss! Using a 50um LC connector through adapters is a huge loss (like -24dbm). After going round and round with the “manufacturer” and making several videos showing the problem, I finally bough a new cable that could be used with no adapters and it still has a problem. They just refunded me all me money for it and never even asked to return it (direct from China). They know that I know why it doesn’t work with “modern” 50um multimode cables (OM-3, OM-4, and maybe OM-5) and that it can’t work without changing the light source for a 50um compatible source. Yes I had to re-teach myself on all this stuff, never really been up to speed on fiber to begin with, but this certainly pushed me to figure it out.

So asking if anyone has seen an adapter/convertor that can be used to go from 62.5um source to 50um fiber, and hopefully for relatively cheap.

The single mode side of the light source works great, but the multimode is what I run at work and will run at home as I move towards some 10gbe stuff in my lab rack. Nothing I currently do requires the distance out of single mode fiber and I certainly wouldn’t try to run it 6 feet from switch to server in my lab.

I was packing up all the adapters that came with these tools, and realized something… I mentioned I needed 850nm and multimode and asked if they had adapters from SC to LC, they kindly said they would throw in a couple and I was happy… I just took a closer look at the label attached to the bags, they are 9um single mode adapters!

Since I have my money back, and they didn’t want the device back, I opened the light source. Inside on the MM connector was an orange cable which is normally an OM-1 62.5um cable, so that’s confirmed. I borrowed an orange OM-1 cable from another department and noticed that even with that cable (ST-ST stuck into the ports), I still didn’t get the proper level. There are four potentiometers inside the light source and messing around with 2 of them I set the level for the 1300nm to correct, and tried to get the 850nm correct, but it’s acting like a dirty or damaged potentiometer. I at least got it closer.

Tried the OM-3 (50um) cable again, and it is still low, but not nearly as bad and possibly more inline with what I found on the web for losses when going from bigger 62.5 down to 50um. The light can spread out around the outside of the smaller fiber resulting in a loss. Depending on the light source the loss can be pretty high.

Time to track down some better adapters and see if I can at least get useable results until I have to fix that pot or burn out the laser.