Question: I have replaced old Cisco 1900 switches with 3850's in my plant process areas.  

Added Fiber links between 3850's for increased performance. I can't get data transfer through the fiber uplinks.

I have assigned some of the LAN ports to the different VLANS and they are communicating correctly. 
The Gib Fiber ports when assigned to the VLAN do not pass data.

As a "Band-Aid" I installed Fiber media convertors to connect the fiber backbone to the VLANs. Data does pass through the convertors to the VLAN ports.

Not sure what I'm missing as why the fiber ports aren't passing data as the LAN ports are.

Gone through several Cisco manuals and checked multiple options with no success.

My process is operational so I am now limited in my access to the switches until the next shutdown.

Any suggestions would be appreciated.

Answer: 
Cisco 3850 Series Switch is a 10-Gbps network switch, which means you need to use 10G SFP+ optical module or under 10G optical module, such as 1G SFP. And make sure the optical modules is correctly connected with the corresponding port on the switch. Hope this would help.
Verify distance limitations of the GBICs.

Make sure the speed commands (if any) match at both ends.

Verify it's a compatible GBIC for Cisco. (There are unofficial commands to use non-Cisco GBICs but I'll let you research that and use at your own risk)

Verify you have fiber transmit and receive flipped on one end. If fiber A is on the left make sure fiber B is on the left at the other end. If you're not sure just try flipping one end. It'll light up if that's the issue.

Try the `switchport trunk nonegotiate` command on the interface. I've had to do this with 3750's and 3850's in the past.