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.
You may be up against a distance limitation. If the old switches were uplinked using 100Base-FX (100Mbps) realize that signal can propagate over 1 mile over FDDI-grade multimode fiber. Newer gigabit uplinks can propogate 1804 feet (550 m).

There are 100Base-FX transceivers for the 3850, so you might need to get those, or upgrade your fiber. There may also be a way for you to use a long haul gigabit optic paired with mode conditioning patch cords.