A fuel nozzle for a gas turbine engine includes a feed arm including a fuel passage for issuing a spray of fuel. A nozzle assembly is fixed at an upstream end of the feed arm having a fuel inlet in fluid communication with the fuel passage. A fiber optic cable is configured to collect burner radiation for a pyrometer input and has a first end centered within an optical connector of the nozzle assembly and a second end exposed from the spray outlet. The fiber optic cable fitted within the feed arm and nozzle assembly has a permanent bend radius preformed in the fiber optic cable. The bend radius can be equal to or greater than the minimum bend radii for the fiber optic cable to serve as a wave guide in wavelengths for monitoring combustion.