Jwst Aspa Fiber Optic Development For Testing At 2.12 Mu M

The James Webb Space Telescope (JWST) requires testing of the full optical system in a cryogenic vacuum environment prior to launch. Challenges with the telescope architecture and the test environment led to placing removable optical test sources at the intermediate focus of this off-axis Three Mirror Anastigmat (TMA) to provide test sources in the Science Instruments. Fiber optic cables will route light whose wavelength is between 600 and 2120 nm from photonics external to the cryo-vacuum chamber to intermediate focus locations. These fiber optic cables will be greater than 50 meters in length and transition from ambient (293K) temperatures outside the chamber to cryogenic (30K) temperatures at the intermediate focus. Presented here are results from risk reduction testing conducted to ensure the fiber optic cables selected will 1) transmit 2.12 mu m light over long fiber runs, 2) show strong macro bending performance, and 3) perform at cryogenic temperatures.