LumiGram Fiber Optic Fabric.

From the website:

This technology allows to wave plastic optical fibers alongside synthetic fibers, forming a luminous fabric. The luminous fabric is similar to a synthetic fabric (it can be sewn, hand washed,…), except that it can emit light when connected to a specific electronic module. This electronic module can be powered either by a disposable or rechargeable battery, or by a small mains transformer (for non wearable items).

Unlike standard optical fibers, the fiber optic fabric emits light along the full lenght of the fibers.

Link - via 2dayBlog