One embodiment of the present invention includes a flexible interconnect assembly that can convert between optical and electrical signals and that is configured to be easily secured to an electrical device, such as a printed circuit board or integrated circuit chip. The flexible interconnect assembly includes a flexible substrate and one or more optical waveguides that are mounted on the flexible interconnect and suitable for transmitting optical signals. One or more conversion devices for converting between electrical and optical signals are arranged on the flexible substrate. The flexible interconnect assembly optionally includes an attachment fixture that enables the flexible substrate to be reversibly coupled to an attachment apparatus. Particular embodiments of the present invention involve methods, devices and systems for using a flexible interconnect assembly with one or more electronic substrates configured with an attachment apparatus.