- CEL is a stable provider of RF & Optoelectronic Components and RF Modules. As the exclusive Sales and Marketing partner in the Americas for Compound Semiconductor Devices from Renesas Electronics Corporation, formerly NEC Electronics Corporation, CEL offers RF Transistors, RF ICs, RF Switch ICs, Optocouplers, Solid State Relays, Fiberoptic devices (Lasers and Detectors) and Blue-Violet Laser Diodes.