24 Nov, 2023

RCLEDs what are they and why are they important in an industrial data link?

The Resonant Cavity Light Emitting Diode (RCLED) is a special type of LED that mixes the technologies used to make conventional LEDs with that of solid-state lasers called Vertical Cavity Surface Emitting Lasers (VCSELs). The design was specifically developed to meet the increasing demands of modern industrial applications which require optical sources to operate reliably over extreme operating conditions while simultaneously meeting stringent optoelectronic specifications. These extreme operating conditions not only concern the ambient operating temperature but also include the demanding electro-magnetic and mechanical environments found for example in high-power motor drives that are used in applications such as trains, wind turbines and heavy machinery.

What does a RCLED offer that traditional LEDs and VCSELs do not?

It is important to note that a RCLED is a special type of LED and therefore takes advantage of the robust nature of LEDs which can endure high electro-static discharge shock (ESD) and endure thousands of hours of operation in both hot, cold, dry, and humid conditions. In the case of the RCLED, the bulk LED structure is finessed by adding some mirror structures of a VCSEL which increases the optical output efficiency and achieves a higher coupled power at high temperature into Plastic Optic Fiber (POF). The RCLED therefore provides stable optical power over a wide operating temperature range typically -40 to +85°C in demanding industrial environments.

RCLEDs emitting visible red light in the 650 to 660 nm wavelength range are specifically designed for use in industrial applications using POF as this emission range matches the low-attenuation window of the fiber. When over-molded with optically clear plastics these RCLED based components form the key optical source for Firecomms transmitter products. These red transmitters can operate over an industrial temperature range, provide high ESD tolerance and immunity to EMI/EMC, and together with excellent reliability, are ideal for use in a wide range of industrial applications. Today Firecomms RCLEDs are found in optical links that control our trains, wind turbines, solar farms, and control power distribution to our cities. RCLEDs have become a work horse of the industrial fiber optic link.