Firecomms RCLEDs (Resonant Cavity Light Emitting Diodes) are high-speed light emitting diodes designed to operate at speeds up to 400 Mbps, eight times faster than conventional LEDs. Specifically designed to meet the specifications of POF data bus standards, such as IEEE 1394b and MOST, our RCLEDs offer all the attractive features of a conventional LED, plus high speeds, high temperature operation, and superior coupling efficiency into optical fiber due to a compact optical output.

Firecomms RCLEDs are used with POF to replace copper cables in higher volume markets, such as home and car networks, where glass fiber is too expensive to terminate, and copper is heavy and sensitive to electromagnetic interference. Unlike the alternatives, POF has a substantially lower installed cost, is not sensitive to electromagnetic interference, is easy to terminate, and is lightweight.

The structure of Firecomms visible RCLEDs shares many of the same features as Firecomms visible VCSELs in that they use the same semiconductor compounds, have a similar vertical cavity structure using epitaxial DBR mirrors, and use the same fabrication process steps. Although the two device types share much in common in terms of their manufacture, each operates according to quite different physical principles. The RCLED’s cavity and thin active region combine to significantly increase both the extraction efficiency of light out of the front surface of the device and the maximum modulation frequency. Thus a RCLED compared to a conventional LED can generate more light for each mA of drive current and be modulated to a higher data rate.

Firecomms' evolutionary approach has been to develop an automotive grade RCLED, designed for the harsh environment of a car network which requires excellent reliability and tolerance to extreme temperatures. The nature of the RCLED technology enables an easy transfer to consumer electronics, like handheld gaming, cellular telephony, multimedia/home networks, and personal computers.

Firecomms is the first to have designed, developed, and tested an automotive-grade RCLED capable of operating over a temperature range of -40°C to 95°C with POF coupled powers in excess of 1 mW at 20 mA DC. With a suitable drive circuit the maximum change in output power between -40 and 95°C is only 3 dB. This performance is achieved through a combination of the epitaxial design of the RCLED and the optical design of the transparent plastic encapsulated package.