Increased fiber communications bandwidth from a resonant cavity light emitting diode emitting at λ=940 nm

Substrate‐emitting InGaAs/AlGaAs resonant cavity light emitting diodes (RCLEDs) emitting at λ=940 nm have been fabricated for use in optical communications. The devices exhibit a high output efficiency, with a far‐field intensity of 85 μW/Steradian from a planar surface at a current of 14 mA. The spontaneous spectrum exhibits a very narrow peak of only 5 nm width, as opposed to the 50‐nm‐wide peak of an 875 nm wavelength reference LED. We show that the narrow spectrum drastically reduces the effects of chromatic dispersion within a 3.37 km length of 62.5 μm core graded index multimode fiber. The resulting −3 dB frequency is 102 MHz for the RCLED and fiber system, as opposed to only 33 MHz for the chromatic dispersion limited reference device.