Microlensed Edge Emitting LEDs For Long Haul Optical Fibre Systems

The low loss window and zero chromatic dispersion at 1.3 pm wavelength in optical fibres has made the use of light emitting diodes (LEDs) as sources a practical solution in multimode telecommunication systems. The microlensed surface emitting LED (SLED) has become an established device in commercial systems operating at 34 Mb/s over repeater distances of up to 10.5 kml. However, the drive for higher data rates (140 Mb/s) and longer repeater distances requires narrower spectral linewidths and higher coupled powers than can be achieved with SLEDs, thus provid-ing the impetus for the development of the Edge Emitting LED (ELED) as a higher output power device. The stimulated emission in the plane of the junction (that contributes to radiance saturation in SLEDs2) can enhance both coupled power and switching speed in the ELED structure. The linewidth of this device is inherently narrower due to self absorption. We have previously reported3 a superluminescent device utilising a deep diffused structure capable of very high launch powers (340 μW into 0.2 NA 50 p core fibre at 250 mA) and fast switching (2.2-2.6ns TR and TF). However, a penalty for placing too much reliance on stimulated emission can be an unacceptable temperature derating of some device performance parameters.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.