Development of a 0.75 micron wavelength, all - Silicon, CMOS based optical communication systems

The utilization of Organic Light Emitting Diodes (OLEDs) and Si Avalanche LEDs emitting at 0.45 - 0.75 micron enable the development of high speed all-Silicon CMOS based optical communication systems without the incorporation of materials such as Ge or III-V components. The development of low loss and high curvature optical waveguides in CMOS technology at these wavelengths, however, offers major challenges. Advanced optical simulation software was hence used in order to develop effective CMOS based waveguides, using CMOS materials characteristics, processing parameters, and the spectral characteristics of CMOS Av LEDs. The analyses show that both silicon nitride and Si oxi-nitride offer good viability for developing such waveguides, utilizing 0.2 to 1.5 micron wide CMOS over-layer as well as trench-based technology. Particularly, trench based technology are very attractive, since the optical sources can then be integrated with silicon avalanche based LEDs with trench-based waveguides on the same plane with standard CMOS processing procedures. Effective single mode wave-guiding with calculated loss characteristics of 0.65 dB.cm^-1 and modal dispersion characteristics of 0.2 ps.cm^-1 and with a bandwidth-length product of higher than 100 GHz-cm are predicted.