Abstract. This paper analyzes the optical propagation and refraction phenomena in various complementary metal-oxide-semiconductor (CMOS) structures at 750 nm wavelength. Operation at these wavelengths offers the potential realizations of small microphotonic systems and micro-optoelectro-mechanical systems (MOEMS) in CMOS integrated circuitry, since Si-based optical sources, waveguides, and silicon (Si) detectors can all be integrated on a single chip. It could also increase the optical coupling efficiencies to external optical fibers. With the help of Monte Carlo and RSoft BeamPROP simulations, we demonstrate achievements with regard to optimizing vertical emission, focusing, refraction, splitting and wave guiding in 0.35 to 1.2 μm CMOS technology at 750 nm wavelength. The material properties, refractive indices, and thicknesses of various CMOS over-layers were incorporated in the simulations and analyses. The analyses show that both Si nitride and Si oxi-nitride offer good viability for developing such waveguides. Effective single-mode wave-guiding with calculated loss characteristics of 0.65 dB · cm −1 , with modal dispersion characteristics of less than 0.2 ps · cm −1 and with a bandwidth-length product of higher than 100 GHz-cm seems possible. A first iteration realization of an optical link is demonstrated, utilizing specially designed avalanche-based Si-LEDs and a specially designed first iteration CMOS waveguide. Potential applications of avalanche-based Si LEDs into microphotonic systems and MOEMS are furthermore proposed and highlighted.

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Micron dimensioned on-chip optical links of 50 micron length, utilizing 650 -850 nm propagation wavelength, have been realized in a Si Ge bipolar process. Key design strategies is the utilization of high speed avalanche based Si light emitting devices (Si Av LEds) in combination with silicon nitride based wave guides and high speeds Si Ge based optical detectors. The optical source, waveguide and detector were all integrated on the same chip. TEOS densification strategies and state of the art Si-Ge bipolar technology were further used as key design strategies. Best performances show up to 25 GHz RF carrier modulation and -40dBm total optical link budget loss with a power consumption of only 0.1 mW per GHz bandwidth. Improvement possibilities still exist. The process used is in regular production. The technology is particularly suitable for application as optical interconnects utilizing low loss, side surface, waveguide to optical fibre coupling.

We present a fabrication method that produces azimuthally symmetric long-period fibre gratings using a carbon dioxide laser operating in the TEM01∗-mode. The outlay and optimization of the optical system are introduced, and the long-period fibre grating fabrication method is outlined. A uniform long-period grating written in a boron-doped fibre exhibited a maximum transmission loss of 10.83 dB at 1538.5 nm. The peak transmission loss of a non-uniform long-period grating also written in the boron-doped fibre yielded a value of 10.25 dB at 1552.6 nm. The polarization properties of the fabricated long-period fibre gratings were investigated to determine the quality of the grating structures. The uniform long-period grating structure exhibited a maximum polarization-dependent loss of 0.97 dB at 1542.1 nm, and the non-uniform long-period grating yielded a maximum polarization-dependent loss of 2.48 dB at 1551.4 nm.