Silicon as a platform for photonics has recently seen a very large increase in interest
because of its potential to overcome the bandwidth limitations of microprocessor
interconnects and the low manufacturing cost given by the high compatibility
with the already established micro-electronics industry. There has therefore been
a signicant push in silicon photonics research to develop all silicon based optical
components for telecoms applications. The work reported in this Thesis is con-
cerned with the design, fabrication and characterisation of coupled ring resonators
on silicon-on-insulator (SOI) material. The nal objective of this work is to pro-
vide a robust and reliable technology for the demonstration of optical buers and
delay-lines operating at signal bandwidths up to 100 GHz and in the wavelength
region around 1550 nm. The core of the activity focused on the optimisation
of the fabrication technology and device geometry to ensure the required device
performance for the fabrication of long chains of ring resonators. The nal pro-
cess has been optimised to obtain both intra-chip and chip-to-chip reproducibility
with a variability of the process controlled at the nanometre scale. This was made
possible by careful control of all the variables involved in the fabrication process,
reduction of the fabrication complexity, close feature-size repeatability, line-edge
roughness reduction, nearly vertical sidewall proles and high uniformity in the
ebeam patterning. The best optical propagation losses of the realized waveguides
reduced down to 1 dB=cm for 480 220 nm2 rectangular cross-section photonic
wires and were consistently kept at typical values of around 1.5 dB=cm. Control
of the coupling coecients between resonators had a standard deviation of less
than 4 % for dierent realizations and resonance dispersion between resonators
was below 50 GHz. All these gures represent the state-of-the-art in SOI photon-
ics technology. Considerable eort has also been devoted to the development of
ecient thermal electrodes (52 W=GHz) to obtain a recongurable behaviour of
the structure and polymer inverse tapers to improve the o-chip coupling (inser-
tion losses < 2 dB). Phase-preserving and error-free transmission up to 100 Gbit=s
with continuously tunable optical delay up to 200 ps has been demonstrated on the
nal integrated systems, proving the compatibility of these devices with advanced
modulation formats and high bit-rate transmission systems