Four-wave mixing can be stimulated or occur spontaneously: the latter effect, also known as parametric fluorescence,
can be explained only in the framework of a quantum theory of light, and it is at the basis of many
protocols to generate nonclassical states of the electromagnetic field. In this work we report on our experimental
study of spontaneous four wave mixing in microring resonators and photonic crystal molecules integrated on a
silicon on insulator platform. We find that both structures are able to generate signal and idler beams in the
telecom band, at rates of millions of photons per second, under sub-mW pumping. By comparing the experiments
on the two structures we find that the photonic molecule is an order of magnitude more efficient than the
ring resonator, due to the reduced mode volume of the individual resonators.
The design, modeling, fabrication, and experimental measurements on optical nanobeam cavities that change resonant frequency in response to changes in the
refractive index of the surrounding environment are presented. Nanobeam cavities based on Silicon-On-Insulator (SOI) that work at telecommunication
wavelengths (1550 nm) provide an ideal platform for label-free sensing, due to their features of high resonance Q-factors, high sensitivity and capability for integration with silicon CMOS.
We present the design modelling and fabrication of Silicon-On-Insulator (SOI) nanobeam cavities that are immersed in
a microfluidic system for refractive index sensing. The device has sensitivity value of greater than 200 nm/RIU with a
Q-factor more than 20 000 in water. It was fabricated on a SOI platform and working at telecom wavelengths. The use
of the SOI platform also offers further possibilities of integration with CMOS technologies.
Planar devices that can be categorised as having a nanophotonic dimension constitute an increasingly important area of
photonics research. Device structures that come under the headings of photonic crystals, photonic wires and
metamaterials are all of interest - and devices based on combinations of these conceptual approaches may also play an
important role. Planar micro-/nano-photonic devices seem likely to be exploited across a wide spectrum of applications
in optoelectronics and photonics. This spectrum includes the domains of display devices, biomedical sensing and sensing
more generally, advanced fibre-optical communications systems - and even communications down to the local area
network (LAN) level. This article will review both device concepts and the applications possibilities of the various
In this paper we outline recent results which combine defect mediated Photo-Detectors (PDs) in a Ring Resonator (RR)
structure. By exploiting the multiple-pass of the optical signal through the detector, we are able to significantly decrease
the size of the detector structure while maintaining good responsivity (typically 0.1 A/W). In such a geometry the
detector bandwidth is not capacitance limited, while the leakage current is reduced toward 1 nA. We also show that these
PDs may be used in the drop port of a RR to monitor the propagating signal. These devices have applicability in
multiplexing and potential for integration with high speed modulation functionality.
Ultrahigh Q/V lineic silicon Fabry Perot (FP) microcavities relying on silica substrate have been fabricated. Two cavities
designs are studied based respectively on cavity mode losses recycling and on mirrors with tapered sections. The
experimental evolution of cavities characteristics are studied as a function of sample temperature. The authors achieve a
quality factor of 58000 for a modal volume of 0.6 (λ/n)<sup>3</sup>.
Short microcavities consisting of two identical tapered hole mirrors etched into silicon-on-insulator ridge waveguides are investigated. They are designed for operating at telecom wavelength. We describe theoretically and experimentally two different ways to boost quality factors to some thousands. In one hand, we investigate the adaptation of mode profile to suppress mismatch losses. In an other hand, we explore the recycling of the losses. We obtained quality factor up to 3000, which opens the route to WDM applications.