Juan Hurtado

Vertical multiple-slot waveguide ring resonators in silicon nitride

This article describes the first demonstration of ring resonators based on vertical multiple-slot silicon nitride waveguides. The design, fabrication and measurement of multiple-slot waveguide ring resonators with several coupling distances and ring radii (70 microm, 90 microm and 110 microm) have been carried out for TE and TM polarizations at the wavelength of 1.3 microm. Quality factors of 6,100 and 16,000 have been achieved for TE and TM polarization, respectively.

Midinfrared filters based on extraordinary optical transmission through subwavelength structured gold films

An experimental study is made of the enhanced optical transmission of nanostructured gold films in the midinfrared region. Results indicate that the excitation of surface plasmon polaritons due to periodicity plays a fundamental role in producing extraordinary optical transmission. The influence of the surrounding claddings, hole shape, and periodicity on the resonance wavelength and the quality factor is investigated. The aim is to use the subwavelength structures as ultracompact optical filters whose spectral features can be easily tuned and scaled. For filter design purposes, the results show that the main parameters affecting the resonance wavelength are the lattice constant and dielectric cladding. The hole shape and size are found to cause transmission enhancement and there is only a small resonance redshift when the hole area is increased. However, a lower quality factor is achieved when the hole area is increased.

High sensitivity and label-free oligonucleotides detection using photonic bandgap sensing structures biofunctionalized with molecular beacon probes

A label-free sensor, based on the combination of silicon photonic bandgap (PBG) structures with immobilized molecular beacon (MB) probes, is experimentally developed. Complementary target oligonucleotides are specifically recognized through hybridization with the MB probes on the surface of the sensing structure. This combination of PBG sensing structures and MB probes demonstrates an extremely high sensitivity without the need for complex PCR-based amplification or labelling methods.

Tapered Fibre Optic Biosensor (TFOBS) by Optically Controlled Etching for Label-Free Glucose Concentration Monitoring - Biomedical Optics

This paper proposes, designs and demonstrates experimentally a tapered fibre optic biosensor (TFOBS) fabricated by an optically controlled HF chemical etching. The fabricated device is demonstrated to operate properly as a label-free sensor for glucose concentration detection. This work presents a novel fabrication method of a single-mode TFOBS controlling the reaction rate by changing the HF concentration and monitoring the optical power variation at the fibre output. Two TFOBS fabricated with different cladding diameters are evaluated experimentally to sense different glucose concentrations observing the changes in the refractive index of the medium in various solvents. The sensing capabilities are evaluated by modal interferometry measurement of both intensity and phase variations of the received optical signal.

Fabrication of modulators and 2×2 switches in SOI based on the carrier depletion mechanism for optical interconnects

Silicon-photonic 2×2 electro-optical switching elements and modulators based on the carrier depletion mechanism using both dual-resonator and MZI layout configurations have been developed. The passive photonic structures were developed and optimized using a fast design-fabrication-characterization cycle. The main objective is to deliver smallfootprint, low-loss and low-energy silicon photonic electro-optical switching elements and modulators equipped with standard input-output grating couplers and radio-frequency electrical contact tips to allow their characterization in highspeed probe-station setups. The insertion losses, crosstalk, power consumption and BER performance will be addressed for each electro-optical structure. The fabrication steps, including low loss waveguide patterning, pn junction and low resistive ohmic contact formation have been optimized to produce high performance devices with relaxed fabrication tolerances, employing both optical and electron-beam lithography.