Search

A compact, mass producible Silicon On Insulator (SOI) based pressure sensor consisting of a folded Micro Ring Resonator (MRR) on a circular diaphragm is successfully designed, fabricated and characterized. An application of pressure deflects the diaphragm, causing stress in the MRR, which elongates the waveguide length and changes the effective refractive index of the guided mode. This results in a shift in its resonant wavelengths, which represents the applied pressure. This integrated device is successfully fabricated and a linear dependence between the resonance wavelength shift and the applied pressure at a constant temperature is measured. Such a pressure sensor finds applications in environments in which only minimal invasion is tolerated.

A compact, mass producible Silicon On Insulator (SOI) based pressure sensor consisting of a folded Micro Ring Resonator (MRR) on a circular diaphragm is successfully designed, fabricated and characterized [1-3]. The MRR is designed to be single mode for TE polarized light at 1550 nm. The folded MRR has a total length of 1500 μm which is folded to cover an area of 50X400 μm2 and has a guide-width of 450 nm. The circular diaphragm having a diameter of 1350 μm and a thickness of 15 μm is fabricated by reactive ion etching from the substrate side. Light is coupled into the MRR through the “in” port and measured at the “through” port using grating couplers. An application of pressure deflects the membrane, causing stress in the MRR, which in turn changes the effective refractive index the waveguide [4]. This results in a shift in its resonant wavelengths, which represent the applied pressure. Figure 1A shows the measured linear dependence between the resonance wavelength shift and the applied pressure at a constant temperature. Figure 1 B shows a SEM image of part of the membrane with MRR and Figure 1 C shows a schematic of the folded MRR. Such a pressure sensor finds applications in environments in which only minimal invasion is tolerated, such as in medical instrumentation.

One of the important issues of System-on-a-package integration is the interconnection between independent Photonic Integrated Circuits (PICs). In this work, this issue is addressed by the use of Vertical Grating Couplers (VGCs) as the element for the interconnection between two Silicon-on-Insulator (SOI) PICs. Theoretical simulations using the finite-difference time-domain (FDTD) computational technique have shown that the coupling efficiency can be at least as good as 41%. In order to prove the principle, two SOI-PICs fabricated in ePIXfab have been stacked vertically via the foundry's standard VGCs.

Silicon based SOI PICs are finding new applications in the field of sensing. Since Silicon does not produce light, to deploy these sensors in real-world applications a fiber-chip connection is required. In this work we detail the fabrication of V-grooves for fiber attachment to the chip, including the design, (hard) masking and the etching process. Our results show that V-groove attached fibre is an optimized solution for SOI based sensor PICs.

Integrated Nano Photonic (INP) sensors will be used in medical and space applications in the near future. Therefore, these devices must also be able to withstand harsh environments without failure. For space and medical applications radiation hardness is a very important issue. At TNO we have investigated the radiation hardness of nano photonic devices using electro-magnetic radiation and high energy particles. We have bombarded various ring resonators and couplers with gamma rays, protons and electrons. After the tests the device operation is verified and compared to non-radiated devices.