Determination of a statistical lack of volume matter by resonance principle: experiential approach and modeling

In integrated photonics, the calculation of the solutions regarding the propagation equations modes may be summed up as a problem with eigenvalues and eigenvectors to be solved. Based on such global principle, we have investigated the ability to monitor the impact of a lack of material (or void) on the evolution of eigenvalues of waveguides. To this end, specific families of resonators have been designed with several slits nano-inscribed upon them. The signal resonant light is then characterized while considering the whole geometry taking account of the void: thus, it contains the information regarding the pre-defined recessed volume. The UV 210 polymer is processed (deep UV 248 nm) so as to shape specific slots within a set of waveguides. Then, such waveguides have been re-looped as micro-resonators circuits with a view to measuring experimentally relevant variations of the eigenvalue considering the Free Spectral Range (FSR) associated with resonances. Experiments allowed us to highlight such changes in effective indices clearly correlated to the amount of void. As the lack of material reaches 10% (imprinted within space), a noticeable variation can be observed. It made possible to measure the impact of a given lack of material (defined grooved volume) within the cyclic resonators, on the measured and normalized FSR optical quantity showing then a dynamic evolution close to 1.5%. Moreover, simulations have been carried out so as to confirm the experimental measurements: accordingly, the relevant results allow us to validate a quantified description regarding the hollowed out volume (or mass recessed). Then, by way of the COMSOL software, apt simulations allowed us to confirm the measured evolution in agreement with experiments. This study provides a way to evaluate the global dynamic ranging effect due to a given mass hollowed out from such looped structures as regards the entailed spectral signature linked to the eigenvalues.