Ultra-sensitive silicon temperature sensor based on cascaded Mach-Zehnder interferometers.

An ultra-sensitive temperature sensor without sacrificing detection range is demonstrated on the silicon-on-insulator (SOI) platform using cascaded Mach-Zehnder interferometers (MZIs). The sensitivity enhancement is achieved by tailoring the geometric parameters of the two MZIs to have similar free spectral ranges (FSRs) but quite different sensitivities. The proposed sensor only needs single lithography for the sensing unit, without introducing negative thermo-optic coefficient (TOC) materials.

On-chip simultaneous sensing of humidity and temperature with a dual-polarization silicon microring resonator.

It is still challenging to realize an on-chip optical sensor that can detect humidity and temperature at the same time. In this paper, we demonstrate a silicon-based dual-polarization micro-ring resonator (MRR) with a polyvinyl-alcohol (PVA) upper-cladding, which enables the simultaneous measurement of humidity and temperature. Due to the significant polarization-dependence of the silicon-on-insulator (SOI) nanophotonic waveguide, the transverse electric (TE) and transverse magnetic (TM) polarization modes have quite different sensitivities towards the changes of ambient relative humidity (RH) and temperature.