The effect of changes of RI in the microcavity for standard conditions, i.e., the liquid is exchanged manually using a pipette, is shown in Fig. . When the RI increases the minima shift towards shorter wavelength and reduce their transmission. The phenomenon is originated by change in guiding conditions of the mode propagating in the cavity and interference at the distant cavity wall . The RI sensitivity of the fabricated µIMZI measured in standard and microfluidic conditions has been compared in Fig. ). It can be seen that for the longer loop applied, i.e., longer exposure to the elevated next, the performance of the device tends to the one investigated at standard conditions, while for the shorter loop, it is slightly lower. The results indicate that exchange of the liquid in the microcavity at the microfluidic conditions requires certain amount of liquid to effectively exchange.