The data processing in Python is also able to extract the FSR and ground index for the measured data. The FSR was extracted from the measured data and shown to be 6.05nm which is then compared to the equation based calculations shown in Table 1, for an MZI with \(\Delta L=100\mu m\) the FSR is 5.72nm. These values show very close agreement. Using the measured data the group index was also extracted and is shown in Fig. 15 below. Similarly, the group index extracted value of 4.16 is also very close to the calculated value of 4.2 in Table 1.