“…It is device loss. Thermo-optic phase shifter can be easily fabricated on MZI switch, which has power consumption 400 mW for π phase shift and it can be reduced to 45 mW with proper technology [60,61]. Liquid crystal phase shifter is also operated with very low-driving voltage (4-5 V), low-power consumption (in mW range) and high transmission rates [62][63][64][65].…”