I. Introduction
The accomplishment of ultra-high temperature measurement is one of the greatest advances in temperature measurement technology. This perfects the temperature measurement system and guides the design of an aero-engine. The temperature sensor is employed to detect the turbine inlet temperature of aero-engine with the purpose of solving some essential problems such as thermal environment analysis and in-situ real-time temperature measurement of aero-engine turbine blades. It can also effectively counteract inadvertent overheating damage, to guarantee the service life of the hot end components of the engine and reduce the engine manufacturing cost. The thermocouples are pyroelectric temperature sensors converting a temperature signal into a potential signal. The temperature can be measured by an instrument or converter that can detect the potential signal. Thin Film Thermocouple (TFTCs) is a passive temperature sensor for real-time temperature measurement in the field [1-6]. TFTCs are fabricated on the surface of the object and could measure the high temperature of the object. Meanwhile, the thickness of the thermal junction of the TFTCs is typically on the order of micrometer or nanometer, which has many advantages. It is characterized by fast response, high sensitivity, and easy integration, and small thermal capacity. Consequently, the TFTCs are appropriate for real-time temperature measurement. During the temperature measurement procedure, the characteristics of the surface to be measured will not be affected, and the interference to the measured object will be significantly smaller, facilitating in-situ temperature measurement. Moreover, TFTCs are frequently used to measure the high temperature of the turbine engine owing to their superior spatial resolution, high-volume cost-effectiveness, and fast response [7-10].