The most common source of polarization crosstalk is a physical misalignment between the Polarization-Maintaining (PM) fiber and the modulator chip's principal axis. In a typical intensity modulator setup, light must be launched into the "slow axis" of the PM fiber. 1) Fiber axis misalignment at fiber connection interfaces, of discrete coupling result in sharp, distinct peaks in the x-talk such as connectors or fusion splices, typically causes extremely measurement trace, with the width of the peak determin d by. Polarization-maintaining filter couplers serve as an important technological solution to overcome current polarization and interference challenges. At Liobate, we recognize that as the industry transitions toward Thin-Film Lithium. 1) It is an 'in-line' method, measuring the crosstalk within a user-selected region of the PM fiber itself. However, a comprehensive assessment of its polarization maintenance capability remains elusive. In this. temperature induced stress determination.