采用Agilent81910A光子全参量测试仪，首次实验研究了InP／In_1－xGa_xAs_1－yP_y－MQW(Multiple－Quantum－Well，MQW)材料与衬底间因应力而产生的M－Z型光调制器的PDL影响以及由此引起的由差分群时延(Differential Group Delay，DGD)表征的偏振模色散(Polarization Mode Dispersion，PMD)．研究结果表明，半导体MQW光调制器的PDL与DGD是一致的．因此在半导体光器件的制作过程中，应尽可能地减小衬底与波导芯层之间的因残存应力的存在造成对光器件的高速性能的不利影响．

Polarization Dependent Loss (PDL) accumulated by devices such as optical modulators,switches,filters,isolators in fiber-optic communications system remarkably degradated the transmission property of the whole link so that PDL of passive components became an important specification parameter. PDL of M-Z modulator influenced by stress between InP/In_1－X Ga_XA_S1－y P_y-MQW and its substrate and hence the Polarization Mode Dispersion (PMD) represented by Differential Group Delay(DGD) were first experimently observed by Agilent 81910A Photonic All Parameter Analyzer. The outcome shows PDL and DGD of semiconductor Multiple-Quantum-Well(MQW) are consistent. During the fabrication of semiconductor optical devices,the residual stress between InP/In_1－X Ga_XA_S1－y P_y-MQW and its substrate should be lessened as greatly as possible to avoid its impact on high speed optical devices'performance.