Electrical power, changing with differential group delay (DGD) and detected from an optical communication link, can be used as feedback signals of compensating for PMD. Theoretical calculations and curves are given representing the change of electrical power with DGD. Experimental results confirming the theoretical calculations are presented for voltage V changing with DGD. A setup is built for experiments of PMD compensations. Several factors affecting the feedback signals are proposed and methods are given to make the fluctuations less. Results of PMD compensation prototype for a 10 Gb/s pseudo random sequence are shown through eye patterns. These results are also shown by receiver sensitivity improvements after compensation. Receiver sensitivity under 3 different bit error rates are measured using BER measuring equipment. Comparisons of results using different fibers are made,confirming the effectiveness of compensation.