Professor Wu’s research interests include Optical communications, computer communications, and communications systems. He studies optical orthogonal codes (OOC). He investigates the perfect difference codes (PDC) which have the cross correlation value exactly equal to one. Combining these codes with multiuser interference cancellation receivers, Professor Wu’s group propose the best synchronous optical code division communications system, which is applicable to broadband access networks. Based on PDC and relaxing the cross correlation value to larger than one, one can get more OCCs which are suitable for asynchronous optical code division communications. Because the Ethernet passive optical network (EPON) is the most promising Candidate for broadband access networks. This group implements an optical code division based EPON with A 10Gb/s / 1.25Gb/s EPON transmission rate. For the computer communications, Professor Wu proposed a variable packet length Self-routing switch architecture. An 8x8 1Gb/s switch was demonstrated . Furthermore ,This group is investigating the feed forward and feedback type optical switches with various buffer management schemes under long range dependent traffic. The performance analysis and the best buffer management scheme will be reported.