Try NS-3. There is a module for it according to this paper

http://www.google.iq/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0CE4QFjAE&url=http%3A%2F%2Fbib.irb.hr%2Fdatoteka%2F604446.MileticMikacDzanko-MONCNSBA.pdf&ei=56pgUdDwBcPWswbOsIGQBA&usg=AFQjCNFhOUvbiLdqjrIT9kG9VGwDKQXORg&sig2=KIXWuVy6SFIWa49nBC846w&bvm=bv.44770516,d.Yms&cad=rja

Also I guess OPNET modeler 14.5 supports it. check it.

ns2 can be a good alternative. Many WDM extensions to ns2 are mentioned in literature, but, to my knowledge, only OWns, OBS-ns and nOBS are publicly available. I use OBS-ns which is developed at Optical Internet Research Center on the basis of OWns.