1.IWDM is combined by a pump coupling WDM and a 1550nm polarization insensitive optical isolator, which is based on mature technology of thin film filter. The IWDM is a low cost module with excellent performance including low insertion loss, high isolation, high return loss, low polarization dependent loss. This product offers integrated solutions to EDFA applitcations by combining more functions into a ultra compact package. 2.ISOG is combined with Isolator and Gain Flattening Filter(GFF), which is based on thin film filter platform. The product features low insertion loss, excellent thermal stability, and compact package. 3.The DWIG is combined by two WDM, a Gain flattening filter and an isolator in a compact package. This product is widely used in EDFAs. It has an extremely low insertion loss and compact-size.