The package of the modulator usually adopts cavity type stainless steel magnetic shielding package, brazing high and low frequency feed pass structure or ceramic high frequency differential feed pass structure, with optical fiber coupling interface on the side, GPPO, FPC adaptation.This type of packaging package products can meet the high-speed transmission requirements of more than 25Gbps. The supporting cover plate adopts the step cover structure to meet the parallel seam welding process.