A low-cost reconfigurable optical add/drop multiplexer（ROADM） with system upgrade capability and dynamic gain equilibrium is studied.This module consists of planar Arrayed-Waveguide Grating（AWG）

Switch Integrated Variable Optical Attenuator（SiVOA）

circulator

tap PD

coupler and isolator.The flexible application of SiVOA contributes to the realization of the two-way transmission of wavelengths and module cost reduction.Optical signals with single or multiple wavelengths can be added/dropped at any add/drop ports with power adjusted at random by regulating SiVOA.The fundamental work principle and index test results of the new module are given.