An optical module that processes an input optical signal and outputs a processed optical signal is disclosed. The optical module provides a housing and an optical processing device in the housing. The housing provides an optical input port and an optical output port in a first wall thereof in side-by-side arrangement. A third wall of the housing only provides RF terminals. Second and fourth walls of the housing provide DC terminals. Electrical connection between the DC terminals with DC pads on the device is realized through a wiring substrate whose top avoids an optical path from the optical input port to the input port of the device.