A module for amplifying a signal light with a remote excitation-light, includes (a) a first optical input/output line through which a signal light is transmitted, (b) a second optical input/output line through which a signal light is transmitted, (c) an optical amplifier which amplifies a signal light on receipt of an excitation light transmitted through the first or second optical input/output line, (d) a bypass circuit which allows the signal light to bypass the optical amplifier, (e) a first optical connector which optically connects the first optical input/output line to the optical amplifier, and further optically connects the first optical input/output line to the bypass circuit, and (f) a second optical connector which optically connects the second optical input/output line to the optical amplifier, and further optically connects the second optical input/output line to the bypass circuit.