A wideband optical module includes a downward wideband light source for
generating downward light, an upward wideband light source for generating
upward light, a first circulator including a first to a third port for
outputting multiplexed downward optical signals to the second port and
for outputting multiplexed upward optical signals to the first port, a
second circulator including a first to a third port for outputting
multiplexed upward optical signals to the second port and for outputting
multiplexed downward optical signals to the first port, a first optical
coupler connected to the third port of the first circulator and the
second port of the second circulator for outputting the downward light to
the third port of the first circulator, and a second optical coupler
connected to the second port of the first circulator and the third port
of the second circulator for outputting the upward light to the third
port of the second circulator.