A self-healing passive optical network is disclosed. The network includes
a central office and a remote node connected to the central office
through a main optical fiber. The remote node transmits one portion of
power of the upstream optical signal, which has been input from each of
the optical network units, to the central office, and returning a
remaining portion of the power of the upstream optical signal to the
optical network unit. The network also includes a plurality of optical
network units connected to the remote node through a plurality of
distribution optical fibers. Each of the optical network units transmits
an upstream optical signal to the remote node through the directly
connected distribution optical fiber, and detects abnormality occurrences
from a state of the upstream optical signal returning from the remote
node.