Device and method for monitoring failures of time division multiplexing optical network link

The invention relates to an optical fiber communication network failure monitoring technology, in particular to a device and a method for monitoring failures of a time division multiplexing optical network link, and solves the problems that the present time division multiplexing passive optical network failure monitoring technology is low in spatial resolution, complicated in structure, low in sensitivity and small in dynamic range. The device comprises a time division multiplexing optical network and a monitoring device, wherein the time division multiplexing optical network comprises an optical line terminal, a feeder fiber, an n-branch optical splitter, n branch fibers and n optical network units; the monitoring device comprises an isolator-free semiconductor laser, a coupler, an optical coupling device, a photoelectric detector, a signal acquisition and treatment device and n optical feedback devices. The semiconductor laser is connected with the coupler, and the large-scale output terminal of the coupler is connected with the input terminal of the optical coupling device. The device is suitable for monitoring failures of a time division multiplexing passive optical network.