WAVELENGTH DIVISION MULTIPLEXING OPTICAL TRANSMISSION SYSTEM HAVING FUNCTION MONITORING TRANSMISSION CHANNEL OPTICAL POWER

摘要

PURPOSE: A wavelength division multiplexing(WDM) optical transmission system having a function monitoring transmission channel optical power, is provided to convert optical signals proportioned to each optical power of optical transmission signals into electric signals, and to perform an alarming process if the converted electric signals deviate from a preset critical range. So that errors can be promptly confirmed without an optical power meter and a wavelength detector, and gains of an optical amplifier can be automatically regulated according to the number of normal channels. CONSTITUTION: A predetermined ratio of optical signals, outputted to a wavelength division multiplexer(200) after passing an optical transmission module(120) and a tap coupler(310), are branched by the tap coupler and supplied to a photo diode(410) of a monitoring circuit(400). The supplied optical signals are converted into detection voltages of an electric signal level corresponding to the optical power of the optical signals. The detection voltages are commonly supplied to a first comparator(420) and a second comparator(430), and compared with preset critical ranges of a maximum critical level and a minimum critical level. If the voltages exceed the critical ranges, an alarm state is displayed through first/second alarm display circuits(440,450).