Optical packet signal transmission device and WDM optical communication network

A WDM optical communication network comprising:

• a plurality of optical packet signal transmission devices, wherein each of the plurality of optical packet signal transmission devices includes:
• a transmitting unit which sends a plurality of data signals, obtained by decomposing continuous data included in an optical packet signal received from a client side, to a plurality of light emission units with various wavelengths, converts the plurality of data signals into optical packet signals, and transmits WDM optical packet signals generated by wavelength-multiplexed with the converted optical packet signals with wavelengths to a network side, wherein the transmitting unit includes:
• a plurality of data delay circuits which has variable delay amounts and separately delays the data signals sent to the light emission units;
• a plurality of optical branch units which branches some of the optical packet signals with the wavelengths, which are output from the light emission units, as monitor lights;
• an optical switch which selects one of the monitor lights with the wavelengths to be branched by the optical branch units;
• a test signal generation circuit which generates a test signal which is used to adjust the delay amount in the data delay circuits;
• a reference optical pulse generation circuit which generates a reference optical pulse based on a test signal generated by the test signal generation circuit;
• an optical phase comparator, into which the monitor light selected by the optical switch and the reference optical pulse generated by the reference optical pulse generation circuit, detects an relative optical phase difference by comparing the phases of the monitor light and the relative optical pulses;
• and
• a control circuit, before an operation of the optical packet signal transmission device starts, which sequentially sends the test signals, generated by the test signal generation circuit instead of the data signals, to the data delay circuits, switches the monitor light selected by the optical switch corresponding to the data delay circuit as an adjustment object to which the test signal is sends, detects the monitor light selected by the optical switch and a relative optical phase of the reference optical pulse, determines the delay amount in the optical phase difference is smaller than a maximum limit value determined in advance based on a detection result, and sets the delay amount after the operation starts in the data delay circuit as the adjustment object.