| 摘要 |
PROBLEM TO BE SOLVED: To determine with only a transmission side configuration whether the phase of 1:2DEMUX output is correct or not.SOLUTION: An optical transmitter comprises: a 16:1MUX 2 which aggregates transmission data; a 1:2DEMUX 3 which divides a data sequence from the 16:1MUX 2 into two sequences by using a clock; drivers 6 and 7 which amplify a data sequence from the 1:2DEMUX 3; a QPSK optical modulator 11 which optically modulates the amplified data sequence; a data output control unit 1 which outputs to the 16:1MUX 2 transmission data of fixed pattern consisting of a data sequence for the QPSK optical modulator 11, one side of which is an AC pattern and the other side is a DC pattern; a phase shifter 12 which shifts the phase of the clock; a driver ON/OFF control unit 12 which controls output of the drivers 6 and 7; an optical coupler 14 which branches the light from the QPSK optical modulator 11; a photodiode 15 which monitors the branched light; and a clock phase control unit 16 which controls the amount of shift exercised by the phase shifter 12 on the basis of the result of monitoring in a driver output controlled state. |
