| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical transmission device capable of stabilizing optical output with a small-scale circuit and that does not require a dedicated circuit. <P>SOLUTION: The optical transmission device includes a drive circuit 106 which generates a drive voltage corresponding to an input signal, an external modulator 102 which modulates projection light of a light source, according to the drive voltage generated by the drive circuit and converts the input signal into an optical signal, and a bias supply circuit 107 which supplies bias for operating point driving to the external modulator 102. The optical transmission device is provided with a coupler 103 which makes the output optical signal branch from the external modulator, a PD 104 which receives and converts the output signal from the external modulator branched by the coupler into an electrical signal, an A/D 105 which converts the electrical signal generated by the PD into digital data, and a control unit 108 which reads in the data obtained by the A/D and sets a bias to be supplied to the external modulator for the bias supply circuit, and the control unit automatically calculates a proper operating point for the external modulator. <P>COPYRIGHT: (C)2007,JPO&INPIT |
