| 摘要 |
PROBLEM TO BE SOLVED: To provide optical transmission equipment for correcting the degradation of quenching ratio characteristics. SOLUTION: For continuous-wave beams(CW beams) 47 from a laser diode(LD) 40 for which the output is stabilized by an automatic power control(APC) circuit 41 and an automatic temperature control(ATC) circuit 42, a data signal 51 is amplified to the voltage amplitude required for driving an electro- absorption(EA) modulator 48, and afterwards, the strength is modulated at the EA modulator 48 by a modulator drive signal 53 to which a DC bias is applied by a bias tee 52. Modulated signal monitor light 59 which is split by a beam splitter 56 is optically/electrically converted opto-electrically, while detecting the optical power level through a second photodetector 59. Meanwhile, with the optical power level detected by a first photodetector 44 as a reference, the bias level of the EA modulator 48 is controlled, so that the optical power levels detected by the first and second photodetectors 44 and 59 can be made into a predetermined ratio. |
