| 摘要 |
PROBLEM TO BE SOLVED: To obtain a variable wavelength optical transmitter, suitable for stabilizing the wavelength of a semiconductor laser used in DWDM system by incorporating a section for detecting the wavelength of light emitted from a variable wavelength light source element in a laser package so that the oscillation wavelength of the variable wavelength light source element can be stabilized and the optical output therefrom can be controlled. SOLUTION: A part of light, emitted from the variable wavelength light source element 2 is monitored directly by a second photodetector 7 and APC control is performed through an APC circuit 14. It is also passed through a filter 5, having a transmittance dependent on the wavelength and monitored by a first photodetector 6. An AFC circuit 15 performs AFC control, while detecting variation of wavelength using the filter output and the direct monitor output. According to the arrangement, the structure is simplified extremely and the size and cost can be reduced. |
