| 摘要 |
A wavelength stability circuit used in a WDM optical transmission system maintains the spacing of wavelengths between two optical signals at a prescribed value. The two optical signals with different wavelengths may be respectively generated by two laser diodes 1-1, 1-2 and multiplexed by an optical coupler 2. A portion of the multiplexed optical signals is supplied to an optical heterodyne detective circuit 4, where the spacing of the wavelengths between the two optical signals is detected. The spacing of the wavelengths between the optical signals is converted into an electrical signal by an O/E converter 5 and a frequency counter 6, and the electrical signal is compared with a standard voltage in a comparator 7. The lasing wavelength of one of the two laser diodes is controlled in accordance with the result of comparison. |
