| 摘要 |
A first (1) and a second (6) narrowband laser device (1, 6) are each connected to an optical coupler means (3, 8) and also to each an input (13, 14) of a directional coupler (15). The coupler means (3, 8) have their respective outputs (5, 10) connected to a photo detector (18). The laser devices (1, 6) are each connected to their respective control circuit (17, 20). The control circuit (20) of the second laser device (6) is in turn connected to the output (19) of the photo diode (18) and to an exterior control signal (V2) with a frequency f0. Controlled by its control circuit (17) the first laser device (1) transmits a light signal (S1) with a fixed frequency f1, and the second laser device (6) transmits a light signal (S3) with a frequency f2. The photo detector (18) transmits a signal (V1) with a frequency f2-f1 and the second control circuit (20) controls the second laser device (6) so that f2-f1=f0. An information carrying signal (V3) resets the directional coupler (15) and alternatingly switches the laser devices (1, 6) to the output (16) of the directional coupler (15). From this output there is sent a coherent frequency modulated signal S7 with the frequencies f1 and f2. |
