| 摘要 |
Heterodyne and homodyne lightwave communication systems require transmitter optical sources and receiver local oscillators to be locked to a particular frequency. In accordance with the present invention, each transmitter laser and each receiver local oscillator laser is independently and locally stabilized to the same absolute frequency standard using species exhibiting atomic or molecular absorption lines in the wavelength range of interest. Frequency stabilization of the lasers is achieved by employing an optogalvanic effect element in a feedback control loop with the laser. Absolute frequency standards are obtained using gas discharge tubes containing, for example, noble gases such as argon (1.2 mu m to 1.4 mu m) and krypton (1.4 mu m to 1.6 mu m) and the like. Standard synchronous detection and feedback control techniques are used to insure proper long-term frequency stability.
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