| 摘要 |
A reflective modulator (10) includes a light splitter (12) which divides light into two portions, one of which is applied to a directional coupler (14) by a first path (20), and the other of which is applied to the directional coupler (14) by way of cascaded electrooptic (e-o) modulators (18a, 18b). One port of the directional coupler (14) is terminated in a reflector (22), and the other in an absorptive termination (24). Electrical signals A and B are applied to the modulators (18a, 18b), with the result of generation of sum and difference frequencies modulating the light. The light leaves the reflective modulator (10) and is coupled to a utilization apparatus (64) by a second directional coupler (28). A further e-o modulator (26) may be coupled in the first path, for controlling the long-term average phase shift. In a particularly advantageous embodiment of the invention, the signal sources (30a, 30b) are elemental antennas of an array (30).
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