Microwave light modulators with spaced crystals
Abstract
A biaxial microwave light modulator was developed for optical high-precision range meters Mekometr MYe-3000 and DVSD-1200, its reference prototype version consisting of a resonator loaded with a crystal-capacitor. An analysis of the electric field distribution around the crystal mount in the resonator cavity indicates the possibility of mounting in the cavity two identical crystals spaced symmetrically with respect to the cavity center so far apart as to facilitate matching the receiver-transmitter optics with the modulator. The correct location of the crystals corresponds to the first two maxima of the Bessel function describing the radial distribution of the electric field. Two 30 mm long crystals only 8 x 8 sq mm in cross-section replace a single 35 mm long crystal with a larger 10 x 10 sq mm cross-section. A coaxial E sub 10-mode modulator and a biaxial E sub 20-mode modulator are possible, depending on how the effect of the metal conductors on the electric field distribution is utilized. The biaxial version is preferable for optical microwave range meters and refractometers, being both simpler and more efficient because it requires fewer mirrors behind the receiver optics and smaller metal conductors inside the resonator cavity. The spacing between receiver light beam and transmitter light beam is 35 mm, the tuning range is 120 MHz, and the figure of merit of this modulator is .016 sq rad/W.
- Publication:
-
USSR Rept Phys Math JPRS UPM
- Pub Date:
- April 1987
- Bibcode:
- 1987RpPhM.......14G
- Keywords:
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- Bessel Functions;
- Electric Fields;
- Light Modulation;
- Microwaves;
- Modulators;
- Cavity Resonators;
- Prototypes;
- Receivers;
- Transmitters;
- Optics