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US 4,381,139 AGranted
Velocity mismatched modulator
AssigneeBell Telephone Laboratories, Incorporated
InventorRodney C. Alferness
Life of this patent
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Abstract
The coupling efficiency between a pair of identical optical waveguides (11, 12) is modulated by a traveling electrical wave (14, 15). Because the propagating constants of the optical and modulating systems are not equal, the interaction between them is limited to periodic intervals along the optical wavepaths. By the appropriate selection of this spatial period, a velocity match between the modulating and optical systems is simulated.
Claims9
A modulator (10) comprising:
- a pair of substantially identical optical waveguides (11, 12) embedded in a substrate (13) of electrooptic material of lower refractive index;
- said optical waveguides being in coupling relationship over a distance L;
- and modulating means (14, 15), supportive of a traveling wave, for locally changing the propagation constants (.beta..sub.1, .beta..sub.2) of at least one of said waveguide (11, 12) at longitudinally spaced intervals (14-1, 15-1;
- 14-2, 15-2;
- . . . 14-n;
- 15-n) therealong.
3 more elements
Dependencies are inferred from the claim text.