| 摘要 |
PURPOSE:To obtain the light waves of two different frequencies having a low differential frequency and reduce the size of the titled shifter by branching output optical waveguides oppositely to each other from different places in the midway of an optical waveguide for inout and changing periodically the refractive index in the respective parts. CONSTITUTION:The frequencies of the incident light IB and surface acoustic wave SAW1 of an optical waveguide 12 are respectively designated as f(lambda) and F1 in optical waveguide for outputs branched to the sides opposite to each other with the optical waveguide for input in-between from the different places in the midway of the waveguide for input. If the equation sintheta1=lambdaF1/2V is satisfied, the light IB is partly Bragg- diffracted and deflected at an angle 2theta1 by interaction with the SAW1 in a branch part 10. The deflected light advances to an optical waveguide 13 and the frequency of the deflected light D1 attains f+F1. If the frequencies F2, (f) and angle theta2 of the SAW2 satisfy the above-described equation as well, the light IB past the branch part 17 deflected at an angle 2theta2 by interfaction with the SAW2 in the branch part 18. The deflected light advances to an optical waveguide 14 and the frequency of the deflected light D2 attains f+F2. The light D1 of the frequency f+F1 and the light D2 of F+F2 are respectively obtd. from the right end of the waveguide 13 and 14 and the differential frequency is ¦F1-F2¦. |
