| 摘要 |
PURPOSE:To superpose an auxiliary signal on a main signal without externally providing an electric circuit by applying the auxiliary signal to a primary electro-optical element perpendicularly to a light propagating direction. CONSTITUTION:A light emitted from a semiconductor laser 1 is converted to a parallel beam having a diameter (d) via a lens 2, and linearly polarized in a direction of 45 deg. with respect to a direction (z) (direction of an electric field) of a primary electrooptical element 4 via a polarizer 3. This linearly polarized wave is incident to the primary electrooptical element 4, an optical phase difference GAMMA is generated in two direction components (directions z and x') in the electrooptical element 4 to become an elliptically polarized wave. The phase difference GAMMA is varied dspending upon variation in an electric field responsive to the auxiliary signal by applying the auxiliary signal to the electrooptical element 4 from an auxiliary signal voltage source 8. As a result, the output of the electrooptical element 4 is transmitted via the polarizer 5 perpendicularly crossing the incident wave polarizing direction to obtain an amplitude modulation light corresponding to the applied auxiliary signal, i.e., a lateral amplitude modulation light. |
