|Budget Amount *help
¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1993 : ¥200,000 (Direct Cost : ¥200,000)
Fiscal Year 1992 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1991 : ¥700,000 (Direct Cost : ¥700,000)
In the study of optical logic devices using the polarization switching by the injected light in a transverse Zeeman laser, the following results were obtained.
(1) In a 633 nm HeNe laser with internal mirrors, adjacet longitudinal modes show orthogonal polarizations each other. A good correlation between natural axs of the polarization and loss anisotropy of cavity Q was found.
(2) In the transverse Zeeman laser, the polarization characteristics depend on cavity loss anisotropy. The polarization in the laser with a large loss anisotropy keeps the directions of the natural axs. On the other hand, the polarization in the laser with small loss anisotropy, the direction depends on applied magnetic fields strength and the angle between the laser and the magnetic field. In a magnetic field strength, a polarization rotating phenomenon from sigma and pi mode direction is observed by varing magnetic strength. This rotated polarization switches alternatively between adjacent longitudinal modes and these alternating polarizations are not perpendicular to each other.
(3) Optical polarization switching of the laser with a polarizer in external cavity depends on the quantities of feedback light and cavity anisotropy. When the feedback light is strong, the polarization switching occurs with natural axis in laser with large anisotropy. On the other hand, when the feedback light is strong and the laser has small anisotropy, polarization switching is induced with respect to the anisotropy of the external cavity. These switchings were also found in the system of a slave laser using injected ltight by a master laser. Sweeping injected laser frequency, the hysteresis phenomenon on the switching has been observed. This can utilize as an optical flip-flop.
(4) In the transverse Zeeman laser, the polarization switching condition can control by the magnetic fields strength. Then this system may expect to use as a practical logic device by small-sized and stable improvements.