Study of Optical Logic Devices Using the Injected Light in a Transverse Zeeman Laser

在横向塞曼激光器中利用注入光进行偏振开关的光学逻辑器件的研究中，得到了以下结果：(1)在633 nm内反射镜的HeNe激光器中，相邻的纵模表现出相互垂直的偏振。在横向塞曼激光器中，偏振特性依赖于腔损耗各向异性。具有大损耗各向异性的激光的偏振方向保持了自然轴的方向。而损耗各向异性较小的激光中的偏振方向取决于外加磁场强度和激光与磁场的夹角。在一定的磁场强度下，通过改变磁场强度，观察到了从sigma模和pi模方向的极化旋转现象。这种旋转偏振在相邻纵模之间交替切换，并且这些交替偏振彼此不垂直。(3)外腔带有偏振器的激光器的光偏振切换依赖于反馈光量和腔内各向异性。当反馈光较强时，各向异性较大的激光沿自然轴方向发生偏振切换。另一方面，当反馈光强并且激光器具有小的各向异性时，相对于外腔的各向异性诱导偏振切换。在使用主激光器注入的从激光器的系统中也发现了这些开关。在扫描注入激光频率时，观察到了开关的滞后现象。在横向塞曼激光器中，偏振开关条件可以由磁场强度来控制。经过小型化、稳定性的改进，该系统有望成为一种实用的逻辑器件。

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.