关键词: 长波长垂直腔面发射激光器/
偏振旋转光反馈/
偏振开关
English Abstract
Polarization switching with low power consumption induced by optical feedback in long-wavelength vertical-cavity surface-emitting lasers
Wang Xiao-Fa1 2 3,Wu Zheng-Mao1 3,
Xia Guang-Qiong1
1.School of Physical Science and Technology, Southwest University, Chongqing 400715, China;
2.School of Optoelectronics Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China;
3.School of Mathematics and Statistics, Southwest University, Chongqing 400715, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 61178011, 61275116, 11304409, 61475127, 61575163), and the Natural Science Foundation of Chongqing City, China (Grant No. CSTC2013icyjA40004).Received Date:28 August 2015
Accepted Date:28 September 2015
Published Online:20 January 2016
Abstract:The polarization switching (PS) characteristics of vertical cavity surface emitting lasers(VCSELs) have received sustained attention for the past years. With the development of manufacturing technology, the performances of 1550 nm VCSELs have been improved, however the researches on the PS of 1550 nm VCSELs are relatively inadequate for the PS characteristics in the long-wavelength VCSELs may have wide application prospects in optical information processing and optical communications. In this paper, based on the extended spin-flip model (SFM), we theoretically investigate the PS with low power consumption induced by optical feedback in long-wavelength VCSELs. Results show that the PS, which is failed to realize in free-running long-wavelength VCSELs, can be achieved by introducing a moderate-strength polarization-rotation optical feedback. By comparing two different linear dispersion effects, some interesting phenomena have been found. For weak linear dispersion, the PS is relatively easy to realize for a low injection current level, and the range of feedback strength used to control the PS is wide. However, for strong dispersion effect, the PS cannot be obtained all the time since two mode-coexisting zones will appear, and the value of injection current where the PS happens is relatively high. Meanwhile, as observed in short-wavelength VCSELs, the polarization mode hopping and multiple PS have also been found in long-wavelength VCSELs, indicating that the physics nature thet induces the PS is similar for both long and short wavelength VCSELs. In addition, because the PS in long-wavelength VCSEL is more difficult to realize as compared with that in short-wavelength VCSELs, reasonable analyses and explanations may be as follows: since the linear dispersion effect in 1550 nm-VCSEL is much stronger than that of short wavelength VCSEL, the frequency difference between the two linear polarization modes is up to 60 GHz (or 0.48 nm), thus leading to the decrease of the correlation between two linear polarization modes. As a result, it is relatively difficult to obtain the PS phenomenon at low injection current level in long-wavelength VCSEL; while using suitable polarization-rotated optical feedback can partially compensate the deficiency of this correlation. We believe that the results obtained in this work will be helpful in investigation of low power consumption for all optical buffers by using long-wavelength VCSELs.
Keywords: long-wavelength vertical-cavity surface-emitting lasers/
polarization-rotated optical feedback/
polarization switching
