Study of ultrafast optical buffer memory using long wavelength VCSELs

我们主要研究了以下四个方面的问题，以建立工作在长波长区域的全光缓冲存储器。我们制备了方形台面结构的vcsel。通过注入光脉冲实现了偏振双稳态开关。我们证明了设置和复位光脉冲的低开关能量为0.2 fJ和0.3 fJ，并在触发器操作中记录了10 GHz的高开关频率。我们提出了一种基于VCSELs偏振双稳定的新型3R再生器。VCSEL输出信号经过偏振器后成为与数据信号具有相同位模式的再生信号。VCSEL输出的上升和下降时序由设定脉冲和复位脉冲的时序决定。从而减少了数据信号的时序抖动。在我们的实验中，将2 ns的峰间时序抖动减小到0.7 ns.3。我们提出了一种利用二维偏振双稳vcsel阵列的光缓冲存储器。首先，利用光复位脉冲对vcsel的偏振进行复位。将光信号转换成空间并行信号，与光集脉冲一起注入到vcsel中。只有当光信号和光集脉冲同时注入到vcsel中时，vcsel的偏振才会发生改变。因此，vcsel发射的输出极化取决于输入信号的“0”和“1”。输出信号脉冲是由vcsel的连续波0°输出产生的，并被转换成超快光信号。我们已经通过实验证明了1位光学缓冲。利用光抽运的方法制备了1.55 μm的VCSEL结构，并获得了激光振荡。这一结果使光学缓冲存储器在长波长区域成为可能。

We investigated mainly the following four topics to create the all-optical buffer memory working in the long-wavelength region.1. We have prepared VCSELs with a square mesa-structure. The polarization bistable switching was obtained by injection of optical pulses. We demonstrated the record low switching energy of 0.2 fJ and 0.3 fJ for the set and reset optical pulses and the record high switching frequency of 10 GHz in the flip-flop operation.2. We proposed a novel 3R regenerator based on the polarization bistability in VCSELs. The VCSEL output signal through a polarizer becomes the regenerated signal which has the same bit pattern as the data signal. The rise and the fall timings of the VCSEL output are determined by the timings of the set pulse and the reset pulse. Thus, the timing jitter of the data signal is reduced. In our experiment, the peak-to-peak timing jitter of 2 ns was reduced to 0.7 ns.3. We have proposed the optical buffer memory using a two-dimensional array of the polarization bistable VCSELs. First, the polarization of the VCSELs are reset by an optical reset pulse. Optical signals are converted to spatially parallel signals and injected into the VCSELs together with optical set pulses. Only when the optical signals and the optical set pulses are simultaneously injected into the VCSELs, the VCSELs change their polarization. Therefore, the VCSELs emit the outputs with the polarization which depend on '0' and '1' of the input signal. The output signal pulses are created from the CW 0° output of the VCSELs and are converted to an ultrafast optical signal. We have experimentally demonstrated 1-bit optical buffering.4. We have made a 1.55 μm VCSEL structure have obtained laser oscillation by optical pumping. This result makes the optical buffer memory possible in the long wavelength region.