垂直腔面发射激光器低温光电特性

Optoelectronic properties of vertical-cavity surface-emitting laser at low temperature

垂直腔面发射激光器通常被用作常温下 850 nm 波段短波长短距离光互连领域的激光光源,多在室温下进行测试和使用.在低温环境下垂直腔面发射激光器工作状态的表征是本文的研究重点.我们表征了在不同温度下直流驱动垂直腔面发射激光器的发光光谱和 10%占空比脉冲电流驱动垂直腔面发射激光器的发光光谱和功率-电流-电压曲线.通过测试激光器在室温和 10 K 温度下性能的变化,证明了现有的垂直腔面发射激光器在低温下仍能工作,激光器在 10 K 低温环境下仍可以作为光互连的光源使用,这一特点使得该激光器的应用范围可拓展至低温领域,预示着垂直腔面发射激光器在低温光互连系统中具有应用价值.

The vertical-cavity surface-emitting laser (VCSEL) is usually used as an 850nm short wavelength source for short-distance optical interconnection at normal temperature. In this study, the characterization of the VCSEL at low temperature was mainly studied. The laser spectra and the P-I-V curves are obtained with direct current and pulse current with 10% duty-cycle at different temperatures. It indicates that the VCSEL can work at 10K temperature environment. When the VCSEL laser is driven by direct current in a temperature range from 295 K to 10 K, the central wavelength of the laser is first red-shifted and then blue-shifted due to the change of environmental temperature and thermal effect on the device. With a pulsed-current driven source, the smaller the duty cycle, the less the heat generated by the device will be. The laser spectrum shows a blue-shift trend in the cooling process. The spectral width remains approximately stable in the cooling process. With temperature decreasing, the laser threshold current increases, and the lower the temperature, the larger the threshold current will be. It shows that the cavity mode and the gain spectrum shift with temperature changing. The cavity mode and the gain spectrum both shift to red with temperature increasing, and they shift to blue with temperature decreasing. But their shifting speeds are different. The mismatch between the cavity mode and the gain curve causes the device to need more energy for lasing. So the laser will work at a higher current driven at low temperature. The laser can work at low temperature as a stable light source. Therefore, the VCSEL has potential applications in optical interconnection system as a source at low temperature.