宽光谱聚合物热光开关的制备及容噪特性研究

Fabrication and driving-noise-tolerance characteristics of wide-spectrum polymer thermo-optic switch

利用聚合物/SiO2混合材料脊形波导结构以及化学气相沉积(CVD)、涂膜和湿法刻蚀等工艺,设计并制备了一种低功耗马赫-曾德尔干涉(MZI)热光开关。测试了波导芯层和包覆层材料的色散特性,模拟分析了器件的输出功率和光谱性能。以可调谐激光器作为光源,实验测试了所制备器件的开关、响应和光谱特性。在1 550nm中心波长下,器件的开关功耗约为7.8mW,ON与OFF状态间的消光比达32.6dB。在纯净方波驱动电压信号(峰峰值为3 Vpp)作用下,测得器件的上升和下降时间分别为107和71μs。保持器件在1 550nm波长下的驱动功率不变,测得器件的输出光谱约为50nm(1 520～1 570nm),且在此范围内,器件的消光比大于18dB。利用NE555等集成电路自主制作了一种噪声幅度可调的含噪信号驱动源,借此研究了器件的容噪特性。结果显示,当要求器件的消光比大于10dB时,可允许的最大噪声幅度为1.1 Vpp。

By adopting polymer/silica hybrid rib waveguide structure, a low power-consumption Mach-Ze- hnder interferometer （MZI） thermo-optic switch is designed and fabricated with techniques including chemical vapor deposition （CVD）, spin-coating, wet-etching, etc. The wavelength dispersions of waveguide core, buffer and cladding materials are measured, and output power and output spectrum are theoretically analyzed. Switching response and spectrum characteristics are measured using a tunable laser as input source. Under 1 550 nm wavelength,the driving power of the switch is about 7.8 mW,the extinction ratio between ON state and OFF state is up to 32.6 dB,and under the function of pure squarewave switching signal （peak-to-peak amplitude of 3Vpp）,the rising time and falling time are 107 μs and 71μs,respectively. Keeping applying the driving power at 1550 nm wavelength on the device,the measured spectrum width is about 50 nm （1520-1570 nm） with an extinction ratio over 18 dB. A noise-leveltunable driving source is developed with NE555 and other integrated circuits, and then the driving-noisetolerance characteristics are investigated. Experimental results indicate that the allowed maximum noiselevel is about 1.1 Vpp with a required extinction ratio larger than 10 dB. The proposed results in this paper are of good meanings for practical applications of such thermo-optic switches with the hybrid wavegnide structure.