相変化材料を用いた導波路型光ゲートスイッチにおけるスイッチング動作

摘要

Two types of optical gate switch using phase-change material (PCM) were fabricated. The one switch had a 1-μm-thick PCM (Ge_2Sb_2Te_5) layer and the other one had a 20-nm-thick PCM layer. We successfully demonstrated switching by laser pulse irradiation for the first time. As for the switch with a 1-um-thick PCM layer, 'ON' to 'OFF' switching with an extinction ratio of more than 12.5 dB in the wavelength range from 1525 nm to 1600 nm was observed. The switch with a 20-nm-thick PCM layer was operated two cycles, 'ON' to 'OFF' to 'ON. The changes of output power were 14.3 dB ('ON' to 'OFF' 1st), 7.7 dB ('OFF' to 'ON' 1st), 7.4 dB ('ON to 'OFF' 2nd), and 4.4 dB ('OFF' to 'ON' 2nd), respectively. We used a laser pulse with a width of 453 ns and a peak power of 63 mW for crystallization and with a width of 10 ns and a peak power of 150 mW for amorphization. The wavelength of laser pulses was 660 nm.%膜厚が1μmと20nmの相変化材料（Ge_2Sb_2Tb_5）薄膜を有する光ゲートスイッチを設計・試作し，光パルス照射によるスイッチング動作に初めて成功した．厚膜型ゲートスイッチでは，波長1525nmから1600nmにおいてONからOFFへの一方向スイッチングを観測し，12.5dB以上の消光比を得た．薄膜型ゲートスイッチでは，二回のON/OFF/ON動作を観測し，出力光強度変化は一回目のON/OFF/ONにおいて14.3dB及び7.7dB，二回目のON/OFF/ONにおいて7.4dB及び4.4dBであった．結晶化光パルスはパルス幅453ns，ピークパワー63mW，アモルファス化光パルスはパルス幅10ns，ピークパワー150mWであり，それらの波長は660nmである．