Whispering gallery mode resonances from Ge micro-disks on suspended beams
Whispering gallery mode resonances from Ge micro-disks on suspended beams
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DOI：
10.3389/fmats.2015.00043
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发表时间：
2015-01-01
影响因子：
3.2
通讯作者：
Saito, Shinichi
中科院分区：
文献类型：
--
作者：
Al-Attili, Abdelrahman Zaher;Kako, Satoshi;Saito, Shinichi
Ge被认为是实现在硅（Si）光子芯片上的光源的完全单片集成的最有前途的材料之一。需要张应变将Ge转换成光学增益材料并减少粒子数反转所需的泵浦。在文献中提出了几种应变施加到Ge的方法，其中使用由微机电系统（MEMS）工艺制造的独立梁能够提供非常高的应变值。然而，它是具有挑战性的，使独立的Ge梁内的光学腔，在这里，我们演示了一个简单的腔的制造，同时施加拉伸应变的悬浮使用Geon-Insulator（G 01）晶片。通过部分去除支撑Si衬底，在悬浮的Si_0（2）梁上制作了Ge微盘。根据拉曼光谱，通过弯曲SiO2梁向Ge盘施加轻微的拉伸应变。回音壁模式（WGM）的共振观察到从一个磁盘的直径为3 μ m，与有限域的时间差模拟一致。Q值为192，随着抽运功率的增加，由于加热引起Ge直接带隙吸收边的红移，Q值下降。
Ge is considered to be one of the most promising materials for realizing full monolithic integration of a light source on a silicon (Si) photonic chip. Tensile-strain is required to convert Ge into an optical gain material and to reduce the pumping required for population inversion. Several methods of strain application to Ge are proposed in literature, of which the use of free-standing beams fabricated by micro-electro-mechanical systems (MEMS) processes are capable of delivering very high strain values. However, it is challenging to make an optical cavity within free-standing Ge beams, and here, we demonstrate the fabrication of a simple cavity while imposing tensile strain by suspension using Geon-Insulator (G01) wafers. Ge micro-disks are made on top of suspended Si0(2) beams by partially removing the supporting Si substrate. According to Raman spectroscopy, a slight tensile strain was applied to the Ge disks through the bending of the Si02 beams. Whispering-Gallery-Mode (WGM) resonances were observed from a disk with a diameter of 3 mu m, consistent with the finite-domain time-difference simulations. The quality (Q) factor was 192, and upon increasing the pumping power, the Q-factor was degraded due to the red-shift of Ge direct-gap absorption edge caused by heating.