兼顾量子阱材料增益与折射率变化的研究

Study on Balancing Gain and Refractive Index Change of Quantum Well

对比分析了量子阱材料增益谱及其折射率变化谱随阱宽、应变和载流子浓度的变化特性,在此基础上以两谱线3dB谱宽交叠区面积为度量,分析了各因素对兼顾材料增益与折射率变化的影响,并剖析了其中的物理机理。研究表明,两谱线3dB谱宽交叠区面积随阱宽的变化过程中存在一个极大值;引入压应变有利于增大交叠区面积;交叠区面积随载流子浓度单调增加的过程中存在一个转折点,在转折点之前增加迅速,在转折点之后增加放缓。基于以上影响规律,选取适当的阱宽与压应变量,在载流子浓度为3.0×10^(24) m^(-3)时,设计出的In0.583Ga0.417As/In0.817Ga0.183As0.4P0.6量子阱在C波段内可恰当地兼顾增益与折射率变化,两谱线3dB谱宽交叠区面积为3.7×10~4 nm/cm。

Active optical switches, wavelength converters and active microring resonators are the key devices to develop opti- cal packet-switched networks characterized by high speed and flexibility. Refractive index change induced by carrier concen- tration change in active region is the operating mechanism of these devices, while optical gain is needed when these devices operate. Characteristics of gain and carrier-induced refractive index change of active material have been widely studied re- spectively. However, only by balancing gain and refractive index change can these devices satisfy the performance request. Till now, no research of balancing gain and refractive index change is reported. In this paper, the spectrum characteristics of gain and refractive index change of quantum well versus well width, strain and carrier concentration are comparatively ana- lyzed. The influences of the above factors on balancing gain and refractive index change are further investigated by introdu- cing overlap region area of 3 dB spectrum width, and the physical mechanisms are dissected. Research shows that the over- lap region area of 3 dB spectrum width of the two spectra has a maximum during its variation with well width. The compres- sive strain is propitious for the increase of overlap region area. An turning point exists during the monotone increasing of o- verlap region area with carrier concentration, before which the overlap region area increases rapidly, and after which the o- verlap region area slows down its increasing. Based on the above laws, In0. 583 Ga0. 417 As/In0. 817 Ga0.183 As0. 4 P0. 6 quantum well with suitable well width and compressive strain value can appropriately balance gain and refractive index change within C wave-band, the overlap region area of 3 dB spectrum width of the two spectra is 3. 7×10^4 nm/cm.