Considering the compensation of thermo-optic coefficients (TOC) between GaN-based cavity and TiO2 photonic crystal (PhC) layer, we have theoretically designed a photonic crystal surface emitting laser (PCSEL) with temperature-insensitive wavelength. The structure includes a freestanding GaN membrane with embedded multiple InGaN/GaN quantum well (QW) layer and the top TiO2 PhC layer. The high refractive index (RI) of PhC and the freestanding membrane cavity structure cooperate to enable a stronger field-coupling in PhC, thus fulfill the athermal coupling condition. Interestingly, the wavelength temperature dependence is only 0.0015 nm/°C for such PCSEL with a 82% PhC confinement factor, and its athermal property is proportional to the field confinement factor in TiO2 PhC layer. To illustrate, a general formula has been developed after the investigations of thermo-optic effect and thermal expansion effect.

中文翻译：

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具有温度不敏感激光波长的 GaN 基 PCSEL 设计


考虑到GaN基腔与TiO2光子晶体(PhC)层之间热光系数(TOC)的补偿，我们从理论上设计了一种波长对温度不敏感的光子晶体表面发射激光器(PCSEL)。该结构包括一个独立式 GaN 膜，内嵌多个 InGaN/GaN 量子阱 (QW) 层和顶部 TiO2 PhC 层。 PhC的高折射率（RI）和独立式膜腔结构配合使PhC具有更强的场耦合，从而满足非热耦合条件。有趣的是，对于这种具有 82% PhC 限制因子的 PCSEL，波长温度依赖性仅为 0.0015 nm/°C，并且其无热性能与 TiO2 PhC 层中的场限制因子成正比。为了说明这一点，在研究了热光效应和热膨胀效应后，得出了一个通用公式。