Design of GaN-Based PCSEL With Temperature-Insensitive Lasing Wavelength

• Main Authors: Qifa Liu, Zhenhai Wang, Xinyu Ma, Jin Wang, Weidong Zhou
• Format: Article
• Language: English
• Published: IEEE 2021-01-01
• Series: IEEE Photonics Journal
• Subjects: Temperature-insensitive wavelength; PCSEL; TiO<named-content xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" content-type="math" xlink:type="simple"> <inline-formula> <tex-math notation="LaTeX">$_2$</tex-math> </inline-formula> </named-content> photonic crystal; thermo-optic effect; thermal expansion
• Online Access: https://ieeexplore.ieee.org/document/9462485/
• ISSN: 1943-0655

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&#x002F;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&#x002F;&#x00B0;C for such PCSEL with a 82&#x0025; 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.