Fan Yaqiang, Sun Zhenxing, Zhang Yue, Lv Yuan, Xia Haolin, Zhang Jingxuan, Xu Zhenzhen, Wang Wenxuan, Xiao Rulei, Chen Xiangfei
Opt Express. 2025 Feb 10;33(3):6304-6318. doi: 10.1364/OE.544055.
In this paper, an ultra-wideband distributed feedback (DFB) laser array with matrix grating based on the enhanced self-heating effect is proposed and experimentally demonstrated. 12 lasers are monolithically integrated with a 4 × 3 matrix style with a wavelength spacing of 5 nm. The reconstruction-equivalent-chirp technique is used to simplify the grating fabrication and enhance the precise control of the wavelength spacing. A cascaded Y-branch sharing identical active layers with the lasers is used to realize one waveguide output, which only requires a small current to compensate for the material absorption. This can reduce fabrication complexity compared to using the butt-coupling technique. A semiconductor optical amplifier (SOA) is integrated in front of the laser array to amplify and adjust the optical power. By optimizing the doping concentration of the p-waveguide region, the self-heating effect of the DFB laser has been enhanced, thereby increasing the wavelength current tuning range of a laser unit. As a result, the wavelength of the laser array is precisely controlled, with the wavelength deviation of all 12 lasers maintained within ±0.2 nm. The wavelength current tuning range of a DFB laser unit reaches 5.8 nm. Consequently, without adjusting the thermoelectric cooler (TEC), the laser array can achieve a continuous wavelength current tuning range of up to 60 nm. After SOA amplification, the output power of the laser array is above 55 mW, and the relative intensity noise (RIN) is lower than -130 dB/Hz. Additionally, its side-mode suppression ratio (SMSR) is greater than 45 dB, indicating excellent single-longitudinal-mode properties. The proposed tunable laser is considered highly advantageous for dense wavelength-division multiplexing (DWDM) systems and optical sensing systems.
本文提出并通过实验验证了一种基于增强自热效应的具有矩阵光栅的超宽带分布反馈（DFB）激光阵列。12个激光器以4×3矩阵形式单片集成，波长间隔为5 nm。采用重构等效啁啾技术简化光栅制造并增强对波长间隔的精确控制。与激光器共享相同有源层的级联Y分支用于实现单波导输出，这仅需小电流来补偿材料吸收。与采用对接耦合技术相比，这可降低制造复杂度。在激光阵列前面集成了一个半导体光放大器（SOA）以放大和调节光功率。通过优化p波导区域的掺杂浓度，增强了DFB激光器的自热效应，从而增加了单个激光器的波长电流调谐范围。结果，激光阵列的波长得到精确控制，所有12个激光器的波长偏差保持在±0.2 nm以内。一个DFB激光器单元的波长电流调谐范围达到5.8 nm。因此，无需调整热电冷却器（TEC），激光阵列就能实现高达60 nm的连续波长电流调谐范围。经过SOA放大后，激光阵列的输出功率高于55 mW，相对强度噪声（RIN）低于-130 dB/Hz。此外，其边模抑制比（SMSR）大于45 dB，表明具有优异的单纵模特性。所提出的可调谐激光器被认为对密集波分复用（DWDM）系统和光学传感系统非常有利。
