用于共封装光学的高功率连续波DFB激光器

High-Power CW-DFB Laser for Co-Packaged Optics

摘要:

为了应对共封装光学(CPO)系统对硅光外置光源提出的高功率、低噪声、低功耗等要求,设计了一种波长在1310nm附近的AlGaInAs多量子阱(MQW)高功率连续波(CW)分布反馈(DFB)激光器芯片。通过在有源层MQW的下方插入一层InGaAsP远场减小层,实现光模场向n型包层下移,减小远场发散角的同时降低了量子阱区的光限制因子和整体的光吸收损耗,制作的激光器可以实现高斜率效率、非致冷高温高功率工作。测试结果显示,该激光器在25℃下,阈值电流为20mA,斜率效率为0.46W/A,输出功率为173mW@400mA；当注入电流为300mA时,激光器的水平和竖直发散角分别是15.2°和19.1°,边模抑制比大于55dB,洛伦兹线宽小于600kHz,相对强度噪声(RIN)小于-155dB/Hz；在85℃高温下,激光器阈值电流为32mA,输出功率达到112mW@400mA。

Abstract:

In order to meet the requirements of co-packaged optics (CPO) system, a multi-quantum well (MQW) continuous wave (CW) high-power distributed feedback (DFB) laser with high power, low noise and low loss is designed with the wavelength of 1310nm. There is a specially optimized far-field reduction layer (FRL) below the MQW active layers to pull optical mode into the lower n-cladding layers. This design can reduce the internal loss of waveguide and the optical confinement factor. The fabricated DFB laser exhibits high slope efficiency and enables uncooled CW operation at high ambient temperatures. Test results indicate that the output power, threshold current and slope efficiency of the DFB laser are achieved to 173mW@400mA, 20mA and 0.46mW/mA at 25℃, respectively. When the injection current is 300mA, the far-field patterns divergence angle is 15.2°×19.1°, the sidemode suppression ratio (SMSR) is higher than 55dB, the relative intensity noise (RIN) of laser is less than -155dB/Hz, and the Lorentz linewidth is less than 600kHz. The output power and the threshold current of the DFB are achieved to 112mW@400mA and 32mA at 85℃, respectively.