Distributed feedback (DFB) lasers, characterized by compact structure and dynamic single mode, are the core light sources for applications such as high-speed optical communication, large-scale photonic integration, LIDAR and microwave photonics. In particular, the artificial intelligence field represented by ChatGPT is showing an explosive trend, which urgently needs high-computing power, high-integration, low-power optical computing chips as physical support, and puts forward higher requirements on the temperature stability, high-temperature operating characteristics, optical feedback stability, single-mode quality, and volumetric cost of the core light source.
Recently, the team of Yang Tao-Yang Xiaoguang, a researcher at the Key Laboratory of Materials Science, Institute of Semiconductor Research, Chinese Academy of Sciences, and researcher Lu Dan, in conjunction with Ji Chen, a professor at Zhejiang University and Zhijiang Laboratory, have made significant progress in the study of high-power, low-noise quantum dot DFB single-mode lasers. The team used a high-density, low-defect stacked InAs/GaAs quantum dot structure as the active region, combined with a low-loss lateral coupling grating as an efficient mode-selective structure, to develop a high-performance O-band quantum dot DFB laser with high power, high stability, low noise, and anti-feedback in a wide temperature region. In the range of 25-85 °C, the output power of the laser is greater than 100 mW, and the maximum side-mode suppression ratio is more than 62 dB; the lowest white noise level is only 515 Hz2 Hz-1, corresponding to an intrinsic linewidth as low as 1.62 kHz; the minimum average RIN is only -166 dB/Hz (0.1-20 GHz). In addition, the laser has an anti-optical feedback threshold of up to -8 dB, which meets the technical standard for stable operation without external optical isolators. With excellent overall performance, low cost and small size, the device has the prospect of large-scale applications in the fields of high-capacity optical communication, high-speed on-chip optical interconnect, and high-precision detection.
The research results were published in Laser & Photonics Reviews under the title of High-Power, Narrow-Linewidth, and Low-Noise Quantum Dot Distributed Feedback Lasers. Photonics Reviews. The research work was supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China.
Institute of Semiconductors and others make progress in high-power, low-noise quantum dot DFB single-mode laser research
Fig. 1 Morphology and fluorescence properties of quantum dot materials, and device and grating structures
Fig. 2 Output characteristics, spectral characteristics, optical frequency noise characteristics and spectral stability under external optical feedback of the device
