The semiconductor Institute has made progress in the study of high power and low noise quantum dot DFB single-mode lasers

Recently, the team of Yang Tao-Yang Xiaoguang, a researcher at the Key Laboratory of Materials Science of the Institute of Semiconductors of the Chinese Academy of Sciences, and Lu Dan, a researcher, together with Ji Chen, a professor at the Zhijiang Laboratory of Zhejiang University, have made important progress in the research of high-power, low-noise quantum dot DFB single-mode lasers.

Distributed feedback (DFB) lasers are compact and dynamic single-mode, and are the core light sources for applications such as high-speed optical communication, large-scale photon integration, liDAR and microwave photonics. 

In particular, the field of artificial intelligence represented by ChatGPT shows an explosion trend, which urgently needs optical computing chips with high computing power, high integration and low power consumption as physical support, and puts forward higher requirements for the temperature stability, high temperature operating characteristics, optical feedback stability, single mode quality, and volume cost of the core light source.

By using a high density, low defect laminated InAs/GaAs quantum dot structure as the active region and a low loss lateral coupling grating as an efficient mode selection structure, the team developed 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 edge mode rejection ratio is more than 62 dB. The lowest white noise level is only 515 Hz2 Hz-1, and the corresponding intrinsic line width is as low as 1.62 kHz. The minimum average RIN is only -166 dB/Hz (0.1-20 GHz). 

In addition, the anti-optical feedback threshold of the laser is as high as -8 dB, which meets the technical standards for stable operation without external optical isolators. The device has excellent comprehensive performance, low cost and small size, and has a large-scale application prospect in the fields of large-capacity optical communication, high-speed on-chip optical interconnection, high-precision detection, etc.

The relevant research results are as follows: High-Power, Narrow-Linewidth, and Low-Noise Quantum Dot Distributed Feedback Lasers. Published in Laser & Photonics Reviews. The research work is supported by the National key research and development Plan and the National Natural Science Foundation.

Figure 1. Morphology and fluorescence characteristics of quantum dot materials, as well as device and grating structures

Figure 2. Output characteristics, spectral characteristics, optical frequency noise characteristics and spectral stability under external optical feedback of the device

Paper link: https://doi.org/10.1002/lpor.202200979

Source: Semiconductor Research Institute