Chirped Microwave Signals Generation Using a Distributed Feedback Laser With Alternating Structure of Active- and Passive-Cavity

• Published in: IEEE photonics journal 2021-08, Vol.13 (4), p.1-6
• Main Authors: Xu, Changda, Jin, Ya, Wang, Jian, Sun, Wenhui, Xiong, Liangming, Chen, Yinfang, Chen, Wei, Zhu, Ninghua
• Format: Article
• Language: English
• Subjects: active- and passive-cavity; Butt joints; Chirp; chirped microwave signals; Distributed feedback laser; Distributed feedback lasers; Frequency modulation; Holes; Injection current; Lasers; Masers; Microwave imaging; Microwave photonics; Microwave theory and techniques; Quantum wells; Signal generation; Thermodynamic efficiency; Vertical cavity surface emitting lasers; Waveforms; Working conditions
• ISSN: 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2021.3103008

We proposed a new type of distributed feedback laser with alternating active- and passive-cavities (APC DFB), which enjoys the same quantum well layer where the butt-joint re-growth process can be avoided. By utilizing the chirp characteristics of the APC DFB laser in a delayed self-heterodyne system, a chirped microwave signal with a sweep range up to 40 GHz and a sweep period of 25 μs is generated. The power fluctuation of the generated signal between 0-40 GHz within 30 minutes does not exceed 3 dB, and the scanning range fluctuates about 600 MHz. And experiment results show that the thermal efficiency of the current is always related to the working environment. In the static wavelength measurement, it is controlled by the injection current; when the chirped signal is generated, it is determined by the bias current. In particular, the waveform and the period as well as the sweep range of the generated chirped microwave signals can be accurately tuned by adjusting the modulating current, which has provided a deeper insight into the photonic generation of microwave signals.