The external-cavity diode laser is advantageous in terms of low noise, high side-mode suppression ratio, high temperature stability, simple structure, and low cost, which has been the preferred scheme to realize wide-tuning and narrow-linewidth characteristics. Thus, it has been widely used in optical communication, lidar, environmental monitoring, spectral analysis, optical coherence tomography, and other frontier fields. Herein, we introduce the technical scheme and review the development status of wide-tuning and narrow-linewidth external-cavity diode lasers in detail. Primarily, the structure, working principles, and performance characteristics of external-cavity diode lasers are deeply analyzed according to different structures. The structural characteristics, key technologies, optical performance and application fields of state-of-theart studies in recent years are discussed. Finally, the challenges and potential development prospects of wide-tuning and narrow-linewidth external-cavity diode lasers are analyzed and discussed.
The spontaneous emission recombination lifetime of carriers in the active region of transistor lasers (TLs) is significantly reduced due to the accelerated carrier transport in the base region under the collector bias. Thus, it has the potential for use as a high-speed optical fiber communication light source. The unique three-electrode structure of TL notably enriches the modulation methods of the light source. As an important parameter to measure the data transfer rate, the modulation bandwidth of TL has been studied extensively. This paper briefly analyzes the inherent characteristics and advantages of TL and then discusses the progress in the research on TL modulation characteristics. Currently, the common methods to increase the modulation rate include optimizing the device structure, intracavity photon-assisted tunneling, and adding external auxiliary circuits. Through these techniques, single quantum well GaAs- based TL can achieve error-free transmission of 22 Gb/s, and simulation data show that for InP- based TL, this can reach 40 Gb/s. Finally, the challenges faced by TL in the area of optical fiber communication are elucidated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.