Dynamics Simulation of Self-Mode-Locking in a Semiconductor Disk Laser Using Delay Differential Equations

Self-mode-locked semiconductor disk lasers possess compact resonant cavity and stable construction. These devices have a wide application prospect because of their picosecond to sub-picosecond pulse width, excellent beam quality and tailorable emission wavelength. In this paper, dynamics simulations of self-mode-locking in a semiconductor disk laser are performed by using delay differential equations for the first time. The corresponding conditions of different modality of mode-locking, including Q-switched mode-locking, continuous-wave mode-locking and harmonic mode-locking are calculated, and their dynamics evolution processes are presented. We also analyze the characteristics of the three different mode-locking modalities and summarize their overall dynamics evolution tendency. This kind of numerical simulation and analysis provides an understanding of the dynamics process of self-mode-locking, and may be referenced for related experiments

Dynamics Simulation of Self-Mode-Locking in a Semiconductor Disk Laser Using Delay Differential Equations

Self-mode-locked semiconductor disk lasers possess compact resonant cavity and stable construction. These devices have a wide application prospect because of their picosecond to sub-picosecond pulse width, excellent beam quality and tailorable emission wavelength. In this paper, dynamics simulations of self-mode-locking in a semiconductor disk laser are performed by using delay differential equations for the first time. The corresponding conditions of different modality of mode-locking, including Q-switched mode-locking, continuous-wave mode-locking and harmonic mode-locking are calculated, and their dynamics evolution processes are presented. We also analyze the characteristics of the three different mode-locking modalities and summarize their overall dynamics evolution tendency. This kind of numerical simulation and analysis provides an understanding of the dynamics process of self-mode-locking, and may be referenced for related experiments

108 m Underwater Wireless Optical Communication Using a 490 nm Blue VECSEL and an AOM

Advanced light sources in the blue-green band are crucial for underwater wireless optical communication (UWOC) systems. Vertical-external-cavity surface-emitting lasers (VECSELs) can produce high output power and good beam quality, making them suitable for UWOC. This paper presents a 108 m distance UWOC based on a 100 mW 490 nm blue VECSEL and an acousto-optic modulator (AOM). The high-quality beam, which is near diffraction-limited, undergoes relatively small optical attenuation when using a conventional avalanche photodiode (APD) as the detector and employing 64-pulse position modulation (PPM). At the time-slot frequency of 50 MHz, the bit error rate (BER) of the UWOC was 2.7 × 10−5. This is the first reported AOM-based UWOC system with a transmission distance over 100 m. The estimated maximum transmission distance may be improved to about 180 m by fully utilizing the detection accuracy of the APD according to the measured attenuation coefficient of the blue VECSEL used. This type of UWOC system, composed of a high-beam-quality light source and a conventional detector, make it more closely suited to practical applications