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.

中文翻译：

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使用 490 nm 蓝色 VECSEL 和 AOM 的 108 m 水下无线光通信

蓝绿波段的先进光源对于水下无线光通信 (UWOC) 系统至关重要。垂直外腔面发射激光器（VECSEL）可以产生高输出功率和良好的光束质量，使其适合UWOC。本文提出了基于 100 mW 490 nm 蓝色 VECSEL 和声光调制器 (AOM) 的 108 m 距离 UWOC。当使用传统的雪崩光电二极管 (APD) 作为检测器并采用 64 脉冲位置调制 (PPM) 时，接近衍射极限的高质量光束会经历相对较小的光学衰减。在时隙频率为 50 MHz 时，UWOC 的误码率为 2.7 × 10−5。这是第一个报道的基于AOM的传输距离超过100 m的UWOC系统。根据实测所用蓝色VECSEL的衰减系数，充分利用APD的检测精度，预计最大传输距离可提高至180m左右。这种类型的UWOC系统由高光束质量光源和传统探测器组成，使其更贴近实际应用。