Green light is generally used as the transmitter of underwater wireless optical communication (UWOC) system, but the currently available light-emitting diode (LED)-based green light has a poor luminous flux density (i.e., low brightness) and a low wall-plug efficiency (WPE), known as the “green gap”. In this work, it is proposed to produce the laser-driven green light by using blue laser diodes to pump the narrow-band green-emitting β-Sialon phosphor-in-glass (PiG) film. The dominant wavelength of the laser-driven green light can be tuned in the range of ≈520–540 nm, required for UWOC, by controlling the phosphor content at ≈60–80% and the film thickness at ≈150–185 µm. By introducing highly reflective TiO₂ into the PiG film, the laser-driven green light exhibits a maximum luminous flux density of 1260 lm mm⁻² under blue laser excitation with a power density of 15.49 W mm⁻². For UWOC application, the green light is demonstrated to have a modulation bandwidth of 1.76 MHz, a high WPE of 8.7%, and a long transmission distance of ≈61.6 m. This work suggests that the laser-driven high-brightness green light will be a promising light source for UWOC.

中文翻译：

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用于水下无线光通信的激光驱动高亮度绿光

绿光一般用作水下无线光通信（UWOC）系统的发射器，但目前可用的基于发光二极管（LED）的绿光光通量密度差（即亮度低），壁厚低。插头效率（WPE），被称为“绿色差距”。在这项工作中，建议通过使用蓝色激光二极管泵浦窄带绿色发射β-赛隆玻璃荧光粉（PiG）薄膜来产生激光驱动的绿光。通过将荧光粉含量控制在 ≈60-80% 并将薄膜厚度控制在 ≈150-185 µm，可以将激光驱动的绿光的主波长调整在 ≈520-540 nm 的范围内，这是 UWOC 所需的。通过将高反射性 TiO ₂引入 PiG 薄膜，激光驱动的绿光表现出 1260 lm mm 的最大光通量密度^-2在蓝色激光激发下，功率密度为 15.49 W mm ^-2。对于 UWOC 应用，绿光被证明具有 1.76 MHz 的调制带宽、8.7% 的高 WPE 和 ≈61.6 m 的长传输距离。这项工作表明，激光驱动的高亮度绿光将成为 UWOC 很有前途的光源。