Abstract. We propose an all-fiber configuration of tunable bandpass filter (TBPF), consisting of a mode selective coupler (MSC) and an acoustically induced fiber grating (AIFG). Either the MSC or the AIFG can act as high-order mode converters in a few-mode fiber. The working wavelengths of the MSC and the AIFG are chosen to achieve complete conversion cycle between the core-mode linearly polarized (LP01) mode and the LP11 mode. The tunability of the TBPF is achieved by changing the frequency of the radio frequency signal. An all-fiber tunable ring laser based on the TBPF is used to generate a stable continuous-wave laser with 3-dB bandwidth of around 0.8 nm. The tunable wavelength ranges from 1530 to 1580 nm. Furthermore, the TBPF is introduced into the cavity of a mode-locked fiber laser. Wavelength-tunable mode locking pulses are obtained at central wavelengths from 1530 to 1560 nm.

中文翻译：

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基于芯模转换的锁模激光器全光纤波长可调带通滤波器

摘要。我们提出了可调谐带通滤波器 (TBPF) 的全光纤配置，由模式选择耦合器 (MSC) 和声诱导光纤光栅 (AIFG) 组成。MSC 或 AIFG 都可以作为少模光纤中的高阶模式转换器。选择MSC和AIFG的工作波长以实现芯模线性偏振（LP01）模式和LP11模式之间的完整转换周期。TBPF 的可调性是通过改变射频信号的频率来实现的。基于 TBPF 的全光纤可调谐环形激光器用于产生稳定的连续波激光器，其带宽为 3 dB，约为 0.8 nm。可调波长范围为 1530 至 1580 nm。此外，TBPF 被引入锁模光纤激光器的腔中。