Abstract

We demonstrate two all-fiber low-frequency shift schemes based on the acousto–optic interaction in a few-mode fiber (FMF). Two acoustically induced fiber gratings (AIFGs) are cascaded in reverse to achieve an efficient cycle conversion between LP₁₁ and LP₀₁ core modes in the FMF while obtaining a frequency shift of 1.8 MHz. In addition, a long-period fiber grating (LPFG) is employed to replace the AIFG, which achieves a lower frequency shift of 0.9 MHz, and its tunable wavelength range exceeds 100 nm. Both schemes show the characteristics of an upward frequency shift. Moreover, we also present a heterodyne detection system based on the above frequency shift schemes, which is verified in response to micro-vibration signals ranging from tens to hundreds of kilohertz, as well as speech signals in a lower frequency range. The experimental results show that these all-fiber frequency shift schemes have potential applications, such as in fiber optic hydrophones, laser speech detection, and fiber optic sensors.

© 2022 Optica Publishing Group

Optical heterodyne micro-vibration measurement based on all-fiber acousto-optic frequency shifter

Wending Zhang, Wei Gao, Ligang Huang, Dong Mao, Biqiang Jiang, Feng Gao, Dexing Yang, Guoquan Zhang, Jingjun Xu, and Jianlin Zhao
Opt. Express 23(13) 17576-17583 (2015)

All-fiber frequency shifter consisting of a fiber Bragg grating modulated via an acoustic flexural wave for optical heterodyne measurement

Zeyang Gao, Pengfa Chang, Ligang Huang, Feng Gao, Dong Mao, Wending Zhang, and Ting Mei
Opt. Lett. 44(15) 3725-3728 (2019)

All-fiber acousto-optic frequency shifter

B. Y. Kim, J. N. Blake, H. E. Engan, and H. J. Shaw
Opt. Lett. 11(6) 389-391 (1986)

Dynamic vortex mode-switchable erbium-doped Brillouin laser pumped by high-order mode

Jiangtao Xu, Longkun Zhang, Xing Liu, Liang Zhang, Jiafeng Lu, Longtao Wang, and Xianglong Zeng
Opt. Lett. 46(3) 468-471 (2021)

Acousto-optic frequency shifter-based microwave photonic channelized receiver using a single optical frequency comb

Ning Li, Huan Huang, Chongfu Zhang, and Kun Qiu
Opt. Lett. 47(11) 2662-2665 (2022)