Abstract

The resonance wavelength, where a fiber mode converter grating written using periodic external perturbations achieves phase matching, is both a critical design parameter and a device parameter. However, a method to precisely predict the resonance wavelength for any new fiber and grating writing apparatus has been missing so far. The missing link was the lack of direct experimental methods to estimate the modified intermodal phase after writing with external perturbations. The presented method can make this estimation from a single experiment, over a broad wavelength range, based on a novel mathematical connection between two-mode interference and mode conversion. Using the novel methods, experimentally measured resonance wavelengths for different pitch and irradiation conditions have been predicted within relative errors of $4 \times {10^{- 3}}$.

© 2020 Optical Society of America

Gas sensing with mode-phase-difference photothermal spectroscopy assisted by a long period grating in a dual-mode negative-curvature hollow-core optical fiber

Pengcheng Zhao, Hoi Lut Ho, Wei Jin, Shangchun Fan, Shoufei Gao, Yingying Wang, and Pu Wang
Opt. Lett. 45(20) 5660-5663 (2020)

Dual interference effects in a line-by-line inscribed fiber Bragg grating

Bo Huang, Zuowei Xu, and Xuewen Shu
Opt. Lett. 45(11) 2950-2953 (2020)

All-fiber mode converter based on long-period fiber gratings written in few-mode fiber

Yunhe Zhao, Yunqi Liu, Chenyi Zhang, Liang Zhang, Guangjun Zheng, Chengbo Mou, Jianxiang Wen, and Tingyun Wang
Opt. Lett. 42(22) 4708-4711 (2017)

Ultra-broadband fiber mode converter based on apodized phase-shifted long-period gratings

Yunhe Zhao, Zuyao Liu, Yunqi Liu, Chengbo Mou, Tingyun Wang, and Yongsheng Yang
Opt. Lett. 44(24) 5905-5908 (2019)

All-fiber third-order orbital angular momentum mode generation employing an asymmetric long-period fiber grating

Xiaodong He, Jiajing Tu, Xiaowen Wu, Shecheng Gao, Lei Shen, Chenglong Hao, Yuanhua Feng, Weiping Liu, and Zhaohui Li
Opt. Lett. 45(13) 3621-3624 (2020)