Abstract

We demonstrate a compact all-fiber mode selective converter enabled by femtosecond laser micro-machining on the few-mode fiber (FMF) facet. By introducing a micro-structure into the FMF core, we can achieve a $\pi $ spatial phase difference to the fundamental mode of light to be converted. Theoretical optimization reveals that various high-order modes, including ${{\rm LP}_{11}}$, ${{\rm LP}_{02}}$, and ${{\rm LP}_{21}}$ modes, can be selectively converted by various micro-structures on the FMF facet, with a mode extinction ratio of more than 25 dB and mode coupling efficiency of better than 45% over the C-band. Finally, a proof-of-concept experiment is conducted by inscribing a micro-slot on the two-mode fiber facet for the ${{\rm LP}_{01}}$ to ${{\rm LP}_{11}}$ mode conversion. A micro-slot with a width of 6.7 µm and a depth of 5.4 µm is fabricated under the optimal femtosecond laser parameters. A ${{\rm LP}_{01}}$ to ${{\rm LP}_{11}}$ mode conversion with an average insertion loss of 2.7 dB is realized over the C-band, together with a mode intensity profile correlation efficient of more than 65%. Efficient higher-order mode conversion is feasible with a precise femtosecond laser micro-machining.

© 2019 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
All-fiber broadband multiplexer based on an elliptical ring core fiber structure mode selective coupler

Hu Zhang, Zhaocai Wang, Lixia Xi, Cheng Du, Xiaoguang Zhang, Hui Li, Xiangsen Jiao, and Wenbo Zhang
Opt. Lett. 44(12) 2994-2997 (2019)

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)

Analysis of optical fiber-based LP01 ↔ LP02 mode converters for the O-, S-, and C-Band

Hakim Mellah, Xiupu Zhang, and Dongya Shen
Appl. Opt. 54(17) 5568-5575 (2015)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (7)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (1)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription