This paper proposes a lighting scheme based on optical fiber technology to introduce natural light into the tunnel portal section.

On-Demand Tunnel Lighting System Utilizing Daylight: A Case Study

Lingna Shi, Yun Tu, Xiaoyu Wang, Shiyong He, Pramod Bhusal, Zeyu Hou and Chaoyu Zhang

https://econpapers.repec.org/article/gamjsusta/v_3a15_3ay_3a2023_3ai_3a3_3ap_3a2013-_3ad_3a1042777.htm