Open AccessCMOS monolithic photodetector with a built-in 2-dimensional light direction sensor for laser diode based underwater wireless optical communications
Author(s) -
Zhijian Lv,
Gufeng He,
Chengfeng Qiu,
Youyou Fan,
Hongyi Wang,
Zhaojun Liu
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.425792
Subject(s) - optical wireless , free space optical communication , optics , computer science , bandwidth (computing) , bit error rate , adaptive optics , optical communication , modulation (music) , underwater , underwater acoustic communication , wireless , physics , telecommunications , acoustics , channel (broadcasting) , oceanography , geology
Underwater wireless optical communications (UWOC) are considered an emerging high-speed wireless network for underwater applications and compete with underwater radio frequency (RF) communications and underwater acoustic communications (UAC). Even though the utilization of laser diodes (LDs) enhances the -3dB modulation bandwidth extraordinarily from a few tens of MHz to GHz, LDs have the features of high collimation and narrow spectrum. Without the point-to-point optical alignment, the performance of the LD-based UWOC system drops exponentially because the received optical power determines the signal-to-noise ratio (SNR) of the UWOC system. To achieve a high-performance and reliable UWOC link based on LDs requires focusing optics and an alignment system. In this paper, we demonstrated a CMOS monolithic photodetector with a built-in 2-dimensional light direction sensor for the UWOC link by using a 450 nm LD and none-return-to-zero on-off keying (NRZ-OOK) modulation method. Employing this innovative technique, the field of view (FOV) was enlarged to 120 ° , and data rates up to 110 Mb/s at a bit error rate (BER) of 2.3×10 -10 were obtained. The establishment of a proposed UWOC physical link showed enhanced communication performance for more practical and robust wireless communication applications.