Simultaneous underwater beam steering and PAM4 transmission enabled by the acousto-optic effect.

In this paper, an underwater wireless optical communication (UWOC) system that can simultaneously achieve beam steering and pulse amplitude modulation (PAM) enabled by the acousto-optic effect is proposed and experimentally demonstrated. An approach to manipulate the driving signal of an acousto-optic modulator (AOM) is utilized to simultaneously achieve precise laser emission angle control and signal modulation, which enables high-speed link-switching for multi-user access. The system is tested in a 7-m water tank with a water attenuation coefficient of 0.

Bridging optical fiber communication and underwater wireless optical communication via third harmonic generation.

In this paper, we propose an optical module, consisting of an Erbium/Ytterbium co-doped fiber amplifier (EYDFA) and a cascaded periodically poled lithium niobate (cascaded-PPLN), to bridge the conventional telecommunication and the emerging underwater wireless optical communication (UWOC). Compared with using two discrete crystals to achieve the third harmonic generation (THG), using a cascaded crystal simplifies the optical system. Under a fundamental power of 5 W at 1550 nm, we have generated an optical power of 6.

Fisheye lens-based UWOC system with an FOV of ±90°.

The link alignment is a challenge in underwater wireless optical communication (UWOC). This paper proposes a UWOC system adopting a fisheye lens with a field of view (FOV) of ±90° at the receiver to alleviate alignment requirement, and a mobile scanning device (MSD) is exploited to track the variation of the imaging position generated by the fisheye lens due to different incidence angles. In a 7-m tap water channel, a transmission with a data rate of 400 Mbps and an FOV of ±90° is realized with 16-quadrature amplitude modulating-orthogonal frequency division multiplexing (16-QAM-OFDM) modulation and orthogonal matching pursuit (OMP) channel estimation algorithm.

Omnidirectional optical communication system designed for underwater swarm robotics.

In this paper, an omnidirectional underwater wireless optical communication (UWOC) system is proposed, including six lens-free transceivers. An omnidirectional communication with a data rate of 5 Mbps in a 7-m underwater channel is experimentally demonstrated. The optical communication system is integrated into a self-designed robotic fish, and the signal is processed real-time through an integrated micro-control unit (MCU).

Zusanli (ST36) acupoint injection for preventing postoperative ileus: A systematic review and meta-analysis of randomized clinical trials.

Objective: To evaluate the preventive effect of Zusanli (ST36) acupoint injections with various agents, for postoperative ileus (POI).

Methods: We searched electronic databases for randomized controlled trials from inception to 1st February 2015 evaluating ST36 acupoint injection for preventing POI. Revman 5.