# Transmitters and Receivers for High Capacity Indoor Optical Wireless Communication  
[PERSON]  
1 Eindhoven Hendrik Casimir Institute (EHCI), Eindhoven University of Technology (TU/e), 5616 AP Eindhoven, The Netherlands; [EMAIL_ADDRESS] (M.W.); [EMAIL_ADDRESS] (E.M.)  
[PERSON]  
1 Eindhoven Hendrik Casimir Institute (EHCI), Eindhoven University of Technology (TU/e), 5616 AP Eindhoven, The Netherlands; [EMAIL_ADDRESS] (M.W.); [EMAIL_ADDRESS] (E.M.)  
[PERSON]  
1 Eindhoven Hendrik Casimir Institute (EHCI), Eindhoven University of Technology (TU/e), 5616 AP Eindhoven, The Netherlands; [EMAIL_ADDRESS] (M.W.); [EMAIL_ADDRESS] (E.M.)  
[PERSON]  
Eindhoven Hendrik Casimir Institute (EHCI), Eindhoven University of Technology (TU/e), 5616 AP Eindhoven, The Netherlands; [EMAIL_ADDRESS] (M.W.); [EMAIL_ADDRESS] (E.M.)  
[PERSON]  
1 Eindhoven Hendrik Casimir Institute (EHCI), Eindhoven University of Technology (TU/e), 5616 AP Eindhoven, The Netherlands; [EMAIL_ADDRESS] (M.W.); [EMAIL_ADDRESS] (E.M.)  
Eindhoven Hendrik Casimir Institute (EHCI), Eindhoven University of Technology (TU/e), 5616 AP Eindhoven, The Netherlands; [EMAIL_ADDRESS] (M.W.); e.muller@tue.  
space. Infrared light offers a unique set of advantages to the 6G network. Unlike visible light, infrared light (IR) can operate at a higher power level while being eye-safe, as it is predominantly absorbed by the cornea and does not reach the retina. In the case for the C-Band (1550 nm) wavelengths we use, this allows approximately 10 dBm of free-space optical power [2], significantly higher than the allowed for visible light. Moreover, IR's not visible nature provides another layer of privacy and not disturbance as the users cannot see the beams. The narrow beam-steering OWC system matches the requirements of 6G with respect to high capacity wireless transmission, due to the very wide available bandwidth and the high density of users, due to dense frequency reuse. However, optical communication requires a line-of-sight between the transmitter and receiver, which can hinder transmission depending on the environment [3]. In such a case where there is no line of sight between the transmitter and the receiver, a hybrid system with OWC and RF would be useful. Users would still have a connection, albeit at a lower data rate.  
In this work, we are targeting indoor beam-steered OWC which is characterized by a stable environment, because of which we assume no turbulence effects on the beam, and short ranges in the order of a few meters, as illustrated on Figure 1. The main challenge of indoor OWC is the wide angle of transmission and reception. The transmitter must have a wide bandwidth for high-capacity data transmission and a wide and precise beam-steering range for alignment to the receiver. The receiver, on the other hand, must have a large aperture to capture as much light as possible, a wide field of view to receive light from various directions, and high bandwidth for high-speed data transmission [2].  
This experimental research explores the innovative application of established optical communication theories to develop novel approaches in OWC. Focusing on the experimental validation and practical implementation of advanced OWC concepts, demonstrating how scientific principles can be transformed into new telecommunication technologies.  
The paper is organized as follows. Section 2 discusses the transmitter for OWC with piezoelectric actuators, Section 3 presents the receivers for OWC such as the photodiode array and the photonic integrated circuit-based receiver, and finally Section 4 concludes the paper.