Free Space optical wireless communication offered ultra high capacity using optical pencil beam to per individual device. By using this we are tuning the beam wavelength as 2D steering takes place, crossed grating pair also plays vital role in this process. This system is a part of indoor communication and so designed that angular steering of 2D beams takes place over an area approximately 2.5 meters and was achieved by wavelength tuning at a wavelength of 1550nm. System experiment by using Karhunen-Loeve method for DPSK without saddle point have shown the BER is shows the optical communication at a wavelength of 850nm i.e. near infrared region.
Deepali Choudhary (2026) studied this question.