Towards AO-Free FSO Communication
Abstract
Free space optical (FSO) communication can provide an orders-of-magnitude increase in capacity while reducing the antenna size correspondingly in comparison with the state-of-the-art radio-frequency (RF) communication systems. A serious challenge for FSO communication is the difficulty of maintaining a reliable communication link through turbulent atmospheric conditions. Adaptive optics (AO) in conjunction with wavefront sensors and feedback controls has been the dominant technology used for wavefront correction in FSO communication. The disadvantages of the conventional AO FSO communication systems are: 1) perfect wavefront correction is hard to achieve because of the limited spatial resolution of the AO and the stroke-resolutions trade-off of each AO element, 2) response time of wavefront sensing and AO are slow, and 3) AO FSO systems have large size, weight and power consumption (SWaP) as well as high costs. The objective of this research is to use multimodal pre-amplified receivers to achieve high sensitivity detection, in spite of wavefront distortions, for FSO communications without AO. The basic rationale for the proposed approach is as follows. A distorted wavefront is a superposition of the fundamental mode (Gaussian) and high-order modes (e.g. Hermite-Gaussian). We will ensure that the few-mode EDFA and the PD can both accommodate all modal contents of the distorted wavefront. Preliminary research shows that the sensitivity of the proposed receiver is a very weak function of wavefront distortion, therefore is ideally suited for FSO communication This represents an important step towards AO-free FSO communication systems with high performance, reliability and low cost. It is anticipated that the results of this STIR program will experimentally establish the feasibility of AO-free FSO communication and provide a justification for further research on this and other AO-free FSO communication technologies.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2018
- Source ID
- W911NF1710500
Entities
People
- Guifang Li
Organizations
- Army Contracting Command
- United States Army
- University of Central Florida