Discuss Performance of Corner-Cube Prism for Modulating Retro-Reflector Terminal in Free-Space Laser Communication
Modulating Retro-reflector terminal does not need capture, tracking, targeting(ATP) sub-system .The key unit of this type structure is corner- cube prism,its performance will cause the light beam intensity distribution and light beam divergence angle .There are several factors ,such as effective area , right-angle accuracy, surface-type errors .Those errors caused loss of light power result in communication fail,so in this paper we made a precise analysis as a supplement.
On the effective reflection area of a cubic corner reflector
The effective reflection area of a cubic corner reflector is defined , it is testified for the cubic corner reflector that the ray reflect from this prism is not parallel with the ray incident on the corner of undersurface of this prism , the effective reflection area is calculated in the case of the ray incident on the undersurface of this prism vertically , the acreage of the effective reflection area is two thirds as that of the undersurface of this prism .
Free-space optical communication link across 16 kilometers over the Chesapeake Bay to a modulated retroreflector array
This paper presents the results of a successful bidirectional free-space optical link across 16 km to a modulated retroreflector array. The link was implemented at the Naval Research Laboratory's Chesapeake Bay Detachment laser test range. A 6-W cw 1550-nm class 1 M interrogation beam was used to illuminate an array of three modulated cat's-eye retroreflectors located on a tower across the Chesapeake Bay on Tilghman Island. The modulated retroreflectors had a diameter of 16 mm and were arranged in a triangular pattern with a spacing of 30 cm. The interrogating terminal employed a 100-µrad divergence and a high-speed pointing and tracking system to maintain link alignment. Link testing occurred over 12 days in the months of September, October, and November of 2006. Topics presented in this paper include the link scenario for the 16-km free-space optical link, the link budget, and terminal designs, as well as link acquisition and performance. Link performance results presented include data transmission throughput, scintillation data, and pointing and tracking results.