Far Field Analysis of Fiber Laser Phased Array for Free-Space Communication

Application of fiber laser array for free-space communication has great predominance. This paper studies the far field properties of the fiber laser phased array. An analytical expression for the far field pattern is obtained based on the Huygens-Fresnel principle. The far field properties, the scanning/steering angle range, and the angular resolution are numerically studied. It is found that for a 20×20 array with wavelength of 1.545μm, fiber core radius of lOμm, and central distance between any two adjacent elements of 30μm, the beam steering is valid within +1.476° above which there will be "twin peaks" and "unexpected scanning" phenomena in the far field Meanwhile, with the increasing of central distance between the adjacent elements, the range will become smaller. But the steering angles have few effects on the angular resolution. Furthermore, these two phenomena are studied deeply and their eliminations are discussed.