Abstract

Optical switches are important devices in optical interconnects and optical communications. Until now there have developed many kinds of optical switches by different mechanisms. In this paper we present a new kind mechanism to realize the optical switch. This new mechanism for realizing optical switch is termed the correlation (or diffraction) induced spectral change. To illustrate optical switch by using this new mechanism, we first consider the optical system shown in Fig. 1. An annular, spatially incoherent, polychromatic, planar source σ of the outer radius as and inner radius bs is in the front of a thin lens L of focal length f. The ratio of the central obstruction of the source is εs (εs = bs /as, 1 >εs ≥ 0). The source is assumed to be uniform, i.e. its spectrum S(0)(ω) to be the same at all source point. An opaque screen with a circular aperture A of radius a is in the back focal plane of the lens, and this “output” plane is taken to be z = 0. The point P located by position vector (r→,z) denotes the observation point in the far zone of the aperture. We begin our investigation on axial observation points, i.e. to the case of r→=0. We are interested in determining the spectrum S(z, ω) at the axial observation point in the far zone.

© 2001 IEEE