Patent ID: 7483602

Claim:
An optical switch for directing an optical signal between a first fiber end and a selected second fiber end of a plurality of output fibers, said optical switch comprising: first focusing optics, disposed in known spatial relation to the first fiber end, for receiving said optical signal from said input fiber end and forming a focused beam, wherein said focused beam includes rays that converge to create an image of the first fiber on second focusing optics; said second focusing optics being operative for imaging the second fiber end onto the first focusing optics, wherein said second focusing optics is disposed in known spatial relation to the selected second fiber end, and is operative for receiving said focused beam from said beam directing unit and focusing said focused beam onto the selected second fiber end; wherein said first focusing optics includes a first lens having a first surface facing the input fiber end and a second surface facing opposite said first surface of said first lens, and said second focusing lens is a second lens having a first surface facing the output fiber end and a second surface facing opposite said first surface of said second lens; and a beam directing unit, optically disposed relative to said first focusing optics for receiving said focused beam, for selectivity directing said focused beam relative to said selected second fiber end so as to optically connect said first fiber end and said selected second fiber end for transmission of said optical signal therebetween; wherein with D representing the effective aperture of said first and second lenses, u representing the distance between said first lens and the input fiber end and the distance between said second lens and the output fiber end, v representing the distance between said first and second lenses, NA representing the numerical aperture of the input and output fiber ends, and f representing the focal length of said first and second lenses, the following equations are satisfied: D=2 u tan(sin −1 (N.A.))+d l/f=l/v+l/u d/u =D/v when a thin lens approximation is assumed.