Patent ID: 6249619
Filing Date: 2001-06-19
Classification: G02F,Y10S

Abstract:
A device comprising an optical isolator for preventing back reflection in the path of an optical signal having two parts, the isolator comprising a sandwich of layers comprising a walk-off plate, a reciprocal half-wave plate, a non-reciprocal rotator plate and a lens-containing plate, each of said plates having contiguous face surfaces including lithographically defined raised or depressed elements to align successive plates:the walk-off plate disposed along the optical path for separating each of the two parts of the signal into two spacially displaced rays;the reciprocal half-wave plate disposed along the optical path adjacent the walk-off plate, the half-wave plate designed to produce polarization conversion of the two rays of one part of the signal by a pre-determined angle when the rays pass therethrough, the half-wave plate further having a gap to allow the rays of the other part of the signal to pass therethrough without change;the non-reciprocal rotator plate disposed adjacent the half-wave plate and oppositely disposed to the walk-off plate, the rotator plate comprised of material designed to produce Faraday rotation of the first and second rays of each of the two parts of the signal by a predetermined angle;the lens-containing plate adjacent the non-reciprocal rotator plate opposite the half-wave plate, the lens-containing plate having an end surface with a common intersection region, wherein a lens is disposed in the lens-containing plate between the non-reciprocal rotator plate and the end surface for collimating the two parts of the signal as the signal is transmitted through the walk-off plate, the half-wave plate, and the rotator plate, and for focusing the two parts of the signal so they are coupled at the common intersection region.