US 11,990,936 B2
Reduced thickness optical isolator and method of use thereof in a laser optic system
Ramesh Sundaram, Fremont, CA (US)
Assigned to II-VI Delaware, Inc., Wilmington, DE (US)
Filed by II-VI Delaware, Inc., Wilmington, DE (US)
Filed on Oct. 10, 2022, as Appl. No. 17/962,751.
Prior Publication US 2024/0121001 A1, Apr. 11, 2024
Int. Cl. H04B 10/2507 (2013.01)
CPC H04B 10/2507 (2013.01) 20 Claims
OG exemplary drawing
 
1. A method of optically isolating an optical signal source from an external optical circuit, the method comprising:
a) receiving at a polarizer, having a first polarization optical axis, an optical signal from an optical signal source, the polarizer outputting at least a part of the optical signal received at the polarizer;
b) receiving in a body of a garnet directly from the polarizer the at least part of the optical signal output by the polarizer in step a), the garnet rotating, with respect to the first polarization optical axis, a polarization of the at least part of the optical signal output by the polarizer in step a) by an angle of 45°−θ1° and outputting at least a part of the polarization rotated optical signal of this step b), wherein 5°≤θ1°<42°;
c) receiving at an analyzer, having a second polarization optical axis at 45°+θ2° with respect to the first polarization optical axis, directly from the garnet the part of the polarization rotated optical signal output by the garnet in step b), the analyzer outputting at least a part of the optical signal received from the garnet in this step c) directly to an external optical circuit, wherein 5°≤θ2°<42°;
d) receiving at the analyzer directly from the external optical circuit a reflection of at least a part of the optical signal output by the analyzer in step c), the analyzer outputting at least a part of the reflected optical signal;
e) receiving in the body of the garnet directly from the analyzer the at least a part of the reflected optical signal output by the analyzer in step d), the garnet rotating, with respect to the first polarization optical axis, a polarization of the part of the reflected optical signal output by the analyzer in step d) by an angle of 45°−θ10 in the same direction as the polarization rotation in step b) and outputting at least a part of the polarization rotated reflected optical signal of this step e); and
f) receiving at the polarizer, having the first polarization optical axis, directly from the garnet the polarization rotated optical signal of step e), the polarizer blocking ≥25 dB of the polarization rotated optical signal received from the garnet.