Abstract A nonresonant interferometric optical isolator is provided with an element having an index of refraction anisotropy. The isolator is a device having two beam paths and any input beam which passes through is split into two individual component beams, with each component being transmitted along a separate path before interfering with the other component and exiting from the isolator. The anisotropy causes the effective optical length through the isolator to be responsive to the direction of travel of an optical beam through the element so that an optical beam passing through the anisotropic element in a forward direction experiences an optical length which is different from the optical length the beam would experience traveling in a reverse direction. The two beam paths of the isolator have effective optical lengths in the reverse direction which differ from each other by half a wavelength and the components of an optical beam transmitted through the isolator in the reverse direction undergo destructive interference and leave the isolator along a path which is different from the input beam direction. Therefore, an input beam of optical energy is readily transmitted through the isolator in the intended direction, but any feedback beam passes through the isolator in a reverse direction and exits the isolator along a path which is different from the input beam direction.
A nonresonant interferometric optical isolator comprising: an interferometer which has first and second independent beam paths therethrough; and a fixed anisotropic index of refraction element which is disposed in said first beam path to cause the effective optical length of said first beam to be dependent on the direction of travel of an optical beam across said beam path, wherein the optical length of an optical beam when passed across said first beam path in a forward direction is different than the optical length of an optical beam when passed across said first beam path in a reverse direction by an odd integer number of half wavelengths.
Claim 2
Dependent Claim
107 words
A nonresonant interferometric optical isolator comprising: an interferometer which has first and second independent beam paths therethrough; and a fixed anisotropic index of refraction element which is disposed in said first beam path to cause the effective optical length of said first beam to be dependent on the direction of travel of an optical beam across said beam path, wherein the optical length of an optical beam when passed across said first beam path in a forward direction is different than the optical length of an optical beam when passed across said first beam path in a reverse direction by an odd integer number of half wavelengths.
Claim 3
Dependent Claim
13 words
An optical isolator according to claim 1 wherein the odd integer is one.
Claim 4
Dependent Claim
24 words
An optical isolator according to claim 1 wherein an element having an index of refraction anisotropy is disposed in each of the beam paths.
Claim 5
Dependent Claim
104 words
In combination, a Mach Zehnder interferometric circulator which has a first and a second beam path which transmit electromagnetic radiation having an optical wavelength therethrough; a fixed anisotropic index of refraction element which is disposed in said first beam path causing the optical path length for the radiation transmitted in a forward and reverse direction across said first beam path to be different by an odd number of half of said wavelengths; and feedback control means to maintain the difference in the optical path length of each of the two beam paths in the forward direction at substantially an integer number of said wavelengths.
Claim 6
Dependent Claim
104 words
In combination, a Mach Zehnder interferometric circulator which has a first and a second beam path which transmit electromagnetic radiation having an optical wavelength therethrough; a fixed anisotropic index of refraction element which is disposed in said first beam path causing the optical path length for the radiation transmitted in a forward and reverse direction across said first beam path to be different by an odd number of half of said wavelengths; and feedback control means to maintain the difference in the optical path length of each of the two beam paths in the forward direction at substantially an integer number of said wavelengths.
Claim 7
Dependent Claim
29 words
An optical isolator according to claim 4 wherein the optical length in the forward direction is the same for both said first beam path and said second beam path.
Claim 8
Dependent Claim
31 words
An optical isolator according to claim 4 wherein the difference in optical path length in the forward and reverse directions across said first beam path is one-half of a said wavelenGth.