Patent ID: 6914722

Claim:
An optical circulator comprising: a first collimator and a second collimator opposite to said first collimator; said first collimator defining a first port, said second collimator defining a second port, said first collimator further defining a third port; a circulator core disposed between said first collimator and said second collimator, said circulator core including first and second birefringent crystals respectively confronting the first collimator and the second collimator, said circulator core further including first and second subassemblies between the first crystal and the second crystal and respectively confronting the first crystal and the second crystal with a third crystal sandwiched therebetween; and a forward light path being defined from the first port to the second port, and a backward light path being defined from the second port to the third port and different from the forward path; wherein at least one of said forward light path and said backward light path experiences total internal reflection in the third crystal; wherein said one of the forward light path and the backward light path is the backward light path; wherein the other of said forward light path and the backward light path only refracts in the third crystal.