| 摘要 |
PURPOSE:To obtain the same functions as heretofore by simple optical circuits which are shorter in their lengths and are fewer in constituting element circuits by inserting 45 deg.C nonreciprocal polarization rotators and half-wave plates inclined at a specific angle from the circuit plane in this order into optical paths without holding a double refractive optical medium. CONSTITUTION:This optical circulator consists of two pieces of 3dB directional couplers 1, an M-Z type optical interference circuit consisting of two pieces of the optical paths A, B of an equal optical path length therebetween, two pieces of the nonreciprocal 45 deg. polarization rotators 3 inserted into the optical paths A and B and the half-wave plate 2 connected thereto without holding the double refractive optical medium therebetween. The 45 deg.C nonreciprocal polarization rotator 3 and the half-wave plate 2 are inserted in this order into the optical path A in the part where the Z direction is the optical axis. The half-wave plate 2 is so installed that its optical axis has an angle of +22.5 deg.C when viewed in the Z direction. On the other hand, the half-wave plate 2 and the 45 deg. nonreciprocal polarization rotator 3 are inserted in this order 10 the optical path B by reversing the order from the order in the optical path A in the part where the Z direction is the optical axis. Further, the half-wave plate 2 is so installed that its optical axis has an angle of -22.5 deg. when viewed in the Z direction. |
