| 摘要 |
PURPOSE:To use a device in high backward loss and low insertion loss, by setting a central wavelength where the backward loss of an optical isolator on one side of two optical isolators becomes maximum at 1.3+ or -0.1mum, and the central wavelength where that of the optical isolator on the other side becomes maximum at 1.55+ or -0.1mum. CONSTITUTION:The titled isolator is two-linked optical isolators 4 and 5 consisting of a Faraday rotor FR arranged in the center of hollow magnets 3a and 3b magnetized in the advancing direction of light, polarizers P1 and P2 and optical detectors P2 and P3 arranged at both sides of the rotor FR. In the isolators 4 and 5, the central wavelength where the backward loss becomes maximum of the isolator on one side is set at 1.3+ or -0.1mum, and the central wavelength where the backward loss becomes maximum of the isolator on the other side is set at 1.55+ or -0.1mum, and different length are given on two Faraday rotors FR1 and FR2 connoted in two-linked optical isolators 4 and 5. Thereby, it is possible to obtain the optical isolator replying to a wavelength multiplex communication system which satisfies both wavelength bands, a 1.3mum band and a 1.55mum band, simultaneously. |
