| 摘要 |
An optical attenuator using an isolator (200), and an optical communications system including the same, are provided. The optical attenuator controls the intensity of an input optical signal and includes an isolator (200) including a Faraday rotator in which a polyrization rotation angle varies depending on the intensitiy of an applied magnetic field, for changing the level of isolation of an optical signal according to the polarization rotation angle and outputting an attenuated optical signal, a magnetic field generator (206) for generating a mangetic field whose intensity is controlled by the intensity of current, and applying the generated magnetic field to the isolator, and a power supply for supplying current to the magnetic field generator and controlling the intensity of the current. Accordingly, a magnetic core (204) and a coil (206) are installed on the optical isolator (200), currents to be applied to the coil are controlled to adjust the intensity of a magnetic field which is formed on the isolator, and accordingly isolation of an optical signal is controlled. In this way, the optical signal is attenuated. Therefore, the optical attenuator is easily mounted on the system because of its small size, and can change the level of attenuation by controlling only the intensity of current.
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