| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an in-line optical isolator in which insertion loss and deterioration in isolation are suppressed, even when amplified spontaneous emission (ASE) is returned from a fiber amplifier. <P>SOLUTION: In the in-line optical isolator, a first polarization separation element 91, a Faraday rotator 6 made of a BIG film, and a second polarization separation element 92 are placed in that order. The in-line optical isolator further includes a first optical fiber collimator 1a, placed at the forward-beam incident side of the first polarization separation element 91 and includes a collimating lens 101 and a first optical fiber 31; and a second optical fiber collimator 2a, placed on the forward-beam exit side of the second polarization separation element 92 and including a collimating lens 102 and a second optical fiber 32 connected to a fiber amplifier, as well as, the optical fiber 32 connected to the fiber amplifier is an in-line optical isolator; and an edge filter 100, which transmits a light emitted from the first optical fiber 31 and having a wavelength equal to the oscillation wavelength and which reflects a light emitted from the first optical fiber and having wavelengths shorter than this wavelength, is placed between the second optical fiber collimator 2a and the second polarization separation element 92. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
