![]() ![]() 2A-2C show an operating principle of the waveguide-type optical isolator 101. ![]() Incidentally, the non-reciprocal phase shifter 106 is provided with a cladding layer 107 composed of a magneto-optical material, and magnetic field applying means 108 for completing magnetization of the magneto-optical material in a predetermined direction, and the non-reciprocal phase shifter 106 is formed that the magnetic field applying means 108 is provided on the cladding layer 107.įIGS. The above conventional optical isolator 101 is constituted that a waveguide layer 103 using a semiconductor material is provided on a compound semiconductor substrate 102, a waveguide 104 is formed in the waveguide layer 103, a tapered branching/coupling device 105 is provided on the waveguide layer 103, and further a non-reciprocal phase shifter 106 is provided on the waveguide layer 103. 1 with the perspective view has been proposed as an optical isolator suitable for integration with a semiconductor laser. However, since the optical isolator allows the light to transmit only in one direction, it is possible to prevent the unintentional backward light from being incidence of to the optical active element.Ĭonventionally, an interference-type optical isolator (waveguide-type optical isolator) 101 shown in FIG. In optical active elements such as not only the aforementioned semiconductor laser but also an optical amplifier or the like, by unintentional incidence of light from an opposite direction, operating characteristics of the optical active elements may be degraded or unintentional operation may be performed. Namely, the optical isolator serves to block the light which is going to be incident on the semiconductor laser, and to maintain a stable oscillation without degrading the characteristics of the semiconductor laser. Unless the optical isolator is placed at the emitting end of the semiconductor laser, a reflected return light will be incident on the semiconductor laser, and thereby a degradation of oscillation characteristics of the semiconductor laser is caused. Conversely, the light which is going to be input on the semiconductor laser through the optical isolator is prevented by the optical isolator, so that the light cannot be input on the semiconductor laser. For example, by arranging the optical isolator at an emitting end of a semiconductor laser, the light output from the laser transmits through the optical isolator, and it is possible to be used the light as a light source for optical fiber communications. The present invention relates to a polarization-independent optical isolator, and more particularly, relates to a polarization-independent optical isolator that allows for the isolation of both TM-mode and TE-mode, as well as for the completely preventing any propagation to the backward propagating light in a designed wavelength.Īn optical isolator is an element which allows a light to transmit only in one direction but prevents the light from propagating in a direction opposite thereto. ![]() National Phase Application under 35 USC 371 of International Application PCT/JP2007/056114 filed Mar. ![]()
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