| 摘要 |
PURPOSE:To transmit in TM waveguide mode and to remove light in TE waveguide mode by substituting part of an upper clad layer formed on a YIG thin film Zcut lithium niobate (LN) crystal and mounting it directly on the YIG thin film so that the C axis is parallel to a normal to the YIG thin film. CONSTITUTION:The Zcut LN crystal 5 operates as the upper clad layer which has a smaller refractive index than the YIG thin film to the TM among waveguide modes in which light is propagated in the YIG thin film 2 in. Light in TM waveguide mode is therefore transmitted through the part where the Zcut LN crystal is mounted, but the crystal operates as the upper clad layer having a larger refractive index than the YIG thin film of the TE waveguide mode. Consequently, the waveguide mode is converted into a radiation mode where the Zcut LN crystal is mounted and electric power in the TE waveguide mode is radiated into the Zcut LN crystal and has large loss, so that the TE waveguide mode is removed. |
