Abstract: A crystal substrate, with an adhesive uniformly applied to its entire rear surface, is fixed to the inner wall of an element housing. By adjusting the thickness of a wall of the element housing, forming grooves in the wall, or fixedly attaching a deadweight to the wall, the resonant frequency of the element housing is adjusted so as to restrain the optical waveguide element from resonating. Further, by mounting the optical waveguide device on a printed board via an elastic member or the like, propagation of the vibration to it is suppressed.

Abstract: An apparatus, such as an optical modulator, which includes an optical waveguide and a polarizer housing device. The optical waveguide has an input end to receive light, and the polarizer housing device is connected to the input end of the optical waveguide. The polarizer housing device includes a polarizer which polarizes light, and a lens. A propagation space is in the polarizer housing device between the polarizer and the lens. The light polarized by the polarizer travels through the propagation space to the lens and is guided by the lens to the input end of the optical waveguide. The polarizer is bonded to the polarizer housing device with an adhesive so that no excess adhesive flows into the propagation space. Therefore, it is not necessary to use an optical adhesive to bond the polarizer to the polarizer housing device.

Abstract: The invention provides an improved simplified waveguide-optical fiber connection structure for connecting a waveguide and an optical fiber. The waveguide-optical fiber connection structure comprises an optical fiber, a waveguide substrate having a waveguide integrally formed thereon and having a first guide groove formed thereon adjacent an end portion of the waveguide for positioning the optical fiber therein, and a fiber substrate provided in an opposing relationship to the first guide groove for cooperating with the first guide groove to hold the optical fiber thereon. The waveguide-optical fiber connection structure can be applied to a waveguide circuit which is employed for optical communication, optical information management and so forth.

Abstract: An optical waveguide device having an optical waveguide chip, first and second adapters, and an optical fiber plug. The optical waveguide chip has an optical waveguide structure having a connection end, and an end surface of the chip is flush with the connection end. The first adapter is fixed to the chip, and has an outer surface set in predetermined positional relation with the connection end. The second adapter has an inner surface including a first region and a second region, and is detachably mounted to the first adapter so that the outer surface of the first adapter comes to close contact with the first region. The optical fiber plug has an optical fiber having an excitation end and a ferrule in which the optical fiber is inserted and fixed. The optical fiber plug is detachably mounted to the second adapter so that the outer surface of the ferrule comes to close contact with the second region.

Abstract: The invention provides an improved simplified waveguide-optical fiber connection structure for connecting a waveguide and an optical fiber. The waveguide-optical fiber connection structure comprises an optical fiber, a waveguide substrate having a waveguide integrally formed thereon and having a first guide groove formed thereon adjacent an end portion of the waveguide for positioning the optical fiber therein, and a fiber substrate provided in an opposing relationship to the first guide groove for cooperating with the first guide groove to hold the optical fiber thereon. The waveguide-optical fiber connection structure can be applied to a waveguide circuit which is employed for optical communication, optical information management and so forth.