Embodiments of the present invention relate to systems, computer-implemented methods, and computer program products for managing a tiered archive. The apparatus comprises a first directional coupling means and a mixer. An insulating layer disposed between the first and second waveguides in a coupling region in the semiconductor substrate layer to isolate the first optical waveguide from the second optical waveguide. in an N2O atmosphere while irradiating with ultraviolet light, and then carrying out a heat treatment at 300-700 C. Videophone enhancing means, in an option, includes a motor configured for moving the reflection device andor the image reproducing device upward andor downward for bringing to eye level an image reflected in the reflection device or a rotating unit configured for rotating the reflection device for the purpose of improving eye contact and enhancing convenience of use. There are also provided projections extending from the spear which may be transversely moved and either transversely compressed or expanded but never being released from the lock as the cable is rotated.