The present invention relates to a single-mode optical fiber having a configuration which enables lowering of dispersion slope while securing a sufficient MFD. The present invention also relates to a method of making and using the imaging powder for use with the CADCAM dental imaging device. The second semiconductor module has a second housing and a second base plate. Further, the control range of the objective lens is set for each of the recording layers of the optical disc. The partition wall has at least one connecting channel and the chambers alternately change in volume and are filled completely with a hydraulic liquid.