Substrate cleaning for integrated optical waveguides

Losses in integrated optical waveguides depend upon the homogeneity of the guiding layer. Successful production of acceptable guides by sputtering or solution deposition depends critically on the methods used to clean the substrate. Cleaning methods that produce films adequate for ordinary coatings have proved inadequate for integrated optical films. The extreme cleanliness required to produce low-loss waveguides can be achieved by a process described in this paper, which utilizes a precleaning step in an ultrasonically agitated detergent bath followed by careful rinsing in an ultrasonically agitated bath of heated, deionized, and filtered water. In addition to the cleaning method, we discuss the design of a cleaning station that combines the necessary apparatus in a portable unit.

Laser properties of nd(+3) and ho(+3) doped crystals with the apatite structure

A great variety of compounds occur in nature or have been synthesized in the laboratory that crystallize with the apatite structure. We have investigated a number of the apatites and found them to be excellent laser hosts for neodymium and holmium. The apatites described in this paper were grown using the Czochralski method, have low optical losses in the pump and emission spectral regions for neodymium and holmium, and the hosts have been developed to readily accept large concentrations of doping ions. This paper describes the crystal growth, physical properties, spectroscopy, and laser performance of this family of new laser materials.