Abstract

There have been numerous reports of narrow and broad band tunable laser oscillations from Nd³⁺ and Cr³⁺ ions in garnet bulk crystals¹⁾ However, thin film waveguide laser are also required for miniaturization of light sources and applications to direct amplification of coherent optical signals in integrated optical circuits. We are presently investigating the fabrication of waveguide laser and laser amplifier using Nd³⁺ or Cr³⁺ doped yttrium gallium garnet thin fi1ms.^2,3,4) Optically pumped oxide waveguide amplifier is indispensable to construct integrated optical circuit consisting of transparent oxide materials as a monolithic type. Figure 1 shows schematic of the integrated optical amplifier. In this paper, we report characteristics of rf-sputtered thin fi1ms and spectroscopy of Nd³⁺ and Cr³⁺ ions following the single pass gain measurement of the coherent light. We, also, discuss the relation between the quantum efficiency of Nd³⁺ and Cr³⁺ ions and crystal field strength surrounding the ions

© 1988 Optical Society of America