With the ever increasing demand for low-cost, high performance Er-doped opticalamplifiers and light sources for both civilian and military applications, compactintegrated Er-doped planar waveguide devices have recently been extensively explored.Substantial research effort is still focused on developing host materials suitable for theincorporation of the high Er concentration required in devices of limited waveguidelength, critical to compensate for the small optical transition cross sections of Er ions.In this work, we present breakthroughs both in performance of Er-doped hostmaterials and on the schemes whereby the materials are employed to achieve the highestpossible performance. We have substantially improved the performance of the Er-dopedAlGaAs native oxides by a new post-oxidation Er-implantation method (as demonstratedby a ~2-3X increase in intensity and 7-8X increase in fluorescence lifetime in roomtemperature continuous photoluminescence). We also demonstrate the excellentperformance of a new Er host material of native oxides of InAlP, high Er-solubility of upto ~ 12 wt.%, a very long excited lifetime of 6-8 ms, and an unusually broad bandwidth,making them quite competitive with other host materials utilized for the aboveapplications.A novel vertical intra-cavity pumping (VIP) scheme, proposed in this study,should provide an alternative way to compensate for the length limitation issue in Erdopedwaveguide through a more efficient design for optical excitation of the Er ions.This VIP scheme should be able to increase overall pumping power, provide uniformlydistributed pump power along Er-doped waveguides, and better noise control comparedto conventional end pumping techniques.Finally, as the Er host materials developed in this work are based on GaAssubstrates, they provide (when integrated with the proposed VIP excitation scheme) aunique advantage over other candidate hosts in their potential for achievingmonolithically-pumped Er-doped optical devices of greatly reduced size and cost, pavingthe way for a possible future revolution in more agile optical networks, compact lasersfor range finding, sensors and other applications.