Abstract-New integrated optical devices combining an InGaAsP/InP HPT and an inner-stripe LED are proposed and their fabrication processes are described. The device functions of light amplification, optical bistability, and optical switching are demonstrated in the 1-um wavelength region. I. INTRODUCTION MONOLITHIC integration of well-developed discrete devices such as lasers, light-emitting diodes (LED’s), phototransistors, p-i-n diodes, and avalanche photodiodes (APD’s) has been drawing much attention for better performance and higher reliability [ 11, [2]. By integration, on the other hand, new functions which cannot be expected for the discrete optoelectronic devices can be realized utilizing the optical or electrical interactions between two or more optoelectronic devices...