Optical interconnections based on surface-normal optical devices are expected to eliminate bottlenecks in electrical connections. They are also expected to be used in constructing a switching network that requires a large bandwidth and in implementing new electrical parallel paradigms such as massively parallel processors. For these new paradigms, it is important to develop a pixel that allows for appropriate routing of optical signals and optical loss compensation. One candidate for this is a combination of a vertical-cavity surface emitting laser (VCSEL) and a microdetector with some amplification or level-regeneration functions. Such functions are also necessary for avoiding electrically-induced noise in the detector section. One aim of the vertical-to-surface transmission electro-photonic device (VSTEP) is to achieve such a combination in a compact size. This paper focuses on this research into pnpn-VSTEP pixels. These pixels are easy to fabricate, and therefore production yield is high. A pixel consisting of the VCSEL-thyristor and double-vertical-cavity HPT was therefore formed using the same layer structure as that in the pnpn-VC-VSTEP except for a GaAs spacer layer (λ/2 thickness) inserted into the lower DBR of the HPT. The VCSEL-thyristor is switched electrically or optically, and then function as a VCSEL modulated by the light incident on the HPT when they are connected in series. The pair numbers of the upper and lower DBR in the VCSEL-thyristor are 14.5 and 23. The threshold current and slope efficiency are 0.8 mA and 0.25 W/A, respectively. Single transverse mode oscillation is also obtained. Uniform I-L characteristics and good production yield are confirmed in a 10×10 array. The spacer layer for the HPT is formed on 7.5 AlAs/ GaAs layers in the lower DBR. The absorptivity bandwidth is abort five times larger than that of the single-vertical-cavity structure without the spacer, and was 50. A photocurrent gain of 230 A/W is obtained with 10 μW incident-light power.