A high-speed wavelength channel selector has properties of relatively easy manufacturing and easy extension to multi-channel integration, and a high-speed space and wavelength multiplexed channel selector uses the high-speed wavelength channel selector. One embodiment employs a bore in the plug so that the thin wall of the plug flexes outward at high pressures to partially fill the gap between the chamber member and the plug where the o-ring is located, thereby preventing the o-ring from extruding through the narrowed gap. A variation is determined during a predetermined time interval of the stimulation signal preceding the current instant of injection and exempt from injection, to accelerate the charge or the discharge of the floating substrate of the transistor.