We give on overview of recent advances in collisionally pumped optical
field-ionization soft X-ray lasers developed at LOA. Saturated
amplification has been achieved on the 5d-5p transition in Xe8+
at 41.8 nm, and on the 4d-4p transition in Kr8+ at 32.8 nm. We
demonstrate a significant increase of the energy output from the
Xe8+ laser driven within two types of wave-guide. Finally, we
present results of a pioneering work aimed to set up and characterize the
first true soft X-ray laser chain.