Passive signal regeneration based on the Membrane InP Switch (MIPS) is demonstrated. Because of the high confinement of light in the active region of the MIPS, the device acts as a saturable absorber with a highly non-linear response. Using this effect, the extinction ratio (ER) of low-ER signals can be tripled and a receiver sensitivity enhancement of 4.5dB is demonstrated using an input signal at 1Gb/s with an ER of 2dB. Regenerator operation up to 5Gb/s is demonstrated and using a device simulator a strategy to reach higher bitrate operation is proposed.