A novel 40 Gb/s all optical 3R regenerator was proposed. High finesse Fabry-Pérot (F-P) filter was used in clock recovery. Before clock recovery, a stable laser was used in wavelength conversion to aim the wavelength of input signal at the window of F-P filter. After clock recovery, the low frequency noise in the recovery clock was suppressed using semiconductor optical amplifier (SOA). In the all optical decision gate, dual SOAs in series were used to lengthen active region of SOA and to rise the optical switching speed. The pattern effect of the output of decision gate was eliminated by using narrow band filter. In experimental study, new 40Gb/s optical signal was regenerated from degraded optical signal using this 3R regenerator. The timing jitter and pulse width of the degraded signal were larger than 5 ps and 16 ps. Compared with these, the timing jitter of the regenerated pulse was 1.5 ps. The signal noise ratio improved 14 dB. This regenerator was recorded to work continually more than 15 h. This experiment testified that the new scheme of regenerator can work successfully in 40 Gb/s all optical 3R pulse regeneration.