Photonic Nyquist Pulse Generation Based on Phase-Modulated Fiber Bragg Gratings in Transmission

Nyquist pulses are critical in optical communication networks and signal processing systems. We present, to our best knowledge, the first demonstration of all-optical Nyquist pulse generation using phase-modulated fiber Bragg gratings (PM-FBGs) in transmission. PM-FBGs are a class of fiber gratings that have a nearly uniform coupling strength and a spatially varying grating period. As examples, we have designed and numerically simulated photonic Nyquist pulses with roll-off factors of 0.9, 0.5, and 0.1, respectively. The grating profiles are obtained employing numerical optimization algorithms. Numerical simulations confirm that the generated pulses are in good agreement with ideal Nyquist pulses over a 500 GHz bandwidth and have a good tolerance to the variations in the input pulse width.