A Novel Dual-Amplitude Fixed Length Digital Pulse Interval Modulation Scheme

Abstract

In this letter, a novel scheme which can realize high-speed optical signals transmission and reception by using 4-pulsed amplitude (4-PAM) modulation and demodulation in 10 Gb/s free-space optical (FSO) systems. In this scheme, one PAM sequence generator module, one M-element pulse generator (MPG) module and one Mach-Zehnder Modulator are used to generate 10Gb/s 4-PAM optical signals. And then, the generated optical signal is transmitted in free space. Finally, it is directly detected and demodulated (IM/DD). We measure time-domain sequential waveform curves, optical spectrum curves, eye diagrams, and analyze the reception performance of 10Gb/s 4-PAM signals before and after transmission.