We propose a novel optical transmission technique, 3D QAM-DPSK, that employs a single Mach-Zehnder modulator based on a direct detection system. Through 3D QAM-DPSK, the optical signal is simultaneously transmitted via the intensity and phase of the optical source. The QAM signal is transmitted via the intensity of the optical source, similar to conventional optical direct detection systems. The modified DPSK signal is transmitted via the phase of the optical source. As a QAM signal has two axes, and a DPSK signal has a single axis, the optical modulation technique can be treated as 3D QAM-DPSK. In the proposed optical transmission technique, signal transmission capacity and signal performance were enhanced in terms of bit error rate, as compared with ASK-DPSK. The signal transmission performance of the proposed modulation technique was numerically and experimentally demonstrated.
Bibliographical noteFunding Information:
Manuscript received April 3, 2020; revised June 12, 2020 and July 17, 2020; accepted July 18, 2020. Date of publication July 24, 2020; date of current version November 16, 2020. This work was supported by the National Research Foundation of Korea under Grant funded by the Korea government (MSIT; Ministry of Science and ICT) under Grant 2019R1A2C3007934. (Corresponding author: Sang-Kook Han.) The authors are with the Department of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749, South Korea (e-mail: phjokokok@yonsei. ac.kr; email@example.com; firstname.lastname@example.org; whshin0902@ yonsei.ac.kr; email@example.com).
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics