Improving modulation bandwidth of tunable three sections distributed Bragg reflector lasers by using asymmetric nonlinear gain: Design and simulation

• Published in: Optics communications 2021-01, Vol.479, p.126439, Article 126439
• Main Authors: Liu, Ye, Chen, Da, Yu, Yonglin
• Format: Article
• Language: English
• Subjects: Direct modulation; Multimode rate equations; Nonlinear gain; Three sections DBR laser; Tunable semiconductor laser
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2020.126439

Asymmetric nonlinear gain in tunable three sections distributed Bragg reflector (3s-DBR) laser is theoretically studied with multimode rate equations. It is found, with a special design, anomalous interaction between adjacent modes can be used to enhance modulation bandwidth of the 3s-DBR laser. Tuning characteristics and direct modulation response of a designed laser are simulated and analyzed. Results show that, by taking advantages of the nonlinear gain, 3 dB bandwidth of the 3s-DBR laser could be improved from 18 GHz up to 27 GHz, 9 nm tuning range is kept meanwhile. Combining high speed direct modulation with tunability, this design may be attractive for future short reach optical communication. •The asymmetric nonlinear gain is firstly used to enhance direct modulation bandwidth of tunable 3 sections DBR laser.•A long weak-coupled grating is designed and optimized to introduce a side mode to take advantages of the asymmetric nonlinear gain.•Necessary conditions for making use of the nonlinear gain are discussed.•Direct modulation bandwidth (27 GHz) and 9 nm tuning range are demonstrated; 25 and 40G NRZ eye diagram are also presented.