Impact Statement:The paper investigates dynamic characteristics of C-band directly modulated InP membrane lasers (DMLs) in response to active phase tuning in an external cavity. The tunin...Show More
Abstract:
InP membrane directly modulated semiconductor lasers (DMLs) with photon-photon resonance (PPR) have a lot of potential to be used in short-range telecommunication systems...Show MoreMetadata
Impact Statement:
The paper investigates dynamic characteristics of C-band directly modulated InP membrane lasers (DMLs) in response to active phase tuning in an external cavity. The tuning helps to extend the laser bandwidth without changing its bias current. Additionally, the laser performance is precisely simulated and main design parameters influencing the bandwidth are studied. While most of the published research on DMLs only investigates cavities with passive external feedback, we for the first time investigate the mechanism of active feedback. The proposed laser design and phase tuning mechanism can be used to greatly improve device yield and performance stability of high-speed directly modulated lasers. Ultimately this research contributes to the field of short-range optical communication systems, where compact and energy efficient transmitters based on DMLs are in a great demand.
Abstract:
InP membrane directly modulated semiconductor lasers (DMLs) with photon-photon resonance (PPR) have a lot of potential to be used in short-range telecommunication systems due to their small footprint, high energy efficiency, and high modulation bandwidth. However, the stability of the S21 response in PPR-based devices is sensitive to precise phase-matching between the lasing mode and PPR mode. We designed, fabricated, measured, and analyzed a C-band DML with active phase-tuning achieved by a thermal phase shifter on top of a long passive waveguide. The phase shifter enables tuning of the PPR frequency in the range of 5 GHz resulting in the PPR peak power enhancement of 16 dB. We study the small-signal responses at different combinations of bias current and phase shifter current and show, that in some cases the phase shifter enables a bandwidth that cannot be achieved by sweeping the bias current. The laser dynamic behavior is simulated and the influence of the most important design and processing parameters on bandwidth is studied in detail.
Published in: IEEE Journal of Quantum Electronics ( Volume: 60, Issue: 6, December 2024)