High-speed and single-mode FP laser based on parity-time symmetry

TL;DR

This paper demonstrates a novel single-mode Fabry-Pérot laser utilizing parity-time symmetry, achieving high output power, wide bandwidth, and effective single-mode operation for high-speed optical communication.

Contribution

It introduces a PT symmetric FP laser with independently controlled gain and loss, enabling stable single-mode lasing and high-speed modulation, which is a significant advancement over traditional designs.

Findings

Single-mode lasing with 1.7 dBm output power

3 dB bandwidth of 7.9 GHz achieved

Successful high-speed data transmission over 10 km fiber

Abstract

The ability to manipulate cavity resonant modes is of critical importance in laser physics and applications. By exploiting the parity time (PT) symmetry, we propose and experimentally realize a single-mode FP laser with improved output power and high-speed modulation have been demonstrated. The proposed PT symmetric laser consists of two coupled structurally identical FP resonators. The gain and loss in two FP resonators can be manipulated independently by changing the injection currents. In the PT symmetric FP laser, single-mode operation is accomplished by selectively breaking of PT symmetry depending solely on the relation between gain-loss and coupling. Single-mode lasing with output power of 1.7 dBm and a sidemode suppression ratio (SMSR) exceeding 24 dB is demonstrated. The 3 dB bandwidth of 7.9 GHz is achieved and clear eye-openings were obtained for 2.5 Gbps and 10Gbps NRZ operation over 10 km single-mode fibers. Furthermore, the PT symmetry breaking is experimentally confirmed with measured loss and coupling coefficient of two FP resonators. The influence of cavity length, facet reflectivity, and electrical isolation between two P-side electrodes on the side mode suppression ratio and output optical power is also been demonstrated, paving the way for further improvement of the PT symmetric FP laser.