Photonic Crystal Surface Emitting Laser Operating in Pulse-Periodic Regime with Ultralow Divergence Angle

Ziye Wang,Cunzhu Tong,Sicong Tian,Huanyu Lu,Lijun Wang,Lijie Wang

doi:10.3390/photonics8080323

Abstract

The nanosecond-level pulse-operation characteristics of photonic-crystal surface-emitting lasers (PCSELs) with ultralow divergence were investigated in detail. We demonstrate a maximum peak output power of 14 W for a current pulse width of 9 ns, which is about 28 times the saturated power under continuous wave (CW) operation. The full width at half maximum (FWHM) of the optical response pulse is about 3 ns wider than the current pulse. The maximum repetition frequency reaches 400 kHz at 10 A without significant degradation of output power while the value is 100 kHz at 40 A. Moreover, the multimode behavior of the PCSEL at a high peak current was analyzed.

Highlights

The light detection and ranging (LiDAR) system, converting distance measurements into signal pulses, has promising applications in driverless vehicles, atmosphere observing, etc
Traditional semiconductor lasers like edge-emitting lasers suffer from some disadvantages, such as the large divergence angle and elliptic beam
It indicates that the full divergence angle is in the range from 0.38◦ to 0.96◦, which decreases firstly with the increasing current and tends to be stable

Summary

Introduction

The light detection and ranging (LiDAR) system, converting distance measurements into signal pulses, has promising applications in driverless vehicles, atmosphere observing, etc. The optical sources of LiDAR can be solid-state lasers [1,2], fiber lasers [3,4] and semiconductor lasers [5,6,7], and are expected to have high peak power [8], high repetition frequency [9], short pulse width [9], and low beam divergence angle [10]. The short pulse width is important for obtaining enough detecting precision and ensuring eye safety, especially for wavelengths less than 1.5 μm [9] Until now, it has lacked detailed investigation in this regard, their other properties such as polarization and beam pattern have been discussed previously [22,23,24,25]. The impact of different repetition frequencies and pulse widths on the peak power was analyzed

Sample Structure and Lasing Principles

Results and Discussion

Conclusions