Bragg Reflection Waveguide Photonic Crystal Laser

Bragg reflection waveguide (BRW) laser is a new class1D photonic crystallaser with a line defect, where photonic band-gap effect rather than the total internalreflection is utilized to provide optical confinement in the vertical direction. TheBRW lasers (BRLs) possess a variety of advantages compared with conventionalindex-guiding lasers, including the high gain coefficient, large mode volumes, andstrong mode discrimination, allowing for high power and single mode operation.This helps to raise the catastrophic optical damage threshold power and reduce thevertical beam divergence of the diode laser. Another significant advantage of theBRL is that it could produce different beam patterns through controling thenear-field electric field distribution, which are are in demand for a wide variety ofapplications.The objective of this thesis is to develop high-performance BRLs. The mainwork is as follows:1) The mode dispersion equation of the Bragg reflection waveguide is solved bythe transfer matrix method and Bloch theory. The design and calculation methods ofthe BRLs are presented.2) The further analysis shows that the intrinsic reason for the far-fielddistribution is determined by the mode shape in the cavity. The single-sided BRLwith dual-lobed far field is demonstrated. 3) The fabricated50μm-wide asymmetric BRL exhibites more than1.5Wcontinuous-wave output power with high efficiency of48%. The threshold currentdensity is as low as253A/cm~2.4) A Bragg reflection waveguide twin-beam laser is designed and demonstrated.Nearly the entire emitted power of the BRL is concentrated in two near-circularlobes in the vertical direction. The full-width at half maximum divergence angles areas narrow as7.2°and5.4°respectively in the vertical and lateral directions.5) The continuous-wave and single-mode operation of the ridge BRL isdemonstrated. The lasing spectrum showed an ultra-narrow linewidth of0.052nmand large side mode suppression ratio (SMSR) exceeding33dB. Periodic spectrummodulation with a uniform mode spacing of3.3nm is also observed.6) High brightness808nm edge-emitting Bragg reflection waveguide laserswith a nearly circular output beam was firstly demonstrated. The vertical beamdivergence is as narrow as8°at the full width at half maximum. The significantlyreduced vertical beam divergence while maintaining stable single transverse modeoperation is beneficial for fiber coupling.