Demonstration of electrically injected vertical-cavity surface-emitting lasers with post-supported high-contrast gratings
Jing Zhang, Chenxi Hao, Wanhua Zheng, D. Bimberg, Anjin Liu
Abstract
We experimentally demonstrate for the first time to our knowledge electrically injected vertical-cavity surface-emitting lasers (VCSELs) with post-supported high-contrast gratings (HCGs) at 940 nm. The HCG-VCSELs have two posts to support the air-suspended HCGs, which are realized by simple fabrication without critical point drying. The HCG-VCSEL achieves a threshold current of about 0.65 mA and a side-mode suppression ratio of 43.6 dB under continuous-wave operation at 25°C. Theoretically the HCG-VCSEL with a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"><mml:mi>λ</mml:mi><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:math> -cavity for the transverse magnetic polarization has a smaller effective mode length of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m2"><mml:mrow><mml:mn>1.38</mml:mn><mml:mo>·</mml:mo><mml:mo stretchy="false">(</mml:mo><mml:mi>λ</mml:mi><mml:mo>/</mml:mo><mml:mi>n</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> . Thus, the relaxation resonance frequency can be increased by 16% compared with that of the conventional VCSEL. The modulation speed of 100 Gbit/s for the HCG-VCSEL is expected in the on–off keying modulation format. Our easy design of HCG-VCSELs has great potential for applications in optical interconnects, sensing, illumination, and so on.