Plasmonic crystal defect nanolaser.

Surface plasmons are widely interesting due to their ability to probe nanoscale dimensions. To create coherent plasmons, we demonstrate a nanolaser based on a plasmonic bandgap defect state inside a surface plasmonic crystal. A one-dimensional semiconductor-based plasmonic crystal is engineered to have stopbands in which surface plasmons are prohibited from travelling in the crystalline structure. We then confine surface plasmons using a three-hole defect in the periodic structure. Using conventional III-V semiconductors, we achieve lasing in mode volumes as small as V(eff) = 0.3(λ0/n)³ at λ0 = 1342 nm, which is 10 times smaller than similar modes in photonic crystals of the same size. This demonstration should pave the way for achieving engineered nanolasers with deep-subwavelength mode volumes and attractive nanophotonics integration capabilities while enabling the use of plasmonic crystals as an attractive platform for designing plasmons.

Enhanced modulation bandwidth of nanocavity light emitting devices.

We show that the direct modulation bandwidth of nano-cavity light emitting devices (nLEDs) can greatly exceed that of any laser. By performing a detailed analysis, we show that the modulation bandwidth can be increased by the Purcell effect, but that this enhancement occurs only when the device is biased below the lasing threshold. The maximum bandwidth is shown to be inversely proportional to the square root of the modal volume, with sub-wavelength cavities necessary to exceed conventional laser speeds.

Strong optical injection-locked semiconductor lasers demonstrating > 100-GHz resonance frequencies and 80-GHz intrinsic bandwidths.

By using strong optical injection locking, we report resonance frequency enhancement in excess of 100 GHz in semiconductor lasers. We demonstrate this enhancement in both distributed feedback (DFB) lasers and vertical-cavity surface-emitting lasers (VCSELs), showing the broad applicability of the technique and that the coupling Q is the figure-of-merit for resonance frequency enhancement. We have also identified the key factors that cause low-frequency roll-off in injection-locked lasers. By increasing the slave laser's DC current bias, we have achieved a record intrinsic 3-dB bandwidth of 80 GHz in VCSELs.

Scaling of resonance frequency for strong injection-locked lasers.

It has been shown that strong optical injection locking can significantly enhance the resonance frequency of semiconductor lasers. In this Letter, we describe the trade-off between the maximum resonance frequency enhancement and the quality factor (Q) of the lossless laser cavity and show that the time-bandwidth product (product of photon lifetime and maximum resonance frequency) is equal to one half the square root of the external power injection ratio. The theoretical model agrees well with our experimental data.

Novel cascaded injection-locked 1.55-mum VCSELs with 66 GHz modulation bandwidth.

We demonstrate a novel cascaded configuration of optically injection-locked (COIL) VCSELs, which enables a wide and tailorable direct modulation bandwidth. Up to 66 GHz bandwidth is achieved using VCSELs with an original, free-running 10 GHz bandwidth. Different configurations of cascading are discussed in detail with the focus on optimizing the modulation bandwidth. We also discuss scaling capability of this technique to achieve tailorable modulation response.