Here we experimentally characterize photonic crystal nanolasers where the first endhole of the mirror has been systamatically shifted. FDTD simulations of similar passive cavities are done in order to find the expected evolution of the quality factor. We find that the predicted increase in the quality factor of the equivalent passive cavities leads to a decrease in the threshold power of the active nanolasers as expected. The maximum output power for varying endhole shifts has also been investigated and shifting the holes to optimize quality factor leads to lower maximum output power, when measuring from the top. The mirror of the photonic crystal cavity is further investigated as the mirror phase and penetration depth into the mirror are determined as a function of the endhole shift.
Replacing a conventional mirror in a photonic crystal laser by one based on Fano interference leads to rich laser dynamics, including realization of stable self-pulsing and potential for ultra-fast modulation. In particular, the narrowband Fano mirror guarantees single-mode operation and significantly alters the modulation response compared to Fabry-Perot lasers. In this work the small-signal response is analyzed using a dynamical model based on coupled-mode theory and rate equations, which shows how the 3-dB bandwidth of the frequency modulation response may exceed tens of THz, orders of magnitude larger than for conventional semiconductor lasers.
We present our work on photonic crystal membrane devices exploiting Fano resonance between a line-defect waveguide and a side coupled nanocavity. Experimental demonstration of fast and compact all-optical switches for wavelength-conversion is reported. It is shown how the use of an asymmetric structure in combination with cavity-enhanced nonlinearity can be used to realize non-reciprocal transmission at ultra-low power and with large bandwidth. A novel type of laser structure, denoted a Fano laser, is discussed in which one of the mirrors is based on a Fano resonance. Finally, the design, fabrication and characterization of grating couplers for efficient light coupling in and out of the indium phosphide photonic crystal platform is discussed.
In the talk we will discuss the role of disorder-induced losses on the threshold of line-defect photonic crystal lasers. Experiments reveal an optimum cavity length, on the order of 10 unit cells, where the laser threshold density attains a minimum. The results can be explained by considering the role of slow-light propagation on the threshold of a photonic crystal laser. We will also discuss the possibility of alleviating this dependence on cavity length by replacing one of the mirrors with a narrow-band mirror based on a Fano resonance.
We present theoretical and experimental results for a novel laser structure where one of the mirrors is realized by a Fano resonance between the laser waveguide and a side-coupled nano cavity. The laser may be modulated via the mirror resonance, enabling ultrahigh modulatioon speeds and pulse generation. Experimental results for a photonic crystal structure with quantum dot active layers will be presented.
Self-assembled lateral aligned InAs quantum dot molecules (QDMs) with InxGa1-xAs strain-reducing layer are grown on
GaAs substrate by metal-organic chemical vapor deposition. The effects of growth temperature and In content of InxGa1-xAs on the structural and optical properties of QDMs are investigated by using atomic force microscopy and
photoluminescence. It is found that through appropriately selecting growth parameters, QDMs composed of two closely
spaced InAs QDs are formed, and a redshift of emission wavelength and wideband photoluminescence spectra of QDMs
are observed, which make QDM a potential candidate for broadband optical devices.
A theoretical study is presented to solve the semiconductor optical amplifier (SOA) polarization dependent problem. We
take InAs quantum dot (QD) coupled with tensile-strained InyGa1-yAsP quantum well (QW) structure as SOA active
region. A theoretical model which describes the carrier transport process in QD, QW and barrier is established and the
carrier rate equations and optical propagation equations are achieved based on the above model. The performance of QD
coupled QW SOA is simulated. Optical gain spectrums of transverse electronic (TE) mode and transverse magnetic (TM)
mode are presented and the polarization power ratio between TE mode and TM mode as the function of injection current
and input optical signal wavelength is also achieved. By optimal designing of the structural parameters of SOA and
operation conditions, we can get polarization independent QD coupled QW SOA in certain ranges of input optical