Switching characteristics of an InP photonic crystal nanocavity: Experiment and theory

Abstract

The dynamical properties of an InP photonic crystal nanocavity are experimentally investigated using pump-probe techniques and compared to simulations based on coupled-mode theory. Excellent agreement between experimental results and simulations is obtained when employing a rate equation model containing three time constants, that we interpret as the effects of fast carrier diffusion from an initially localized carrier distribution and the slower effects of surface recombination and bulk recombination. The variation of the time constants with parameters characterizing the nanocavity structure is investigated. The model is further extended to evaluate the importance of the fast and slow carrier relaxation processes in relation to patterning effects in the device, as exemplified by the case of all-optical wavelength conversion.

An efficient all-optical gate based on photonic crystals cavities and applications

“…Indium Phosphide photonic crystal cavities have been demonstrated by us and by DTU [10], [11], [12] providing large switching contrast and a fairly fast dynamics, with a typical two time constant relaxation, first observed by NTT in silicon and InGaAsP PhC cavities [9]. In this talk we will focus on the properties of the so-called "photon molecules", resulting form the coupling of two photonic cavities.…”

Fano resonance control in a photonic crystal structure and its application to ultrafast switching

“…A detailed analysis (SI, section B.3) based on temporal coupled mode theory further supports the conclusion that Fano structures are superior to Lorentzian structures for high-speed signal-processing. We notice that the Lorentzian structure exhibits an oscillatory characteristic in the initial decay, which is due to interference beating between the signal and cavity mode 6,29 . Finally, to investigate the system properties, we characterize the BER when the Fano structure is used to modulate a weak continuous wave probe with a data-modulated pump signal.…”

“…The shape of the transmission spectrum is then very important, since it determines the refractive index shift, and thereby the control energy required for achieving a certain on-to-off ratio. The long tails of a Lorentzian spectrum thus imply large switching energies as well as slow dynamic components dominated by a long carrier lifetime 6 , which prevent high-bit-rate signal-processing unless the slow dynamics can be efficiently suppressed 7 . In contrast, a Fano resonance 8 has an asymmetric spectrum, featuring a large transmission change within a narrow wavelength range determined by the transition from constructive to destructive interference between the discrete resonance and the continuum, thus enabling low-energy switching 9 .…”

Optical time domain demultiplexing using fano resonance in InP photonic crystals

“…When the pump pulse couples into the nanocavity, free carriers are generated by two-photon absorption, which induce a blue shift in the resonance frequency through plasma dispersion and bandfilling effects [4], allowing the OTDM signal to transmit through the waveguide. The eye diagrams of the OTDM signal, pump pulse and the demuliplexed channels are shown in Fig.…”