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.
In this study, we have investigated metal-organic vapor phase epitaxial nano-patterned selective area growth of InGaAs/InP on non-planar (001) InP surfaces. Due to high etching resistance and the small molecular size of negative tone electron beam HSQ resist, the protection mask formed in HSQ has small feature sizes in ten nanometers scale and allow realization of in-situ etching. As was observed in the SAG regime, in-situ etching of InP by carbon tetrabromide leads to formation of self-limited structures. By altering etching time, the groove shape can be changed from a triangular trench to a trapeze. Another appealing aspect of in situ etching is that the shape of InGaAs can be tuned from a crescent to a triangular or a line by varying growth parameters. Quantum well wires can be fabricated by growing directly in the bottom of V-shaped groove. In addition, changes of mask orientations lead to anistropic or isotropic character of etching. The investigated technique of nano-patterned selective area growth allows obtaining different profiles of structures and different quantum structures such as quantum well or wires in the same growth run. To investigate the shape and crystalline quality of the active material, the cross-sectional geometry was observed by field emission scanning electron microscopy and scanning transmission electron microscopy. The optical properties were carried out at room temperature using micro-photoluminescence setup. The results showed different deposition rates for openings oriented along [0-11] and [0-1-1] directions with higher rate along [0-1-1]. The fabricated active material was incorporated into photonic crystal waveguides.
We review the theory of slow and fast light effects due to coherent population oscillations in semiconductor waveguides,
and potential applications of these effects in microwave photonic systems as RF phase shifters. In order to satisfy the
application requirement of 360° RF phase shift at different microwave or millimeter-wave frequency bands, we present
several schemes to increase the achievable RF phase shift by enhancing light slow-down or speed-up. These schemes
include integrating gain and absorption sections, optical filtering and the exploitation of the initial chirp effects. As a real
application in microwave photonics, a widely tunable microwave photonic notch filter with 100% fractional tuning range
is also proposed and demonstrated.