InP-based Two-dimensional Photonic Crystal Research Articles

Carrier transport through a dry-etched InP-based two-dimensional photonic crystal

The electrical conduction across a two-dimensional photonic crystal (PhC) fabricated by Ar/Cl2 chemically assisted ion beam etching in n-doped InP is influenced by the surface potential of the hole sidewalls, modified by dry etching. Carrier transport across photonic crystal fields with different lattice parameters is investigated. For a given lattice period the PhC resistivity increases with the air fill factor and for a given air fill factor it increases as the lattice period is reduced. The measured current-voltage characteristics show clear ohmic behavior at lower voltages followed by current saturation at higher voltages. This behavior is confirmed by finite element ISE TCAD™ simulations. The observed current saturation is attributed to electric-field-induced saturation of the electron drift velocity. From the measured and simulated conductance for the different PhC fields we show that it is possible to determine the sidewall depletion region width and hence the surface potential. We find that at the hole sidewalls the etching induces a Fermi level pinning at about 0.12 eV below the conduction band edge, a value much lower than the bare InP surface potential. The results indicate that for n-InP the volume available for conduction in the etched PhCs approaches the geometrically defined volume as the doping is increased.

High contrast reflection modulation near 1.55μm in InP 2D photonic crystals on silicon wafer

We report on reflection modulation results near 1.55 mum in InP-based two-dimensional photonic crystals. The fabrication technology uses a polymeric bonding technique to integrate the InP thin-slab onto a Silicon wafer. Reflectivity modulation greater than 90% is obtained by pumping at 810 nm with optical excitation densities of 15 muJ/cm(2). The resulting optical broadband modulation is based on the saturation of absorption of InGaAs quantum wells at a photonic mode frequency tunable by lithography.

InP-based two-dimensional photonic crystals filled with polymers

Polymer filling of the air holes of indium-phosphide-based two-dimensional photonic crystals is reported. After infiltration of the holes with a liquid monomer and solidification of the infill in situ by thermal polymerization, complete filling is proven using scanning electron microscopy. Optical transmission measurements of a filled photonic crystal structure exhibit a redshift of the air band, confirming the complete filling.

Room-temperature simultaneous in-plane and vertical laser operation in a deep-etched InP-based two-dimensional photonic crystal

The first observation, to the authors' knowledge, of laser emission in a defect-free deep-etched 2-dimensional photonic crystal is reported. The structure explored here consists in a triangular lattice of 4.5 μm-deep air holes drilled in a low index contrast InP-based waveguide. Simultaneous guided and vertical directions laser operation is demonstrated at room temperature. A laser threshold of 15 kW/cm2 (average intensity) is measured with a pump diameter corresponding to only 9 periods of the photonic crystal.

Ultrafast dynamics of the third-order nonlinear response in a two-dimensional InP-based photonic crystal

We report experimental demonstration of very fast nonlinear response around 1.5μm in an InP-based two-dimensional photonic crystal. The nonlinearity produced by low pump powers via carrier induced nonlinear refractive index, leads to an efficient wavelength shift of a photonic crystal resonance observed in reflectivity. Thus we show that it is possible to obtain round the clock (rise and recovery) switching times shorter than 10ps with contrast ratio higher than 80%.

Selective area MOVPE growth of InP and InGaAs pillar structures for InP-based two-dimensional photonic crystals

Fabrication of high-quality photonic crystals (PCs) is an important issue for precise control of photon propagation. In particular, high aspect ratio, smooth surface, and high uniformity are required to achieve two-dimensional PCs (2DPCs). We report on the fabrication of InP and InGaAs pillar structures on InP substrates by using selective area metal-organic vapor-phase epitaxy (SA-MOVPE) for application to InP-based 2DPCs. This method is very promising as a way to form semiconductor 2DPCs because it makes it possible to obtain PC structures without process-induced damage. To form uniform pillar arrays, we investigated the properties of SA-MOVPE growth on InP (1 1 1) A and (1 1 1) B substrates. We found that pillar shapes strongly depended on the TBP pressure and growth temperature, and on the optimum growth conditions of uniform pillar structures having {1 1 0} vertical side facets.

InP-based two-dimensional photonic crystal on silicon: In-plane Bloch mode laser

Defectless two-dimensional photonic crystal structures have been fabricated by drilling holes in a thin multi-quantum-well InP-based heterostructure transferred onto a silicon host wafer. Extremely low group velocity modes, which correspond to the predicted photonic valence band edge, have been observed for different filling factors. Under pulsed optical pumping, room temperature laser operation around 1.5 μm has been achieved on these structures with a threshold in the milliwatt range.