Optimization of a 60° waveguide bend in InP-based 2D planar photonic crystals

Abstract

We present a novel design for a W1 (one missing row of holes) waveguide 60°bend implemented in a substratetype InP / InGaAsP / InP planar photonic crystal based on a triangular array of air holes. The bend has been designed to provide high transmission over a large bandwidth. The investigated design improvement relies only on displacing holes while avoiding changing individual holes diameter in the interest of better process control (homogenous hole depth). Two-dimensional (2D) finite-element simulations were used to increase the relative transmission bandwidth from 18% to 40% of the photonic bandgap for unoptimized and optimized 60°b ends, respectively. The 2D results were verified by means of rigorous three-dimensional (3D) finite-difference time-domain (FDTD) simulations. We show that excellent agreement between 2D and 3D simulations can be obtained, provided a small effective-index shift of −0.024 ͑−0.74% ͒ and an imaginary loss parameter ͑⑀Љ = 0.014͒ is introduced in the 2D simulations. To demonstrate the applicability of our improved design, the bend was fabricated and measured using the endfire technique. A bending loss of 3 dB is obtained for the optimized W1 waveguide bend compared to more than 8 dB in the unoptimized case.

Optimization of a Cl2–H2 inductively coupled plasma etching process adapted to nonthermalized InP wafers for the realization of deep ridge heterostructures

“…1,4,11-14 But the etching speed and the selectivity over dielectric mask are simultaneously significantly decreased in this case. 4,13,14 Finally, H 2 has been added to a standard Cl 2 / Ar process, 2 InP / InGaAsP heterostructures with smooth and vertical sidewalls has been demonstrated in a specific regime balancing the Cl 2 -H 2 chemical etch and the Ar physical component, with all the epitaxial layers being etched at approximately the same rate. In this article, we investigate the use of Cl 2 -H 2 chemistry with no additive gas to etch deep ͑Ͼ5 m͒ InGa͑Al͒As/ InP heterostructures with smooth and vertical sidewalls. The process is adapted to the etching of nonthermalized InP wafers in order to avoid the use of thermal grease, which is convenient for an industrial process and/or for critical subsequent steps such as epitaxial regrowth.…”

Passivation of Interfacial States for GaAs- and InGaAs/InP-Based Regrown Nanostructures

“…A parallel study was carried out on plasmaprocessed InGaAs/InP samples. n-Type InGaAs, grown on an InP (110) substrate, was exposed to two different etch chemistries in a SiCl 4 /Cl 2 /Ar or CH 4 /H 2 /Ar/BCl 3 /Cl 2 -based RIE plasma [19][20][21][22] environment that have been used in the formation of III-V device structures. The etching conditions, such as gas flow rates and pressures, were optimized to obtain smooth surface morphology after etching and a low and controlled overall etch rate.…”

High contrast all-optical logic gates based on 2D nonlinear photonic crystal

“…Besides this advantage, photonic crystals (PCs) have low losses; hence they are suitable candidate for high speed communications. Due to the special properties of photonic crystals to control the light propagation, they have been utilized to construct devices such as waveguides [1], reflectors [2], multi/demultiplexers [3], radiation sources [4] and micro-cavities [5]. Also nonlinear photonic crystal devices based on Kerr effect have been proposed and studied so far.…”