T. de Vries

TOWARDS APPLICATION OF FIBER METAL LAMINATES IN LARGE AIRCRAFT

Fibre metal laminates were developed at Delft University during the last two decades as a family of new hybrid materials consisting of bonded thin metal sheets and fibre/adhesive layers. This laminated structure provides the material with excellent fatigue, impact and damage tolerance characteristics and a low density. While the 20 per cent weight reduction was the prime driver behind the development of this new family of materials, it turns out that additional benefits like cost reduction and an improved safety level have become more and more important. The combination of these aspects in one material makes fibre metal laminates a strong candidate material for fuselage skin structures of the new generation of high capacity aircraft. The focus on this application currently leads to industrialization and qualification that makes this material available to the aircraft designer.

Lasing of wavelength-tunable (1.55μm region) InAs∕InGaAsP∕InP (100) quantum dots grown by metal organic vapor-phase epitaxy

The authors report lasing of InAs∕InGaAsP∕InP (100) quantum dots (QDs) wavelength tuned into the 1.55μm telecom region. Wavelength control of the InAs QDs in an InGaAsP∕InP waveguide is based on the suppression of As∕P exchange through ultrathin GaAs interlayers. The narrow ridge-waveguide QD lasers operate in continuous wave mode at room temperature on the QD ground state transition. The low threshold current density of 580A∕cm2 and low transparency current density of 6A∕cm2 per QD layer, measured in pulsed mode, are accompanied by low loss and high gain with an 80-nm-wide gain spectrum.

Heterogeneously integrated III-V/silicon distributed feedback lasers

Heterogeneously integrated III-V-on-silicon second-order distributed feedback lasers utilizing an ultra-thin DVS-BCB die-to-wafer bonding process are reported. A novel DFB laser design exploiting high confinement in the active waveguide is demonstrated. A 14 mW single-facet output power coupled to a silicon waveguide, 50 dB side-mode suppression ratio and continuous wave operation up to 60°C around 1550 nm is obtained.

Fatigue and Damage Tolerance of Glare

Methods have been developed to describe the fatigue initiation and propagation mechanisms in flat panels as well as mechanically fastened joints and to determine the residual strength of large flat panels. Glare shows excellent crack growth characteristics due to the mechanism of delamination and fibre bridging. The fatigue insensitive fibres restrain the crack opening and transfer load over the crack in the metal layers. During the initiation phase fibre bridging does not occur and the behaviour is dominated by the metal initiation properties. Mechanically fastened joints introduce additional effects such as secondary bending, load transfer and aspects related to the fastener installation. The residual strength of Glare is dependent on the amount of broken fibres and the delamination size and can be described with the R-curve approach.The impact resistance of Glare is related to the aluminium and glass/epoxy properties and is significantly higher than the impact resistance of monolithic aluminium. The same has been proven for fire resistance. Depending on the Glare grade and thickness, the outer aluminium layer will melt away, whereas the other layers will remain intact due to carbonisation of the glass/epoxy layers and delamination of the laminate. The air in the delaminations will act as insulation, keeping the temperatures at the non-exposed side relatively low.

Integrated two-state AWG-based multiwavelength laser

An integrated InP-InGaAsP two-state coupled-laser device for use in optical packet switching and signal processing is presented. The two states are identified by distinct lasing wavelengths. Single-mode lasing occurs in both states and the contrast ratio between the two states is 35 dB. Switching between states with optical pulses is demonstrated. The use of an arrayed waveguide grating (AWG) and ring laser configuration permits monolithic integration without the need for cleaved facets. How the AWG can be used to obtain partial isolation between multiple interconnected devices is also discussed.

Glare Technology Development 1997–2000

Fibre Metal Laminates (e.g., Glare) are composed of a bonded structure of metallic layers and fibre reinforced adhesive layers and were developed by laboratory testing and design during the last fifteen years. The Glare Technology Development (GTO) has been aiming at final technology readiness for application in aircraft design, production and service. The current paper gives an overview of the work that was done in this large project.

Monolithic AWG-based Discretely Tunable Laser Diode With Nanosecond Switching Speed

A novel concept for an arrayed-waveguide-grating (AWG)-based fast tunable laser is presented. It is fabricated in the InP-InGaAsP monolithic integration technology. Laser peaks have a sidemode suppression ratio of 30-40 dB. The wavelength switching speed is in the order of a few nanoseconds and switching is achieved by a 1-mA bias current. The switching between AWG channels is discrete and no laser operation takes place at wavelengths corresponding to other channels during the tuning process.

Low-Footprint Optical Interconnect on an SOI Chip Through Heterogeneous Integration of InP-Based Microdisk Lasers and Microdetectors

We present a proof-of-principle demonstration of a low-footprint optical interconnect on a silicon-on-insulator (SOI) chip. The optical link consists of a heterogeneously integrated, InP-based microdisk laser (MDL) and microdetector, coupled to a common SOI wire waveguide. Applying an electrical current to the MDL resulted in a detector current up to 1 muA.

Delamination behavior of spliced Fiber Metal Laminates. Part 1. Experimental results

The sizes of Fiber Metal Laminate (FML) sheets available can be increased considerably with the application of the splicing concept. A disadvantage of this concept can be the occurrence of delamination caused by load transfer over the splice. An experimental program has been carried out to investigate the delamination behavior for different splicing geometries and metal layer thicknesses. Griffiths energy criterion is applied to calculate a delamination resistance for the configurations tested. The approach is modified for the presence of residual stresses in the laminate and plasticity in the metal layers.

Monolithically Integrated InP 1

The static and dynamic characteristics of a monolithically integrated InP 1 × 16 optical phased-array switch are presented. The device demonstrates static switching with an average extinction ratio of 18.6 dB, on-chip loss below 7 dB, and wavelength dependence of less than 0.8 dB in the entire C-band. A 40-Gb/s nonreturn-to-zero signal is transmitted through the switch with a power penalty below 0.4 dB. Using a programmable electronic circuit, dynamic switching to all 16 outputs is achieved with response times less than 11 ns.