In recent years, smart phone applications have both raised the pressure for cost and time to market reduction, and the
need for high performance MEMS devices. This trend has led the MEMS community to develop multi-die packaging of
different functionalities or multi-technology (i.e. wafer) approaches to fabricate and assemble devices respectively. This
paper reports on the fabrication, assembly and packaging at INO of various MEMS devices using heterogeneous
assembly at chip and package-level. First, the performance of a giant (e.g. about 3 mm in diameter), electrostatically
actuated beam steering mirror is presented. It can be rotated about two perpendicular axes to steer an optical beam within
an angular cone of up to 60° in vector scan mode with an angular resolution of 1 mrad and a response time of 300 ms. To
achieve such angular performance relative to mirror size, the microassembly was performed from sub-components
fabricated from 4 different wafers. To combine infrared detection with inertial sensing, an electroplated proof mass was
flip-chipped onto a 256×1 pixel uncooled bolometric FPA and released using laser ablation. In addition to the microassembly
technology, performance results of packaged devices are presented. Finally, to simulate a 3072×3 pixel
uncooled detector for cloud and fire imaging in mid and long-wave IR, the staggered assembly of six 512×3 pixel FPAs
with a less than 50 micron pixel co-registration is reported.
An object oriented simulation framework, called KARMA, was developed over the last decade at Defence Research and
Development Canada - Valcartier (DRDC Valcartier) to study infrared countermeasures (IRCM) methods and tactics. It
provides a range of infrared (IR) guided weapon engagement services from constructive to HWIL simulations. To
support the increasing level of detail of its seeker models, DRDC Valcartier recently developed an IR scene generation
(IRSG) capacity for the KARMA framework. The approach relies on Open-Source based rendering of scenes composed
of 3D models, using commercial off-the-shelf (COTS) graphics processing units (GPU) of standard PCs. The objective
is to produce a high frame rate and medium fidelity representation of the IR scene, allowing to properly reproduce the
spectral, spatial, and temporal characteristics of the aircraft's and flare's signature. In particular, the OpenSceneGraph
library is used to manage the 3D models, and to send high-level rendering commands. The atmospheric module allows
for accurate, run-time computation of the radiative components using a spectrally correlated wide-band mode. Advanced
effects, such as surface reflections and zoom anti-aliasing, are computed by the GPU through the use of shaders. Also, in
addition to the IR scene generation module, a signature modeling and analysis tool (SMAT) was developed to assist the
modeler in building and validating signature models that are independent of a particular sensor type. Details of the IR
scene generation module and the associated modeling tool will be presented.
The main goals of this work is the development of a large dual-axis MEMS mirror, ~3mm in diameter, capable of
steering a laser beam within an angular cone of 60°. The targeted application involves the control of a laser beam with a
particular interest for the resulting far field beam direction and profile. Finite element simulations using ANSYS
modeling program were conducted to optimize the mirror design and determine the main characteristics of the mirror.
The voltage required to tilt the mirror by 15° around each of the two axes was evaluated to be in the range of 700 V. The
construction of this device is based on high precision structural dies assembly which relies on innovative developments
in the fields of selective electroplating, deep reactive ion etching (DRIE) and thermocompression flip-chip bonding. The
fabrication process involved the microassembly of 4 mirror parts, i.e. address electrodes, thick pedestal, gimbals
structure and mirror plate. Single crystal silicon was used as material for the fabrication of the thick pedestal and mirror
plate which provided the required large mirror-electrode gap and a high quality mirror with high flatness and low
roughness. Soldering based on SnAu was considered for the microassembly of the thick pedestal to the address
electrodes die, while Au-Au thermocompression bonding was considered to achieve the assembly of gimbals and mirror.
The gimbals were supported by a polyimide sacrificial film to avoid damaging the hinges during mirror plate assembly.
We present results of propagation measurements (over 545 m and 5.7 km paths) carried out with a pulsed laser beam (12 ns pulse width) at a wavelength of 3.7 um under sunny and cloudy atmospheric conditions. The objective of the study was to evaluate, for these distances, the effects of atmospheric turbulence on the deposited power levels achievable on targets having diameters of a few tens of mm. Measurements of scintillation levels, probability distributions, and durations of intervals where the power level stays continuously above or below its mean value were carried out. The results show that, for all atmospheric conditions encountered, the lognormal probability distribution can be used to correctly describe the probability of obtaining some given power levels. Also, the statistics of continuous time intervals spent above and below the mean power are shown to follow an exponential probability distribution. Experimental results relating the mean durations of these intervals to the scintillation levels, the wind speeds, and the probability distribution of collected power levels are also presented. These results could help in determining the source power required to ensure a given level of exposure on targets with a pre-determined probability, taking into account the reaction times of the targets.
Broad-area semiconductor lasers naturally emits on several lateral modes even at injection currents very close to the threshold current. An external cavity terminated by an apodizing holographic grating has been used to favor the oscillation of only one longitudinal mode and one lateral mode. It is possible to obtain laser oscillation on two different wavelengths simultaneously by using a grating that contains two grating periods. The fabrication technique of the apodizing holographic grating is explained. The spectrally-resolved near-field intensity distributions are presented.
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