The magneto-optical (MO) oxide layer consists of (Bi,Y)₃Fe5O₁₂ or BiYIG, bismuth garnet. This material was selected because it has a better figure of merit than the CeYIG previously used, especially at lower wavelengths (1310 nm vs. 1550 nm). A top-down deposition process was developed in which BiYIG/YIG stacks are grown on the Si waveguide with YIG on top. The stack is annealed at 800°C/5 min to crystallize both layers, with the YIG templating the BiYIG leading to garnet phases rather than other oxides, and the BiYIG is directly on the Si waveguide. Initial attempts led to a film with Bi oxide phases, because the Bi was in excess and could not escape during the anneal as occurs in Si/YIG/BiYIG stacks. Hence the composition was adjusted to include slightly more Fe, which yielded films with only garnet peaks.

Despite enormous advances in integrated photonics over the last decade, an efficient integrated phase delay remains to be demonstrated. This problem is fundamental – most monolithic thin film deposition relies on centro symmetric materials (such as silicon, silicon dioxide, silicon nitride), which by definition do not have an electro-optic effect. Such materials have been shown to be excellent transparent materials, however they are either optically passive, or rely on very small plasma dispersion effect or power-hungry thermo-optic effect for tunability. These phase change materials have losses associated due to heating or carrier injection in the waveguides. This research shows that graphene can be used to provide electro-optic properties to traditionally passive optical materials.

The major goals of this research project included two parts. First, an ultracompact plasmonic electro-optical (EO) modulator was to be developed and investigated for efficient intensity modulation. Second, an ultracompact and high-speed EO modulator based on a dielectric platform was to be developed for straightforward integration with existing CMOS technology. Both modulators were targeted to facilitate next-generation interconnects for integrated photonic circuits.

There have been several news headlines lately about offenders pointing commercial lasers at helicopters or police personnel, temporarily blinding and distracting them. An increasing number of “laser assault” incidents have led to tougher penalties with fines and jail time in various countries. The lasers typically used in these attacks operate in the visible light spectrum; therefore, these lasers can be blocked by special absorbing optical dyes contained in special laser defense eyewear.

More and more aerospace applications are incorporating fiber optics technology into their designs due to its many advantages over copper. The thinner fiber solutions provide higher speed over a longer distance, are more reliable, offer higher noise immunity and, in many cases, lower the cost of ownership. Additionally, for the same diameter, fiber can pack more data than copper. Fiber is faster than the category 5 and 6 copper cables, approaching the speed of light (31% lower). For copper, pushing the speed beyond 1G is a challenge, but for fiber 10G is quite common. Copper is limited by distance. Usually, signal degradation with copper will occur after about 90 meters (2.7 km maximum for custom systems), while fiber can achieve more than 1.5 km without a problem and can deliver over 80 km depending on transmission signal quality.

The concept of an imaging system that captures both spatial and spectral information has existed for a while. An example of one such imaging system that encodes both location and wavelength into an image is a Fourier Transform Spectrometer (FTS).

A new research project announced recently as a collaboration between the Georgia Institute of Technology and satellite communications provider Xenesis could help open the bottleneck that now limits the flow of data from Earth-orbiting satellites to ground stations.

BAE Systems
Nashua, NH
603-885-4321
www.baesystems.com

The U.S. Defense Advanced Research Projects Agency (DARPA), through the U.S. Air Force Research Laboratory, has awarded BAE Systems a $13.1 million contract to demonstrate a new, cost-effective optical seeker for precision-guided munitions. The seeker is designed to improve navigation, as well as automate target location and homing, for different types of munitions that are used in GPS-denied and other contested environments.

AeroVironment, Inc.
Monrovia, CA
626-357-9983
www.avinc.com

AeroVironment, Inc., a specialist in unmanned aircraft systems (UAS) for both defense and commercial applications, and ESG Elektroniksystem- und Logistik-GmbH, a system and software house in Germany for development and service, recently announced that the German Navy has acquired the AeroVironment Puma™ maritime unmanned aircraft system. The Puma systems will include the Mantis i45 sensor and pocket Remote Video Terminal (p/RVT). AeroVironment partnered with ESG to satisfy the requirement of the Bundesamt fur Ausrustung, Informationstechnik und Nutzung der Bundeswehr (BAAINBw) for an urgent operational requirement.

Laser diodes and laser diode arrays (LDAs) are widely used throughout military systems, for sighting and range finding, but also at high power levels as offensive and defensive weapons. In companion with much higher-power chemical lasers, these high-power optical sources can generate kilowatts of optical power (as arrays) for use in neutralizing incoming missiles, rockets, and armaments and for long-distance offensive strikes. But laser diodes are also still inefficient, and a great deal of the energy supplied to a laser diode or an LDA is converted into heat, which must be safely dissipated to ensure a long operating lifetime for the solid-state devices.