R&D Profile: Passive Light Power Control Enabled by Nanotechnology, A. Donval, KiloLambda Technologies Ltd, IL
The need to regulate and control light power is relevant not only for sophisticated communication systems but also to everyday optical equipment such as cameras or car rear-view mirror and require an active electronic feedback control.
Overview and Research Updates courtesy of Dr. Ariela Donval. Dr. Donval is VP R&D of Optical Power Control (OPC) division at KiloLambda, which has headquarters in Tel Aviv, Israel.
The need to regulate and control light power is relevant not only for sophisticated communication systems but also to everyday optical equipment such as cameras or car rear-view mirror and require an active electronic feedback control. We explore the unique capabilities and advantages of nanotechnology in developing next generation non-linear components and devices to control and regulate optical power in a passive way to reduce complexity and cost.
At NSTI Nanotech 2008, we reported on passive optical power control (OPC) devices based on film or layers with a range of photonic nanostructures, including mainly nanostructures for spatial field localization to enhance optical nonlinearities (refer to Figure 1). We presented two main optical power control mechanisms: blocking and limiting, as well as their corresponding nano-scale phenomena. The blocking mechanism is based on catastrophic breakdown, which is an irreversible event, can be advantage for over power and spikes protection device applications. However, the limiting mechanism, which is based on diffusion or scattering of the light, is a complete reversible phenomena, leading to power regulation device applications. We presented device examples of three novel generic optical power control components: fiber optical fuse, fiber optical limiter (refer to Figure 2) and free-space wideband protection filter. We presented also preliminary design for future applications such as optical power regulating of sunlight (DSF) and its possible applications.
Recently, we demonstrated in our lab a limiting behavior at free space configuration (in the green light) of our OPC technology as a first step towards the realization of filter capable of sun power regulation (DSF). We continue our research in the field of nano-materials possessing higher sensitivity to optical power examining various nano-structures and nano-composites. Our R&D goal is achieving sun power regulation in a passive way to realize the DSF device.
Figure 1: Passive optical power control (OPC) film or layer based on a range of photonic nanostructures. In the normal state (top), when incident light is below a predefined level the OPC film is highly transparent, light just passes through it. As the light level is increased and gets more intense, the OPC film transmission decreases accordingly, eventually reaching a darkened state (bottom).
Figure 2: Output power vs. input power cycles as recorded for an of approximately 7dBm optical power limiter, an example of OPC film product application in Telecom market.
