ECE Seminar: George Gordon on "Digital Holographic Modal Control of Optical Fibers"

George GordonPost-doctoral Research FellowUniversity of Cambridge, UK-- Digital Holographic Modal Control of Optical Fibers -- Abstract:Recently, there has been a resurgence of interest in the multi-modal propagation characteristics of optical waveguides, in particular optical fibers. This has been driven largely by society's exponentially growing demand for data that is pushing existing long-haul optical communication links to their limit, but in parallel with this new applications in imaging and sensing have emerged.At the University of Cambridge, we have developed a system that can precisely launch modes of arbitrary amplitude and phase profile into a multimode fiber and then determine the modal composition of light emerging from the output facet. Furthermore, the system utilizes arrays of single-mode fibers at the transmitter and receiver to enable spatial multiplexing on different groups of modes. To achieve this, appropriate digital holograms are calculated using a GPU-accelerated optimization algorithm and they are then displayed on spatial light modulators (SLMs). Polarization diversity optics are used to achieve dual polarization operation.In this talk I will first present a discussion of the operation of this system, including techniques for alignment, focus correction and high-order aberration correction. Next, I will demonstrate the characterization of the modal properties of an OM2 multi-mode fiber and a custom fabricated ring-core fiber in both the spatial and temporal domains. Finally, I will show how the system can be used as a single-pixel coherent imaging device. Future applications to endoscopic imaging will be discussed.About the speaker (if necessary):

When 2:00 pm to 4:00 pm on Tuesday, September 23, 2014
Location Boston University Photonics Center, Saint Marys Street, Boston, MA, United States (PHO 536)