FTh4E.5.pdf CLEO 2018 © OSA 2018 Optical Trapping and Manipulation of Multiple Microparticles Using SDM Fibers Joel A. Hernández-García 1 , Amado M. Velázquez-Benítez, 1* K. Yanín Guerra-Santillán, 2 Raúl Caudillo- Viurquez, 2 J. Enrique Antonio-López, 3 Rodrigo Amezcua-Correa, 3 Juan Hernández-Cordero 4 1Centro de Ciencias Aplicadas y Desarrollo Tecnológico, UNAM, Cd. Universitaria, Mexico City, 04510, México 2Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, 04510, México 3CREOL, The College of Optics and Photonics, the University of Central Florida, Orlando, Florida, 32816, USA 4Instituto de Investigaciones en Materiales, UNAM, Cd. Universitaria, Mexico City, 04510, México *Corresponding author: amado.velazquez@ccadet.unam.mx Abstract: We demonstrate optical trapping and dynamic manipulation of microparticles using multicore and few-mode fibers. Tuning of the input state of polarization of the trapping beam allows for particle rotation and adjustable trapping distances. OCIS codes: (350.4855) Optical tweezers or optical manipulation; (060.2310) Fiber optics; (030.4070) Modes. 1. Introduction Manipulation of particles at the micro and nanometric sizes has become an important requirement for research in diverse fields such as physics, chemistry, biology, and biomedical sciences [1]. The preferred method for non- contact trapping and manipulation is based on the use optical forces. A wide variety of approaches capable to generate and dynamically adjust specific light patterns to trap multiple particles have been demonstrated [2]. However, the techniques to manipulate trapped particles usually rely on optical setups involving complex alignment processes resulting in bulky arrangements. A simple approach to achieve optical trapping entails the use of optical fibers, reducing the complexity and size of the optical arrangements for trapping and manipulation. Nevertheless, trapping of multiple particles using optical fiber based techniques typically requires elaborated setups and/or devices involving complicated fabrication procedures [3,4]. Current research in optical communications has focused on the development of new optical fiber technologies seeking to increase the amount of information transmitted through a single fiber. This has driven to explore the spatial domain in optical fibers [5], leading to technologies involving multicore fibers (MCFs) and few-mode fibers (FMFs), providing a means to generate on-demand multimode signals [5]. Complementary to these technologies, the development of spatial multiplexers, such as photonic lanterns, allows to selectively exciting individual LP modes in optical fibers [6,7]. In this paper, we present a new approach for microparticle trapping using optical fibers for space-division multiplexing. In particular, we demonstrate that MCFs and FMFs can be used to generate dynamically adjustable modal patterns useful for trapping and manipulation of multiple microparticles. 2. Experiments Optical trapping was performed by selectively generating different light patterns at the output of either a MCF or a FMF using the experimental setup shown in Figure 1a. Control of the generated patterns was achieved through adjustments in the state of polarization (SOP) of the signal launched into each fiber under test (FUT). For this purpose, a laser diode (LD,  = 1550 nm) was coupled to a fiber-optic polarization synthesizer (PSY-101, General Photonics) used to control the input polarization. The output end of the FUT was fixed to a XYZ - translation stage and placed inside a cuvette containing a solution with deionized water and dispersed microparticles. Two kinds of particles were used for the solutions: silica spheres (≈ 8 μm average diameter) and polystyrene spheres (≈ 4.8 μm average diameter). Fig. 1. a) Experimental setup for optical trapping and manipulation. End facets and output mode profiles of the fibers: b) seven core (MCF) and c) few-mode (FMF) fiber. Two different fibers were used in these experiments: a seven-core MCF (Fig. 1b) with 11 μm core diameters and with 2 μm core separation [8], and a 15 μm graded-index core FMF (Fig. 1c) supporting 2-LP modes. For light