title: Giant tunable optical dispersion using chromo-modal excitation of a multimode waveguide.
abstract: The ability to control chromatic dispersion is paramount in applications where the optical pulsewidth is critical, such as chirped pulse amplification and fiber optic communications. Typically, devices used to generate large amounts (>100 ps/nm) of chromatic dispersion are based on diffraction gratings, chirped fiber Bragg gratings, or dispersion compensating fiber. Unfortunately, these dispersive elements suffer from one or more of the following restrictions: (i) limited operational bandwidth, (ii) limited total dispersion, (iii) low peak power handling, or (iv) large spatial footprint. Here, we introduce a new type of tunable dispersive device, which overcomes these limitations by leveraging the large modal dispersion of a multimode waveguide in combination with the angular dispersion of diffraction gratings to create chromatic dispersion. We characterize the device's dispersion, and demonstrate its ability to stretch a sub-picosecond optical pulse to nearly 2 nanoseconds in 20 meters of multimode optical fiber. Using this device, we also demonstrate single-shot, time-wavelength atomic absorption spectroscopy at a repetition rate of 90.8 MHz.
authors: Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA. ediebold@ucla.edu
authors: Eric D
authors: ED
authors: Diebold
authors: Nick K
authors: NK
authors: Hon
authors: Zhongwei
authors: Z
authors: Tan
authors: Jason
authors: J
authors: Chou
authors: Todd
authors: T
authors: Sienicki
authors: Chao
authors: C
authors: Wang
authors: Bahram
authors: B
authors: Jalali
mesh_terms: D003116:Color; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*