Ultra-high bandwidth signal and pump wavelength division multiplexer based on all-dielectric metasurface

Metasurfaces are two-dimensional planar structures composed of artificial atoms with special electromagnetic properties in a certain arrangement, which can flexibly control the amplitude, phase, and polarization of incident light, and have strong light field manipulation capabilities, so they have attracted extensive attention. In this work, a WDM based on all- dielectric metasurface is proposed to realize the beam combination function of ultra-wideband signal and narrowband pumping. The WDM can realize the low-loss and high-efficiency wavelength division multiplexing function of one ultra- wideband signal and one or two narrowband pumps by punching holes in the fused silica thin layer, with a signal passing bandwidth of more than 400nm, almost no energy loss on the signal wavelength, a pump loss of less than 1dB, and a pump occupied bandwidth of less than 3nm. It can well solve the problem of serious limitation of signal bandwidth of the current wavelength division multiplexer and provide important support for the key components and equipment of ultra-high bandwidth optical communication such as ultra-high bandwidth optical fiber amplifiers.