Design Constraints of Photonic-Lantern Spatial Multiplexer Based on Laser-Inscribed 3-D Waveguide Technology
Design Constraints of Photonic-Lantern Spatial Multiplexer Based on Laser-Inscribed 3-D Waveguide Technology
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DOI：
10.1109/jlt.2014.2370673
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发表时间：
2015-03-15
影响因子：
4.7
通讯作者：
Koonen, Ton (A. M. J. )
中科院分区：
文献类型：
--
作者：
Chen, Haoshuo;Fontaine, Nicolas K.;Koonen, Ton (A. M. J. )
Laser-inscribed 3-D waveguide (3DW) technology has been applied to realize photonic-lantern spatial multiplexer (SMUX), which potentially enables lossless mode (de)multiplexing. However, the index contrast Delta n between the transparent substrate and the spatially-inscribed waveguides by femto-second laser pulses is generally smaller than 6 x 10(-3). It is simulated that a 3DW SMUX with Delta n < 6 x 10(-3) is able to provide a low mode-dependent loss (MDL) and coupler insertion loss (CIL) when coupling to a three-mode few-mode fiber (FMF). However, in six-and 15-mode cases, to guide all supermodes, few-mode region created by coupled or merged waveguides at the FMF side of the 3DW SMUX cannot be very small. This results in mode-profile mismatch between the 3DW SMUX and a low differential group-delay FMF, which is generally with Delta n around 1 x 10(-2). Instead of employing bulky imaging optics, uptapering FMF is proposed to enlarge the modes of the FMF for minimizing the mode-profile mismatch. Simulation shows MDL and CIL enhancement can be achieved by the uptapering solution. It also points out that as mode number increases to 15, although uptapering FMF still improves coupling performance, low MDL < 1dB cannot be acquired with Delta n
