“…Meanwhile, the MZI with different length of PCF also shown high fringe visibility, the max attenuation depth of which were about 17.2 dB, 20.3 dB, 19.9 dB and 24.1 dB, respectively, as illustrated in Figure 3 . The max fringe visibility of our proposed MZI with SMPS fiber structure was higher than those of MZI with TCF-MMF-TCF structure (21 dB) [ 34 ] or MMF-TCSMF-MMF structure (14 dB) [ 35 ], MZI based on asymmetrical twin core fiber and multimode fiber (15 dB) [ 36 ] and some PCF interferometer structures, such as PCF-MZI with two waist-broadened tapers (11 dB) [ 37 ] or with up-tapered joints (11.5 dB) [ 38 ], normal PCF-MZI (21 dB) [ 28 ], TC-PCF MZI (10 dB) [ 16 ], TCF-PCF structure MZI (20 dB) [ 39 ] and S-tapered PCF (12 dB) [ 40 ]. In addition, it can be observed that the insertion loss of the proposed MZI is larger than that of MZI with SMF-PCF-SMF structure [ 8 ], which is due to the increase in the number of fusion.…”