This paper proposes and demonstrates a LP01-LP11 mode converter based on SLPG in PCF. PCF-SLPG is insensitive to temperature and pressure and has a wide wavelength harmonization range, compared with traditional fiber gratings. On the basis of the finite element method and local coupled mode theory, a theoretical model of PCF with SLPG was established and the transmission spectrum of the mode converter was analyzed by simulation. Experimental results show that the conversion efficiency of the PCF-SLPG mode converter is 10 dB approximately and the bandwidth of the 3 dB is about 84 nm, which approaches 1.5 times of the PCF-LPG mode converter. The mode converter is proposed to further expand the bandwidth of PCF-LPG, which lays a theoretical and experimental foundation for the application of PCF gratings technology in optical communication field.