With the continuously increasing demand for optical network bandwidth, high-speed data transmission and large-capacity optical fiber communication technologies are being developed to meet the goal. In Mode Division Multiplexing (MDM) systems, the orthogonal fiber modes are made advantage of carrying different user information in the form of Multiple-input and Multiple-output (MIMO) channels. In the case, both the system spectral efficiency and transmission capacity can be effectively improved by means of MIMO digital signal processing technology. At the same time, to save the system cost and reduce complexity of implementation, more attention is being paid to low-complexity MIMO technology, or even MIMO-free MDM high-speed signal transmission, with applications to short-distance application scenarios such as optical access networks, data centers, and supercomputer interconnections.On the other hand, the mode multiplexer/demultiplexer, as a key component for MDM communication systems, are required for a low mode-dependent loss and mode crosstalk as possible. Their performance parameters can directly affect the system's bit error rate and the difficulty of algorithm compensation at the receiver. There are several kinds of mode multiplexers, including those of free space type, optical waveguide, fiber coupler, and photonic lantern. Free-space multiplexers have some advantages in mode purity and mode crosstalk, but are limited by complex optical platforms. The multiplexing/demultiplexing scheme based on the waveguide structure has large connection loss with few-mode fibers since the width of the optical waveguides is much smaller than the core radius of the few-mode fibers. The other two multiplexer/demultiplexer are in the form of fiberization and capable of seamless connection to few-mode fiber systems. Among them, the commercially available Mode-selective Photonic Lantern (MSPL) mode multiplexer, as a passive optical device, has the advantages of simple structure, low insertion loss, and multi-port input. The MSPLs are also compatible with other technologies such as wavelength division multiplexing, polarization multiplexing.In the paper, we focus on the high-speed signal transmission capability of MIMO-free Mode Division Multiplexing (MDM) system constructed by the 3-port MSPLs, where each mode channel carries a Dual-polarization Quadrature Phase Shift Keying (DP-QPSK) signal at a bit rate of 100 Gb/s. The state of the Few-mode Polarization Controller (FMPC) used in the experiment can be accurately characterized by the Signal-to-crosstalk Ratios (SXRs) of LP₀₁ and LP₁₁ mode channels. The relationship between the Bit Error Rate (BER) and the SXRs is measured by adjusting the FMPC. The experimental results show that, no bit error after forward error correction can be achieved when the SXR of each mode channel is more than about 8 dB. When the SXRs of the two channels are respectively 14.25 dB and 13.81 dB, the corresponding degradation of received optical power relative to the back-to-back transceiver system are 1.40 dB and 4.76 dB at the BER threshold of 10^-2, respectively. The effects of fiber attenuation, polarization mode dispersion and mode crosstalk on the high speed transmission system are analyzed, and the transmission distance limited by crosstalk is estimated to be about 30 km for the few-mode fiber system of interest. Compared with the technologies reported so far, the research in this paper has the highest channel rate, and indicates that the MIMO-free crosstalk limited distance is about 30 km. The 2×2 high-speed MIMO-free mode division multiplexing experiment is carried out before. 100 Gb/s DP-QPSK has higher requirements on the SXR of the channel. Using the same experimental system, appropriately reducing the channel data rate can achieve 3×3 mode division multiplexing system.