TFLN coherent modulator chip developed by Liobate Support the world's first 260G baud DP-QPSK signal transmission over 100km fiber

Introduction：

Liobate, Sun Yat-sen University, in cooperation with Bell Labs (France), III-V Labs (France), and Yestech (Germany), has achieved for the first time a transmission distance of 100 km for DP-QPSK signals at baud rates up to 260G baud, based on a TFLN coherent modulator chip developed by Liobate. The experimental results of this ultra-high-rate fiber optic communication are presented as a PDP paper (post-deadline paper) at the European Conference on Optical Communications 2022 (ECOC 2022).

Key Innovations:

In January 2022, Sun Yat-sen University, in collaboration with Huawei, published the world's first polarization-multiplexed coherent optical modulator chip based on TFLN in the prestigious international journal Optica (M. Xu, et al. Optica 2022, 9(1): 61-62), achieving a single-carrier transmission rate of up to 1.96 Tb/s for the first time. However, the chip demonstrated a symbol rate of only 130 Gbaud baud rate. Increasing the baud rate above 200 Gbaud still faces many challenges, requiring sufficient bandwidth for all optoelectronic components in the system, and the amplitude of the electrically driven signal at high baud rates is only in the order of a hundred millivolts, placing severe requirements on both the electro-optical modulator chip and the test instrumentation.

Based on the above work, a joint R&D team formed by Liobate, Sun Yat-sen University, Bell Labs (France), III-V Labs (France), and Yestech further optimized the optical design and microwave design of the TFLN electro-optical modulator, achieved ultra-low microwave loss using a quartz substrate, and realized the on-chip synchronous transmission of microwave rate and optical wave rate using a capacitive traveling wave electrode A high-performance dual-polarization coherent optical modulator with a 3 dB electro-optical bandwidth of 110 GHz and a half-wave voltage as low as 1 V has been successfully developed, as shown in Figure 1. To carry out stable transmission experiments, Liobate has also completed the coupling of low-loss fiber arrays to the modulator chip and realized a package module with a flexible arrangement of RF interfaces.

Fig 1 TFLN IQ modulator developed by Liobate and Sun Yat-sen University

The joint team further utilized the highest performance arbitrary waveform generator (AWG) available, the Yestech M8199B prototype with a sampling rate of up to 260Gsa/s and a bandwidth of over 75GHz, to achieve record-breaking 260G ultra-high baud rate DP-QPSK modulation (shown in Figure 2) and demonstrate 100km single-mode fiber optic transmission. It also further utilizes

The 1.84 Tb/s achievable information ratio (AIR) was further achieved using 185G baud PCS-64QAM high-order modulation format (shown in Figure 3). The excellent performance of the TFLN modulator with large bandwidth and low drive voltage eliminates the need for nonlinear DSP algorithms and MLSE equalizers with complex algorithms in transmission experiments, thus setting another record in coherent optical transmission with lower DSP complexity and power consumption.