High-performance silicon and thin-film lithium niobate hybrid electro-optic modulators are demonstrated. In order to break the voltage–bandwidth limit in a normal traveling-wave modulator, a periodic capacitively loaded traveling-wave electrode is employed in this hybrid platform. The silicon substrate is undercut-etched to achieve index matching of the optical wave and microwave. A hybrid waveguide with a lithium niobate thin film bonded on a silicon wire is employed. Lithium niobate etching is not required for making the hybrid optical waveguides. We realize an intensity modulator of 12.5 mm long modulation section, which exhibits a low half-wave voltage of 1.7 V and a large 3 dB modulation bandwidth of >70 GHz. Data transmissions with various modulation formats beyond 100 Gbit/s are successfully achieved with dynamic extinction ratios of >8 dB. Combining the advantages of the silicon and thin-film lithium niobate platforms, a compact dual polarization coherent modulator is also experimentally demonstrated, on which 96 Gbaud 16-level quadrature amplitude modulation signals in both polarizations are successfully transmitted.

A receive-diversity-aided power-fading compensation (RDA-PFC) scheme is proposed and demonstrated to eliminate the chromatic dispersion (CD)-induced power fading for C-band double-sideband (DSB) intensity modulation and direct detection (IM/DD) orthogonal frequency division multiplexing (OFDM) systems. By combining the responses before and after a dispersive element using a maximal-ratio combining (MRC) algorithm, the CD-induced power fading dips within the signal bandwidth of around 50 GHz can be effectively compensated for, which results in an up to 17.6-dB signal-to-noise ratio (SNR) improvement for the fading subcarriers after transmission over 10 km of standard single-mode fiber (SSMF). Using the 16 quadrature amplitude modulation (QAM) format, a diversity receiver with the proposed RDA-PFC scheme can support 170.6-Gbit/s OFDM signal transmission over a 10-km SSMF and reduces the bit error rate (BER) by more than an order of magnitude compared with a conventional receiver. Moreover, 208.1-Gbit/s adaptive bit and power loading OFDM signal transmission over a 10-km SSMF is realized by the proposed RDA-PFC scheme, which improves the capacity by 15.3% compared with the case without RDA-PFC at a BER of 3.8 × 10−3. The proposed RDA-PFC scheme shows great potential in CD-induced power-fading compensation for high-speed IM/DD OFDM systems.

A high speed, low voltage polarization controller based on Si-LN heterogeneous integration is fabricated and characterized. of 3.2 - 5.2 V is realized in a frequency range of 60 Hz to 6 MHz.

We propose and experimentally demonstrate a low-complexity pilot-assisted analytical method for polarization demultiplexing in SV-DD systems, achieving a 224-Gb/s 16QAM transmission over 40-km SSMF and can tolerate up to 75-krad/s RSOP at BTB.

We demonstrate simultaneous 60 GBaud 16-QAM transmissions and vibration sensing over a single 100-km deployed fiber link. Vibration localization is realized by extracting the phases of a co-propagating pilot and a counter-propagating tone.