We demonstrate a high efficiency, high linearity and high-speed silicon Mach-Zehnder modulator based on the DC Kerr effect enhanced by slow light. The two modulation arms based on 500-µm-long grating waveguides are embedded with PN and PIN junctions, respectively. A comprehensive comparison between the two modulation arms reveals that insertion loss, bandwidth and modulation linearity are improved significantly after employing the DC Kerr effect. The complementary advantages of the slow light and the DC Kerr effect enable a modulation efficiency of 0.85 V·cm, a linearity of 115 dB·Hz2/3, and a bandwidth of 30 GHz when the group index of slow light is set to 10. Furthermore, 112 Gbit/s PAM4 transmission over 2 km standard single mode fiber (SSMF) with bit error ratio (BER) below the soft decision forward error correction (SD-FEC) threshold is also demonstrated.

To investigate the efficacy of utilizing mixed reality technology-assisted teaching of a spinal medial branch nerve block. Twenty undergraduate students from a 5-year clinical medicine program in Fujian Medical University were selected. They were divided into group A and group B using a random number generator, with 10 students in each group. Group A used the traditional teaching method and Group B used the mixed reality technologyassisted teaching method. At the end of the teaching period, both groups were assessed on the blocking operation, number of punctures required, puncture time, and final error value (distance between the final position and the reference position). A questionnaire was administered to both groups to assess teaching satisfaction. The number of punctures required was 7.40 ± 1.26 and 2.10 ± 0.74 for groups A and B, respectively. The puncture time in group A was 297.80 ± 50.95 s and 65.60 ± 22.02 s in group B. All differences were significant p < 0.01. The final error of the puncture in group A was 2.24 ± 0.35 mm and 1.96 ± 0.26 mm in group B-not significant. Group B had (p < 0.01) higher evaluation scores than group A for teaching effectiveness, learning interest, initiative, and teaching satisfaction. The application of mixed reality technology in the teaching of posterior medial branch blocks of the spinal nerve is superior to previous methods. This method should be adopted wherever possible to enhance learning of this difficult technique.

A polarization-insensitive multimode antisymmetric waveguide Bragg grating (MASWBG) filter based on an SiN–Si dual-layer stack is demonstrated. Carefully optimized grating corrugations patterned on the sidewall of a silicon waveguide and SiN overlay are used to perturbate TE and TM modes, respectively. Furthermore, the lateral-shift apodization technique is utilized to improve the sidelobe suppression ratio (SLSR). A good overlap between the passbands measured in TE and TM polarization states is obtained. Insertion losses, SLSRs, and 3-dB bandwidths of measured passbands in TE/TM polarizations are 1/1.72 dB, 18.5/19.1 dB, and 5.1/3.5 nm, respectively.

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We demonstrate Ge/Si high-power and high-speed distributed traveling wave photodetectors (TWPD) by using the inductive gain peaking technique. Input terminals of TW electrodes are open to enhance RF output efficiencies to output loads. Furthermore, optimized on-chip spiral inductors are incorporated at output terminals of TW electrodes to alleviate bandwidth degradations caused by the absences of matching impedances. A comprehensive equivalent circuit model is developed to calculate the frequency response of this scheme. It is used to optimize the design, and then is validated by measurement results. After inducing on-chip inductors, the bandwidths of 4-stage and 8-stage TWPDs are improved from 32 to 44 GHz and 16 to 24 GHz, respectively. Maximum RF output powers of 4-stage and 8-stage TWPDs with on-chip inductors are measured to be 5.7 dBm and 9.4 dBm at 20 GHz, respectively.