We demonstrate the performance of broadband, low loss, and compact three-mode converter and (de)multiplexer utilizing an asymmetric trijunction splitter, multimode interferometer, and a phase shifter; all are designed using on subwavelength grating technology (SWG) and built-in a silicon-on-insulator platform for the first time to the best of our knowledge. SWG enables the flexibility of refractive index engineering for more operating bandwidth and compactness compared with conventional counterparts. The designed device is capable of converting and (de)multiplexing three different input modes TE0, TE1, and TE2 into a fundamental TE0 output mode. The three-dimensional finite-difference time-domain simulation results confirm that the designed device has a low loss of 1 dB and the crosstalk reaches −65 dB over a broad wavelength of 160 nm (1470 to 1630 nm) in the C-band range with an overall size of the designed device is 95 × 4 μm2.

中文翻译：

---

使用多模干涉耦合器的全亚波长光栅紧凑型三模（解）复用器：设计和仿真

我们展示了宽带、低损耗和紧凑型三模转换器和（解）复用器的性能，利用非对称三结分路器、多模干涉仪和移相器；据我们所知，所有这些都是使用亚波长光栅技术 (SWG) 设计的，并首次内置了绝缘体上硅平台。与传统对应物相比，SWG 实现了折射率工程的灵活性，以实现更多的操作带宽和紧凑性。设计的器件能够将三种不同的输入模式 TE0、TE1 和 TE2 转换和（解）复用为基本的 TE0 输出模式。