The silicon-based arrayed waveguide grating (AWG) is widely used due to its compact footprint and its compatibility with the mature CMOS process. However, except for AWGs with ridged waveguides of a few micrometers of cross section, any small process error will cause a large phase deviation in other AWGs, resulting in an increasing cross talk. In this paper, an ultralow cross talk AWG via a tunable microring resonator (MRR) filter is demonstrated on the SOI platform. The measured insertion loss and minimum adjacent cross talk of the designed AWG are approximately 3.2 and -45.1 dB, respectively. Compared with conventional AWG, its cross talk is greatly reduced.

提出并实验研究了一种基于铌酸锂薄膜光波导的电光调谐的光栅辅助定向耦合器。该耦合器由单模与双模脊形波导及制作于双模波导侧壁的长周期光栅构成。长周期光栅的引入补偿了单模与双模波导中基模的相位失配，可在共振波长实现两波导中基模的高效耦合。进一步地，在双模脊形波导两侧制作调谐电极实现了高速、低驱动电压的电光调谐功能。优化了器件的制作工艺，并采用单次干法刻蚀将耦合器的光栅与波导同步制作于X切铌酸锂薄膜上。测试结果表明所制作的器件在1 595.3 nm波长处实现了14.8 dB的隔离度，其电光调谐效率为0.38 nm/V（1 595.3 nm~1 599.0 nm），热光调谐效率为0.14 nm/℃（25 ℃~50 ℃）。该器件可用于实现可调谐滤波、滤模、电光调制及高灵敏度温度传感等功能。

Graphene and related two-dimensional materials have attracted great research interests due to prominently optical and electrical properties and flexibility in integration with versatile photonic structures. Here, we report an in-fiber photoelectric device by wrapping a few-layer graphene and bonding a pair of electrodes onto a tilted fiber Bragg grating (TFBG) for photoelectric and electric-induced thermo-optic conversions. The transmitted spectrum from this device consists of a dense comb of narrowband resonances that provides an observable window to sense the photocurrent and the electrical injection in the graphene layer. The device has a wavelength-sensitive photoresponse with responsivity up to 11.4 A/W, allowing the spectrum analysis by real-time monitoring of photocurrent evolution. Based on the thermal-optic effect of electrical injection, the graphene layer is energized to produce a global red-shift of the transmission spectrum of the TFBG, with a high sensitivity approaching 2.167×10⁴ nm/A². The in-fiber photoelectric device, therefore as a powerful tool, could be widely available as off-the-shelf product for photodetection, spectrometer and current sensor.

We design and fabricate an unbalanced Mach–Zehnder interferometer (MZI) via electron beam lithography and inductively coupled plasma etching on lithium niobate thin film. The single unbalanced MZI exhibits a maximum extinction ratio of 32.4 dB and a low extra loss of 1.14 dB at the telecommunication band. Furthermore, tunability of the unbalanced MZI by harnessing the thermo-optic and electro-optic effect is investigated, achieving a linear tuning efficiency of 42.8 pm/°C and 55.2 pm/V, respectively. The demonstrated structure has applications for sensing and filtering in photonic integrated circuits.

The 4H-silicon carbide on insulator (4H-SiCOI) has recently emerged as an attractive material platform for integrated photonics due to its excellent quantum and nonlinear optical properties. Here, we experimentally realize one-dimensional photonic crystal nanobeam cavities on the ion-cutting 4H-SiCOI platform. The cavities exhibit quality factors up to 6.1×103 and mode volumes down to 0.63 × (λ/n)³ in the visible and near-infrared wavelength range. Moreover, by changing the excitation laser power, the fundamental transverse-electric mode can be dynamically tuned by 0.6 nm with a tuning rate of 33.5 pm/mW. The demonstrated devices offer the promise of an appealing microcavity system for interfacing the optically addressable spin defects in 4H-SiC.