High-efficient subwavelength structure engineered grating couplers for 2-µm waveband high-speed data transmission.

The 2-µm waveband is becoming an emerging window for next-generation high-speed optical communication. To enable on-chip high-speed data transmission, improving the signal-to-noise ratio (SNR) by suppressing the coupling loss of a silicon chip is critical. Here, we report grating couplers for TE and TM polarized light at the 2-µm waveband.

Subwavelength structure engineered passband filter for the 2-µm wave band.

In this work, we experimentally demonstrate a passband filter for the 2-µm wave band on the silicon-on-insulator platform. The device consists of a strip waveguide and an apodized subwavelength-structured waveguide. Fabricated on a 340-nm-thick silicon membrane, the proposed passband filter shows a 3-dB bandwidth of 16-33 nm, a high sidelobe suppression ratio (SLSR) of 24 dB, and a low insertion loss (IL) of 0.

High-efficiency mid-infrared on-chip silicon grating couplers for perfectly vertical coupling.

We present, to our knowledge, the first experimental demonstration of two on-chip gratings for perfectly vertical coupling at wavelengths of 3350 nm and 3550 nm, respectively. An anti-backreflection unit containing a fully etched trench and a subwavelength pillar is introduced in each grating period, together with a binary-approximated blazed unit, interleaving fully and shallow-etched slots in 500-nm thick silicon film. Both gratings show a strong ability to eliminate backreflection and provide predicted directionality of around 80%.

Ultra-compact polarization-independent 3 dB power splitter in silicon.

We experimentally demonstrate an ultra-compact polarization-independent 3 dB power splitter on the silicon-on-insulator platform. Subwavelength structure engineering is employed to balance the coupling coefficients of TE and TM polarizations as well as a footprint reduction. The device possesses ultra-compact (1.

High-order exceptional point based optical sensor.

Exceptional points (EPs) could potentially enhance the sensitivity of an optical sensing system by orders of magnitude. Higher-order EP systems, having more complex physics, can further boost this parameter. In this paper, we investigate the response order of high-order non-Hermitian systems and provide a guideline for designing a sensor with high response order.

High-speed silicon modulator with band equalization.

Electro-optic modulation up to 70 Gbit/s has been demonstrated using a silicon Mach-Zehnder modulator with a bias voltage of -1.5 V. In a wide frequency range from DC, an increasing input impedance of the modulator was designed to equalize its electro-optic frequency response.

Nonblocking 4×4 silicon electro-optic switch matrix with push-pull drive.

A compact rearrangeable nonblocking 4×4 silicon electro-optic switch matrix based on a Spanke-Beneš network is proposed and fabricated by a 0.18 μm standard commercial complementary metal-oxide semiconductor line. By respectively modulating the two modulation arms with a push-pull drive, a cross talk (CT) of less than -18 dB is obtained for the switching element with 150-μm-long modulation arms.