We demonstrate a 3-dB power splitter optimized by an enhanced particle swarm optimization algorithm based on a curved directional coupler, with a set of silicon columns introduced into the coupling region. The proposed device exhibits compact size, low loss and low wavelength dependence in the O-band. We employ the particle swarm optimization algorithm to engineer the dispersion by designing the radius of the silicon columns automatically. The demonstrated 3-dB power splitter enabled by silicon columns in silicon-on-insulator can achieve multiple performance metrics simultaneously according to our simulation results, with a compact footprint as small as 11.9 µm, low excess loss as low as 0.04 dB and broad 3-dB operational bandwidth of 60 nm with transmission fluctuations within 0.05 in the wavelength range from 1270 to 1330 nm. This work pioneers the silicon columns in the coupling region and adopts an enhanced particle swarm optimization algorithm to optimize device properties, providing significant potential for application in large-scale PICs as well as offering a new degree of freedom in the design of power splitters.

Wepropose and experimentally demonstrate the ultra-compact mode (de)multiplexers and polarization beam splitter (PBS) based on tapered bent asymmetric directional couplers. The strong coupling strength introduced by tapered bent waveguides significantly shortens the coupling length. As a result, high coupling and conversion efficiencies over a broad bandwidth can be obtained with small footprint. The coupling length of the fabricated PBS and mode (de)multiplexers are less than 4.9 μm and 8.7 μm, respectively. From 1534-1600 nm, the measured insertion loss (IL) is less than 1.4 and 1.55 dB for the TE ₁ -TE ₀ and TE ₂ -TE ₀ mode (de)multiplexers, respectively, and the crosstalk (CT) is less than −10 dB. The fabricated PBS shows low insertion loss of 0.55 dB and decent crosstalk of < −14 dB for both polarizations over an 85 nm wavelength range from 1505-1590 nm. Meanwhile, the larger fabrication tolerance ensures that the proposed devices can be readily fabricated with the standard complementary metal-oxide-semiconductor (CMOS) process.

We experimentally demonstrate a low-loss and low-crosstalk 16-channel 200 GHz-channel-spacing arrayed waveguide grating router (AWGR) with a size of 0.67 × 0.37 mm ² , targeting for C-band wavelength division multiplexing (WDM) interconnect routing applications. As a result, the AWGR features a channel spacing of 200±10 GHz, a free spectral range of 25.62 nm and a 3 dB channel bandwidth of 0.9 nm. Based on comprehensive optimal design, the measured characterization revealed 5.55 dB maximum channel loss non-uniformity with 1.13 dB best-case channel insertion loss. Besides, the fabricated device exhibits good cyclic-frequency operation for all 16 × 16 port combinations with channel crosstalk of –15.11 dB.

An ultra-broadband and compact 3-dB power splitter has been designed and fabricated using an adiabatic rib silicon waveguide on the silicon-on-insulator (SOI) platform. This device primarily consists of two tapered rib waveguides to facilitate mode evolution for the transverse electric (TE) mode. The results demonstrate that the proposed device can achieve a 150 nm bandwidth in the wavelength range from 1450 nm to 1600 nm for 3-dB power splitting. In addition, the mode evolution footprint is significantly reduced to $78~\mu \text{m}$ with an excess loss of less than 0.18 dB. This proposed device offers a notable trade-off of device performance for power splitters. With multiple performance metrics, the rib waveguide-based adiabatic directional coupler exhibits significant potential for application in high-density photonic integrated chips (PICs).

An ultra-broadband, compact and CMOS-compatible arbitrary ratio power splitter that is based on a directional coupler is proposed on the silicon-on-insulator (SOI) platform. The proposed device consists of an adiabatic sub-wavelength grating (ASWG) and a conventional directional coupler. The wavelength dependence is greatly reduced by introducing an ASWG in the coupling region of the directional coupler. Simulation results show that our proposed device has an operating bandwidth of 250 nm for arbitrary power splitting ratios, with a transmission power variation of less than 8.5%, covering the wavelength range from 1400 nm to 1650 nm. Meanwhile, the device footprint has been narrowed to less than 46 μm. In addition, the power splitters also exhibit a low excess loss of below 0.24 dB. Our proposed ASWG-assisted power splitters show excellent potential for application in large-scale photonic integrated circuits.

Programmable integrated photonic circuits are poised to drive a new revolution in information systems by synergizing with high‐speed digital signals. Central to this vision is the ability to reconfigure optical signal processing for multi‐functional photonic integration. Here, we design and experimentally demonstrate a thermo‐optically reconfigurable adiabatic coupler monolithically integrated on a silicon photonics platform. The device combines adiabatic directional couplers with titanium nitride (TiN) micro‐heaters embedded in the adiabatic transition region, enabling dynamic coupling ratio tuning via the localized thermo‐optic modulation. Experimental results confirm continuous coupling ratio adjustment from 50:50 to 70:30 across 80‐nm bandwidth (1,520–1,600 nm), with insertion loss kept below 0.25 dB. Leveraging its tunability, the device enables programmable spectral routing with free spectral ranges (FSR) of 20 nm and 40 nm. The proposed approach offers enhanced flexibility and scalability for high‐density photonic systems, providing a promising pathway toward next‐generation programmable photonic circuits and optical computing architectures.