Optical Power Splitting Technologies in Photonic Systems

Optical power splitting underpins the distribution and routing of light within photonic integrated circuits, enabling a myriad of applications from data communications to sensing and signal processing. Traditional approaches rely on directional couplers, multimode interference devices and Y-junctions to divide incoming light into predetermined ratios. Advances in subwavelength structuring, inverse-design algorithms and metamaterial concepts have markedly increased functionality, allowing arbitrary splitting ratios, ultra-compact footprints and broadband operation. Modern platforms harness both single-mode and multimode waveguides to support power division across multiple channels or spatial modes, while maintaining low insertion loss and minimal crosstalk. These technologies are crucial for emerging demands in high-capacity data links, on-chip signal synchronisation, distributed sensing networks and reconfigurable photonic processors.

Research from Nature Portfolio

Recent studies have demonstrated a dual-mode 3 dB power coupler on a silicon-on-insulator platform capable of equal power splitting for both fundamental and first-order transverse modes. By employing tapered directional coupling sections, researchers achieved a compact common coupling length of around 15 µm, insertion losses below 0.7 dB and mode crosstalk better than –14 dB across the telecom band. This work represents a significant step towards mode‐division multiplexing systems with simplified layouts and high fidelity in power distribution across guided modes.

Separate efforts have introduced arbitrarily routed mode-division multiplexed photonic circuits based on digitized meta-structures, enabling on-chip splitting and recombination of high-speed signals in complex geometries. These circuits route 112 Gbit/s data streams per mode through compact bends, crossings and splitter elements with bit-error rates under forward error correction limits. The digitization of device footprints has yielded extremely small splitters and combiners that maintain low insertion loss and inter-mode isolation, boosting integration density for next-generation multimode optical systems.

Optical Power Splitting Technologies in Photonic Systems publication trend

The graph below shows the total number of articles in optical power splitting technologies in photonic systems across all publications each year (not limited to Nature Index journals).

Technical terms

Directional coupler: A device that splits optical power between adjacent waveguides through controlled evanescent coupling, often used for fixed-ratio division.

3 dB splitter: A coupler that divides incoming light equally, corresponding to a 50:50 power split and 3 dB insertion loss per branch.

Multimode interference (MMI): A phenomenon in multimode waveguides where self-imaging effects produce uniform power distribution among output ports.

Inverse design: A computational method that optimises device geometry by iteratively adjusting structure to meet target optical performance metrics.

Subwavelength grating: A periodic structure with feature sizes below the wavelength of light, used to engineer dispersion and coupling characteristics.

Mode-division multiplexing (MDM): A technique that encodes information on different spatial modes of a multimode waveguide, requiring power-splitting and combining elements for mode management.

References

1. Integrated dual-mode 3 dB power coupler based on tapered directional coupler. Scientific Reports (2016).
2. Arbitrarily routed mode-division multiplexed photonic circuits for dense integration. Nature Communications (2019).
3. Fabrication of 1 × N integrated power splitters with arbitrary power ratio for single and multimode photonics. Nanophotonics (2024).
4. An Integrated Optical Circuit Architecture for Inverse-Designed Silicon Photonic Components. Sensors (2023).