An ultracompact 3×1 MMI power-combiner based on Si slot-waveguide structures

Eyal Samoi, Yosef Benezra, Dror Malka

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Today, photonic integrated circuits (PIC) that work with a high-modulation speed (100Gb/s and beyond) are required to use more optical power to overcome the losses. One solution is to use a high-level laser with a hundred milliwatts power. However, for a microchip circuit, this solution can be problematic due to the nonlinear effects and high cost. Therefore, to solve this issue, we propose a new design of a 3×1 multimode interference (MMI) power combiner based on a slot waveguide structure that can utilize slot-waveguide technology for reducing losses. In this study, the full-vectorial beam propagation method (FV-BPM) was used to find the optimal geometrical parameters of the MMI coupler, inputs/output taper, and the slot waveguide structure. Simulation results show that after light propagation of 9.82 μm the beam combiner efficiency can reach 97.6 % working within the C-band range. Also, to reduce back reflection losses an angled MMI was designed using a finite difference time domain (FDTD) method and results show a low back reflection of 40 dB. This unique design can lead to an efficient and compact combiner for multiple coherent sources that work with PIC chips.

Original languageEnglish
Article number100780
JournalPhotonics and Nanostructures - Fundamentals and Applications
StatePublished - May 2020
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2020 Elsevier B.V.


  • FDTD
  • FV-BPM
  • MMI
  • Power-combiner
  • Slot-waveguide


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