Simulation of the novel compact structure of an interferometric biosensor based on multimode interference waveguides
- Resource Type
- Authors
- Moisi Xhoxhi; Alma Dudia; Aurel Ymeti
- Source
- SPIE Proceedings.
- Subject
- Interferometry
Wavelength
Multi-mode optical fiber
Optics
Materials science
business.industry
Eigenmode expansion
Power dividers and directional couplers
Ranging
Photonics
business
Power budget
- Language
- ISSN
- 0277-786X
We propose the novel structure of an interferometric biosensor based on multimode interference (MMI) waveguides. We present the design of the biosensor using eigenmode expansion (EME) method in accordance with the requirements and standards of today's photonic technology. The MMI structures with a 90 nm Si3N4 core are used as power splitters with 5 outputs. The 5 high-resolution images at the end of the multimode region show high power balance. We analyze the coupling efficiency of the laser source with the structure, the excess loss and power imbalance for different compact MMI waveguides with widths ranging from 45 μm to 15 μm. For a laser source with a tolerance of ±1mm in linearization we could achieve a coupling efficiency of 52%. MMI waveguides with tapered channels show excess loss values under 0.5 dB and power imbalance values under 0.08 dB. In addition, we show that for a 10 nm deviation of the source wavelength from its optimal value and for a 10 μm deviation of the MMI length from its optimal value, the performance of the MMI waveguides remains acceptable. Finally, we analyze the power budget of the whole biosensor structure and show that it is sufficient for the proper operation of this device.