Limits...
Optimizing SOI slot waveguide fabrication tolerances and strip-slot coupling for very efficient optical sensing.

Passaro VM, La Notte M - Sensors (Basel) (2012)

Bottom Line: In particular, we have focused on Silicon On Insulator (SOI) technology, representing the most popular technology for this kind of devices, simultaneously achieving high integration capabilities, small dimensions and low cost.An accurate analysis of single mode behavior for high aspect ratio slot waveguide has been also performed, in order to provide geometric limits for waveguide design purposes.Finally, the problem of coupling into a slot waveguide is addressed and a very compact and efficient slot coupler is proposed, whose geometry has been optimized to give a strip-slot-strip coupling efficiency close to 100%.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Elettrotecnica ed Elettronica, Politecnico di Bari, Bari, Italy. passaro@deemail.poliba.it

ABSTRACT
Slot waveguides are becoming more and more attractive optical components, especially for chemical and bio-chemical sensing. In this paper an accurate analysis of slot waveguide fabrication tolerances is carried out, in order to find optimum design criteria for either homogeneous or absorption sensing mechanisms, in cases of low and high aspect ratio slot waveguides. In particular, we have focused on Silicon On Insulator (SOI) technology, representing the most popular technology for this kind of devices, simultaneously achieving high integration capabilities, small dimensions and low cost. An accurate analysis of single mode behavior for high aspect ratio slot waveguide has been also performed, in order to provide geometric limits for waveguide design purposes. Finally, the problem of coupling into a slot waveguide is addressed and a very compact and efficient slot coupler is proposed, whose geometry has been optimized to give a strip-slot-strip coupling efficiency close to 100%.

No MeSH data available.


Related in: MedlinePlus

Sensitivity (a) and Γc (b) versus W and H for g = 120 nm. In region (1) only the fundamental TE-like mode is guided (single mode area). In region (2) at least one hybrid mode is supported, with χ typically ranging between 0.1 and 0.8. Region (3) depends on the assumed step resolution of parameters, so a single mode or multi mode excitation could occur; (c) fundamental slot mode field distribution for W =190 nm, H = 540 nm and g = 120 nm (d) hybrid mode field distribution for W = 190 nm, H = 540 nm and g = 120 nm.
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f10-sensors-12-02436: Sensitivity (a) and Γc (b) versus W and H for g = 120 nm. In region (1) only the fundamental TE-like mode is guided (single mode area). In region (2) at least one hybrid mode is supported, with χ typically ranging between 0.1 and 0.8. Region (3) depends on the assumed step resolution of parameters, so a single mode or multi mode excitation could occur; (c) fundamental slot mode field distribution for W =190 nm, H = 540 nm and g = 120 nm (d) hybrid mode field distribution for W = 190 nm, H = 540 nm and g = 120 nm.

Mentions: In the design of a single mode slot waveguide with high aspect ratio, the choice of the gap width becomes critical. In fact, the smaller the gap, the higher the effective index of the waveguide modes, so a single mode behavior becomes extremely difficult to be achieved. On the other hand, sensor performances are significantly deteriorated for large values of g, making not convenient the use of high aspect ratio slot waveguides. We have found g = 120 nm to be a very good trade-off between single mode behavior, technology limitations and sensing performances. In Figure 10(a,b), a contour map of the sensitivity and Γcversus W and H is shown, for g = 120 nm.


Optimizing SOI slot waveguide fabrication tolerances and strip-slot coupling for very efficient optical sensing.

Passaro VM, La Notte M - Sensors (Basel) (2012)

Sensitivity (a) and Γc (b) versus W and H for g = 120 nm. In region (1) only the fundamental TE-like mode is guided (single mode area). In region (2) at least one hybrid mode is supported, with χ typically ranging between 0.1 and 0.8. Region (3) depends on the assumed step resolution of parameters, so a single mode or multi mode excitation could occur; (c) fundamental slot mode field distribution for W =190 nm, H = 540 nm and g = 120 nm (d) hybrid mode field distribution for W = 190 nm, H = 540 nm and g = 120 nm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376618&req=5

f10-sensors-12-02436: Sensitivity (a) and Γc (b) versus W and H for g = 120 nm. In region (1) only the fundamental TE-like mode is guided (single mode area). In region (2) at least one hybrid mode is supported, with χ typically ranging between 0.1 and 0.8. Region (3) depends on the assumed step resolution of parameters, so a single mode or multi mode excitation could occur; (c) fundamental slot mode field distribution for W =190 nm, H = 540 nm and g = 120 nm (d) hybrid mode field distribution for W = 190 nm, H = 540 nm and g = 120 nm.
Mentions: In the design of a single mode slot waveguide with high aspect ratio, the choice of the gap width becomes critical. In fact, the smaller the gap, the higher the effective index of the waveguide modes, so a single mode behavior becomes extremely difficult to be achieved. On the other hand, sensor performances are significantly deteriorated for large values of g, making not convenient the use of high aspect ratio slot waveguides. We have found g = 120 nm to be a very good trade-off between single mode behavior, technology limitations and sensing performances. In Figure 10(a,b), a contour map of the sensitivity and Γcversus W and H is shown, for g = 120 nm.

Bottom Line: In particular, we have focused on Silicon On Insulator (SOI) technology, representing the most popular technology for this kind of devices, simultaneously achieving high integration capabilities, small dimensions and low cost.An accurate analysis of single mode behavior for high aspect ratio slot waveguide has been also performed, in order to provide geometric limits for waveguide design purposes.Finally, the problem of coupling into a slot waveguide is addressed and a very compact and efficient slot coupler is proposed, whose geometry has been optimized to give a strip-slot-strip coupling efficiency close to 100%.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Elettrotecnica ed Elettronica, Politecnico di Bari, Bari, Italy. passaro@deemail.poliba.it

ABSTRACT
Slot waveguides are becoming more and more attractive optical components, especially for chemical and bio-chemical sensing. In this paper an accurate analysis of slot waveguide fabrication tolerances is carried out, in order to find optimum design criteria for either homogeneous or absorption sensing mechanisms, in cases of low and high aspect ratio slot waveguides. In particular, we have focused on Silicon On Insulator (SOI) technology, representing the most popular technology for this kind of devices, simultaneously achieving high integration capabilities, small dimensions and low cost. An accurate analysis of single mode behavior for high aspect ratio slot waveguide has been also performed, in order to provide geometric limits for waveguide design purposes. Finally, the problem of coupling into a slot waveguide is addressed and a very compact and efficient slot coupler is proposed, whose geometry has been optimized to give a strip-slot-strip coupling efficiency close to 100%.

No MeSH data available.


Related in: MedlinePlus