Polymer-cladded athermal high-index-contrast waveguides

__

5.0

0.0

b -5.0

-10.0

-15.0

-20.0

-25.0

0 0.5 1 1.5 2 2.5

TOcore, !c (X104 K1)

Figure 6. Athermal conditions for channel **waveguides** with a large dncore

(materials such as Si or poly-Si. The confinement

dT

factors (Γ’s) are simulated at room temperature, and depend on the waveguide geometry and the intrinsic **index** ratio

ncore/ncl.

The above equation suggests that the **athermal** condition depends on the cladding/core’s material TO coefficients,

the confinement factor, and the product of the two properties. This equation provides the basic

guidelines for choosing the appropriate core/cladding material in designing an **athermal** channel waveguide in

general including SOI **waveguides**, SiN **waveguides**, and even silica **waveguides**.

5. CONCLUSION

We have presented general design criteria for **athermal** HIC channel **waveguides** using polymer cladding materials

with negative thermo-optic coefficients. The temperature dependence on the waveguide effective **index** depends

on 2 variables: materials TO coefficients and mode confinement factor (determined by waveguide geometry and

**index** **contrast**). We studied the feasibility of two polymers (DuPont’s A2 and P2) for achieving an **athermal**

waveguide design.

ACKNOWLEDGMENTS

The authors would like to acknowledge the Canadian National Sciences and Engineering Research Council

Postdoctoral Fellowship (NSERC-PDF) for funding and DuPont Photonics Technologies for technical support.

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Proc. of SPIE Vol. 6897 68970S-7