Novel stepped-width design concept for compact multimode-interference couplers with low cross-coupling ratio

作者：Feng, David J Y^*; Chang, Pai Ying; Lay, T S; Chang, T Y

来源：IEEE Photonics Technology Letters, 2007, 19(2-4): 224-226.

DOI：10.1109/LPT.2006.890762

• multimode-interference (MMI) coupler
• optical waveguide components
• photonic integrated circuit
• planar waveguide

We show through detailed simulations that the length of conventionally designed multimode-interference couplers for low (< 50%) cross-coupling ratios can be shortened significantly by replacing a segment that is 3/2-times the coupling length by a minimum-width design. For the 15% cross-coupling device, this stepped-width design results in 32% length reduction. With additional incorporation of adiabatic tapering, the length reduction can increase to over 44%. Shortening of the device makes it possible to fabricate ring resonators with larger free spectral range, significantly. increases the 1-dB bandwidth for the total transmittance, and also helps to reduce the radiative loss.

• 出版日期2007-2
• 单位中山大学