title: Compact InGaAsP/InP 3 × 3  multimode-interference coupler-based electro-optic switch.
abstract: Optical switches are key components in data links for optical communication networks requiring low crosstalk and insertion loss, high switching speed, and power efficiency. A multimode-interference (MMI)-coupler-based switch with multiple inputs and outputs serving as a switching unit is desired toward forming a large-scale switch matrix. Here we demonstrate a compact 3×3 MMI coupler electro-optic switch based on the carrier injection effect on InGaAsP/InP substrates. This switch device is 2780 μm long by 18 μm wide. The switching states can be controlled by two index-modulation regions through applied bias voltages. Our simulation results show that the device exhibits low crosstalk of <-22  dB, high extinction ratio of ≳23  dB, low electrical switching energy of ∼2.0  pJ/bit, maximum operational frequency of ∼1.0  GHz, and optical bandwidth of ∼20  nm in the C band. We experimentally validated one of the switching states on a fabricated device with maximum current injections of ∼25  mA under combined bias voltages of ∼2.5 and ∼3.0  V. Such monolithic integration schemes make them an ideal candidate for future on-chip photonic integrated circuits.
authors.forename: Sixuan
authors.initials: S
authors.lastname: Mu
authors.forename: Ke
authors.initials: K
authors.lastname: Liu
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.forename: Chenglong
authors.initials: C
authors.lastname: Zhang
authors.forename: Baolu
authors.initials: B
authors.lastname: Guan
authors.forename: Deshu
authors.initials: D
authors.lastname: Zou