This letter demonstrates a compact, very low power consumption, and low crosstalk multimode interference coupler-based polymer thermooptic photonic switch. The fabricated thin-film small-area heater confirmed the simulation results with operating power consumption as low as 8.9 mW. The switching crosstalk obtained was less than - 23 dB.

Very Low Power Operation of Compact MMI Polymer Thermooptic Switch

Photonic switches are becoming key components in advanced optical networks due to their various applications in optical communication. One of the key advantages of photonic switches is the fact that they redirect or convert light without any optical to electronic conversions and vice versa. As one type of optical switch, multimode interference (MMI) switches have received more attention in recent years due to their significant role. The structure and operation principle of various types of MMI switches are introduced, and the recent progresses of MMI switches are also discussed.

https://www.spiedigitallibrary.org/journals/optical-engineering/volume-47/issue-11/112001/Multimode-interference-photonic-switches/10.1117/1.3028349.pdf

Multimode interference photonic switches

This paper analytically and experimentally investigates and compares the characteristics of two kinds of polymer buried-channel waveguide thermo-optic switches such as 1) a multimode interference (MMI) switch using a single MMI coupler and 2) a Mach–Zehnder interferometer (MZI) switch. Especially, the MZI switch experimentally exhibited low-power consumption of 3.5 mW, high-speed with a response time of less than 200 μs, polarization independence as well as in a wideband of about 80 nm. These low-power consumption, relatively high-speed, and polarization-independent switching characteristics are almost coincident with the designed ones. Furthermore, an improved MZI structure is proposed for lower switching power consumption, and it is expected below 0.5 mW with an enhanced thermal localization structure.

Design and Performance of Low-Power, High-Speed, Polarization-Independent and Wideband Polymer Buried-Channel Waveguide Thermo-Optic Switches

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.

Compact InGaAsP/InP 3 × 3 multimode-interference coupler-based electro-optic switch

Advanced photonic networks require high-speed switching in nano-second order switching time, low power consumption and low crosstalk, etc. For these purposes we proposed a semiconductor multi-mode interference photonic switch with partial index-modulation regions (MIPS-P) which can operate by current injection for refractive index change and is expected as a high-speed optical switch. In this letter we have experimentally confirmed small-current and low-crosstalk operation by using InAlGaAs/InAlAs, which is effective for injected carrier confinement. And also high-speed switching operation in a switching time of about 1.5ns has been demonstrated, for the first time, at a repetition rate of 10MHz.

High-speed optical switching of InAlGaAs/InAlAs multi-mode interference photonic switch with partial index-modulation region (MIPS-P)

A semiconductor multi-mode interference photonic switch with partial index-modulation regions (MIPS-P) was fabricated, and we demonstrated high-speed switching operation in a switching time of about 15 ns, for the first time, at a repetition rate of 10 MHz

Introduction Advanced photonic networks in the next generation require high-speed switching with nano-second order switching time as well as low power consumption and low crosstalk, etc. For these purposes a semiconductor multi-mode interference photonic switch with partial index-modulation regions (MIPS-P) was proposed,[1][2] and we experimentally confirmed fundamental switching performances by using InAlGaAs/InAlAs, which is effective for efficient injected carrier confinement.[3][4] Here higher performances of InAlGaAs/InAlAs MIPS-P have been demonstrated under precise control of the fabrication and operation conditions to obtain lower crosstalk and higher-speed switching with even sub-ns switching time.

Shingo Kumai

Papers

High-speed optical switching of InAlGaAs/InAlAs multi-mode interference photonic switch with partial index-modulation region (MIPS-P)

High-speed optical switching of InAlGaAs/InAlAs multi-mode interference photonic switch with partial index-modulation region (MIPS-P)

High-Performance of InAlGaAs/InAlAs/InP Multi-Mode Interference Photonic Switch with Partial Index-Modulation Region (MIPS-P)