On-chip wavelength division multiplexing filters using extremely efficient gate-driven silicon microring resonator array

Abstract

Silicon microring resonators (Si-MRRs) play essential roles in on-chip wavelength division multiplexing (WDM) systems due to their ultra-compact size and low energy consumption. However, the resonant wavelength of Si-MRRs is very sensitive to temperature fluctuations and fabrication process variation. Typically, each Si-MRR in the WDM system requires precise wavelength control by free carrier injection using PIN diodes or thermal heaters that consume high power. This work experimentally demonstrates gate-tuning on-chip WDM filters for the first time with large wavelength coverage for the entire channel spacing using a Si-MRR array driven by high mobility titanium-doped indium oxide (ITiO) gates. The integrated Si-MRRs achieve unprecedented wavelength tunability up to 589 pm/V, or VπL of 0.050 V cm with a high-quality factor of 5200. The on-chip WDM filters, which consist of four cascaded ITiO-driven Si-MRRs, can be continuously tuned across the 1543–1548 nm wavelength range by gate biases with near-zero power consumption.

Breakthrough in Silicon Photonics Technology in Telecommunications, Biosensing, and Gas Sensing

“…These factors can introduce challenges when it comes to maintaining precise control over the resonant wavelength of the Si-µ-RRs. In a notable advancement, a recent experimental study [ 118 ], demonstrated gate-tuning on-chip WDM filters for the first time. The study achieved a substantial wavelength exposure across the entire channel spacing using a Si-µ-RR array (as shown in Figure 5 b) that was controlled by high-mobility titanium-doped indium oxide (ITiO) gates [ 118 ].…”

“…In a notable advancement, a recent experimental study [ 118 ], demonstrated gate-tuning on-chip WDM filters for the first time. The study achieved a substantial wavelength exposure across the entire channel spacing using a Si-µ-RR array (as shown in Figure 5 b) that was controlled by high-mobility titanium-doped indium oxide (ITiO) gates [ 118 ]. The integrated Si-µ-RRs exhibited an unprecedented level of wavelength tunability, reaching up to 589 pm/V or VπL of 0.050 V cm while maintaining a high-quality factor of 5200 [ 118 ].…”

“… ( a ) Schematic diagram of the chip layout [ 108 ]; ( b ) 3D schematic of the on-chip WDM filters. Inset: zoom-in view of µ-RR WG with ITiO/HfO 2 /Si MOS capacitor [ 118 ]. …”

Sub-volt high-speed silicon MOSCAP microring modulator driven by high-mobility conductive oxide

“…Therefore, enhancing the E-O efficiency of the MRM through other mechanisms using more efficient gate material and higher capacitance density becomes crucial. The ITiO-gated MOSCAP Si-MRM in this work improved the E-O efficiency by narrowing the microring waveguide width, which effectively improved the overlapping factor between the accumulated carriers and the optical mode profile 38 . The utilization of high-mobility ITiO reduces the optical waveguide absorption, enabling a balanced Q-factor for sub-volt V pp modulation while still supporting a large photon lifetime-limited bandwidth.…”