CMOS-Compatible and Temperature Insensitive C-Band Wavelength (De-)multiplexer

The high thermal sensitivity of the Silicon Photonics (SiP) platform compromises the performance of variant devices and increases the power consumption to stabilize the temperature. To address this issue, we demonstrate a CMOS-compatible and temperature insensitive $1\times 4$ C-band wavelength division (de-)multiplexer on the 220-nm-thick silicon-on-insulator platform. The (de-)multiplexer design is based on cascading Mach-Zehnder interferometers (MZIs). The waveguide widths of the MZI delay lines are matched to decrease the overall thermo-optic coefficient (TOC). For comparison, an MZI-based (de-)multiplexer with uniform delay lines is also fabricated on the same chip. The transmission spectra of the proposed and reference devices are measured when the wavelength is swept from 1500 nm to 1600 nm and the temperature is varied from 293.15 K to 323.15 K. The measured results show that the TOCs of the proposed and reference device are 4.8 pm/K and 85 pm/K, respectively. This power-efficient multiplexer with high integration density is promising for data center applications.