Low Wavelength Dependency Design for MMI (Multi-Mode Interference) Mode Converter

Abstract

Mode-division multiplexing (MDM) is widely researched, and we are researching mode converter by using multi-mode interference (MMI) waveguide. Wavelength division multiplexing (WDM) must be used in addition to the MDM, however, wavelength dependency exits for MMI in general as it works based on the interference of light. In this paper, we analyze the wavelength dependency of the MMI 0^th to 1^st mode-converter theoretically. As a result, we clarify the design scheme to suppress the wavelength dependency. Moreover, we show the sufficient performance of less than 1.0dB in entire C-band for highly confined waveguide (Si/SiO₂ waveguide) as a design example.