Investigation of Inter-Modal Four Wave Mixing in p-i-n Diode Assisted SOI Waveguides

Usage of multi mode SOI Waveguides including a p-i-n diode is proposed for inter-modal FWM. Devices have been designed, fabricated and characterized. An efficiency improvement of 4.2 dB is demonstrated by adding the diode and reverse bias. Crosstalk is identified as main challenge for integration.

I. Introduction

This paper considers the use of multi mode Silicon-on-Insulator (SOI) waveguides (WGs) for wavelength conversion. Single mode SOI WGs are under investigation for optical phase conjugation [1] , wavelength conversion [2] and even signal regeneration [3] . Intra-modal Four Wave Mixing (FWM) in multi mode SOI WGs is also known for some years [4] . However only recently, multi mode SOI WGs have been studied for inter-modal FWM [5] , [6] . The additional degrees of freedom can be used to achieve larger wavelength translations or broadband operation by proper dispersion engineering. For the current device, we included a lateral p-i-n diode to reduce losses due to Two Photon Absorption (TPA) and subsequent Free Carrier Absorption (FCA). This is the first time such a diode has been used for inter-modal FWM in SOI WGs. This feature improved performance of single mode FWM in SOI WGs significantly [7] and we expect improvements for inter-modal FWM as well.