Chi(3) mid-infrared nonlinear optics in silicon-based waveguide circuits
Main Researcher: Bart Kuyken
The short wave infrared (2 um–3 um) has caught a lot of attention in (integrated silicon) optics lately. The reason has to be sought in a spectroscopic context primarily due the fact that many molecules have specific absorption lines in this region where the (crystalline) silicon on insulator waveguides are still transparent (from 1.1 um – 4 um). A tunable silicon light source in this wavelength range would be a very important component of a fully integrated silicon photonic integrated circuit platform for these spectroscopic lab-on-chip applications. Development of such a source has been hampered by the indirect bandgap of silicon, which makes light emission very inefficient. However, the high optical confinement in a silicon photonic wire surrounded by low refractive index materials such as SiO2 and air can lead to strong nonlinear optical effects.
In this project the goal is to use the strong nonlinear interactions in silicon waveguides to generate light in the Mid-Ir by mixing (near) infrared light sources. As shown in the figure below light at 3.65 um is generated by mixing a pump at 2.15 um with a telecom signal. Additionally it is also possible to up convert light from the mid infrared to the telecom as shown in the figure. Such a spectral translator could pave the way for fast, cheap and low noise detection of mid-ir light by first upconverting mid-ir light to the telecom band and detecting the upconverted light with a telecom detector.
Light is converted to a wavelength at 3.65 um by mixing a telecom signal with a 2.19 um pump
Upconverting light from 2.4 um to the telecom band
Other people involved: