Towards a wavelength tunable squeezed light source

Sammanfattning

In this thesis, we examine waveguide phase matching conditions necessary for the generation and detection of squeezed states of light. In particular, the temperature dependence of the nonlinear interactions that generate squeezed light is investigated. The theoretical expressions for the conversion efficiencies of the waveguides and the possible squeezing levels are derived. Both of these expressions are dependent on the difference in phase between the interacting modes of light. The phase difference can be assumed to vary linearly with both temperature and wavelength, hence to achieve and maintain optimal squeezing conditions the temperature of the waveguides needs to be controlled for different wavelengths. To do this, a PTC10 temperature controller from Stanford Research Systems was implemented into the lab setup. The optimal operating temperatures of the waveguides were obtained by characterizing the waveguides and fitting the theoretical expressions to the obtained data points. This was done for the integer wavelengths between 1548-1552 \SI{}{\nano \meter}. The highest measured squeezing level was \SI{0.83}{dB} at \SI{1550}{\nano \meter}. The optimal temperatures were then mapped to their respective wavelength and programmed into the temperature controller. The results revealed an approximately linear relationship between the fundamental wavelength and the optimal operating temperature. Furthermore, the measured behavior agrees well with the theoretical model, demonstrating reliable wavelength dependent tuning of squeezed light generation in a single-pass waveguide platform.