layers of AlGaAs alloy with different compositions ($Al_xGa_{1-x}As,0\le x \le1$). The semi-periodical structure provides simultaneous confinement of the 783nm pump light and the generated photon pairs around 1566 nm. In addition, the waveguide structure is also designed to satisfy the momentum matching condition that is required for the SPDC process to occur. The conversion efficiency is estimated to be 2.1$\times 10^{-8}$ [@Horn:2012] for a probe-reference photon pair to be generated by a 783nm pump photon.\

![Self pumped semiconductor sources for quantum light. (a)the structure of the laser. (b) the energy level diagram of the device elucidating the down conversion process. (c) the light, current, voltage curves of the pump laser. (d)A scanning electron micrograph of the waveguide cross-section.[]{data-label="SAMPLE"}](fig4_abc.pdf "fig:"){width="0.6\columnwidth"}\
![Self pumped semiconductor sources for quantum light. (a)the structure of the laser. (b) the energy level diagram of the device elucidating the down conversion process. (c) the light, current, voltage curves of the pump laser. (d)A scanning electron micrograph of the waveguide cross-section.[]{data-label="SAMPLE"}](fig4_d.pdf "fig:"){width="0.6\columnwidth"}

Measured Performance
--------------------

We experimentally demonstrated the QTC protocol to confirm its performance enhancement over its classical counterpart (the CI protocol). The target detection experiments of the QTC are carried out under different conditions (probe light flux 