  In this paper, we investigate the single photon response from the reflection
of the Microwave Kinetic Inductance Detector (MKID) array. Reflection
measurements are carried out using two configurations: one is measured
simultaneously with the transmission, and the other is obtained with a
single-ended MKID array terminated with an open load. Compared with the
transmission, reflection measurements significantly reduce the readout noise of
the single-ended MKID array. This is also reflected in the improvement of the
median energy resolving power by around 20%-30% under pulsed photon
illumination at $\lambda = 405$~nm, mainly due to an increase in the size of
the resonance circle on the IQ plane. This method has the potential to be used
to read out large MKID arrays.
