The quantum efficiency and the transient response of the InP semiconductor micro-ring resonant detector are analyzed to get the optimum design parameters. Then the side coupling micro-ring resonant is fabricated using the InP semiconductor material based on the parameters. The micro-ring resonant cavity has the raius of 80 m, waveguide width of 3 m and the coupler gap of 1 m. The test results show that the FSR is 0.75 nm, and the FWHM is 0.5 nm, which are consistent with the theoretical calculation results.Micro-ring resonance is compact wavelength-selective element that finds usage in many applications including adddrop filters, demultiplexers, dispersion compensators, modulators. Their small size and functionality make them a key building block in densely-integrated planar light wave circuits [1,2] . Presently it is easy to fabricate the Si micro-ring resonant, but difficult to fabricate the InP micro-ring resonant because of the complexity of after-processing.In 2006, Gholamreza [3] proposed a micro-ring resonant detector, but he did not realize it. In 2007, Cho et al. [4] implemented the micro-ring resonant detector, however, the vertically coupled micro-ring resonator is fabricated with the polymer rather than semiconductor. In this letter, first, the design of the InP/InGaAsP semiconductor micro-ring resonator detector is made, then the side coupling micro-ring resonant detector is fabricated and tested. The scheme of the micro-ring resonant detector proposed by Gholamreza et al. is shown in Fig.1(a) [3] . For simplicity, we consider a PD consisting of a conventional PIN photodiode and a ring waveguide resonator which is coupled to a straight waveguide. Fig.1(b) illustrates the top view of the micro-ring resonant photo-detector (MRPD) and the optical model used in the analysis of quantum efficiency. When a single unidirectional mode of the resonator is excited and the Fig.1 (a) Scheme of the micro-ring resonant detector (b) Top view and optical model of the detector coupling is lossless, the quantum efficiency of the micro-ring detector could be obtained as [3] 2 2 2 2 2 1 (1 )(1 ) 1 2 c o s r r r r L L L L r t e t e t e te L ,