A new system of multifunction sensors using dark and bright solitons in a Mach-Zehnder interferometer (MZI) is proposed. In this concept, the coincidence dark and bright soliton pair within the MZI can be arranged by using the phase controller, in which (|D)) and (|B)) states represent the orthogonal dark and bright solitons, respectively. We assume that both solitons are input into the MZI ports simultaneously (coincidently). The randomly input dark and bright soliton states into the MZI ports can perform the change in phase after propagating through a phase shifter/sensing unit, in which the phase change recovery using the phase related measurement device can be provided. By using the orthogonal soliton behaviors, a sensing application using a soliton(photon) pair can be formed. Moreover, the soliton power can be reduced to a single photon power (10-6 W), where finally the single photon sensor can be operated. The self calibration concept between signal and referencing arms of a MZI can also be established, which is discussed in details.