Signals and Telecommunication Journal Tahreer S. Mansour Alfalah, Ayah T. Yahiya Al-khalefa 7 2 2018 https://doi.org/10.6025/stj/2018/7/2/43-51 http://www.dline.info/stj/fulltext/v7n2/stjv7n2_1.pdf This paper presents a continuously tunable optical band pass filter based on nested MZI designed by two arms multimode Machzehnder interferometer was proposed. The tunability of the filter is achieved by wavelength tuning of the multimode fiber. Tunability of the filter can be generated by applying Mechanical effect which is strain on the sensing arm of MM-MZI. It has been shown from the simulated results, it is done by Optiwave soft wear obtained that the shifted central wavelength from (1546.01) to (1546.021) nm, full width at half maximum from (279.321) to (273.681) pm, maximum gain is 22.55 dB and phase shift from(0) to (6.0808) rad and in the practical results obtained to the shifted central wavelength from(1545.762)to (1545.764)nm, FWHM from (197.529) to (283081)pm, maximum gain is 21.66 dB, and phase shift from (0) to (6.059) rad. Observed from the results, the relation between the shifted central wavelength and strain is nonlinear.