New opto-micromechanical sensor is proposed as an optical coupler sensor with movable optical waveguide. Power of optical coupler is exponentially sensitive to separation of two optical waveguides of it. Mechanical force is transformed to the separation of two optical waveguides of optical coupler and photodetector measures power of optical coupler. Cantilever structure makes optical waveguide movable. The optical coupler sensor is simulated for optimal design and fabricated. Phosphosilicate glass is used as core layer of fixed optical waveguide on silicon dioxide cladding layer. Silicon dioxide is used as cantilever and core layer of movable waveguide and amorphous silicon is used as sacrificial layer. The length, width and thickness of cantilever beam is 50㎛, 6㎛ and 0.9㎛ respectively, and the width of optical waveguide is 6μm. Single mode ridge waveguide is fabricated. Some performance of prototype device is measured. The potential of this sensor is estimated.