Fiber optic microstructure turbulence sensors (FOMTS) with fiber Bragg gratings can measure the rate of tangential velocity change caused by ocean turbulence. The theoretical principles of the FOMTS and demodulation were verified by a prototype. The demodulation system resolution reached 0.001  pm  /  Hz, the sensitivity was 4.37  ×  10^−  16  m² s²  /  kg, and its natural frequency in air was 595 Hz, similar to the theoretical values. Its resonance frequency in water (534 Hz), exceeded the highest frequency of ocean turbulence (200 Hz). Furthermore, comparative experiments between the FOMTS and a commercially available sensor were performed. Good signal correspondence was observed, proving the effectiveness of the FOMTS and verifying the design principle.