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This Letter reports on an ultraweak intrinsic Fabry–Perot interferometer (IFPI) array fabricated by a femtosecond (fs) laser for distributed sensing applications. Ultralow reflectors (< - 60dB) were obtained. IFPIs with different physical lengths showed identical temperature sensitivity (-1.5GHz/°C). A distributed temperature sensing test was conducted. No crosstalk between IFPS elements in the array was observed, implying the device's utility as a distributed sensing system. The possibility of using smaller bandwiths for sensor interrogation was experimentally proven. A small-scale temperature distribution test was conducted on a continuously cascaded ultraweak IFPI array, demonstrating its high spatial resolution. The temperature detection limit of this system was measured to be less than 0.667°C.