A core holder for core testing includes a body having a cavity. A sleeve is disposed within the cavity. The sleeve defines a chamber to hold one or more core plugs. One or more fiber-optic sensors are disposed at a perimeter of the chamber. Each fiber-optic sensor senses a parameter related to flow of fluid through the chamber. A core testing system includes one or more light sources to provide light to each fiber-optic sensor and one or more light detectors to detect light from each fiber-optic sensor. A method of core testing may include injecting a fluid into one or more core plugs inside the chamber and measuring one or more parameters related to flow of fluid through the one or more core plugs.