Based on nonlinear polarization rotation (NPR) in semiconductor optical amplifier (SOA), a single optical buffer loop theoretically and experimentally demonstrates its switch capability to realize all-optical time slot interchange (TSI) on multiple optical packets (MOPs). Firstly, a series of prerequisites is theoretically deduced with a single optical buffer loop performing all-optical TSI on MOPs. And the corresponding equations which experimental parameters should satisfy are derived from these prerequisites for different cases of all-optical TSI. Accounting to the theoretical results, a single optical buffer loop based on NPR in SOA experimentally realizes all-optical TSI on three packets and four packets at data rate of 10 Gb/s. Experimental results are in accordance with those expected theoretically. These results will be very helpful to make all-optical TSI system more compact and more highly efficient, and have less expensive elements such as SOA, and also significant for developing the all-optical TSI technology.