High capacity NP-Complete problems solver based on dual-comb asynchronous optical sampling

Photonic schemes to solve the Nondeterministic Polynomial-Complete (NP–C) problems could offer an interesting alternative to such computationally intensive tasks. Previous studies had shown that they can be solved by measuring the propagation delays through an optical oracle that corresponds to the NP-C problem. However, to tackle a problem with a large instance, the previous schemes face significant challenges to achieve a large measurement range, fast speed and high resolution, simultaneously. In this work, we propose an optical solver based on asynchronous optical sampling driven by a simple fiber dual-comb laser. It is experimentally demonstrated that it can realize picosecond resolution and tens of nanosecond range with a fiber oracle network consisting of 15 couplers and sections of fibers that represents a typical Traveling Salesman problem. With a width of the pulse interferogram of less than 1.5 ps, i.e. an optical path resolution of ∼0.3 mm in fiber, the output from an oracle with 58 likely paths is measured accurately, from which the Hamilton path is easily identified in ∼0.7 ms. It is expected that further optimizing the parameters of the laser as well as the oracle would enable the solving larger scale NP-C problems.