Analogical gravitation on photonic chips

Exploring and understanding the nature of gravity has always been a human endeavour. In particular, two recent achievements in astronomy, the laser interferometer gravitational-wave observatory (LIGO), which has detected gravitational-wave signals, and the event horizon telescope (EHT), which has captured black hole shadows, have further stimulated broad interest in ancient and mysterious gravity. Despite the tremendous advances in experimental astronomy techniques for detecting gravity, the study of some gravitational phenomena still faces challenges, especially the quantum effects related to gravity. On the other hand, analogical gravity systems provide a new experimental platform for studying gravitational effects; they can be used to study in a laboratory environment those gravitational phenomena that still present challenges for current astronomical observation, for example the quantum gravitational effect near black holes. This paper introduces the simulation of various phenomena in curved space-time realized by photonic chips, which portray a good analogical gravitational system.