The invention belongs to the technical field of converters, and discloses a passive converter from visible light to infrared light. The converter comprises a photovoltaic detector, a circuit board anda silicon-based photon chip, wherein the photovoltaic detector is used for absorbing the visible light and converting photons of the absorbed visible light into a voltage signal for outputting; the circuit board is used for connecting the photovoltaic detector and the silicon-based photon chip, and transmitting the voltage signal to the silicon-based photon chip; the silicon-based photon chip comprises an electrooptical modulator and coupling gratings, the infrared light enters the electrooptical modulator through inlets of the coupling gratings, the electrooptical modulator comprises electrodes, a micro-ring waveguide and a coupling waveguide, the electrodes are connected with the circuit board, the coupling waveguide is used for transmitting the infrared light into the micro-ring waveguide, and the micro-ring waveguide modulates the infrared light under the driving of the voltage signal, so as to enable the infrared light to carry information of the visible light to realize passiveconversion of the infrared light. The passive conversion is efficiently realized, the structure is simple, and the production cost is low.