Optical sensor chip, optical sensor system, and measurement method

An optical sensor chip capable of taking an arbitral connection form via a connector, comprising:

• a first interface to receive a first optical signal from outside via an optical fiber;
• a changer to change the first optical signal depending on a state of a specimen;
• a second interface to output the first optical signal to the outside via an optical fiber;
• a third interface to receive a second optical signal from the outside via an optical fiber;
• a multiplexer to multiplex a first optical signal changed by the changer depending on the state of the specimen and the second optical signal received by the third interface;
• and
• a fourth interface to output an optical signal multiplexed by the multiplexer to the outside via an optical fiber.