Fiber optic sensors have always been highly regarded as an extremely important component of the Internet of Things. From a global market perspective, the global fiber optic sensor market size in 2013 was 1.89 billion US dollars. It is expected that the global fiber optic sensor market will grow at an average annual rate of 18% from 2014 to 2018, reaching a market size of 4.33 billion US dollars by 2018. From the perspective of fiber optic sensing technology research, the United States started researching this technology earliest and is the most advanced in the world. Data shows that in 2007, the market size of fiber optic sensors in the United States was $235 million, and it has been growing at a compound annual growth rate of 30 years since then. It is expected to reach $1.6 billion in 2014.
Compared to the United States, China's fiber optic sensing industry is in its infancy. According to statistics, as of the end of 2013, there were over 260 sensor manufacturing enterprises in China with a scale of over 20 million yuan. However, the overall quality of the industry varies greatly, with small enterprises accounting for nearly 70% and mainly producing low-end products; A small number of leading and foreign-funded enterprises occupy the high-end product market.
Although it started late, the demand for China's fiber optic sensing market has shown explosive growth, with bidding for products related to the power sector alone increasing by nearly a hundred times compared to the past. Industry insiders estimate that in 2013, the scale of fiber optic sensors in the Chinese market was about 1 billion yuan, and it was gradually growing.
At present, there are four most widely used fiber optic sensors in the market, namely fiber optic gyroscope, fiber optic hydrophone, fiber optic grating sensor, and fiber optic current sensor.
There are three types of fiber optic gyroscopes: interference type, resonance type, and Brillouin type. Interference type fiber optic gyroscopes are the first generation of commercially mature technology, resonance type fiber optic gyroscopes are the second generation in the laboratory research stage, and Brillouin type fiber optic gyroscopes are the third generation fiber optic gyroscope sensors in the theoretical research stage.
Fiber optic hydrophone is an underwater sound signal sensor based on fiber optic and optoelectronic technology. This sensor uses highly sensitive fiber optic coherent detection to convert sound signals in water into optical signals, which are then transmitted to the signal processing system through fiber optic to be converted into sound signals. According to the principle, this sensor can be divided into interference type, intensity type, grating type, etc.
Fiber Bragg grating sensor products include strain sensors, temperature sensors, and pressure sensors, among which fiber Bragg grating sensors have been a research hotspot in recent years. Most of them belong to the light intensity type and interference type, and each has its own advantages and disadvantages.
Fiber optic current sensors are mainly used in the field of power, which can effectively avoid accidents caused by excessive power.
Fiber optic sensors can currently directly or indirectly measure nearly a hundred physical quantities, as well as chemical and biological quantities, and are widely used in various fields such as national defense, power, petroleum, construction, and medicine.
In national defense, fiber optic sensors can be used for underwater acoustic exploration (fiber optic hydrophones), fiber optic guidance, attitude control, structural damage detection of spacecraft (intelligent skin), and detection of battlefield environments (electromagnetic environment, biochemical environment, etc.).
In the power system, the harsh electromagnetic environment of high voltage and high current limits the application of electronic sensors. However, fiber optic sensors, with their unique ability to resist electromagnetic interference, can be used to measure the current, voltage, and temperature inside the rotor, stator, and high-voltage transformer of large motors in the power system, which helps to improve the curing degree of the outer protective layer of special micro optical cables. However, beyond a certain range, it has little effect on improving the curing degree.
In recent years, the application of special micro fiber optic cables using UV coating as the outer protective layer has developed rapidly in wired guided weapons and underwater engineering. In the near future, they can be widely used in fields such as missiles, heavy torpedoes, deep-sea submersibles, and underwater monitoring networks.

----------Source from China Sensor Network