Production Technology Progress Of Fiber Bragg Gratings, Combiners, Strippers And Isolators

In order to reduce the production cost of fiber lasers, domestic laser brands have achieved self-made core components to varying degrees. Raycus has mastered laser core components including pump sources, special fibers, fiber couplers, transmission cables, power combiners, and fiber gratings. and key technologies and mass production capabilities of materials. More than 90% of MAX's core optical components such as pump sources, beam combiners, fiber gratings, laser output heads, mode strippers, isolators, acousto-optic modulators, and mode matchers are self-produced. In addition, FEIBO has also achieved some self-made components to varying degrees, conquering the research and development process of most passive optical devices. And BWT has also achieved self-made in the fields of pump source, fiber grating, beam combiner and fiber connector.

At present, low-power fiber gratings can be localized and sold in the market. In terms of the core technology of medium and high power gratings used in fiber lasers, according to Raycus' 2018 annual report, the company has mastered the key technologies of fiber gratings through independent research and development and achieved large-scale production. . In 2019, its large mode field fiber Bragg gratings and special fibers for high-power fiber lasers successfully passed the expert acceptance organized by the Hubei Provincial Department of Science and Technology. Before 2018, MAX was mainly purchased from abroad. Since April 2018, MAX has realized part of the independent production of fiber grating devices. By the second quarter of 2019, the self-made rate of MAX fiber grating had reached 44.6%. MAX's fiber grating technology covers not only single-mode fiber gratings (10 μm core diameter), but also large core diameter multi-mode fiber gratings (20 μm, 25 μm, and even larger core diameters).

The beam combiner is a device formed by synthesizing multiple bundles of optical fibers into one optical fiber by using the fused taper fiber bundle technology. It can combine multiple lower-power lasers into a higher-power laser. The beam combiner is mainly divided into a pump beam combiner and a power beam combiner, among which the pump source beam combiner mainly accounts for 5% of the cost of the entire fiber laser components. The pump combiner is the key device to realize the output of high-power single-module fiber laser; the stable power combiner technology is the basis for the output of multi-mode laser. Overcoming the key technologies of fiber combiners and developing high-efficiency and high-power fiber power combiners to provide strong support for obtaining high-power fiber lasers has become a key problem that needs to be solved urgently in the field of fiber lasers today. At present, the main players in the domestic beam combiner market include laser manufacturers such as Raycus and MAX, and c has basically achieved localization.

The laser output head can realize the long-distance flexible output of the laser in the application site, so as to transmit the output laser to the processing material to complete the laser processing application. The internal structure of the laser output head is complex, and it needs to have multiple functions such as transmission, heat dissipation, anti-reflection, and early warning. The technical content is very high, accounting for 3% of the cost of the entire fiber laser. The main function of the fiber output device is to expand the fiber beam to reduce the power density for use. Due to the large value of the laser output head and the high purchase cost (about 5,000 yuan for the 10,000-watt level, and about 2,000 yuan for the kilowatt level) , The main domestic laser manufacturers Raycus and MAX have mastered the QBH and collimator technology, and have basically realized their own production. At present, some parameters of the domestic manufacturers' QBH devices are comparable to those of foreign manufacturers.

The isolator is a passive optical device that only allows one-way light to pass through. Its working principle is to use the Faraday effect of the magneto-optical crystal, so that the reflected light can be well isolated by the isolator and improve the transmission efficiency of light waves. Isolators allow light to pass in one direction with low loss, while preventing light from passing in the opposite direction with high loss. It is placed on the emission light path to avoid the performance degradation of the laser caused by reflected light.

A few years ago, laser isolators were mainly produced by EOTechnology. At present, my country's laser isolators have been mass-produced to achieve localized substitution. In addition to IPG's own laser isolators, the laser isolator market was once dominated by EOTechnology. With the continuous enhancement of the competitiveness of domestic enterprises, EOTechnology has gradually withdrawn from the competition in the laser isolator market. The isolator players are mainly Castechinc, AFR and Haichuang, each accounting for about 1/3 of the market share, forming a "three-point world" situation.