Optical fiber fusion splicing is a welded joint formed between two optical fibers. Fusion splicing is a permanent, low-loss, high-strength joint compared with other temporary joint such as a mechanical splice. Optical fiber fusion splices play a crucial role in the optical network.
The Ideal Fusion Splicing Process
The goal of fiber fusion splicing is to create a joint with minimum insertion loss yet with mechanical strength and long-term reliability that matches the fiber itself.
The ideal fusion splicing of process should be fast, inexpensive and should not require expensive equipment. But in reality the process needs fusion splicing trade-offs among different applications and requirements. For example, for undersea telecommunications, long-term reliability is the most important goal for fusion splicing.
Advantages of the Optical Fiber Fusion Splicing
There are other approaches for interconnecting fibers such as fiber optic connectors and mechanical splicing. Compared to these two, fusion splicing has many advantages as explained below.
1. Fusion splicing is very compact
2. Fusion splicing has the lowest insertion loss
3. Fusion splicing has the lowest back reflection (optical return loss ORL)
4. Fusion splicing is the mechanical strength
5. Fusion splicing is permanently
6. Fusion splicing can withstand extreme high temperature changes
7. Fusion splicing prevents dust and other contaminants from entering the optical path
Types of fusion Splicing
Fusion splicing environment and applications can be roughly divided into three types: 1 Field and Factory 2nd splicing splicing splicing 3rd Laboratory.
An important example of field splicing is the assembly of fiber cables submarine fiber deployment aboard ships. The example of factory splicing could be the assembly of fiber optic passive devices such as a WDM. An example of laboratory splicing is done by researchers newest fusion splicing the fibers developed to test their compatibility with existing industry standard fibers.
Fiber fusion splicing involves concepts from many subjects including optical waveguide theory, heat transfer, material science, mechanical engineering, fluid mechanics and more.
Introduction to the Fusion Splicing Process
The major steps involved in optical fiber fusion splicing can be summarized as the following.
1. Optical fiber stripping
The fiber cable jacket is removed and then the fiber polymer coating is stripped with fiber optic strippers.
2. Fiber cleaving
The fiber is cleaved with specialized tool called fiber Cleaver. Two types of fiber exist Cleaver: Cleaver high precision single mode fiber for Cleaver and field applications for multiple applications. A mirror like almost perfect front end is achieved by cleaving this process.
3. The alignment of the fiber
The fibers are aligned laterally to each other by step in a motor Fusion Splicers. This may involve the rotating polarization maintaining fibers in fiber splicing.
4. Fiber welding
The fibers are then heated with electric arc or other methods to the fiber glass’s softening point and then both fibers are pressed together to form a solid joint.
5. Insertion loss estimation
The insertion loss is estimated based on the quality and dimensions merger.
6. Pull tension strength testing
The fusion pull proof is tested when opening the cover Fusion Splicers.
7. Fusion splice with splice protection sleeve
The fusion splice joint is then protected with a heat shrink tube with a steel strength member inside to form a solid and reliable fiber joint.