When it comes to the communications industry, it has been revolutionized with the help of optical fibers over the last two decades. In optical components, the continuous innovations made it possible to implement and design a higher bit rate system. The manufacturing processes have continued to become permitting price reductions and more productive.
Since its inception in the two decades, the fiber industry has failed to stabilize manufacturing technologies. In the market, the four distinctly distinctive processes coexist like OVD, MCVD, VAD, and PCVD. In this article, the chief aim is on differentiating MCVD and PCVD.
MCVD vs PCVD
The main difference between MCVD and PCVD is that the method of vapor deposition for high-performance Light guides and optical fibers manufacturing can be referred to as MCVD. On the other hand, a process for thin films deposition on a substrate from gas to solid-state can be referred to as PCVD.
The MCVD generally comprises the glass particle’s deposition on the substrate tube’s inside wall to form the core structure and fiber inner cladding. Due to the thermophoretic force, these adhere to the tubes inside and are then sintered into a glass of amorphous. Together fusing particles is done in MCVD into one solid mass by heat and pressure combination without melting the materials.
PCVD is the process of chemical rapid deposition generally used for deposition on a substrate of thin films from gas to solid-state. Chemical reactions are comprised in the process that occurs after plasma creates the reaction gases. Through radiofrequency or direct current discharge, the plasma is created between two electrodes. Within a few milliseconds, there is no molecules undergo several physical and chemical reactions
Comparison Table Between MCVD and PCVD
What is MCVD?
For the production of graded-index fibers as very low loss, the MCVD process was widely adopted elsewhere. This process is developed mainly for deposition rate increasing the deposition rates in comparison to the conventional CVD process.
As in outside vapor phase deposition, the MCVD also produces perform in mainly two steps. Firstly, through a rotating glass tube, the reactant gases flow made from fused silica. Meanwhile, its narrow zone makes the burner heat by traveling mainly in the back and forth direction within the tube.
Dopants and silica from soot that is deposited on the target tube’s inner surface. A burner heats a narrow zone of this sintering and deposit occurs within the zone. Thus, there is a sintered glass layer. Secondly, the heating of the soot preform is done to collapse the tube into a preform of solid glass.
The subsequently drawn fiber from this preform rod they have a core comprised of the vapor-deposited material as well as the cladding comprising the original silica tube. Then the tube is collapse to offer a solid preform which might be drawn into fiber.
What is PCVD?
Plasma can be described as a gas in which an atom and molecule’s significant percentage are ionized. In plasma, fractional ionization is used for PCVD and related materials processing varies in typical capacitive discharges. Processing plasma is operated at a few millitorrs to a few torr’s pressure.
Swann, Essex, and Harlow are three of the people who worked at STL and discovered that RF discharge promoted the silicon compound’s deposition onto the wall of the quartz glass vessel. In 1964, several interior STL publications were followed by US, British, and French patent applications.
PCVD is often used in the manufacturing of semiconductors to deposit films conformally and onto wafers comprising metal or temperature-sensitive structures. It also yields some deposition rates at the fastest while maintaining film quality.
High-density PCVD of silicon dioxide from oxygen and silane has been widely used for nearly hydrogen-free film creation with good conformality over complex surfaces. From intense ion the latter resulting consequent deposited molecule’s sputtering from vertical onto horizontal surfaces.
Main Differences Between MCVD and PCVD
- The gaseous reaction fails to produce water and that’s why OH contamination’s problem is significantly reduced is the advantage of MCVD. On the contrary, no tube distortion and high efficiency are two of the advantages of PCVD.
- The origin of MCVD can be traced at bell laboratories in which it was invented to adopt widely for the production of graded-index fiber as low loss. On the contrary, the invention of PCVD took by scientists at Philips research.
- When it comes to soot formation, it is a matter’s evolution in which a range of molecules undergo several physical and chemical reactions within a few milliseconds. The soot formation took place in MCVD, whereas in PCVD, there is no soot formation.
- In terms of sintering, it is a together fusing particles process into one solid mass through heat and pressure combination without melting the materials. The sintering takes place in MCVD, while in PCVD it fails to take sintering.
- MCVD can be described as a method of vapor deposition for high-performance Ligh guides and optical fibers manufacturing. Meanwhile, PCVD can be described as a process for thin films deposition on a substrate from gas to solid-state.
Conclusion
It can be concluded that MCVD and PCVD are two of the processes included in the production of optical fibers. The abbreviation for modified chemical vapor deposition is MCVD. In contrast, plasma chemical vapor deposition is the abbreviation for PCVD. The rotation is required in MCVD for deposited silica on the inside of the tube.
Meanwhile, in the case of PCVD, rotation is not needed. When it comes to speed, the speed of MCVD is lower than PCVD, while the speed of PCVD is faster. The RI profile control is accurate in MCVD. On the contrary, in PCVD, the RI profile control is better in comparison to MCVD. In terms of tube temperature, around 1800° C is the tube temperature of MCVD, whereas the tube temperature of PCVD is 1000° C.
References
- https://allwise.yonsei.ac.kr/pdpl/subdir/equipments/paper/mcvd_01131071.pdf
- https://ieeexplore.ieee.org/abstract/document/1074872/