Challenge to improve precision of MT Ferrule (MT connector)
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Create new value through originality and challenge. This is Hakusan Inc.
From this article, we will convey the contents of the research and development handled by Hakusan Inc. Fiber Optic Components Development Division. The theme of the article series is "Challenge to ultra-precision resin molding - Contribution to large-capacity optical communication infrastructure -". Hakusan Inc.'s main product, multifiber optical connector parts "MT Ferrule". So that the word "Multifiber" can be found, It has the required number of holes (8-Fiber or more) into which optical fibers are inserted. In this article, we will report on our development efforts to create as many fiber holes as possible to meet the demands of the times.
MT (Mechanically Transferrable) ferrule. A key component of a connector called an optical connector that mechanically connects optical fibers.
(Length) 8.0mm x (Width) 6.4mm x (Height) 2.5mm resin (plastic) molded part, the end face of the part the size of a coffee bean has fiber holes for inserting countless optical fibers.
Photo: There are 16 fiber holes in the center.
The diameter of the optical fiber is 0.125mm, the fiber hole is the size of the hole of that size, and the dimensional accuracy is completed with submicron (less than 0.1µm) accuracy.
Hakusan Inc. has continued to develop this product since the early 1990s, and today it holds a large share of the global market. The locations used are domestic and international data centers where a lot of data processing takes place.
the internet you use Social media (SNS), video viewing, and data communication exchanged on the Internet are ultimately connected to the data center wirelessly or by wire. This "MT Ferrule" is a part of the connector that connects the optical fiber cables in the data center.
(Optical fiber connectors found in ordinary homes are connected by Singlefiber core connectors consisting of one optical fiber.)
Actually, this MT Ferrule does not work by itself, and these ferrules are connected by passing guide pins through dedicated clips (MT clips) and guide pin holes (holes next to fiber holes) at both ends.
This MT clip-connected connector is called an MT connector.
Photo: MT connector, two MT Ferrule connected by a clip.
However, MT Ferrule is now used all over the world as a key component of Multifiber connectors called MPO (Multifiber Push-On) connectors, rather than simply connecting by clips.
The structure consists of an outer part called a housing, and an inner housing part called a spring and an inner housing. It is multifiber optical connector with excellent detachability.
Therefore, MT Ferrule is a key component of multifiber optical connector (MT connector/MPO connector). By properly aligning and connecting 0.125mm optical fiber cores, stable optical communication can be achieved. Therefore, MT Ferrule that fixes the optical fiber determines the connection accuracy of the optical fiber, so MT Ferrule itself is required to have extremely high precision quality.
What is injection molding?
MT Ferrule are resin molded parts and their production is done by injection molding. Injection molding is a molding method in which resin (plastic) in the form of pellets is heated, melted into a mold that resembles the shape of the product, and then cooled and solidified to produce a product of any shape. .
Resins used in injection molding include thermoplastic resins that become plastic when heated and thermosetting resins that harden when heated. Injection molding is carried out by the following injection molding machines.
Source: Keyence "I see! Introduction to machining - What is injection molding?"
Hakusan Inc. manufactures MT Ferrule by injection molding using thermoplastic resin.
Demand for high-density, high-precision MT Ferrule
MT Ferrule by injection molding using thermoplastic resin. Since multifiber optical connector itself is standardized according to a common standard, the external size of MT Ferrule is basically the same regardless of manufacturer.
Recently, however, the requirements for optical connectors and MT Ferrule have become more diverse.
The background is that the scale of data centers is increasing in response to the ever-increasing amount of data traffic, and the optical fiber wiring inside data centers is also becoming more complex. As a result, the number of optical fibers used has increased exponentially in order to increase the amount of data communication that can be processed, and the number of optical connectors around communication devices (optical transceivers, network switches, etc.) to which optical fiber connectors are connected. increasing.
In one data center There is a need to reduce the number of connectors and reduce the burden on field workers. In that case, the number of optical fiber holes required for one MT Ferrule tends to increase in order to maximize the number of optical fibers that can be connected with one connector.
On the other hand, in order to reduce connector integration (required space for connectors), some connectors are smaller than traditional MPO connectors.
Hakusan Inc. has started developing high-density and high-precision MT Ferrule in response to the need to reduce the number of connectors.
Challenge to Super Multifiber MT Ferrule for Single-mode
We started developing a 48-Fiber MT Ferrule for Single-mode.
The number of fiber holes in MT Ferrule has increased from 8 and 12-Fiber to 24-Fiber.
Recently, 16-Fiber interfaces have also appeared on the market in line with the latest standards for optical transceivers (400G: QSFP-DD, 800G: QSFP-DD/OSFP).
There are MT Ferrule for single mode and for Multimode according to the two types of optical fibers (Single-mode Single-mode Multimode). There are two types of optical fibers, Single-mode and Multimode, depending on the path (mode) that propagates through them. Multimode can propagate multiple modes and is used for short- and medium-distance optical transmission, while Single-mode is used for long-distance and large-capacity optical transmission.
The major difference between these two types is the difference in the diameter of the core (the central part through which light propagates) within the optical fiber.
Single-mode is a mode in which light passes through the core of an optical fiber (approximately 9 to 10 µm) and consists of one propagation mode. Multimode is a mode in which light passes through an optical fiber core (50 µm or 62.5 µm) and consists of multiple propagation modes.
The core of Single-mode fiber is much smaller than that of Multimode fiber, so the connection accuracy is required to be much higher than that of Multimode. Therefore, high precision is required for connectors and connector parts used for connection.
Hakusan Inc. mass-produces Single-mode MT Ferrule with up to 24-Fiber, and Multimode MT Ferrule with up to 32-Fiber fibers.
However, in order to meet the high-density requirements for MT Ferrule (request for increasing the number of optical fiber holes), we have developed 32-Fiber and 36-Fiber MT Ferrule for Single-mode. The development is nearing completion and will be shifted to mass production soon.
Not only that, the demand for even higher densities has increased, and from 2022 last year, we started developing MT Ferrule for 48-Fiber Single-mode.
The greater the number of fiber holes, the more difficult the injection molding of MT Ferrule becomes, but the required dimensional accuracy does not change depending on the number of fiber holes.
Although we have experience with 48-Fiber MT Ferrule for Multimode, 48-Fiber MT Ferrule for Single-mode require dimensional accuracy that sets us apart from that.
The challenge of Hakusan Inc. 's ultra-Multifiber MT Ferrule has begun to realize a further large-capacity optical communication infrastructure. From now on, in this series, we will deliver the state of the challenge.
Editor's Note
Thank you for reading this far.
Could you explain the background behind Hakusan Inc. 's challenge to super Multifiber MT Ferrule? Such small parts play an active role in the infrastructure that supports our convenient Internet. Whether or not the future IT infrastructure society, such as IoT, autonomous driving, and AI, will be realized depends on each of these components. I feel that it is very worthwhile. We will continue to deliver the challenges of Hakusan Inc. See you in the next article!
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