The Origins of MPO Fiber Optic Connectors

MPO (Multi-fiber Push-On) connectors trace their roots back to 1986, developed from Nippon Telephone and Telegraph Corp. (NTT)’s MT (mechanical transfer) technology. The first MPO connector was designed by NTT as a compact physical contact (PC) solution, simplifying plug-and-adapter connections through a convenient push/pull mechanism. This innovation replaced traditional coupling nuts, which required manual rotation and significant space, making them unsuitable for the high-density, high-speed network systems emerging in the 1980s and 1990s. MPO connectors offered the necessary high-density capability along with operational ease.

As data centers rapidly expanded, the demand for fiber increased. Previously, each fiber in a multi-fiber cable had to be individually terminated—a labor-intensive and costly process requiring skilled technicians. Since the 1990s, MPO connectors became widely adopted, streamlining installation and reducing the time, effort, and space required, making them the ideal solution for high-density network environments.

US Conec’s MTP MPO Connectors

US Conec set a new standard with its MTP brand of MPO connectors.

In 1996, the International Electrotechnical Commission (IEC) standardized the MPO format, and US Conec launched the MTP (Multi-fiber Termination Push-on) brand, its high-performance MPO connector line. MTP connectors allowed installers to connect 8 to 12 fibers at once, dramatically cutting installation and testing times. Key features of MTP connectors include a removable housing, a floating ferrule to enhance mechanical performance, stainless steel elliptical guide pins for improved alignment and durability, a metal pin clamp to prevent pin loss and protect fibers, and a spring design that optimizes fiber clearance for 12-fiber and multi-fiber applications.

Molex MTP/MPO Data Center Solutions

IMAGE: Molex MTP/MPO Data Center Solutions support the deployment of high-performance networks, reducing both the required cable volume and, as a result, overall system costs and maintenance.

Key Design Aspects

• Gender: MPO connectors are classified as either male (with alignment pins) or female (with alignment holes).
• Color Coding: Single-mode multi-fiber cable jackets are yellow; multi-mode cable jackets are aqua for OM3 and OM4 (some manufacturers use Erika-violet for OM4), and lime for OM5.
• Connector Types: The MPO-12 connector (one row of 12 fibers) is the most commonly used, although higher-density connectors, such as MPO-24 (two rows of 12 fibers), MPO-16 (one row of 16 fibers), and MPO-32 (two rows of 16 fibers) are also available for greater fiber density in modern data centers.
• Keying: MPO connectors have a key on one side to ensure correct fiber positioning and to ensure that the connector can only be inserted in one orientation into an MPO adapter or transceiver port.
• MPO Testing: MPO systems require polarity verification, continuity confirmation, and quality inspection for optimal link performance.
• Standards: IEC 61754-7 and TIA 604-5 standards apply to MPO connectors.

Fun Fact

In 2020, the original physical contact push-pull technology for fiber optic connectors, developed by NTT in 1986, was recognized as an IEEE Milestone, and a commemorative plaque was placed at NTT’s Tokyo headquarters.