Specifications and Models of Skeleton-Type Optical Cable Connectors

Skeleton-type optical cable connectors, such as MMC and modular SC/LC variants, are designed for precise fiber alignment, low insertion loss, and high-density applications.

Overview

Skeleton-type optical connectors are mechanical devices that align and join optical fibers while allowing easy connection and disconnection. They are widely used in telecom, data centers, FTTH deployments, and industrial networks. These connectors are characterized by a modular or “skeleton” structure that supports precise ferrule alignment, often using ceramic or zirconia ferrules, and ensures minimal optical loss and high repeatability.

Common Models and Types

1. SC (Subscriber Connector)
   • Shape & Coupling: Rectangular body with push-pull latching.
   • Ferrule: 2.5 mm ceramic ferrule.
   • Polishing Options: UPC (flat, return loss ≥50 dB) and APC (8° angled, return loss ≥60 dB).
   • Configurations: Simplex and duplex.
   • Applications: FTTH, CATV, data centers, and telecom backbone networks.
   • Performance: Insertion loss <0.1 dB (SC-UPC), return loss ≥65 dB (SC-APC) .
2. LC (Lucent Connector)
   • Shape & Coupling: Miniaturized 1.25 mm ferrule with latch mechanism.
   • Applications: High-density data centers, duplex or simplex fiber links.
   • Performance: Low insertion loss, high port density .
3. ST (Straight Tip)
   • Coupling: Bayonet-style twist-lock.
   • Applications: Legacy systems, industrial, and military networks.
   • Environmental Resistance: Can be hermetically sealed for wet or particulate-prone environments .
4. FC (Ferrule Connector)
   • Coupling: Threaded for high-vibration environments.
   • Ferrule: Precision ceramic or zirconia.
   • Applications: Factories, railway, aviation systems.
   • Environmental Tolerance: -55°C to 85°C, watertight and hermetically sealed .
5. MMC (Multi-fiber Modular Connector)
   • Ferrule Technology: TMT ferrule compatible with MT/MT-16 ferrules.
   • Size: ~30% thinner and 50% shorter than MT ferrules.
   • Fiber Count: Supports single-mode and multi-mode fibers, up to 12 fibers for SM APC.
   • Standards Compliance: IEC 61755-1 Grade B, IEC 61755-3-31 for end-face geometry.
   • Performance: High precision alignment, low optical attenuation, and compatibility with existing multi-fiber systems .

Key Specifications

• Insertion Loss: Typically ≤0.3 dB; ideal <0.1 dB for high-performance connectors.
• Return Loss: ≥50 dB for UPC, ≥60 dB for APC connectors.
• Durability: ≥1,000 mating cycles without performance degradation.
• Materials: Ceramic or zirconia ferrules, precision polymer or stainless steel housings.
• Environmental Resistance: Many skeleton-type connectors are watertight, hermetically sealed, and operate across wide temperature ranges (-55°C to 85°C) .

Applications

Skeleton-type connectors are ideal for:

• High-density data centers: LC and MMC connectors for compact patch panels.
• Telecom networks: SC/APC connectors for PON and CATV systems.
• Industrial and harsh environments: FC and ST connectors with hermetic sealing.
• FTTH deployments: SC/APC connectors for low back-reflection and easy field termination.

Summary

Skeleton-type optical connectors combine modular design, precise ferrule alignment, and environmental robustness. Models like SC, LC, ST, FC, and MMC provide options for single-mode or multi-mode fibers, high-density applications, and harsh environmental conditions, ensuring low insertion loss, high return loss, and long-term reliability in modern optical networks.