What is an MPO-LC Fanout Cable?

An MPO-LC fanout cable (also called a branch cable or breakout cable) has an MPO multi-fiber connector at one end that branches out into multiple individual LC (or SC, FC) single-fiber connectors at the other end. This allows a high-fiber-count MPO trunk cable to be connected to individual single-fiber transceiver ports on switches, servers, and storage arrays. For example, a single 12-fiber MPO-LC fanout cable can connect one 12-fiber MPO trunk port to twelve individual LC duplex ports (using 6 LC duplex connectors, or 12 LC simplex connectors for parallel optics). OMC's MPO-LC fanout cables are the essential transition element in any data center using MPO-based structured cabling, enabling the migration from legacy duplex LC infrastructure to high-density MPO backbone architectures without replacing existing equipment.

Configuration Options and Fiber Mapping

OMC MPO-LC fanout cables are available in multiple configurations to match different network architectures. The most common is 12-fiber MPO to 12 LC/UPC simplex or 6 LC/UPC duplex connectors, serving 40G to 10G breakouts per IEEE 802.3ba. For 100G to 25G applications, 12-fiber MPO to 24 LC simplex fanouts allow 4x25G channel breakout. For 400G SR8 interfaces, 16 or 32-fiber MPO fanouts to LC duplex connectors provide the required port density. The fanout module (also called a harness or breakpoint) uses individual 900 um tight-buffered or 2.0 mm jacketed subunits for each fiber, with premium LC connectors featuring ceramic ferrules, spring-loaded strain relief boots, and color-coded housings (beige for multimode, blue for SM UPC, green for SM APC). Each subunit is properly managed for minimum bend radius to prevent signal degradation.

Mechanical Design and Density

The fanout section of the cable requires careful mechanical engineering to protect individual fibers while maintaining manageability. OMC's fanout cables use a seamless molded fanout body (also called a furcation plug or breakout housing) that transitions tight-buffered subunits from the MPO connector housing to individual 2.0 mm or 1.6 mm or 1.2 mm subunits. The fanout body provides strain relief at the MPO connector body, organizes the subunits into a neat harness, and protects the transition point from mechanical damage. The overall cable diameter at the fanout section is typically 6-12 mm depending on fiber count and subunit diameter, with a minimum bend radius of 20x cable diameter during installation and 10x in operation. Color-coded subunits following TIA-598-C color coding (blue for SM, orange for OM1, aqua for OM3, etc.) enable quick identification of individual fibers in the harness.

Application in Data Center Structured Cabling

In a typical leaf-spine data center topology, MPO trunk cables run between End-of-Row (EoR) or Middle-of-Row (MoR) patch panels and Top-of-Rack (ToR) switches as the permanent backbone links. MPO-LC fanout cables then connect the LC ports on the ToR switches to the individual server NICs via short patch cords. This architecture satisfies TIA-942 data center cabling standards and supports 40G/100G/400G switch migration paths without recabling the backbone infrastructure. OMC's MPO-LC fanout cables are compatible with all major switch platforms including Cisco Nexus, Arista 7050/7060, Juniper QFX, Mellanox Spectrum, and Dell S series. They are also used in fiber channel SAN environments (16G/32G FC) where MPO trunk cables serve as the backbone and LC fanouts connect to HBAs.

Testing and Quality Assurance

Every OMC MPO-LC fanout cable undergoes comprehensive end-to-end testing from the MPO connector to each individual LC connector. Each of the N fibers is tested for insertion loss (LC side typically less than 0.15 dB, MPO side less than 0.35 dB), return loss (LC UPC greater than 45 dB, LC APC greater than 55 dB, MPO greater than 20 dB for MM, greater than 30 dB for SM), and continuity. End-face geometry of both MPO and LC connectors is verified per IEC 61300-3-35 using interferometric inspection. Test reports with per-fiber data in table and graphical OTDR trace format are serialized and provided with each shipment. OMC also offers custom fanout configurations including MPO to mixed connector types, armored fanout cables for industrial environments, and outdoor-rated fanout cables for outside-plant fiber distribution cabinets. Volume pricing and project kitting services are available for large data center deployments.