CommScope Andrew 7578409-00 Optical Coupler 4-Way 6HP 1310+1550

The CommScope Andrew 7578409-00 is a passive 4-way optical coupler module developed for the ION-M radio-over-fiber (RoF) distributed antenna system (DAS). It performs bidirectional optical signal splitting and combining at the wavelengths of 1310 nm (downlink) and 1550 nm (uplink), fully compatible with the Wavelength Division Multiplexing (WDM) architecture used in the ION-M platform. The module divides one optical input signal into four equal output ports or, in the reverse direction, combines four optical inputs into a single output, supporting various fiber distribution topologies including star, tree, and cascaded configurations between the Master Unit (MU) and multiple Remote Units (RUs).This coupler is constructed as a compact 6HP (horizontal pitch) plug-in module that installs directly into ION-M subracks or chassis, allowing integration alongside OTRx optical transceiver modules (such as the 7566564-00 OTRx 8-9/18/21 MU-G) and band-specific RF combiner cards. It is optimized for single-mode fiber (E9/125 µm) operation and maintains low insertion loss with high port-to-port uniformity. The design ensures high directivity, low polarization-dependent loss (PDL), and high optical return loss, preserving the overall optical link budget of the ION-M system (typically 0 to 10–12 dBo inclusive of connectors and fiber attenuation).
The 7578409-00 features standard E2000/APC 8° angled connectors on the front panel, consistent with ION-M optical interface requirements. This connector type provides minimum 45 dB return loss and prevents damage from mismatched straight and angled interfaces. The fully passive architecture eliminates the need for external power, active electronics, or additional cooling on the optical path, contributing to high reliability and low heat dissipation in densely populated master unit racks.
Operationally, the coupler enables one OTRx module to serve up to four remote units via individual optical fibers, reducing the quantity of active optical transceivers required at the head-end while optimizing rack space and system power consumption. It integrates seamlessly with the ION-M system controller for centralized monitoring and alarm handling through the subrack backplane. The module supports composite power levels and signal characteristics typical for multi-band DAS applications covering 2G, 3G, 4G LTE, and related services across low- and mid-band frequencies.
This optical coupler is commonly applied in neutral-host and multi-operator DAS deployments for in-building and outdoor wireless coverage in venues such as office buildings, airports, stadiums, shopping malls, campuses, tunnels, and high-rise structures. It facilitates efficient expansion of coverage zones by distributing optical signals from a centralized head-end to multiple remote antenna locations without introducing additional noise or active components in the optical distribution layer.
Installation must comply with CommScope ION-M guidelines. Key requirements include maintaining a minimum fiber bend radius of 4 cm, thorough cleaning and inspection of optical connectors using fiber end-face microscopes, and verification of insertion loss and uniformity at each port with an optical power meter or OTDR during commissioning. Proper port assignment and balanced optical power distribution to connected remote units are essential for optimal system performance and automatic levelling functionality.
Due to its passive design, maintenance is limited primarily to periodic visual inspection and cleaning of optical connectors. The 7578409-00 is backward-compatible with legacy ION-M systems and supports incremental network expansions or technology upgrades by adding remote units without replacing the existing head-end infrastructure.