Single-mode optical interface module

Single-mode optical modules typically use LC connectors and operate over a 9 µm core fiber at 1310 nm or 1550 nm wavelengths for long-distance transmission.Fiber and Core CharacteristicsSingle-mode optical modules are designed for long-distance, high-speed communication. They use a narrow fiber core of about 9 µm with a 125 µm cladding, allowing light to travel in a single mode with minimal dispersion and attenuation . This enables transmission distances ranging from 2 km up to 120 km, depending on the module type and wavelength . Common wavelength standards include 1310 nm and 1550 nm, with some modules supporting CWDM or DWDM wavelengths for extended reach .Connector TypesThe physical interface of single-mode modules is most commonly the LC connector, which is compact and supports high-density deployments . Legacy networks may use SC connectors, while MPO/MTP connectors are reserved for high-density backbone applications . The connector type determines how the fiber physically couples with the transceiver and affects patch cable selection, insertion loss, and network scalability.Module Form FactorsSingle-mode modules are available in various SFP form factors, including SFP, SFP+, and QSFP, which are hot-pluggable and compatible with switches, routers, and other network devices . Each form factor supports different data rates, such as 1G, 10G, 25G, 40G, and 100G, and must match the device port for proper operation .Transmission TypesSingle-mode modules can be dual-fiber (separate fibers for TX and RX) or single-fiber bidirectional (BIDI), which uses two wavelengths on a single fiber for transmit and receive . Dual-fiber modules are widely supported and standard in most networks, while BIDI modules are useful for reducing fiber usage in constrained environments.SummaryFiber type: Single-mode (9 µm core, 125 µm cladding)Wavelengths: 1310 nm, 1550 nm, CWDM/DWDM optionsConnector type: LC (standard), SC (legacy), MPO/MTP (high-density)Form factors: SFP, SFP+, QSFPTransmission: Dual-fiber or single-fiber BIDIDistance: 2 km to 120 km depending on module and wavelength Using the correct single-mode module with compatible fiber and connector ensures minimal signal loss, reliable long-distance communication, and proper integration with network devices .