What types of 100Mbps optical modules are there

100Mbps optical modules are classified primarily by fiber type, wavelength, distance, and duplex configuration, with single-mode and multi-mode being the main categories.Fiber Type ClassificationSingle-mode (SMF) Modules: Designed for long-distance transmission, typically operating at 1310nm or 1550nm wavelengths. They offer low signal attenuation and high bandwidth, making them suitable for distances exceeding 2 kilometers, such as inter-building or metro links .Multi-mode (MMF) Modules: Optimized for short-distance links, usually under 2 kilometers, with a typical wavelength of 850nm. Multi-mode modules are cost-effective and ideal for campus networks, data centers, or intra-building connections .Duplex and Fiber Strand ConfigurationDual-fiber (Duplex) Transceivers: The most common type, using two fiber strands—one for transmitting (Tx) and one for receiving (Rx). They are simple, reliable, and widely used in standard 100M Fast Ethernet deployments .Single-fiber (BiDi) Transceivers: Use a single fiber for both transmission and reception, employing different wavelengths for each direction. BiDi modules are useful when fiber availability is limited or for cost-saving in existing infrastructure .Standard Types and Applications100BASE-SX: Multi-mode, short-range (up to 550 meters on OM4 fiber), typically used in data centers or campus networks .100BASE-LX/LH: Single-mode, long-range (up to 10 kilometers), suitable for enterprise or metro networks .100BASE-EX: Single-mode, extended reach (up to 40 kilometers), used for long-haul connections .Wavelength ConsiderationsMulti-mode modules generally operate at 850nm, while single-mode modules operate at 1310nm or 1550nm. Choosing the correct wavelength ensures compatibility with the fiber type and minimizes signal loss .Practical Selection TipsMatch the module to your device to avoid network failures.Select fiber type based on distance: multi-mode for short links, single-mode for long links.Check duplex configuration: dual-fiber for standard setups, BiDi for limited fiber availability.Verify wavelength and distance specifications to ensure proper signal transmission and avoid module damage . By understanding these classifications, network engineers can select the appropriate 100Mbps optical module for their infrastructure, balancing cost, distance, and performance requirements.