Cisco SFP Multimode/Single mode 

1. Multimode SFP (MM-SFP):

   • Fiber Type: Multimode fiber (MMF)
   • Core Diameter: Larger core (typically 50 or 62.5 microns)
   • Transmission Distance: Shorter distances, usually up to a few hundred meters.
   • Light Source: Typically uses a VCSEL (Vertical-Cavity Surface-Emitting Laser) as the light source.
   • Applications: Used for short-distance connections within data centers, LANs, and campus networks.

2. Single-Mode SFP (SM-SFP):

   • Fiber Type: Single-mode fiber (SMF)
   • Core Diameter: Smaller core (9 microns)
   • Transmission Distance: Longer distances, potentially spanning several kilometers or more.
   • Light Source: Uses a laser (such as a Fabry-Perot or Distributed Feedback laser) as the light source.
   • Applications: Ideal for long-distance connections between different buildings, metropolitan area networks (MANs), and wide area networks (WANs).