The main disadvantage of single mode optical fiber is that it is more expensive and difficult to work with compared to multimode fiber. Single mode fiber requires more precise alignment and more expensive light sources and connectors, making it a less practical choice for shorter distances or in applications where cost is a concern. Additionally, single mode fiber is less forgiving of misalignment or bending, making it more difficult to install and maintain.

Single-mode fiber is connected to a single-mode optical module, because the transmission distance is relatively long, so the structure of single-mode fiber is different from that of multi-mode fiber. The core diameter of single-mode fiber patch cord is relatively small, 8μm to 10μm, and is along a straight path for light propagation, not bouncing from the edge, thus completely avoiding the dispersion and waste of light energy, so the single-mode fiber patch cord can achieve lower attenuation, so that the signal can spread faster and farther.

Single-mode fiber optic patch cords are available in two types: OS1 single-mode fiber and OS2 single-mode fiber. OS1 single-mode patch cords are suitable for optical transmission over a maximum distance of 10km, with a maximum attenuation value of 1.0db/km in the 1310nm and 1550nm bands. OS2 single-mode patch cords are suitable for transmission over a maximum distance of up to 200km, with a maximum attenuation value of 0.4db/km in the 1310nm and 1550nm bands. OS1 fiber optic patch cords and OS2 fiber optic patch cords are used in Gigabit and 10 Gigabit Ethernet networks, and OS2 fiber optic patch cords can be used in 40G and 100G Ethernet networks.

Advantages of single mode fiber.

Transmission Distance: Single-mode fiber optic patch cords can support data transmission over longer distances because of lower attenuation. For example, the maximum transmission distance of multi-mode fiber optic patch cord is several hundred meters, while single-mode fiber optic patch cord can reach 200km.

Bandwidth capacity: Single-mode fiber optic patch cords can provide higher bandwidth than multi-mode fiber optic patch cords.

Inter-mode dispersion: Single-mode fiber transmits only one mode of light, so there is no inter-mode dispersion.

Transmission Rate: Due to the absence of intermodal dispersion, mode noise and some other effects, single mode fiber patch cords can transmit signals at a higher rate.

Disadvantages of single-mode fiber optic patch cords:

Difficulty of coupling: Because the core diameter of single-mode fiber is small, it is more difficult to couple light into single-mode fiber than into multi-mode fiber.

Higher cost: because the optical termination machine is very expensive, so the cost of using single-mode fiber patch cords will be higher than the cost of multi-mode fiber patch cords.

More stringent technology: It is more difficult to manufacture and handle single-mode fiber than dual-mode fiber.