OM4 is a type of multimode optical fiber, and its distance capabilities for 100Gb Ethernet depend on the specific optics and transceivers used. OM4 fiber is designed to support higher bandwidths and longer distances compared to previous multimode fibers like OM1 and OM2.

For 100Gb Ethernet over OM4 multimode fiber, several types of transceivers are commonly used:

1. SR4 (Short Range 4):

• Using parallel optics, 100GBASE-SR4 transceivers can support a reach of up to 100 meters over OM4 fiber.

2. eSR4 (extended Short Range 4):

• This is an extended reach variant of SR4, providing a longer reach. It can support distances of up to 150 meters over OM4.

3. SWDM4 (Short Wave Division Multiplexing 4):

• SWDM4 technology enables the use of multiple wavelengths on a single fiber strand. With SWDM4, 100Gb Ethernet can reach up to 400 meters over OM4.

It's important to note that the specific reach can vary based on factors such as the quality of the fiber, connectors, splices, and the characteristics of the transceivers. Additionally, the industry may introduce new technologies or improvements over time that can impact the reach of 100Gb over OM4.

Always refer to the datasheets and specifications provided by the equipment manufacturers for accurate and up-to-date information on the reach of specific transceivers over OM4 fiber in your networking environment.