Dark fiber vs lit fiber

Dark Fiber vs. Lit Fiber: What’s the Difference?

Many of Brightlio’s customers are interested in fiber internet services for their connectivity needs.  However, understanding the difference between dark fiber vs. lit fiber services can be confusing.

One of the questions we are asked most often by customers interested in fiber connectivity is:  What’s the difference between dark fiber and lit fiber? 

This article explains why fiber is a popular medium for network connectivity and the differences between dark and lit fiber services.  To learn more, or for pricing for fiber connectivity services, contact us.

Why Fiber for Internet Connectivity? 

Why use fiber for internet connectivity?  In a word:  Speed. 

If you want to transmit lots of bandwidth as fast as possible and over long distances, fiber is your medium.  Fiber transmits data over glass fiber-optic cables using laser lights.  Due to the properties of light, fiber transmits data as fast as physically possible – At the speed of light. Also, fiber allows data to travel over exceptionally long distances with almost no cross-talk or electromagnetic interference. 

These properties make fiber a fantastic transport medium for customers looking to procure network connectivity services. 

Dark Fiber vs Lit Fiber 

Fiber is purchased as either “dark” or “lit”.  Dark fiber is fiber that is not in use, meaning no light is currently traversing the fiber-optic cables.  Customers buy or lease dark fiber for their exclusive use.  Often, customers are responsible for providing and maintaining the hardware to transmit data across the dark fiber service. 

Dark fiber allows customers to pass almost unlimited amounts of data across the fiber optic cables, with no congestion from other users.  Customers using dark fiber services can leverage traditional Ethernet switches and routers with long-range optics.  Alternatively, customers can leverage Dense Wave Multiplex Divisioning (DWDM) equipment. DWDM splits light into various wavelengths allowing for up to 400 Gbps of capacity across a single fiber strand. 

Dark fiber allows customers to build dedicated networks between multiple facilities and colocation facilities, often in a ring configuration for greater redundancy.  Also, dark fiber is secure, as no other users are on the network. 

Dark fiber pricing is expensive to deploy and maintain, especially over long distances.  Crown Castle, Lumen, and Zayo are examples to dark fiber providers through which Brightlio can offer dark fiber services.

Depending on your location, local municipalities or utilities may offer dark fiber services.  City of Pasadena, CA and City of Palo Alto, CA are both examples of municipalities offering dark fiber services for lease.  As these are typically offered to attract business to the community, they may be less expensive than offerings from private companies.

Lit Fiber

In contrast to dark fiber, lit fiber is fiber that is currently in use.  The network equipment is managed by a network provider.  The network provider typically has many customers leveraging the same fiber network, thus allowing customers with more limited budgets access to the performance and distance benefits of fiber.  The service is typically sold with a Service Level Agreement (SLA) guaranteeing specific uptime and capacity.  AT&T Business Fiber is an example of a lit fiber business internet service that Brightlio offers to its clients. 

The drawback to lit fiber services is that many other customers are on the network, which sometimes leads to network congestion.  It is important to read the details of the lit fiber service, to understand what capacity you are guaranteed, and what the impacts of network congestion might be on your service.  Customers requiring guaranteed capacity should look for network connectivity options offering dedicated internet bandwidth, or dark fiber services. 

Brightlio Delivers Dark and Lit Fiber Connectivity

If you are in need of fiber network connectivity solutions for your organization, Brightlio can help.  We partner with leading global providers of both dark and lit fiber services to deliver services to meet your technical requirements and budget.  If you are looking for dark fiber pricing, or pricing on lit fiber services, please reach out.  There is never a cost for quotes or solution designs. 

Are fiber services not a fit for your needs?  No worries.  Brightlio offers a wealth of network connectivity solutions from leading global providers.  Contact Brightlio today and start on a quote or solution design.