Directional Drilling of Texas LLC (DDoT.co) specializes in comprehensive underground conduit and fiber-optic installation services using advanced Horizontal Directional Drilling (HDD) methods. In addition to placing conduits, we provide full end-to-end fiber solutions, including composite work, cable installation, handhole placement, and precision fiber-optic splicing. Our team is equipped with the technical expertise to prepare and transition fiber infrastructure from main feeder lines to end-user connections, ensuring a seamless, reliable, and fully engineered installation process.
Fiber optic installation involves placing protective tubes called conduits underground, typically through Horizontal Directional Drilling (HDD), to house the glass strands that carry data. Once conduits are in place, technicians use specialized methods like pulling or blowing to thread the cable through, ensuring it remains protected from the elements. This infrastructure transitions from high-capacity feeder lines to localized drop lines using a network of underground access points and precision splicing.
The number of individual fibers in a cable can range greatly. Common counts in a cable include 2, 4, 12, 24, 48, 144, or more. A single splice closure or tray can accommodate many splice points, from 12 to over 1000, depending on its capacity and type (e.g., dome or horizontal).
Methods
Horizontal Directional Drilling (HDD) allows for conduit placement without the need for continuous open trenches, minimizing surface disruption.
Cable Blowing (Jetting) uses compressed air to “float” the fiber through the conduit, reducing friction and allowing for longer installation distances.
Cable Pulling is a traditional method where a mechanical winch or pull-tape is used to physically draw the cable through the pipe.
Handholes (Flowerpots) serve as critical underground access points where cables can be stored, spliced, or diverted to individual properties.
Fusion Splicing is the process of using heat to join two fiber optic strands together, ensuring a seamless connection with minimal signal loss.
Methods of Laying Fiber in Conduits
- Pre-installed (Cable-in-Conduit) In some scenarios, the fiber optic cable is manufactured directly inside the conduit. This is known as Cable-in-Conduit (CIC). This method is highly efficient for new developments because the drilling or trenching and the cable placement happen in one single step.
- Pulling Through Laid Conduit This is the most common method for shorter distances or complex routes. A “pull-tape” or “mule tape” is first threaded through the conduit (often using a vacuum or compressed air) or may already be installed in the conduit. A winch then pulls the fiber cable through, although for shorter distances it may be pulled manually. Technicians must carefully monitor pulling tension to ensure the delicate glass strands do not stretch or break.
- Blowing (Cable Jetting) For long-distance runs, cable blowing is preferred. A machine uses high-pressure compressed air to “push” the cable while simultaneously “floating” it within the conduit. This significantly reduces friction against the conduit walls, allowing the cable to travel thousands of feet without the need for mechanical pulling. Note on Aerial Connections: While this article focuses on underground methods, underground conduits often begin or terminate at a utility pole. At this “riser” point, the underground fiber is spliced to or from aerial fiber, which travels overhead to reach areas where drilling may not be feasible.
From Feeder Lines to Your Front Door
The journey of internet data begins with high-capacity feeder lines (the backbone) that branch into distribution lines (neighborhood branches) and finally into drop lines (the final connection to a building).
The Role of Splicing and Handholes
To transition from a massive distribution cable (which may contain hundreds of fibers) to a single drop line, specialized infrastructure is used: Handholes (Flowerpots): These are small, buried enclosures with removable lids (often looking like green plastic lids in a yard). They provide a protected space for “slack” cable to be stored and for splicing to occur. Splicing the Feeder: Inside a handhole or a nearby “splice closure” (a waterproof box), a technician performs splicing. They “tap” into the distribution line, selecting a specific pair of fibers to be joined to a smaller drop cable that will head toward a specific home or office. Technicians use two main methods to physically join the glass strands at the flowerpot.
Fusion Splicing (The Gold Standard)
A specialized machine uses an electric arc to melt two glass fiber ends together, “fusing” them into a single continuous strand.
- Pros: Lowest signal loss (typically < 0.1dB) most permanent.
- Cons: Requires expensive machinery and precision cleaning.
The Step-by-Step Tapping Process
To physically connect your new drop cable to the main line, a technician follows these precision steps:- Stripping and Cleaning: The technician uses specialized strippers to remove the outer jacket and the thin “cladding” of the fiber strand, revealing the bare glass (about the thickness of a human hair). The glass is then cleaned with 99% isopropyl alcohol.
- Cleaving: The fiber must be cut at a perfect 90-degree angle using a precision cleaver. If the cut is even slightly jagged, light will escape, and your internet will be slow or non-functional.
- Fusion Splicing: The technician places the main line fiber and your drop cable fiber into a Fusion Splicer.
- The machine uses cameras to align the two glass cores perfectly.
- An electric arc melts the two ends together.
- The machine then tests the connection by passing a light through it; a “good” splice usually loses less than 0.02 dB of signal.
Mechanical Splicing / Field Connectors
The fibers are aligned inside a small plastic sleeve with a special “index-matching gel” that helps light pass between the two ends.
- Pros: Fast; requires only hand tools; no power source needed for a machine.
- Cons: Slightly higher signal loss; the gel can degrade over many years.
The Serial Path: Handhole to Handhole
The main cable is typically pulled through a continuous run of conduit. It does not simply “stop” and “start” at every box. Instead, it follows a specific path through each junction:
- Entry: The cable enters the handhole from one conduit.
- The Slack Loop: Instead of going straight to the next conduit, the technician pulls an extra 50–100 feet of cable and coils it inside the handhole. This “slack” is vital; it allows the technician to lift the cable (and the heavy splice closure) out of the hole and into a clean environment (like a van) to perform the precision work.
- Exit: After the loop is formed, the cable enters the next conduit to continue to the next hand hole.
The “Express” Method (Mid-Span Access)
If a handhole needs to serve a house, the technician does not cut the entire main cable. Cutting a 144-strand cable would require 144 individual fusion splices just to get the signal back to the other side—a massive waste of time and a risk to signal quality. Instead, they perform Mid-Span Access:
- The Window Cut: The technician carefully removes about 2–3 feet of the outer black jacket of the main cable, exposing the “buffer tubes” (colored plastic tubes) inside.
- Expressing Fibers: Most of the buffer tubes remain completely untouched and are simply “expressed” (looped) through the splice closure. They continue their journey to the next junction without any interruption in service.
- The Tap: Only the specific buffer tube containing the fiber strands assigned to that neighborhood is opened. The technician “clips” only the necessary strands (e.g., 2 or 4 strands out of 144) to splice them to the drop cables heading toward the modems.
How the “Split” Happens: Passive Optical Networks (PON)
In many residential setups, the “splitting” isn’t just a physical wire branch; it uses a PLC Splitter (Planar Lightwave Circuit). Inside the splice closure in the handhole:
- Input: One “feeder” fiber from the main cable is spliced into the input of a 1:32 splitter.
- Output: The splitter uses a specialized glass prism to divide that single light signal into 32 separate outputs.
- Distribution: Each of those 32 outputs can now be spliced to a “drop cable” that runs through a smaller lateral conduit directly to a customer’s building.
The Final Connection
Once the drop line is spliced in the handhole, a small-diameter conduit is typically run from the handhole to the exterior of the building. This is often done using a “vibra-plow” or a small trenching tool that leaves almost no trace on the lawn. The fiber first reaches a small weather-proof box on the outside wall of your home, known as the NID (Network Interface Device) or CSP (Customer Service Point).6
- The Transition: This box acts as the boundary between the ISP’s network and your home.
- Slack Storage: Extra fiber is coiled here (slack) to allow for future repairs or movement of the cable without having to re-run the entire line from the street.
The fiber enters the premises through a small drilled hole and connects to an Optical Network Terminal (ONT), which converts the light signals back into the electrical signals your router understands.
Practical Takeaway
- Infrastructure Longevity: Placing fiber in conduits rather than direct burial makes it easier to upgrade or replace the cable in the future without re-digging.
- Minimal Disruption: Underground drilling (HDD) is the preferred method for urban areas as it avoids tearing up roads and sidewalks.
- Serviceability: Handholes (flowerpots) are essential for maintenance; if a connection fails, technicians can access the splice point without excavating the entire yard.
- Signal Quality: Fusion splicing ensures that the transition from the main street line to your home has the lowest possible signal loss, providing the “gigabit” speeds fiber is known for.