With the rapid development and large-scale deployment of FTTH (Fiber to the Home), the global trend of replacing copper with fiber and accelerating bandwidth upgrades has intensified. As a critical information infrastructure for digital societal transformation, fiber optic access networks are expanding swiftly under national broadband strategies. By the end of 2018, China’s broadband access subscribers exceeded 400 million, with 100 Mbps access becoming widespread. This broadband proliferation has profoundly transformed lifestyles and work patterns while unlocking opportunities for innovative services.

Video services have emerged as the cornerstone of fixed broadband, replacing voice as a primary revenue stream for operators. This shift drives the adoption of 4K/8K services, whose high-bandwidth demands necessitate new network architectures and deployment strategies. Requirements such as edge device placement closer to users, network cloudification/virtualization, smart home networks, and fiber replacing copper lines are accelerating the transition to all-optical access.

In fiber access network construction, small-capacity OLTs (Optical Line Terminals) have gained operator favor due to their compact size, lightweight design, environmental adaptability, and cost efficiency. These devices align with trends toward decentralized optical nodes, diverse deployment scenarios, higher bandwidth delivery, and resource optimization, enabling cost-effective network builds.

I. Comparative Analysis: Small vs. Large/Medium-Capacity OLTs

In network planning, operators choose between large/medium-capacity and small-capacity OLTs based on specific requirements and deployment models.

Small-capacity OLTs excel in scenarios demanding flexibility and adaptability, such as:

• Space-constrained central offices
• Low-density area coverage
•  (OLT/distributed placement)
• Smart campus quick deployment
• Co-location with mobile base stations

They also offer flexible uplink networking and protection mechanisms to ensure service security and efficiency. Small-capacity OLTs come in two form factors:

1. 1U Pizza-Box OLTs: Fixed-configuration, non-hot-swappable line cards, low cost.
2. 2U Compact OLTs: Carrier-grade redundancy (power, fans, control boards), enhanced reliability.

II. Application Scenarios for Small-Capacity OLTs

1. Low-Density Area Coverage
Small-capacity OLTs reduce costs for trunk fiber, conduits, power, and HVAC infrastructure. Paired with high-power Class D optical modules, they extend coverage to distant users. Their outdoor-ready designs suit harsh environments, enabling rapid FTTH deployment for small/medium operators.

Advantage: Minimal initial investment for sparse user bases.

2. Remote Region Coverage
In vast, sparsely populated areas, small OLTs deployed at POP (Point of Presence) nodes minimize central costs. Multiple small OLTs aggregate to a central hub via 10/40/80 km optics and 10GE uplinks, ideal for regions with moderate user density and growth potential.

Solution: Cascade large and small OLTs to deliver broadband to rural users far from urban cores.

3. Light-Asset Operator Deployments
Mobile or enterprise-focused operators leasing infrastructure prioritize cost-effective solutions. Small OLTs reduce space, power, and HVAC demands while offering high PON port density per slot.

Benefit: Lower TCO (Total Cost of Ownership) for quick deployment and scalability.

4. Smart Industrial Parks & Commercial Buildings
POL (Passive Optical LAN) solutions dominate modern campus networks, offering security, energy efficiency, and simplified O&M. Leveraging PON expertise, operators deploy small OLTs for:

• Enterprise POL in office buildings
• High-speed hotel bandwidth
• Industrial IoT in factories
• Surveillance systems (e.g., parking access)

In multi-tenant buildings:

• Dedicated OLTs per tenant occupying multiple floors.
• Multiple PON ports for single-floor tenants.
• Shared ONUs for co-located businesses.

5. Fixed-Mobile Convergence (FMC)
Mobile operators repurpose backhaul resources and cabinet space for FTTH, transitioning to multi-service models. Small OLTs co-located with base stations enable:

• Rapid home coverage via short-reach drop fibers.
• Shared/rack resources, cutting mobile network costs.
• Utilization of idle FTTx ports and PON timing synchronization for mobile backhaul.

ZTE’s Small-Capacity OLT Portfolio

1. ZXA10 C320: The industry’s first 2U carrier-grade OLT, deployed in 30+ operator networks.
2. ZXA10 C620: Next-gen 2U OLT supporting GPON/XGS-PON/Combo/P2P, with SDN/NFV readiness, NSR (Non-Stop Routing), and network slicing for multi-tenant/ISP applications.
3. ZXA10 C610: 1U pizza-box OLT with 8/16 PON ports, designed for flexible, cost-efficient FTTx deployments.