Leading manufacturers of fiber optic grating (FBG) systems for tunnel temperature measurement include FJINNO, AtGrating, FBGS, Nanjing Zhunzhi, and Tempsens.

Key Manufacturers and Their Offerings

FJINNO specializes in fiber optic grating tunnel fire monitoring systems, providing linear FBG temperature sensing for long tunnels such as highways and subways. Their systems use patented encoding and broadband gratings, enabling real-time monitoring over distances up to 20 km without relays. Features include intrinsic safety, electromagnetic immunity, differential temperature alarms, self-checking functions, and remote monitoring capabilities, making them suitable for large-scale tunnel fire safety applications . AtGrating offers FBG-based sensors for temperature, strain, pressure, and displacement, applicable to tunnels, bridges, and other infrastructure. They provide full technical support, installation, calibration, and customized solutions. Their FBG sensors can be embedded in structures to monitor strain and temperature distribution, enabling predictive maintenance and structural health monitoring . FBGS provides high-quality FBG sensing components such as Draw Tower Gratings (DTG®), FemtoSecond Gratings (FSG®), and All Grating Fiber (AGF®). They offer turnkey solutions for temperature, strain, and pressure monitoring in infrastructure, energy, and transportation sectors. Their sensors are highly resistant to harsh environments and electromagnetic interference, suitable for tunnel and industrial applications . Nanjing Zhunzhi Sensing Technology develops fiber optic grating sensors, demodulators, and distributed temperature measurement (DTS) systems. Their products are widely used in tunnels, bridges, dams, and industrial pipelines. They integrate R&D, production, and service, focusing on high-precision, long-distance temperature monitoring in complex environments . Tempsens manufactures FBG sensors capable of measuring temperature, strain, vibration, and pressure over a wide range (-20°C to 900°C). Their sensors provide high accuracy (±1°C) and can be configured for single-point or multi-channel networks, making them suitable for tunnel monitoring and other industrial applications .

Considerations for Selection

When choosing a manufacturer for tunnel temperature measurement:

• Distance and coverage: Ensure the system supports the tunnel length without signal degradation.
• Safety and environment: Look for intrinsic safety, explosion-proof design, and electromagnetic immunity.
• Real-time monitoring: Systems with differential temperature alarms and self-checking functions improve reliability.
• Customization: Some manufacturers offer tailored solutions for specific tunnel geometries or structural monitoring needs.
• Support and maintenance: Technical assistance, calibration, and installation support are critical for long-term operation. These manufacturers provide robust FBG-based solutions suitable for tunnel temperature monitoring, fire detection, and structural health applications.