Circulator

Product Description

The Circulator is a non-reciprocal optical component that routes light signals in a specified direction through multiple ports, typically 3-port or 4-port configurations. Leveraging Faraday rotation and polarization optics, it ensures that light entering Port 1 exits Port 2, light entering Port 2 exits Port 3, and so on, while blocking reverse propagation. This device supports a wide wavelength range (1260–1625 nm) and features low insertion loss, high isolation, and robust mechanical design. The circulator is ideal for applications requiring unidirectional signal flow, such as laser systems, optical amplifiers, and microwave photonics.

Features

Unidirectional Routing: Achieves isolation ≥25 dB between non-adjacent ports (e.g., Port 1 to Port 3) and ≥30 dB for reverse transmission (Port 2 to Port 1).

Low Loss Operation: Insertion loss ≤0.5 dB for 3-port models and ≤0.8 dB for 4-port models, ensuring minimal signal degradation.

Wide Wavelength Support: Compatible with standard telecom bands (1310 nm, 1550 nm), DWDM channels (1530–1565 nm), and specialty wavelengths (1064 nm, 2050 nm).

High Power Handling: Supports up to 2 W CW optical power, with thermally optimized designs for high-power laser applications.

Compact Design: ≤25mm length for 3-port devices, with optional hermetic sealing for harsh environments (e.g., aerospace, industrial).

Applications

Fiber Laser Systems: Routes pump light to the gain medium and directs output laser light to the output port, protecting the laser from back reflections.

Optical Amplifiers: Isolates EDFA input and output ports to prevent signal feedback that causes gain instability.

Microwave Photonics: Enables bidirectional signal separation in radio-over-fiber (RoF) systems for 5G fronthaul networks.

Sensor Networks: Facilitates bidirectional communication in FBG sensing arrays by separating input and reflected signals.

Aerospace & Defense: Reliable performance in airborne laser rangefinders and satellite communication payloads with strict size constraints.

Faq

Q: How does a circulator differ from an isolator?

A: A circulator has three or more ports for sequential signal routing, while an isolator has two ports and blocks reverse transmission entirely.

Q: Can it be used in both single-mode and multi-mode systems?

A: Single-mode circulators are standard; multi-mode versions are available for 850 nm/1310 nm applications with reduced isolation (≥20 dB).

Q: What is the maximum operating temperature?

A: -40°C to 85°C for standard models; extended temperature versions (-55°C to 125°C) available for rugged environments.

Q: Does it require external power?

A: No, it operates passively using the Faraday effect, which relies on a permanent magnet for polarization rotation.

Q: Can I use a 3-port circulator as a 2-port isolator?

A: Yes, by terminating the third port with a matched load, it functions as an isolator with enhanced isolation.