Optical Circulators

Optical circulators of Fibrain Directivity family are passive optical devices, usually having 3 or 4 ports, that are used for switching signals between the ports in a given order. It is a way of achieving high directional isolation and low-loss transmission between specified pairs of ports. The most frequently used type of optical circulator is the 3-port version. It transmits the signal from port 1 to port 2 and from port 2 to port 3, blocking the transmission between other port pairs. The 3-port circulator is usually used for switching from a piece of link that uses bidirectional transmission in one fiber to a piece with standard bidirectional transmission in two fibers.

The circulators are available in versions optimized for 1310, 1490, 1550, 1590, and 1625 nm windows. They are delivered with a report containing attenuation and isolation values in the operation band and with labeled ports and direction of transmission.
  • High channel isolation
  • 1310, 1490, 1550, and 1590 nm operation windows
  • Wideband versions for C+L bands
  • Insensitive to polarization
  • 3- and 4-port versions
  • Different casing versions
  • Delivered with test reports
  • Wide range of available connectors
Technical Data
Parameter 3-port circulator 
Central wavelength 1310,1490,1550,1590* 1625
Operating band

Λc  ± 30 nm

IL ≤ 0.8 dB
Directional isolation ≥ 40 dB
RL ≥ 55 dB ≥ 50 dB
PDL  ≤ 0.15 dB
Max optical power 500 mW
PMD < 0.1 ps
Temp. of operation from – 50C to + 750C
Temp. of storage from – 400C to + 850C


Notice: Parameters listed in the table refer to components without connector terminations

  • Telecommunication networks
  • Dispersion compensating systems
  • Optical amplifiers
  • WDM systems: ADD/DROP
  • Metro systems

Optical circulators with output fibers with 250/900 µm coating have a 5.5x50 mm pipe casing with a serial naumber printed on the pipe with an indicated direction of transmission.

Additional possibilities:

  • 90x20x10 mm black box housings for isolators with output fibers in 0.9/2.0/3.0 mm coating
  • assembly in LGX modules, 19’’ panels, etc.