Micro-Optics Inc. has launched a series of polarization-maintaining fiber optic circulators for 1550 and 1300 nm and other wavelengths. The devices are configured in three or four ports. They exhibit insertion loss of 0.5 dB, extinction ratio of >25 dB and return loss of >55 dB. Various fibers can be used, and high-extinction-ratio polarization-maintaining fiber connectorization is available. The company says that the product offers stability and reliability in a compact in-line package.