Integration of in-line optical isolators

A new configuration of an optical isolator chip, which is suitable for use in integrated in-line optical isolators, has been proposed. The chip consists of a birefringent plate, a pair of birefringent wedges, and a Faraday rotator. The configuration makes the best use of transmission characteristics of expanded-core fibers in which the chip is embedded. The measured insertion loss and isolation of an assembled isolator at the wavelength 1.55 /spl mu/m are 0.8- and 33-dB, respectively.