1. Field of the Invention
This invention relates to optical components generally and, more specifically, to optical components having multiple ports.
2. Description of the Prior Art
Optical systems and subsystems, such as an exemplary fiber amplifier as shown in FIG. 3, utilize multiple optical isolators to provide isolation between various optical components in the amplifier. These isolators essentially allow only one way propagation of optical energy between the input and output of the isolator and may be of the type shown in U.S. Pat. No. 4,548,478, incorporated herein by reference. In the fiber amplifier 10 of FIG. 3, the isolators 11, 12 assure one-way amplification by Eb-doped fiber 13. Since the isolation function is duplicated in the amplifier, it is desirable to eliminate one of the components to reduce the cost of the fiber amplifier 10. An exemplary amplifier which utilizes the shared isolator is shown in FIG. 2. Here, the isolator 20 has two optical paths, each isolated from each other but sharing a common package. Such isolators were heretofore unavailable.
Therefore, there exists a need for a reliable technique for sharing in a common package an isolator with multiple optical paths therein with substantially no interaction between the paths.