1. Field of the Invention
The present invention generally relates to the field of fiber optical circulators. More particularly, the present invention relates to the field of compact, low cost and high performance optical circulators with at least three ports, which can expanded to more ports.
2. Description of the Prior Art
In general, the fiber optical circulator transfers light from a port to another sequentially. It has at least three ports. The light enters the circulator through a first port and exits through a second port. Another light that enters the second port exits through a third port and so on. Since the optical circulator is an inherently non-reciprocal device, the light never goes to other ports.
Such an optical device has a broad range of applications in the field of fiber optic communication systems, such as in bi-directional communication, dense Wavelength Division Multiplexing (WDM) and Dispersion Compensation.
Many types of optical circulators have been developed and manufactured. However, the high cost and bulky size of the circulator have limited the popular acceptance for system applications.