Design of optical circulators with a small-aperture Faraday rotator by applying two pairs of confocal cylindrical lenses

Abstract

This letter proposes a new and low-cost design of four-port optical circulator. By introduction of two pairs of confocal cylindrical lenses, a small size Faraday rotator is required. To show the feasibility of the design, a prototype of four-port optical circulator was fabricated. The insertion losses are 0.69 dB, the isolations are 23.04–29.65 dB, and return losses are 27.72 dB. This design should bear merits of a simple and symmetric structure that is low cost, easily fabricated, polarization-independent, and polarization-mode dispersion resolved, and exhibits high performance.