Abstract: An optical switch includes an array of optical fibers to conduct optical signals. A biconvex lens has a front convex surface facing the fibers' tips and has a back convex surface facing a microelectromechanical (MEMS) mirror. The MEMS mirror can be selectively oriented to reflect the optical signals incident to the MEMS mirror so the optical signal input from one fiber can be selectively routed to another of the fibers.

Abstract: A single-ended output circulator includes a three-core optical fiber head having first, second, and third optical fiber cores; a walk-off crystal having a first surface facing towards the second end of the three-core optical fiber head tube and a second surface facing away from the second end of the three-core optical fiber head tube; a plurality of half-wave plates each having a first surface coupled to the second surface of the walk-off crystal and a second surface facing away from the second surface of the walk-off crystal; a collimating lens having a first end and a second end; a reflection mirror configured to reflect light beams from the collimating lens; an optical prism between the collimating lens and the reflection mirror and configured to transmit a light beam along a propagation direction according to a polarization direction of the light beam; and a polarization rotator.

Abstract: An optical isolator has high isolation and low insertion loss in bandwidth. An input fiber collimator, isolator cores, and an output fiber collimator are connected in sequence in an optical path. Acute ends of wedge surfaces of lenses and fiber heads of the collimators are polished to form small platforms. Faraday crystals of the cores are optically active and are different in wavelength; birefringent wedges of the cores are different in wedge angle; and an optical axis of the birefringent wedges at an emitting end of the first core is perpendicular to an optical axis of the birefringent wedges at an incident end of the second core. The two stages of Faraday crystals with different wavelengths are overlaid to extend and widen isolation performance in bandwidth, and a small-spot collimator design is adopted so coupling loss is low, performance is stable, and reliability is high.

Abstract: A single-ended output circulator includes a three-core optical fiber head having first, second, and third optical fiber cores; a walk-off crystal having a first surface facing towards the second end of the three-core optical fiber head tube and a second surface facing away from the second end of the three-core optical fiber head tube; a plurality of half-wave plates each having a first surface coupled to the second surface of the walk-off crystal and a second surface facing away from the second surface of the walk-off crystal; a collimating lens having a first end and a second end; a reflection mirror configured to reflect light beams from the collimating lens; an optical prism between the collimating lens and the reflection mirror and configured to transmit a light beam along a propagation direction according to a polarization direction of the light beam; and a polarization rotator.