Photonic rotators integrated on a substrate are disclosed for manipulating light polarization.

In various embodiments magnetically actuated liquid crystals are provided as well as method of manufacturing such, methods of using the liquid crystals and devices incorporating the liquid crystals. In one non-limiting embodiment the liquid crystals comprise Fe.sub.3O.sub.4 nanorods where the nanorods are coated with a silica coating.

To a co-precipitating aqueous solution, aqueous solutions containing (a) Tb ions, (b) at least one other rare earth ions selected from the group consisting of Y ions and lanthanoid rare earth ions (excluding Tb ions), (c) Al ions and (d) Sc ions are added; the resulting solution is stirred at a liquid temperature of 50 C. or less to induce a co-precipitate of the components (a), (b), (c) and (d); the co-precipitate is filtered, heated and dehydrated; and the co-precipitate is fired thereafter at from 1,000 C. to 1,300 C., thereby forming a sinterable garnet-type complex oxide powder.

A paramagnetic garnet-type transparent ceramic is a sintered body of complex oxide represented by the following formula (1), comprising SiO.sub.2 as a sintering aid in an amount of more than 0% by weight to 0.1% by weight or less, and has a linear transmittance of 83.5% or more at the wavelength of 1,064 nm for an optical path length of 25 mm:

(Tb.sub.1-x-yY.sub.xSc.sub.y).sub.3(Al.sub.1-zSc.sub.z).sub.5O.sub.12 (1)

wherein 0.05x<0.45, 0<y<0.1, 0.5<1xy<0.95, and 0.004<z<0.2.

Embodiments herein relate to photonic integrated circuits with an on-chip optical isolator. A photonic transmitter chip may include a laser and an on-chip isolator optically coupled with the laser that includes an optical waveguide having a section coupled with a magneto-optic liquid phase epitaxy grown garnet film. In some embodiments, a cladding may be coupled with the garnet film, the on-chip isolator may be arranged in a Mach-Zehnder interferometer configuration, the waveguide may include one or more polarization rotators, and/or the garnet film may be formed of a material from a rare-earth garnet family. Other embodiments may be described and/or claimed.

Provided are a Faraday rotator having a high light transmittance and a high Verdet constant and an optical isolator using the same. The Faraday rotator of the present invention contains a garnet type crystal represented by (Tb.sub.3-x-yR.sub.xBi.sub.y)Al.sub.5O.sub.12 (R represents one or more elements selected from Y, Er, Yb, or Lu, 0<x, and 0y). It is preferable that the Faraday rotator contains a garnet type crystal represented by (Tb.sub.3-x-yR.sub.xBi.sub.y)Al.sub.5O.sub.12 (R is one or more elements selected from Y or a lanthanoid (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu), 0x, and 0<y)).

Provided are a practical method for manufacturing TAG single crystal. The method of manufacturing a garnet type crystal brings a raw material solution into contact with a substrate formed of a Y.sub.3Al.sub.5O.sub.12 crystal or a Dy.sub.3Al.sub.5O.sub.12 crystal and performs liquid phase epitaxial growth. The garnet type crystal is represented by (Tb.sub.3-x-yR.sub.xBi.sub.y) Al.sub.5O.sub.12 (R is one or more elements selected from Y or a lanthanoid (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu), 0x, and 0y)).

Provided is a magneto-optic element that enables size reduction of an optical isolator without damaging the magneto-optic element even if the diameter of the magneto-optic element is reduced. A magneto-optic element is made of a columnar glass material with a diameter of 20 mm or less and has a laser damage threshold of 10 J/cm.sup.2 or more.

A transparent ceramic material is manufactured by molding a source powder into a compact, the source powder comprising a rare earth oxide consisting of at least 40 mol % of terbium oxide and the balance of another rare earth oxide, and a sintering aid, sintering the compact at a temperature T (1,300 C.T1,650 C.) by heating from room temperature to T1 (1200 C.T1T) at a rate of at least 100 C./h, and optionally heating from T1 at a rate of 1-95 C./h, and HIP treating the sintered compact at 1,300-1,650 C. The ceramic material has improved diffuse transmittance in the visible region and functions as a magneto-optical part in a broad visible to NIR region.

A transparent complex oxide sintered body is manufactured by sintering a compact in an inert atmosphere or vacuum, and HIP treating the sintered compact, provided that the compact is molded from a source powder based on a rare earth oxide: (Tb.sub.xY.sub.1-x).sub.2O.sub.3 wherein 0.4x0.6, and the compact, when heated in air from room temperature at a heating rate of 15 C./min, exhibits a weight gain of at least y% due to oxidative reaction, y being determined by the formula: y=2x+0.3. The sintered body has a long luminescent lifetime as a result of controlling the valence of Tb ion.