Optical device and optical system

1. An optical device comprising:

at least one magnetic element including a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer sandwiched between the first ferromagnetic layer and the second ferromagnetic layer;

a laser diode; and

a waveguide, wherein

the waveguide includes at least one input waveguide optically connected to the laser diode and an output waveguide connected to the input waveguide,

at least some of light propagating in at least one of the input waveguide and the output waveguide is applied to the magnetic element, and

at least part of the waveguide is between the laser diode and the magnetic element along a direction of propagation of light emitted from the laser diode.

2. The optical device according to claim 1 , wherein the waveguide contains lithium niobate as a main component.

3. The optical device according to claim 1 , further comprising a substrate, wherein

the waveguide is formed on the substrate, and

the substrate contains aluminum oxide.

4. The optical device according to claim 1 , further comprising a substrate, wherein

the waveguide is formed on the substrate, and

the magnetic element is on or above the substrate.

5. The optical device according to claim 1 , further comprising a reflector, wherein the reflector reflects at least some of the light propagating in at least one of the input waveguide and the output waveguide toward the magnetic element.

6. The optical device according to claim 1 , wherein at least some of the light propagating in at least one of the input waveguide and the output waveguide is applied to the magnetic element from a direction intersecting a lamination direction of the magnetic element.

7. The optical device according to claim 1 , wherein at least some of the light propagating in at least one of the input waveguide and the output waveguide is applied to the magnetic element from a lamination direction of the magnetic element.

8. The optical device according to claim 1 , further comprising a support body which is different from a substrate on which the waveguide is formed and supports the magnetic element.

9. The optical device according to claim 1 , wherein

the waveguide further includes a monitoring waveguide,

the monitoring waveguide is connected to at least one of the input waveguide and the output waveguide, and

at least some of the light propagating in at least one of the input waveguide and the output waveguide propagate in the monitoring waveguide.

10. The optical device according to claim 1 , wherein

the at least one input waveguide comprises a plurality of input waveguides,

the at least one magnetic element comprises a plurality of magnetic elements and monitoring waveguides connected to the respective input waveguides are further provided, and

light propagating in the monitoring waveguides is applied to the respective magnetic elements.

11. An optical device comprising:

a plurality of magnetic elements each including a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer sandwiched between the first ferromagnetic layer and the second ferromagnetic layer;

a laser diode; and

a waveguide, wherein

the waveguide includes at least one input waveguide optically connected to the laser diode and an output waveguide connected to the input waveguide,

at least some of light propagating in at least one of the input waveguide and the output waveguide in a direction from the laser diode toward the input waveguide or the output waveguide is applied to a first magnetic element of the magnetic elements, and

at least some of light output from the output waveguide and reflected by an object to be irradiated is applied to a second magnetic element of the magnetic elements.

12. An optical system comprising:

the optical device according to claim 11 ; and

an optics system which guides light output from the optical device to an object to be irradiated.