Light steering apparatus and system including the light steering apparatus

1. A light steering apparatus comprising:

a tunable laser source configured to output a plurality of optically coherent laser beams, the tunable laser source comprising a first waveguide and a second waveguide, the first waveguide comprising a first side and a second side, and the second waveguide comprising a first side, adjacent to the first side of the first waveguide, and a second side, adjacent to the second side of the first waveguide; and

a steering device on which the plurality of optically coherent laser beams, output from the tunable laser source, are incident, the steering device comprising a plurality of modulation units configured to beam steer the plurality of optically coherent laser beams,

wherein the plurality of optically coherent laser beams comprises a first laser beam output from the first side of the first waveguide and a second laser beam output from the second side of the second waveguide, and the first laser beam and the second laser beam have a time-independent phase difference with respect to each other, and

wherein the light steering apparatus further comprises a phase difference compensation device configured to compensate for the time-independent phase difference between the first laser beam and the second laser beam.

2. The light steering apparatus of claim 1 , further comprising:

a plurality of input/output connection structures connecting the tunable laser source to the steering device, each of the plurality of input/output connection structures corresponding to one of the plurality of optically coherent laser beams.

3. The light steering apparatus of claim 2 , wherein the tunable laser source comprises:

a first ring resonator disposed between the first waveguide and the second waveguide; and

a second ring resonator disposed between the first waveguide and the second waveguide and spaced apart from the first ring resonator.

4. The light steering apparatus of claim 3 , wherein the tunable laser source further comprises an optical amplifier on at least one of the first waveguide and the second waveguide.

5. The light steering apparatus of claim 4 , wherein each of the first ring resonator and the second ring resonator comprises a ring waveguide and a modulator.

6. The light steering apparatus of claim 5 , wherein the modulator comprises one of:

a heating element configured to heat the ring waveguide,

an electro-optic element configured to change a charge density of the ring waveguide by applying a current around the ring waveguide, and

a piezoelectric element configured to change a refractive index of the ring waveguide, or a material surrounding the ring waveguide, according to application of a voltage.

7. The light steering apparatus of claim 3 , wherein the tunable laser source further comprises:

a first output port at the first side of the first waveguide, a second output port at the second side of the first waveguide, a third output port at the first side of the second waveguide, and a fourth output port at the second side of the second waveguide.

8. The light steering apparatus of claim 3 , wherein the steering device comprises a third waveguide, connected to the first side of the first waveguide, on which the first laser beam is incident; and a fourth waveguide, connected to the second side of the second waveguide, on which the second laser beam is incident.

9. The light steering apparatus of claim 8 , wherein the first waveguide and the third waveguide are integrally formed, and the second waveguide and the fourth waveguide are integrally formed.

10. The light steering apparatus of claim 8 , wherein the steering device further comprises a splitter configured to split the third waveguide into a plurality of third waveguides and a splitter configured to split the fourth waveguide into a plurality of fourth waveguides.

11. The light steering apparatus of claim 10 , wherein one of the plurality of modulation units is configured to modulate a phase of a beam that pass through each of the plurality of third waveguides and the plurality of fourth waveguides.

12. The light steering apparatus of claim 1 , wherein the phase difference compensation device is provided on at least one of a path of the first laser beam and a path of the second laser beam and the phase difference compensation device is further configured to apply an electrical signal corresponding to the time-independent phase difference between the first laser beam and the second laser beam.

13. The light steering apparatus of claim 1 , wherein at least one of the plurality of modulation units is configured to apply an electrical signal corresponding to the time-independent phase difference between the first laser beam and the second laser beam.

14. The light steering apparatus of claim 1 , wherein the steering device comprises a plurality of light output portions arranged in a one-dimensional array.

15. A system comprising:

a tunable laser source configured to output a plurality of optically coherent laser beams, the tunable laser source comprising a first waveguide and a second waveguide, the first waveguide comprising a first side and a second side, and the second waveguide comprising a first side, adjacent to the first side of the first waveguide, and a second side, adjacent to the second side of the first waveguide;

a steering device on which the plurality of optically coherent laser beams, output from the tunable laser source, are incident, the steering device comprising a plurality of modulation units configured to beam steer the plurality of optically coherent laser beams; and

a detection unit configured to detect a beam steered by the steering device,

wherein the plurality of optically coherent laser beams comprises a first laser beam output from the first side of the first waveguide and a second laser beam output from the second side of the second waveguide, and the first laser beam and the second laser beam have a time-independent phase difference with respect to each other, and

wherein the system further comprises a phase difference compensation device configured to compensate for the time-independent phase difference between the first laser beam and the second laser beam.

16. The system of claim 15 , wherein the tunable laser source comprises:

a first ring resonator disposed between the first waveguide and the second waveguide;

a second ring resonator disposed between the first waveguide and the second waveguide and spaced apart from the first ring resonator; and

an optical amplifier provided on at least one of the first waveguide and the second waveguide.