3D imaging system and mobile phone having same

1. A 3D imaging system comprising:

a light source;

a modulator connected with the light source and configured to modulate output of the light source with a frequency sweep signal;

an optical module connected to the light source;

a light sensing device connected with the optical module and configured to sense optical output of the optical module and convert the optical output into a plurality of electrical signals; and

a signal processing module connected with the light sensing device and configured to extract 3D information of the object from the electrical signals; wherein:

the optical module comprises:

a first light splitting device connected with the light source and configured to split light from the light source into a light output in a first optical path and a light output in a second optical path, the light output in the first optical path being directed to an object, passing through or being reflected by the object;

a second light splitting device connected with the first light splitting device and configured to split the light output in the second optical path into a plurality of optical signals;

a light collecting and coupling device configured to collect light passing through or reflected by the object and couple the light to the light combining device; and

a light combining device connected with the light collecting and coupling device, the second light splitting device, and the light sensing device, comprising a plurality of light combiners, and configured to combine optical signals coupled from the light collecting and coupling device and optical signals output by the second light splitting device and output a plurality of combined optical signals.

2. The system of claim 1 , wherein the light source is a laser, the laser comprising a VCSEL or a VCSEL array.

3. The system of claim 1 , wherein frequency of the frequency sweep signal varies with time linearly during each sweep.

4. The system of claim 1 , wherein the first light splitting device is a fiber optic fusion coupler.

5. The system of claim 1 , wherein the light collecting and coupling device is a grating coupler that comprises a matrix of pixels with m columns and n rows.

6. The system of claim 5 , wherein the second light splitting device is a light splitter configured to split the light output in the second optical path into k optical signals, k=m×n.

7. The system of claim 6 , wherein the light combining device comprises k light combiners, each light combiner being an optical Y-junction configured to combine an optical signal coupled from the light collecting and coupling device and an optical signal output by the second light splitting device and output a combined optical signal.

8. The system of claim 7 , wherein the light sensing device comprises a matrix of k pixels, each pixel being a light sensor configured to convert the combined optical signal into an electrical signal.

9. The system of claim 1 further comprising an amplifier placed between the light source and the first light splitting device and configured to amplify optical signal input to the first light splitting device; and a collimator placed between the first light splitting device and the object, and configured to collimate light before the light is directed to the object.

10. The system of claim 1 , wherein the optical module and the light sensing device are integrated onto a silicon photonic chip fabricated with SOI processes.

11. The system of claim 10 , wherein the light source, the modulator and the signal processing module are further integrated onto the silicon photonic chip.

12. The system of claim 11 , wherein the chip comprises an optical sub-module, the optical sub-module integrating the light collecting and coupling device and an image sensor.

13. The system of claim 12 , wherein the optical sub-module comprises a matrix of pixels, each pixel comprises a silicon substrate layer, a silicon oxide layer disposed on the silicon substrate layer, a glass layer disposed on the silicon oxide layer, a silicon waveguide layer disposed on the glass layer, and a polysilicon layer partially covering the silicon waveguide layer, a plurality of teeth being formed in the silicon waveguide layer, a photodiode being disposed on the silicon oxide layer and covered by the glass layer.

14. The system of claim 13 , wherein the refractive indexes of the air, the silicon waveguide layer and the glass layer are n1, n2 and n3 respectively, while n2>n3>n1.

15. A mobile phone comprising:

a back cover on which a first window and a second window are defined;

a light source;

a modulator connected with the light source and configured to modulate output of the light source with a frequency sweep signal;

a first light splitting device connected with the light source and configured to split light from the light source into a light output in a first optical path and a light output in a second optical path, the light output in the first optical path being directed to an object, passing through or being reflected by the object;

a second light splitting device connected with the first light splitting device and configured to split the light output in the second optical path into a plurality of optical signals;

an optical sub-module configured to collect light passing through or reflected by the object and couple the light to a light combining device, the light combining device being connected with the optical sub-module and the second light splitting device, comprising a plurality of light combiners, and configured to combine optical signals coupled from the optical sub-module and optical signals output by the second light splitting device and output a plurality of combined optical signals;

a light sensing device connected with the light combining device and configured to sense optical output of the light combining device and convert the optical output into a plurality of electrical signals; and

a signal processing module connected with the light sensing device and configured to extract 3D information of the object from the electrical signals; wherein:

the first window is surrounding and aligned with the optical sub-module; and

the second window is surrounding and aligned with the light output in the first optical path of the first light splitting device.

16. The mobile phone of claim 15 , wherein the second window is further surrounding and aligned with a flash light, the flash light being configured to provide assistive lighting for photo or video shooting with the mobile phone.

17. The mobile phone of claim 15 , wherein the optical sub-module comprises a matrix of pixels, each pixel comprises a silicon substrate layer, a silicon oxide layer disposed on the silicon substrate layer, a glass layer disposed on the silicon oxide layer, a silicon waveguide layer disposed on the glass layer, and a polysilicon layer partially covering the silicon waveguide layer, a plurality of teeth being formed in the silicon waveguide layer, a photodiode being disposed on the silicon oxide layer and covered by the glass layer.

18. A 3D imaging system comprising:

a light source being modulated by a frequency sweep signal;

a first light splitting device connected with the light source and configured to split light from the light source into a light output in a first optical path and a light output in a second optical path, the light output in the first optical path being directed to an object, passing through or being reflected by the object;

a second light splitting device connected with the first light splitting device and configured to split the light output in the second optical path into a plurality of optical signals;

an optical sub-module configured to collect light passing through or reflected by the object and couple the light to a light combining device, the light combining device being connected with the optical sub-module and the second light splitting device, comprising a plurality of light combiners, and configured to combine optical signals coupled from the optical sub-module and optical signals output by the second light splitting device and output a plurality of combined optical signals;

a light sensing device connected with the light combining device and configured to sense optical output of the light combining device and convert the optical output into a plurality of electrical signals; and

a signal processing module connected with the light sensing device and configured to extract 3D information of the object from the electrical signals; wherein:

the optical sub-module comprises a matrix of pixels with m columns and n rows, each pixel comprising a silicon substrate layer, a silicon oxide layer disposed on the silicon substrate layer, a glass layer disposed on the silicon oxide layer, a silicon waveguide layer disposed on the glass layer, and a polysilicon layer partially covering the silicon waveguide layer, a plurality of teeth being formed in the silicon waveguide layer, a photodiode being disposed on the silicon oxide layer and covered by the glass layer;

the second light splitting device is a light splitter configured to split the light output in the second optical path into k optical signals, k=m×n; and

the light combining device comprises k light combiners, each light combiner being an optical Y-junction configured to combine an optical signal coupled from the optical sub-module and an optical signal output by the second light splitting device and output a combined optical signal.

19. The system of claim 18 , wherein the refractive indexes of the air, the silicon waveguide layer and the glass layer are n1, n2 and n3 respectively, while n2>n3>n1.

20. The system of claim 18 , wherein the light sensing device comprises a matrix of k pixels, each pixel being a light sensor configured to convert the combined optical signal into an electrical signal.