Light source apparatus shaping a waveform of a pump light source and using optical parametric process with information acquisition apparatus using same

Patent metadata

Field	Value
Publication number	US-10404029-B2
Application number	US-201615370940-A
Country	US
Kind code	B2
Filing date	Dec 6, 2016
Priority date	Dec 10, 2015
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

An introduction unit that introduces a pump light pulse having a first wavelength, a shaping unit that shapes a waveform of the pump light pulse, a nonlinear optical waveguide that generates a wavelength converted light pulse from a pump light pulse, the pump light pulse being a pulse that has been shaped in the shaping unit, through an optical parametric process, the wavelength converted light pulse including a second wavelength different from the first wavelength. The shaping unit shapes the waveform of the pump light pulse such that an absolute value of a time rate of change of the waveform at a peak area of the pump light pulse that has been shaped is smaller than an absolute value of a time rate of change of the waveform at a peak area of the pump light pulse before being shaped with the shaping unit.

First claim

What is claimed is:

1. A light source apparatus, comprising:
an introduction unit that introduces a pump light pulse having a first wavelength;
a shaping unit that shapes a waveform of the pump light pulse having the first wavelength; and
a nonlinear optical waveguide that generates a wavelength converted light pulse from the pump light pulse having the first wavelength through an optical parametric process, the pump light pulse being a pulse that has been shaped in the shaping unit, the wavelength converted light pulse including a second wavelength different from the first wavelength,
wherein the shaping unit shapes the waveform of the pump light pulse such that an absolute value of a time rate of change of the waveform at a peak area of the pump light pulse that has been shaped is smaller than an absolute value of a time rate of change of the waveform at a peak area of the pump light pulse before being shaped with the shaping unit.

2. The light source apparatus according to claim 1 , wherein the shaping unit shapes the waveform of the pump light pulse such that the absolute value of the time rate of change of the waveform at the peak area of the pump light pulse that has been shaped is smaller than the absolute value of the time rate of change of the waveform at the peak area of the pump light pulse before being shaped, and such that an absolute value of a time rate of change of the waveform that has been shaped at half maximum point of the pump light pulse is larger than an absolute value of a time rate of change of the waveform before being shaped at half maximum point of the pump light pulse.

3. The light source apparatus according to claim 1 , wherein as the waveform of the pump light pulse becomes similarly transformed so that a full width at half maximum of the pump light pulse before being shaped and a full width at half maximum of the pump light pulse after shaping coincide with each other, the shaping unit shapes the waveform of the pump light pulse such that the absolute value of the time rate of change of the waveform at the peak area of the pump light pulse that has been shaped is smaller than the absolute value of the time rate of change of the waveform at the peak area of the pump light pulse before being shaped.

4. The light source apparatus according to claim 1 , wherein in a period in which the waveform of the wavelength converted light pulse and the waveform of the pump light pulse do not overlap each other, the shaping unit shapes the pump light pulse such that an intensity of the pump light pulse that has been shaped is smaller than an intensity of the pump light pulse before being shaped.

5. The light source apparatus according to claim 1 , further comprising:
a seed beam introduction unit that introduces a seed beam of the wavelength converted light pulse; and
a combiner that combines the seed beam of the wavelength converted light pulse introduced by the seed beam introduction unit and the pump light pulse that has been shaped by the shaping unit, the combiner guiding the seed beam and the pump light pulse that have been combined to the nonlinear optical waveguide,
wherein the nonlinear optical waveguide amplifies the wavelength converted light pulse by inducing energy conversion from the pump light pulse that has been shaped to the wavelength converted light pulse.

6. The light source apparatus according to claim 1 , further comprising:
a feedback unit that feed backs a portion of the wavelength converted light pulse generated in the nonlinear optical waveguide; and
a combiner that combines the wavelength converted light pulse that has been fed back by the feedback unit and the pump light pulse that has been shaped by the shaping unit, the combiner guiding the wavelength converted light pulse and the pump light pulse that have been combined to the nonlinear optical waveguide,
wherein the nonlinear optical waveguide performs wavelength conversion of the pump light pulse that has been shaped into the wavelength converted light source through an optical parametric process.

7. The light source apparatus according to claim 1 ,
wherein the pump light pulse satisfies
Δ t r +t wo ≤Δt p ,

whereΔt p is a pulse width of the pump light pulse, Δt r is the pulse width of the wavelength converted light pulse, and t wo is a walk-off time of the wavelength converted light pulse with respect to the pump light pulse in the nonlinear optical waveguide.

8. The light source apparatus according to claim 5 ,
wherein the pump light pulse satisfies
Δ t r +t wo ≤Δt p ,

where Δt p is a pulse width of the pump light pulse, Δt r is the pulse width of the wavelength converted light pulse, and t wo is a walk-off time of the wavelength converted light pulse with respect to the pump light pulse, between the combiner to an output terminal of the light source apparatus.

9. The light source apparatus according to claim 6 , further comprising:
an extracting unit that extracts a portion of an output of the nonlinear optical waveguide and outputs the portion that has been extracted to an outside of the light source apparatus,
wherein the pump light pulse satisfies
Δ t r +t wo ≤Δt p ,

where Δt p is a pulse width of the pump light pulse, Δt r is the pulse width of the wavelength converted light pulse, and t wo is a walk-off time of the wavelength converted light pulse with respect to the pump light pulse, between the combiner to an output terminal of the extracting unit.

10. The light source apparatus according to claim 7 ,
wherein the pump light pulse satisfies
Δ t r +t wo ≤Δt p ≤2(Δ t r +t wo )

where Δt p is a pulse width of the pump light pulse, Δt r is the pulse width of the wavelength converted light pulse, and t wo is a walk-off time of the wavelength converted light pulse with respect to the pump light pulse, between a combiner to an output terminal of an extracting unit.

11. The light source apparatus according to claim 7 ,
the pump light pulse satisfies
| dP ( t )/ dt|≤ 1 THz/γ L,

during a period of Δt r +t wo
where P(t) is an intensity of the pump light pulse, L is a length of the nonlinear optical waveguide, and γ is a nonlinear coefficient of the nonlinear optical waveguide.

12. The light source apparatus according to claim 1 , wherein the shaping unit includes:
a divider that divides the pump light pulse into a plurality of beams of divided light,
a plurality of waveguide units that each guide the corresponding one of the plurality of beams of divided light that have been divided, the plurality of waveguide units having different optical path lengths, and
a combiner that combines the plurality of beams of divided light from the plurality of waveguide units.

13. The light source apparatus according to claim 1 , wherein the shaping unit includes a spatial light phase modulator.

14. The light source apparatus according to claim 1 , wherein the shaping unit includes a fiber Bragg grating.

15. The light source apparatus according to claim 1 , the shaping unit includes an optical waveguide that have at least two tapered portions that have been processed into a tapered shape.

16. An information acquisition apparatus, comprising: a light source apparatus according to claim 1 , an output of the light source apparatus being used as a light source that is used by the information acquisition apparatus to acquire information.

17. The light source apparatus according to claim 1 , wherein a pulse width of the pump pulse is 10 ps or less.

18. A light sou

Assignees

• Canon Kk

Inventors

• Miura Shun

Classifications

• G02F1/39

  for parametric generation or amplification of light, infrared or ultraviolet waves · CPC title

• H01S2301/08

  Generation of pulses with special temporal shape or frequency spectrum · CPC title

• H01S3/1618

  ytterbium · CPC title

• H01S3/06754

  Fibre amplifiers (H01S3/06708 takes precedence) · CPC title

• H01S3/0092

  Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity (nonlinear frequency conversion per se G02F1/35) · CPC title