KR20160011099A - Laser source by simultaneously varying to change of time using multiwavelength-swept and optical system using it - Google Patents

Laser source by simultaneously varying to change of time using multiwavelength-swept and optical system using it Download PDF

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KR20160011099A
KR20160011099A KR1020140092151A KR20140092151A KR20160011099A KR 20160011099 A KR20160011099 A KR 20160011099A KR 1020140092151 A KR1020140092151 A KR 1020140092151A KR 20140092151 A KR20140092151 A KR 20140092151A KR 20160011099 A KR20160011099 A KR 20160011099A
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wavelengths
light source
wavelength
optical
laser light
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KR1020140092151A
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Korean (ko)
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김창석
정명영
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부산대학교 산학협력단
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/105—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the mutual position or the reflecting properties of the reflectors of the cavity, e.g. by controlling the cavity length
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/50—Transmitters
    • H04B10/572—Wavelength control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Plasma & Fusion (AREA)
  • General Physics & Mathematics (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)

Abstract

In order to increase the measurement range of a system for measuring the phase of an interfering signal, a plurality of wavelengths are oscillated at the same time, and a plurality of wavelengths are simultaneously varied according to a change in time. The present invention relates to a laser light source capable of broadening a measurement range of a phase measurement system through a method of generating a plurality of optical interference signals and overcoming phase ambiguity through a relative comparison of the optical interference signals and an optical system using the laser light source. A wavelength selecting unit that selects a specific wavelength signal from the laser light generated from the optical gain unit and adjusts the wavelength interval by moving the selected wavelength signal within the bandwidth of the optical gain unit along the wavelength axis, And a wavelength selecting unit for selecting and outputting a specific wavelength signal selected by the wavelength selecting unit, To have to oscillate a plurality of wavelengths at the same time consists in accordance with the change of the time comprises an optical output coupler for varying that number of wavelengths at the same time within the optical gain bandwidth portion.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser light source in which a plurality of wavelengths are simultaneously oscillated in a plurality of wavelengths,

[0001] The present invention relates to a laser light source resonator in which a plurality of wavelengths are simultaneously oscillated at a plurality of wavelengths and simultaneously changes a plurality of wavelengths according to a change in time, and an optical system for simultaneously generating a plurality of optical interference signals using the same, To a system for simultaneously generating a laser light source and an optical interference signal for causing a plurality of wavelengths of laser to occur simultaneously within a bandwidth of an optical gain unit.

The light source resonator that varies the wavelength is increasing in its variable speed as related technologies and optical parts are developed, thereby increasing the speed of acquiring the data of the system. Such wavelength tunable light sources have been widely applied to optical systems such as optical sensor systems and optical interference systems, which require data acquisition at high speed.

For example, a system for measuring the phase of an interference signal using an optical interference system is used for precise measurement of digital holography, phase shifting interferometry, phase contrast microscopy and phase-sensitive optical coherence tomography.

In this case, when a wavelength-tunable light source oscillating only at a single wavelength is used, phase ambiguity occurs when the phase change of the interference signal exceeds 2 ?, which limits the measurement range of the system to be less than the measurement wavelength . 5 is a graph illustrating a result of measuring a phenomenon in which a measured value is skewed when a surface height of an optical waveguide shape is measured using one wavelength of a light source and the phase is skipped when the value exceeds 2 ?.

This phase ambiguity, for example, makes it difficult to measure more than 0.75 micrometer using a laser with a center wavelength of 1.5 micrometer.

In order to solve the problem through the occurrence of phase ambiguity, software and hardware attempts are continuously performed. However, it is limited due to complicated algorithm and complex system configuration.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a system for measuring the phase of an interfering signal, in which a plurality of wavelengths oscillate at the same time, A resonator and a laser light source capable of widening the measurement range of the phase measurement system through a method of generating a plurality of optical interference signals after passing through the optical interferometer and overcoming the phase ambiguity through relative comparison thereof, The purpose is to provide.

It is another object of the present invention to provide a laser light source and an optical system using the laser light source, which can be applied to an optical system that does not use an optical interferometer and can process as many information as a number of oscillations.

According to another aspect of the present invention, there is provided a laser light source having a plurality of wavelengths simultaneously oscillating at a plurality of wavelengths and varying a plurality of wavelengths simultaneously according to changes in time, A wavelength selector for selecting a specific wavelength signal from the light provided by the optical gain unit and controlling the wavelength interval by moving the selected wavelength signal along the wavelength axis within the bandwidth of the optical gain unit; And an optical output coupler for dividing and coupling the selected wavelength signal to simultaneously oscillate light having a plurality of wavelengths within the bandwidth of the optical gain unit.

Preferably, the laser light source is composed of a ring-shaped resonator or a linear resonator.

Preferably, the wavelength selector adjusts the wavelength interval so that at least two or more wavelengths are included in the bandwidth of the optical gain unit.

Preferably, the number of different wavelengths included in the light oscillated by the optical output coupler is equal to or smaller than a value obtained by dividing the wavelength interval adjusted by the wavelength selector in the bandwidth of the optical gain unit.

According to an aspect of the present invention, there is provided an optical system using a laser light source in which a plurality of wavelengths simultaneously generated from a light source according to the present invention are simultaneously oscillated, A laser light source for simultaneously oscillating light having at least two wavelengths and varying a plurality of wavelengths in accordance with a change in time; and at least two wavelengths simultaneously generated from the laser light source, And a light output distribution unit for outputting the light output from the light output distribution unit and at least two light receiving units for measuring a signal output from the light output distribution unit.

Preferably, the number of the light-receiving portions is equal to or greater than the number of wavelengths oscillated by the laser light source.

According to another aspect of the present invention, there is provided an optical system using a laser light source that simultaneously oscillates a plurality of wavelengths simultaneously generated from a light source according to the present invention, A laser light source that oscillates at least two or more generated wavelengths at the same time and changes a plurality of wavelengths thereof according to a change of time; and a light source that reflects a plurality of wavelengths simultaneously generated from the laser light source on a measurement surface and a reference surface, An optical output distributing unit for dividing the combined interference light from the optical interferometer into a plurality of different wavelengths and outputting the separated interference light; and an optical output distributing unit for measuring the interference signal output from the optical output distributing unit And at least two light receiving portions.

Preferably, the optical interferometer calculates a measurement range of the interference signal using a value determined through a relative comparison of central wavelengths corresponding to the number of wavelengths simultaneously oscillated in the laser light source.

Preferably, the number of the light receiving portions is equal to or greater than the number of wavelengths oscillated in the laser light source.

As described above, the laser light source in which a plurality of wavelengths are simultaneously varied according to a change in time according to the present invention is simultaneously oscillated in a plurality of wavelengths, and an optical system using the laser light source has the following effects.

First, by controlling the wavelength interval of the wavelength selector, laser beams of various wavelengths are simultaneously oscillated within the bandwidth of the optical gain unit, so that it is possible to process a large amount of information at the same time as that of a light source oscillating one wavelength, The efficiency of the treatment can be increased.

Second, a system for measuring the phase of an interference signal through a method of overcoming phase ambiguity has the effect of generating a light source in which a plurality of wavelengths simultaneously oscillate by increasing the measurement range.

1 (a), 2 (b) and 2 (c)] A ring shape of a laser light source in which a plurality of wavelengths simultaneously oscillate at a plurality of wavelengths according to an embodiment of the present invention, A schematic diagram of the configuration and its output spectrum
2 is a conceptual diagram for explaining the simultaneous oscillation of a plurality of wavelengths based on the bandwidth of the optical gain unit and the wavelength interval of the wavelength selection unit in the resonator according to the present invention,
Fig. 3 is a diagram showing the configuration of an optical system including a resonator having the configuration of Fig. 1 (a)
Fig. 4 is a diagram showing the configuration of an optical system according to another embodiment including a resonator having the configuration of Fig. 1 (a)
5 is a graph showing a result of measuring a phenomenon in which a measured value is skipped when the phase height is crossed when the surface height of the optical waveguide shape is measured using one wavelength of a light source,
6 is a graph showing a result of measuring the surface height of an optical waveguide shape using a resonator in which a plurality of wavelengths are simultaneously varied according to a change in time with the oscillation at a plurality of wavelengths simultaneously with the optical system according to the present invention

Other objects, features and advantages of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

A laser light source in which a plurality of wavelengths simultaneously oscillate at a plurality of wavelengths according to the present invention and changes its wavelength simultaneously according to a change in time, and an optical system using the same, will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is provided to let you know. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents It should be understood that water and variations may be present.

1 (a), 1 (b), and 1 (c) illustrate a ring shape of a laser light source in which a plurality of wavelengths simultaneously oscillate at a plurality of wavelengths according to an embodiment of the present invention, And a schematic diagram of the output spectrum thereof.

As shown in the drawing, the laser light source includes an optical gain unit 10 for providing an optical gain to the received laser light, and a controller for selecting a specific wavelength signal from the laser light generated in the optical gain unit 10, A wavelength selection unit 20 for adjusting a wavelength interval by movement along a wavelength axis within a bandwidth of the optical gain unit 10 and a wavelength division unit 20 for splitting and coupling the specific wavelength signal selected by the wavelength selection unit 20, The optical output coupler 30 oscillates a plurality of wavelengths at the same time within a bandwidth of the optical output coupler 10 and changes a plurality of wavelengths simultaneously according to a change in time. At this time, the laser light source may be composed of a ring-shaped resonator shown in Fig. 1 (a) or a linear resonator shown in Fig. 1 (b).

Accordingly, when the laser light source is measured in a wavelength range within the bandwidth of the optical gain unit 10 as shown in the output spectrum shown in FIG. 1 (c), several wavelengths can oscillate at the same time.

2, the bandwidth of the optical gain unit 10 is defined as B.W. When the wavelength interval of the wavelength selector 20 is defined as FSR, when two or more wavelengths are simultaneously oscillated within a bandwidth as defined by Equation (1), a plurality of wavelengths are simultaneously variable can do.

Figure pat00001

Similarly, when defined as Equation (2), at least N wavelengths within the bandwidth can oscillate at the same time.

Figure pat00002

Fig. 3 is a configuration diagram showing a configuration of an optical system including a laser light source having the configuration of Fig. 1 (a).

As shown in FIG. 3, the optical system includes a laser light source that simultaneously oscillates a plurality of wavelengths simultaneously generated from a light source in the configuration of FIG. 1 (a) and changes a plurality of wavelengths simultaneously according to a change in time, And a plurality of light receiving units 50 for measuring the signals output from the optical output distributing unit 40. The optical output distributing unit 40 includes a plurality of light receiving units 50, Since the configuration according to the laser light source is described above, a description thereof will be omitted.

As described above, the light source from the laser light source is divided through the wavelength regions before measurement and output through the light output distribution unit 40, and the light is measured through the plurality of light receiving units 50.

Fig. 4 is a configuration diagram showing the configuration of an optical system according to another embodiment including a resonator having the configuration of Fig. 1 (a).

As shown in FIG. 4, an optical system combining an optical interferometer includes a laser light source having a configuration of FIG. 1 (a) in which a plurality of wavelengths simultaneously generated from a light source are simultaneously oscillated, An optical interferometer (60) for generating a combined interference light by reflecting a plurality of wavelengths simultaneously generated from a laser light source on a measurement plane and a reference plane, and a multiplexing / demultiplexing means for splitting the combined interference light from the optical interferometer (60) into a plurality of different wavelengths And a plurality of light receiving units 50 for measuring the interference signals output from the optical output distributing unit 40. The light receiving unit 50 includes a plurality of light receiving units 50, Since the configuration according to the laser light source is described above, a description thereof will be omitted.

In this way, when the optical interferometer 60 is coupled to the laser light source, a plurality of interference signals can be obtained for each wavelength region, and interference signals can be obtained through the plurality of light receiving portions 50 through the optical output distributor 40 for each wavelength region. Can be measured to obtain respective phase values.

When the interfering signal is measured in such a range, it is possible to measure the interference signal in several ways.

As an embodiment, a case of dividing into two parts can be defined as the following equation (3).

Figure pat00003

Here, n is a refractive index, and k is a wavenumber due to a central wavelength of a light source.

After the fourier transform of Equation (3), each phase value change

Figure pat00004
, It can be defined as the following equation (4).

Figure pat00005

As a result, as shown in Equation 5,

Figure pat00006
Can be defined.

Figure pat00007

At this time,

Figure pat00008
.

Since the maximum range that can be measured without a phase jump can be defined as the following Equation 6,

Figure pat00009
To determine
Figure pat00010
The measurement range can be widened. Preferably
Figure pat00011
= 0.532 占 퐉,
Figure pat00012
= 0.633 mu m.

Figure pat00013

As described in the present invention,

Figure pat00014
) Are plotted on the phase maps 1 and 2, respectively, a graph as shown in FIG. 6 is obtained. That is, if a new best length (Beat Length) map is obtained based on the results of the two phase maps and the measurement results are shown, it can be seen that the micrometer-level step can be expressed without distortion as shown in FIG.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (9)

An optical gain unit for providing optical gain to the transmitted light,
A wavelength selector for selecting a specific wavelength signal from the light provided by the optical gain unit and adjusting the wavelength interval by moving the selected wavelength signal along a wavelength axis within the bandwidth of the optical gain unit;
And a light output coupler for dividing and coupling the specific wavelength signal selected by the wavelength selector to simultaneously oscillate light having a plurality of wavelengths within the bandwidth of the optical gain section and simultaneously outputting a plurality of wavelengths varying according to a change in time And the laser light source is configured to emit light. The method according to claim 1,
Wherein the laser light source comprises a ring-shaped resonator or a linear resonator. The method according to claim 1,
Wherein the wavelength selector adjusts the wavelength interval so that at least two or more wavelengths are included in the bandwidth of the optical gain unit. The method according to claim 1,
Wherein a number of different wavelengths included in light oscillated by the optical output coupler is equal to or smaller than a value obtained by dividing the wavelength interval adjusted by the wavelength selector in a bandwidth of the optical gain unit. A laser light source according to any one of claims 1 to 4, wherein a laser light source oscillates light having at least two wavelengths simultaneously generated from a light source and changes two or more wavelengths simultaneously according to a change in time,
An optical output distributing unit for dividing and outputting at least two wavelengths simultaneously generated from the laser light source for different wavelength regions,
And at least two light-receiving units for measuring a signal output from the light output distribution unit and varying a plurality of wavelengths simultaneously according to a change of time. 6. The method of claim 5,
Wherein the number of the light receiving units is equal to or greater than the number of wavelengths oscillated in the laser light source. A laser light source that oscillates at least two wavelengths simultaneously generated from a light source and simultaneously changes two or more wavelengths according to a change of time,
An optical interferometer for generating a combined interference light by reflecting a plurality of wavelengths simultaneously generated from the laser light source on a measurement plane and a reference plane,
An optical output distributing unit for dividing and outputting the combined interference light from the optical interferometer into a plurality of different wavelengths,
And at least two light-receiving units for measuring an interference signal output from the light output distribution unit. 8. The method of claim 7,
Wherein the optical interferometer calculates a measurement range of the interference signal using a value determined through a relative comparison of central wavelengths corresponding to the number of wavelengths simultaneously oscillated in the laser light source. 8. The method of claim 7,
Wherein the number of the light receiving units is equal to or greater than the number of wavelengths oscillated in the laser light source.
KR1020140092151A 2014-07-21 2014-07-21 Laser source by simultaneously varying to change of time using multiwavelength-swept and optical system using it KR20160011099A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102179521B1 (en) 2019-10-31 2020-11-17 부산대학교 산학협력단 Dual variable-based oscillating optical frequency scanning laser light source and Apparatus for measuring using the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102179521B1 (en) 2019-10-31 2020-11-17 부산대학교 산학협력단 Dual variable-based oscillating optical frequency scanning laser light source and Apparatus for measuring using the same

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