U.S. patent application number 15/431084 was filed with the patent office on 2018-05-17 for apparatus and method for stabilizing a light.
This patent application is currently assigned to Myongji University Industry and Academia Cooperation Foundation. The applicant listed for this patent is Myongji University Industry and Academia Cooperation Foundation. Invention is credited to Dong Sun Seo, Yong Yuk Won.
Application Number | 20180138653 15/431084 |
Document ID | / |
Family ID | 62091514 |
Filed Date | 2018-05-17 |
United States Patent
Application |
20180138653 |
Kind Code |
A1 |
Seo; Dong Sun ; et
al. |
May 17, 2018 |
APPARATUS AND METHOD FOR STABILIZING A LIGHT
Abstract
An apparatus and a method for stabilizing output of a light
source are disclosed. The stabilization device located outside of a
light source comprises a stabilization element, and a stabilization
controller configured to control a light output from the light
source so that a part of the light output and other part of the
light cross propagate in the stabilization element.
Inventors: |
Seo; Dong Sun; (Yongin,
KR) ; Won; Yong Yuk; (Paju, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Myongji University Industry and Academia Cooperation
Foundation |
Yongin |
|
KR |
|
|
Assignee: |
Myongji University Industry and
Academia Cooperation Foundation
|
Family ID: |
62091514 |
Appl. No.: |
15/431084 |
Filed: |
February 13, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01S 3/13013 20190801;
H01S 3/06779 20130101; H01S 3/1306 20130101; H01S 3/067 20130101;
H01S 3/06754 20130101; H01S 3/005 20130101; H01S 3/1001 20190801;
H01S 3/1608 20130101; H01S 3/1305 20130101 |
International
Class: |
H01S 3/13 20060101
H01S003/13; H01S 3/067 20060101 H01S003/067 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2016 |
KR |
10-2016-0152448 |
Claims
1. A stabilization device located outside a light source
comprising: a stabilization element configured to stabilize a
spectrum of a light outputted from a light source by reducing phase
noise of the light; and a stabilization controller configured to
control the light that a part of the output of the light source and
the other part of the light cross propagate in the stabilization
element, wherein the stabilization device is a periodic loss/gain
device and uses an erbium doped fiber (EDF.
2. (canceled)
3. The stabilization device of claim 1, wherein the stabilization
controller includes: an optical divider configured to divide the
output of a light source; and an optical circulator configured to
output a light passing through the stabilization element, and
wherein the optical circulator propagates some of a light not
passing through the stabilization element to the stabilization
element.
4. A light generator comprising: a light source configured to
output a light; and a stabilization device configured to perform a
stabilization operation of a spectrum of a part of the light output
from a light source and the other part of the light, respectively,
wherein the stabilization device is a periodic loss/gain device and
uses an erbium doped fiber (EDF).
5. The light generator of claim 4, wherein the stabilization device
includes: a stabilization element; and a stabilization controller
configured to control the light output from the light source so
that the part of the light output and the other part cross
propagate in the stabilization element.
6. The light generator of claim 5, wherein the stabilization
controller includes: an optical divider configured to divide a
light output from a light source; and an optical circulator
configured to output a light passing through the stabilization
element, and wherein the optical circulator propagates some of a
light not passing through the stabilization element to the
stabilization element.
7. A method of stabilizing output of a light, the method
comprising: stabilizing a spectrum of a part of a light output from
a light source by reducing phase noise of the part of the light;
stabilizing a spectrum of the other part of the light output from
the light source; and producing further stabilized light, wherein
the part of the light and the other part of the light cross
propagate in a stabilization element, and a stabilization device
for the stabilizing is a periodic loss/gain device and uses an
erbium doped fiber (EDF).
8. A stabilization device located outside a light source
comprising: a stabilization element to divide the output of a light
source and single pass and/or cross propagate in the stabilization
element for stabilizing a spectrum of the light; and an optical
reflector configured to reflect a light to single pass and/or cross
propagate through the stabilization element and the stabilization
element is a periodic loss/gain device and uses an erbium doped
fiber (EDF).
9. The stabilization device of claim 8, further comprising: an
optical circulator configured to deliver the light output from the
light source to the stabilization element, wherein the optical
circulator outputs a light transmitted through the stabilization
element.
10. (canceled)
11. The stabilization device of claim 9, wherein the light injects
from the optical circulator to the periodic loss/gain device and
the light delivers to the periodic loss/gain device after reflected
by the optical reflector to cross propagate in the periodic
loss/gain device.
12. The stabilization device of claim 9, wherein the optical
reflector performs a function of amplifying the light transmitted
from the stabilization element as well as a function of reflecting
the light.
13. A method of stabilizing output of a light, the method
comprising: stabilizing a spectrum of a light output from a light
source by passing the light through a stabilization element;
re-stabilizing the stabilized light by reflecting the stabilized
light to counter propagate through the stabilization element; and
producing the re-stabilized light, wherein a stabilization device
for the stabilizing is a periodic loss/gain device and uses an
erbium doped fiber (EDF).
14. The method of claim 13, wherein the stabilized light is
amplified and the amplified stabilized light is reflected to
counter propagate through the stabilization element.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. .sctn.
119(a) to Korean Application No. 10-2016-0152448 filed on Nov. 16,
2016, the entire disclosure of which is incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present disclosure relates to an apparatus and method
for stabilizing the output of a pulsed or CW (continuous wave)
light source.
RELATED ART
[0003] To apply a light source to various fields, it is necessary
to enhance the performance (stability) of the light source.
[0004] A conventional technique inserts specific components inside
a light source (such as a laser resonator) or injects externally a
stabilized light into the light source, so as to enhance the
stability of the light source which operates in pulsed (mode-locked
laser, gain switching laser, etc.) or continuous wave (CW).
[0005] However, the inserted device(s) and/or externally injected
light in conventional techniques change the characteristics of the
laser output. For example, in a pulsed laser, its characteristics
such as pulse period, width, spectrum, and so on, may be changed.
In a CW laser, the characteristics such as oscillation frequency,
etc. may be altered.
SUMMARY
[0006] The invention has been made to address at least the
disadvantages and problems described above, and to provide at least
the advantages described below. An aspect of the invention provides
an apparatus and method for enhancing stability of a light source
by passing simply the light output through a stabilization device
(such as a periodic loss/gain device) without changing the
characteristics of a light source.
[0007] According to one embodiment of the invention, a
stabilization device located outside a light source comprising: a
stabilization element; and a stabilization controller configured to
control the light output so that a part of the light and the other
part of the light cross propagate in the stabilization element.
[0008] According to one embodiment of the invention, a light
generator comprising: a light source configured to output a light;
and a stabilization device configured to perform stabilization
operation for both parts of the cross propagating light.
[0009] According to one embodiment of the invention, a method of
stabilizing output of a light comprising: stabilizing a part of
output of a light source; stabilizing other part of the output; and
producing the stabilized light. Here, the part of the light and the
other part of the light cross propagate in a stabilization
element.
[0010] According to another embodiment of the invention, a
stabilization device located outside a light source comprising: a
stabilization element to which the output of a light source is
injected; and an optical reflector configured to reflect the
injected light and to re-inject the reflected light into the
stabilization element. Here, the direct light output and the
reflected light by the optical reflector cross propagate through
the stabilization element.
[0011] According to another embodiment of the invention, a method
of stabilizing output of a light comprising: stabilizing the output
of a light source by (single) passing the light through a
stabilization element; maximizing the stabilization performance by
reflecting and cross propagating the stabilized light through the
stabilization element; and producing the re-stabilized light.
[0012] An apparatus and method for stabilizing a light according to
the invention make a part of the output of a light source and the
other part of the light cross propagate in a stabilization element,
and thus stability of output of the light may be enhanced.
BRIEF DESCRIPTION OF DRAWINGS
[0013] The aspects, features, advantages and embodiments of the
invention will be more apparent from the following detailed
description taken in conjunction with reference to the accompanying
drawings, in which:
[0014] FIG. 1 is a block diagram illustrating a light generator
according to one embodiment of the invention;
[0015] FIG. 2 is a block diagram illustrating a stabilization
device according to one embodiment of the invention;
[0016] FIG. 3 is a block diagram illustrating a stabilization
device including a stabilization controller according to one
embodiment of the invention; and
[0017] FIG. 4 is a block diagram illustrating a light generator
according to another embodiment of the invention.
DETAILED DESCRIPTION
[0018] In the present specification, an expression used in the
singular encompasses the expression of the plural, unless it has a
clearly different meaning in the context. In the present
specification, terms such as "comprising" or "including," etc.,
should not be interpreted as meaning that all of the elements or
operations are necessarily included. That is, some of the elements
or operations may not be included, while other additional elements
or operations may be further included. Also, terms such as "unit,"
"module," etc., as used in the present specification may refer to a
part for processing at least one function or action and may be
implemented as hardware, software, or a combination of hardware and
software.
[0019] The invention relates to an apparatus for stabilizing output
of a light source (such as, laser), and enhances the stability of
the light by using a simple method of passing the light output from
a light source through an external stabilization element.
Specially, the invention provides a technique for enhancing
stability of output of the light, without changing the original
output characteristics of the light. The timing jitter and phase
noise of the pulsed light source are reduced or the phase noise of
a CW light source is decreased according to the enhancement of
their stability.
[0020] In one embodiment, the invention increases a spatial hole
burning effect by cross propagating a part of the light and the
other part of the light in the stabilization element. As a result,
the phase noise (or timing jitter) of a CW light (or pulsed light)
is considerably reduced, thereby enhancing the stability of the CW
light (or pulsed light).
[0021] Hereinafter, embodiments of the invention will be described
in detail with reference to accompanying drawings.
[0022] FIG. 1 is a block diagram illustrating a light generator
according to one embodiment of the invention, and FIG. 2 is a block
diagram illustrating a stabilization device according to one
embodiment of the invention.
[0023] In FIG. 1, the light generator of the present embodiment
includes a light source 100 in continuous or pulsed wave and a
stabilization device 102.
[0024] The stabilization device 102 stabilizes a light output from
the light source 100 and produces the stabilized light.
[0025] In one embodiment, a part of the light output from the light
source 100 and the other part of the light cross propagate in the
stabilization element of the stabilization device 102, thereby
enhancing stability of the light output.
[0026] Particularly, the stabilization device 102 may include a
stabilization controller 200 and a periodic loss/gain device 202 as
the stabilization element as shown in FIG. 2, so as to enhance the
stabilization of the light.
[0027] The periodic loss/gain device 202 performs an operation of
stabilizing the light, and may use for example an erbium doped
fiber (EDF).
[0028] The EDF performs an active operation of amplifying (or
attenuating) an injected light unlike the conventional optical
fiber for performing only passive operation of propagating a light.
As a result, the propagation loss of the optical fiber may be
minimized or the propagation gain may occur in only a specific
condition.
[0029] The stabilization controller 200 passes the output of the
light source 100 through the periodic loss/gain device 202, thereby
enhancing the stability of the light.
[0030] Particularly, the stabilization controller 200 controls
propagation of the light so that the light can pass through the
periodic loss/gain device 202.
[0031] On the other hand, a technique that a periodic loss/gain
device is installed inside a light source may be considered.
However, it results in characteristic change of output of the
light.
[0032] Whereas, if the periodic loss/gain device 202 is established
outside of the light source 100, it may enhance stability of the
output of the light source without changing the output
characteristics of the light source.
[0033] Specially, the light propagates through the periodic
loss/gain device 202 under the condition that the periodic
loss/gain device 202 is established outside of the light source
100. As a result, the stability of the output of the light source
is enhanced by passing simply through the periodic loss/gain device
202 which is established outside of the light source 100.
[0034] It enhances even further the stability if a part of the
light from the light source 100 and the other part of the light
cross propagates in the periodic loss/gain device 202 as shown in
FIG. 3. Of course, it is possible to enhance the stability of the
light from the light source 100 by simply propagating through the
periodic loss/gain device 202 in case that the cross propagation of
the light through the periodic loss/gain device 202 is
impractical.
[0035] FIG. 3 is a block diagram illustrating a stabilization
device including a stabilization controller according to one
embodiment of the invention.
[0036] In FIG. 3, the stabilization device 200 of the present
embodiment may include an optical divider 300 and an optical
circulator 302.
[0037] The optical divider 300 divides the output of the light
source 100. Particularly, the optical divider 300 may propagate a
part of the output to the optical circulator 302 and transmit the
other part of the output to the periodic loss/gain device 202.
[0038] The optical circulator 302 delivers the part of the light
from the optical divider 300 (port 1) to the periodic loss/gain
device 202 (port 2), and transfers the other part of the light
passing through the periodic loss/gain device 202 (port 2) to the
output of the light (port 3).
[0039] In view of the periodic loss/gain device 202, a part of the
light divided by the optical divider 300 and the other part of the
light from the optical circulator 302 cross propagate through the
periodic loss/gain device 202, and the part of the light is
outputted through the port 3 of the optical circulator 302.
[0040] Briefly, the stabilization device of the present embodiment
makes the part of the light (CW or pulsed) and the other part of
the light cross propagate in the periodic loss/gain device 202,
thereby enhancing the stability of the output of the light source
100.
[0041] In another view, the stabilization device of the invention
may divide the light output from the light source 100 into the part
of the light and the other part of the light, and then perform a
stabilization operation about the part of the light and the other
part of the light, respectively.
[0042] In view of a method, an operation of stabilizing the light
of the invention may include a step of dividing the light output
from the light source 100 into the part of the light and the other
part of the light, a step of stabilizing the part of the light by
passing the part of the light through the periodic loss/gain device
202, a step of stabilizing the other part of the light by passing
the other part of the light through the periodic loss/gain device
202, and a step of producing the stabilization light. Here, the
part of the light and the other part of the light may cross
propagate in the periodic loss/gain device 202.
[0043] FIG. 4 is a block diagram illustrating a light generator
according to another embodiment of the invention.
[0044] In FIG. 4, the light generator of the present embodiment may
include a light source 400, an optical circulator 402, a
stabilization element (such as a periodic loss/gain device) 404 and
an optical reflector 406.
[0045] The light source 400 outputs a light, for example may be a
CW or pulsed laser.
[0046] The optical circulator 402 located outside the light source
400, delivers the light output (port 1) from the light source 400
to the periodic loss/gain device 404 (port 2), and transfers the
reflected light (port 2) by the optical reflector 406 after passing
through the periodic loss/gain device 404, to the output (port 3)
of a (stabilized) light.
[0047] The periodic loss/gain device 404 performs an operation of
stabilizing the light, and may use for example an EDF.
[0048] The optical reflector 406 may reflect the light transmitted
from the periodic loss/gain device 404 to re-inject the reflected
light to the periodic loss/gain device 404.
[0049] In one embodiment, the optical reflector 406 may perform a
function of amplifying the light as well as a function of
reflecting the light. In this case, the optical reflector 406 may
compensate any loss of the periodic loss/gain device 404.
[0050] The light reflected by the optical reflector 406 is
transmitted to the optical circulator 402 through the periodic
loss/gain device 404, and then is outputted outside.
[0051] As a result, the output of the light source 400 and the
light reflected by the optical reflector 406 cross propagate in the
periodic loss/gain device 404. That is, the output of the light
source will be further stabilized by a hole burning effect due to
the cross propagation of the light.
[0052] In view of the periodic loss/gain device 404, the light
transmitted from the optical circulator 402 and the light reflected
by the optical reflector 406 cross propagate in the periodic
loss/gain device 404. That is, the light generator of the invention
enhances the stability of the light by using a way of cross
propagating the light in the periodic loss/gain device 404.
[0053] The embodiments of the invention described above are
disclosed only for illustrative purposes. A person having ordinary
skill in the art would be able to make various modifications,
alterations, and additions without departing from the spirit and
scope of the invention, but it is to be appreciated that such
modifications, alterations, and additions are encompassed by the
scope of claims set forth below.
* * * * *