CN208045930U - A kind of optical fiber laser of length scanning - Google Patents
A kind of optical fiber laser of length scanning Download PDFInfo
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- CN208045930U CN208045930U CN201820354508.5U CN201820354508U CN208045930U CN 208045930 U CN208045930 U CN 208045930U CN 201820354508 U CN201820354508 U CN 201820354508U CN 208045930 U CN208045930 U CN 208045930U
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Abstract
The utility model discloses a kind of optical fiber lasers of length scanning, including resonant cavity, fiber optic collimator mirror, the optical fiber filter and speculum that narrow linewidth quickly scans, resonant cavity is by semiconductor optical amplifier, optical fiber circulator and coupler composition, optical fiber filter is made of plane reflection grating and resonant mirror, the fluorescence of semiconductor optical amplifier transmitting passes through optical fiber circulator, fiber optic collimator mirror and resonant mirror are irradiated on plane reflection grating, the incident light of different wave length is diffracted into different directions after plane reflection grating, one of wavelength is impinged perpendicularly under some incidence angle of resonant mirror on speculum and backtracking, it is coupled into semiconductor optical amplifier, resonance amplification forms laser, it is exported via coupler.The utility model generates the very narrow laser light source of line width in each moment, and wavelength does mechanical periodicity or scanning at any time, and signal-to-noise ratio greatly improves, and the resolution ratio of spectrum greatly improves, and sweep speed can be more up to tens of thousands of times per second.
Description
Technical field
The utility model is related to laser light source technical fields, and in particular to a kind of optical fiber laser of length scanning.
Background technology
When optical-fiber laser passes through beam splitter, it is divided into two-way, all the way as light is referred to, another way passes through lens imaging system
When focusing illumination organic organization, there is scattering in organic organization to incident light, when scatter light with reference to the interference of light when, interference signal it is strong
The phase of scattering strength of the degree depending on organic organization, interference signal depends on scattering depth and optical source wavelength, but interference signal
It is very faint.Therefore, the interference of light and reference light is scattered to Mr. Yu's depth, the phase of interference signal only depends on the wave of light
Long, there are one additional phase shifts for the scattering interference of light of different depth.
When the wavelength of light fixes frequency high-velocity scanning, all interference signals from different depth are all with the wavelength of light
The mechanical periodicity of same frequency is done, therefore up to tens thousand of times of amplification can be carried out to the AC signal, is effectively detected out not
Scattering with tissue to light, to realize to the real-time non-invasively imaged of organic organization.Therefore, the key technology of the imaging is wavelength
The fiber laser light source quickly scanned.Specifically, imaging depth depends on scattering loss of the organic organization to light, and depth bounds take
Certainly in the coherence length of optical-fiber laser, depth resolution depends on the range of length scanning.
Utility model content
Technical problem to be solved in the utility model is to reduce cost, and wave is realized using ready-made fiber optic communication component
Long scan.
In order to solve the above-mentioned technical problem, technical solution used by the utility model is to provide a kind of light of length scanning
Fibre laser, including optical fiber filter and speculum that resonant cavity, fiber optic collimator mirror, narrow linewidth quickly scan, the resonance
Chamber is made of semiconductor optical amplifier SOA, optical fiber circulator and coupler, the optical fiber filter by plane reflection grating and
Resonant mirror forms,
The fluorescence of the semiconductor optical amplifier SOA transmittings passes through the optical fiber circulator, the fiber optic collimator mirror and institute
It states resonant mirror to be irradiated on the plane reflection grating, the incident light of different wave length is diffracted into after the plane reflection grating
Different directions, one of wavelength impinge perpendicularly on the speculum and former under some incidence angle of the resonant mirror
Road returns, and is coupled into the semiconductor optical amplifier SOA, and resonance amplification forms laser, exported via the coupler.
Preferably, the instantaneous line width of the optical fiber laser depends on the institute that the plane reflection grating and resonant mirror form
State the line width of optical fiber filter.
Preferably, the plane reflection grating diffration grating equation is：
Λ [sin (θ)+sin (β)]=m λ；
Wherein, θ and β is respectively angle of light and the angle of diffraction, and Λ is screen periods, and m is the order of diffraction, and λ is incident light true
Aerial wavelength；
When light again passes by the plane reflection grating along backtracking, grating dispersion is represented by：
Preferably, according to Gaussian beam, the optical fiber filter that is made of the plane reflection grating and resonant mirror
Line width is expressed as：
Wherein, W is width of light beam, and W/cos θ are that light beam is radiated at the width on the plane reflection grating, and N shines for light beam
The raster diffraction stripe number being mapped to；
When the resonant mirror rotates Δ φ angles, incidence angle variation of the light beam on the plane reflection grating is 2 Δs
φ, the maximum rotation angle Δ φ of the resonant mirror0Corresponding wavelength change is wavelength scanning range Δ λ, according to described
Plane reflection grating diffration grating equation, wavelength scanning range Δ λ are represented by：
Δλ≈2Δφ(t)Λcos(θ0)。
Preferably, the cycle period of light turns over line width δ λ much smaller than the optical fiber filterGratingTime.
Preferably, in order to realize wavelength mode locking, the length for the fibre delay line being inserted into the optical path is：
Wherein, f is the frequency of the optical fiber filter, and n is optical fibre refractivity.
Preferably, the wavelength line width of the optical fiber laser output is δ λ, is less than the line width δ λ of the optical fiber filterGrating,
Depending on the resonant loss of the resonant cavity, the coherence length of the optical fiber laser is expressed as：
Preferably, the optical fiber of the fiber optic collimator mirror and the composition resonant cavity is polarization-maintaining single-mode fiber or non-polarization-maintaining list
Mode fiber, when the optical fiber for constituting the resonant cavity is non-polarization-maintaining single-mode fiber, by increasing optical fiber controller adjustment control light
Polarization orientation.
Preferably, dispersion compensation device is equipped between the plane reflection grating and resonant mirror.
Preferably, output end is coupled out light appropriate as feedback, controls the resonant frequency of the resonant mirror, to remain same
Step resonance.
The utility model proposes a kind of optical fiber laser of length scanning, generate that line width is very narrow to swash in each moment
Radiant, and wavelength does mechanical periodicity or scanning at any time, and complicated spectral measurement is made to become simple time resolved spectroscopy
It measures, signal-to-noise ratio greatly improves, and the resolution ratio of spectrum greatly improves, and sweep speed can be more up to tens of thousands of times per second, can be used for
Optical coherence tomography (OCT) is imaged and is diagnosed for eye ground structure and vascular distribution.
Description of the drawings
Fig. 1 is a kind of optical fiber laser structure schematic diagram of length scanning in the utility model；
Fig. 2 is the optical fiber laser structure schematic diagram of the utility model medium wave long scan mode locking；
Fig. 3 is the output light spectrogram of the optical fiber laser of the utility model medium wave long scan.
Specific implementation mode
In order to reduce cost, using ready-made fiber optic communication component, the utility model proposes a kind of length scannings
Optical fiber laser generates the very narrow laser light source of line width in each moment, and wavelength does mechanical periodicity or scanning at any time, makes
Complicated spectral measurement becomes simple time resolved spectroscopy and measures, can be used for optical coherence tomography (OCT) imaging with
And it is diagnosed for eye ground structure and vascular distribution.
The utility model is described in detail with specific implementation mode with reference to the accompanying drawings of the specification.
The utility model embodiment provides a kind of optical fiber laser of length scanning, as shown in Figure 1, including resonant cavity,
The optical fiber filter and speculum 20 that fiber optic collimator mirror 10, narrow linewidth quickly scan, resonant cavity is by semiconductor optical amplifier
SOA30, optical fiber circulator 40 and coupler 50 form, and optical fiber filter is made of plane reflection grating 60 and resonant mirror 70,
The fluorescence of semiconductor optical amplifier SOA30 transmittings passes through optical fiber circulator 40, fiber optic collimator mirror 10 and resonant mirror 70
It being irradiated on plane reflection grating 60, the incident light of different wave length is diffracted into different directions after plane reflection grating 60,
One of wavelength is impinged perpendicularly under some incidence angle of resonant mirror 70 on speculum 20 and backtracking, is coupled into
Semiconductor optical amplifier SOA30, resonance amplification form laser, are exported via coupler 50.
Resonant mirror 70 can realize length scanning using the off-resonance speculum of high speed resonant speculum or Linear Driving.
The coupling efficiency of coupler 50 is variable, can optimize the line width and power of laser output.
Fiber optical circulator 40 has the function of isolator so that light can only pass through semiconductor optical amplifier according to a direction
SOA30 and amplification of resonating forms laser, then exported by coupler 50.So that the fiber laser light source of length scanning is in each wink
Between generate the very narrow laser light source of line width, and wavelength does mechanical periodicity or scanning at any time, and complicated spectral measurement is made to become letter
Single time resolved spectroscopy measures.
The instantaneous line width of optical fiber laser depends primarily on the optical fiber filtering that plane reflection grating 60 and resonant mirror 70 form
The line width of device.
The diffraction grating equation of plane reflection grating 60 is：
Λ [sin (θ)+sin (β)]=m λ；
Wherein, θ and β is respectively angle of light and the angle of diffraction, and Λ is screen periods, and m is the order of diffraction, and λ is incident light true
Aerial wavelength；
When light again passes by plane reflection grating 60 along backtracking, grating dispersion is represented by：
In view of Gaussian beam, the line width for the optical fiber filter being made of plane reflection grating 60 and resonant mirror 70 indicates
For：
Wherein, W is width of light beam, and W/cos θ are that light beam is radiated at the width on plane reflection grating 60, and N irradiates for light beam
The raster diffraction stripe number arrived, the wider light beam of use can be irradiated to more raster diffraction stripes, so that optical fiber is filtered
The line width of wave device is narrower, in addition, using the plane reflection grating 60 of high fringe density, can equally make the line of optical fiber filter
Width is narrower.
When resonant mirror 70 rotates Δ φ angles, incidence angle variation of the light beam on plane reflection grating 60 is 2 Δ φ, altogether
The maximum rotation angle Δ φ of galvanometer 700Corresponding wavelength change is wavelength scanning range Δ λ, according to plane reflection grating
60 diffraction grating equation, wavelength scanning range Δ λ are represented by：
Δλ≈2Δφ(t)Λcos(θ0)。
We used small variable approximation sinx ≈ x (x < < 1) herein.The maximum rotation angle Δ φ of resonant mirror 700
Corresponding wavelength change is wavelength scanning range Δ λ or free spectral range (FSR).In order to allow the light of some wavelength to exist
The enough numbers of oscillation in resonant cavity and amplified, then the length of resonant cavity must be short as much as possible, the cycle of light one week when
Between line width δ λ are turned over much smaller than optical fiber filterGratingTime.
As shown in Fig. 2, realize resonance amplification to allow the light of each wavelength to can be transferred through optical fiber filter, it can be in the optical path
Be inserted into one section of fibre delay line, allow just by the wavelength of optical fiber filter at the time of next cycle is identical again by light
Fiber filter, such optical fiber filter is synchronous in resonator cavity resonance with light, i.e., wavelength be locked out or wavelength mode locking optical fiber
Laser.
In order to realize wavelength mode locking, the length for the fibre delay line being inserted into the optical path is：
Wherein, f is the frequency of optical fiber filter, and n is optical fibre refractivity.As f=8kHz, n=1.47, fibre delay line
L=1.275 kilometers of length.When fibre delay line is inserted in the light path of fiber optic collimator mirror 10, it is the length of be inserted in it is humorous
The half of the length for intracavitary of shaking.
The wavelength line width of optical fiber laser output is δ λ, is less than the line width δ λ of optical fiber filterGrating, depend on resonant cavity
The coherence length of resonant loss, optical fiber laser is expressed as：
Fiber optic collimator mirror 10 and the optical fiber for constituting resonant cavity are polarization-maintaining single-mode fiber or non-polarization-maintaining single-mode fiber, work as composition
When the optical fiber of resonant cavity is non-polarization-maintaining single-mode fiber, the polarization orientation for increasing optical fiber controller adjustment control light is needed.
In order to which the wavelength in a broadband can synchronously multipass be made of resonant mirror 70 and plane reflecting grating 60
Optical fiber filter, between plane reflection grating 60 and resonant mirror 70 be equipped with corresponding dispersion compensation device.
Output end is coupled out light appropriate (light that the present embodiment is 10%) as feedback, controls the resonance frequency of resonant mirror 70
Rate, to maintain synchro-resonance, to obtain stable luminous power output.After the resonant frequency of resonant mirror 70 is stablized, pass through tune
The driving current of whole semiconductor optical amplifier SOA30 further maintains light power stabilising.By setting semiconductor optical amplifier
The driving current limit of SOA30 works normally model to ensure that the adjustment of driving current does not exceed semiconductor optical amplifier SOA30
It encloses.
As shown in figure 3, the output light spectrogram of the optical fiber laser quickly scanned for wavelength, in each moment, wavelength is swept
The optical fiber laser output retouched is the very narrow laser light source of a line width.Since wavelength is scanning, time averagely upper this swashs
Radiant is equivalent to wideband light source, and according to the characteristic of laser resonant, power and spectral bandwidth are far wider than similar wideband light source.
Such as 1310 nano waveband semiconductor laser super-fluorescence light source spectral width about 70nm, the scanning of the wave band
Light source is obtained with 150 nanometers.For typical 5 milliwatt wideband light source, power is distributed in 70 nano wave length bandwidth.So
And scanning light source is but readily available 40-50 milliwatts, optical power distribution is in 0.1 nanometer or narrower of wave-length coverage.Unit light
The luminous power of wavelength is 1000-10000 times of common wide light source.Therefore, the fiber laser light source of length scanning removes and is applied to
Optical tomography (OCT) imaging is outer, applies also for light sensing, signal-to-noise ratio greatly improves.
When the measurement of luminous power is synchronous with length scanning, change curve, that is, spectrum of power and time, light source is equal to
One spectrometer.The resolution ratio of spectrum can be much better than bulky expensive spectrometer, and sweep speed can be more up to
Tens of thousands of times per second or higher.This is that conventional spectrograph is unable to reach.
The utility model is not limited to above-mentioned preferred forms, anyone knot made under the enlightenment of the utility model
Structure changes, every to have same or similar technical solution with the utility model, each fall within the scope of protection of the utility model it
It is interior.
Claims (10)
1. a kind of optical fiber laser of length scanning, which is characterized in that quickly swept including resonant cavity, fiber optic collimator mirror, narrow linewidth
The optical fiber filter and speculum retouched, the resonant cavity is by semiconductor optical amplifier SOA, optical fiber circulator and coupler group
At, the optical fiber filter is made of plane reflection grating and resonant mirror,
The fluorescence of semiconductor optical amplifier SOA transmitting passes through the optical fiber circulator, the fiber optic collimator mirror and described total
Galvanometer is irradiated on the plane reflection grating, and the incident light of different wave length is diffracted into difference after the plane reflection grating
Direction, one of wavelength impinges perpendicularly on the roads the speculum Shang Bingyuan under some incidence angle of the resonant mirror and returns
It returns, is coupled into the semiconductor optical amplifier SOA, resonance amplification forms laser, exported via the coupler.
2. the optical fiber laser of length scanning as described in claim 1, which is characterized in that the instantaneous line of the optical fiber laser
Width depends on the line width for the optical fiber filter that the plane reflection grating and resonant mirror form.
3. the optical fiber laser of length scanning as claimed in claim 2, which is characterized in that the plane reflection grating diffration
Grating equation is：
Λ [sin (θ)+sin (β)]=m λ；
Wherein, θ and β is respectively angle of light and the angle of diffraction, and Λ is screen periods, and m is the order of diffraction, λ be incident light in a vacuum
Wavelength；
When light again passes by the plane reflection grating along backtracking, grating dispersion is represented by：
4. the optical fiber laser of length scanning as claimed in claim 3, which is characterized in that according to Gaussian beam, by described flat
The line width of the optical fiber filter of face reflecting grating and resonant mirror composition is expressed as：
Wherein, W is width of light beam, and W/cos θ are that light beam is radiated at the width on the plane reflection grating, and N is irradiated to for light beam
Raster diffraction stripe number；
When the resonant mirror rotates Δ φ angles, incidence angle variation of the light beam on the plane reflection grating is 2 Δ φ, institute
State the maximum rotation angle Δ φ of resonant mirror0Corresponding wavelength change is wavelength scanning range Δ λ, anti-according to the plane
Grating diffration grating equation is penetrated, wavelength scanning range Δ λ is represented by：
Δλ≈2Δφ(t)Λcos(θ0)。
5. the optical fiber laser of length scanning as claimed in claim 4, which is characterized in that the cycle period of light is less than the light
Fiber filter turns over line width δ λGratingTime.
6. the optical fiber laser of length scanning as claimed in claim 5, which is characterized in that in order to realize wavelength mode locking, in light
The length for the fibre delay line being inserted into road is：
Wherein, f is the frequency of the optical fiber filter, and n is optical fibre refractivity.
7. the optical fiber laser of length scanning as claimed in claim 6, which is characterized in that the wave of the optical fiber laser output
Long line width is δ λ, is less than the line width δ λ of the optical fiber filterGrating, the resonant loss of the resonant cavity is depended on, the optical fiber swashs
The coherence length of light device is expressed as：
8. the optical fiber laser of length scanning as described in claim 1, which is characterized in that the fiber optic collimator mirror and composition
The optical fiber of the resonant cavity is polarization-maintaining single-mode fiber or non-polarization-maintaining single-mode fiber, when the optical fiber for constituting the resonant cavity is non-polarization-maintaining
When single mode optical fiber, by the polarization orientation for increasing optical fiber controller adjustment control light.
9. the optical fiber laser of length scanning as described in claim 1, which is characterized in that the plane reflection grating and resonance
Dispersion compensation device is equipped between mirror.
10. the optical fiber laser of length scanning as described in claim 1, which is characterized in that output end is coupled out light appropriate
As feedback, the resonant frequency of the resonant mirror is controlled, to maintain synchro-resonance.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108365509A (en) * | 2018-03-15 | 2018-08-03 | 执鼎医疗科技（杭州）有限公司 | A kind of optical fiber laser of length scanning |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108365509A (en) * | 2018-03-15 | 2018-08-03 | 执鼎医疗科技（杭州）有限公司 | A kind of optical fiber laser of length scanning |
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