CN101976799B - Air slot beam splitting method Fabry-Perot resonant cavity coupling laser - Google Patents

Abstract

The invention discloses an air slot beam splitting Fabry-Perot resonant cavity coupling laser. A Fabry-Perot resonant cavity comprises an air slot, two waveguides and two high-reflectivity reflectors, wherein the air slot inclines to an active waveguide and can be filled with a medium; one waveguide and the active waveguide are coaxial and are respectively positioned at two sides of the air slot; angles between the two waveguides and the air slot are equal and positioned at the same side of the air slot and are coincide with the connecting port of the air slot; the high-reflectivity reflectors are respectively arranged on non-air slot connecting ports of the two waveguides; or tune electrodes cover the two waveguides and a phase matching electrode covers the active waveguide. Light is reflected and transmitted through the air slot for splitting beam. Two waveguides are additionally arranged to form the Fabry-Perot resonant cavity for selecting a die. The invention has the advantages of large free light spectrum range and low manufacture difficulty; and output wavelength of a laser can be largely tuned through regulating the optical length of the waveguides. The laser can operate in a single longitudinal mode.

Description

Air groove beam splitting Fabry Perot resonator coupled laser

Technical field

The present invention relates to a kind of semiconductor laser, but the air groove beam splitting Fabry Perot resonator coupled laser of particularly a kind of single longitudinal mode running.

Background technology

The semiconductor laser that occurred in 1962; With characteristics such as its conversion efficiency are high, volume is little, in light weight, but the high monolithic of reliability is integrated; Become the Primary Component in the information technology, be widely used in a plurality of fields such as interferometry, spectroscopy, optical communication, light sensing, laser processing.Particularly at optical communication field, along with the development of wavelength-division multiplex technique, requiring of noise spectra of semiconductor lasers performance and manufacture view is increasingly high.In optical-fiber network, need a large amount of semiconductor lasers that use, the cost performance that improves semiconductor laser is to reduce the key factor of optical-fiber network cost, also is the research emphasis of current optic communication device.

Semiconductor laser is different according to the structure of resonant cavity, can be divided into distributed feed-back formula laser, distribution reflective laser device, annular resonant cavity laser, polytypes such as Fabry-Perot cavity laser.

Annular resonant cavity laser is a kind of volume semiconductor laser little, simple in structure, and its manufacturing process is simple.Compare distributed feed-back formula laser and distribution reflective laser device needs electron beam lithography and regrowth, annular resonant cavity laser need not add these high accuracy technology, thereby has simplified manufacture process, reduced manufacturing cost.Simultaneously, annular resonant cavity laser has than distribution reflective laser utensil better narrow-band filtering characteristic is arranged.

But because the restriction of loop configuration itself; In design process; The diameter of ring will satisfy the requirement of manufacturing, cannot unrestrictedly dwindle, and need enough refringences to guarantee single mode in the waveguide; Cause the Free Spectral Range of this resonance-cavity laser to be restricted, can not satisfy some certain applications demands.Such as under the bigger situation of the gain spectral scope of gain media, because the Free Spectral Range of annular resonant cavity laser is less, the situation that has a plurality of patterns to be excited simultaneously can appear, output wavelength no longer has monochromaticjty.

In order to overcome above shortcoming, can increase the Free Spectral Range of semiconductor laser through two ring resonators of cascade.The photoelectron laboratory of background technology such as NTT Co., Ltd. (NTT) is described in the article " Full C-Band Tuning Operation ofSemiconductor Double-Ring Resonator-Coupled Laser With Low Tuning Current " that was published on the Photonics Technology Letters in 2007; As shown in Figure 1; Comprise active waveguide 1; Phase matched electrode 11, the first ring resonators 7 and second ring resonator 8; Promptly this semiconductor laser comprises between a gain region, phase control is interval and two ring resonators that Free Spectral Range is different.Each ring resonator is all through a 3dB multi-mode interference coupler and straight wave guide coupling.The light that produces between gain region has only the while all to obtain enough reflections at two ring resonators, i.e. two ring resonator reflection peaks coincidence place just can form laser.Because cursor effect; As shown in Figure 2; Through the different ring resonator of two of cascades reflection spectral line, the reflection peak spacing of the Crossed Circle resonant cavity that obtains is greater than the reflection peak spacing of any one ring resonator wherein, and promptly the Free Spectral Range of Crossed Circle resonant cavity is greater than single ring resonator.This method has enlarged Free Spectral Range, but has increased the complexity of structure, has improved manufacturing cost.

Summary of the invention

The object of the present invention is to provide a kind of air groove beam splitting Fabry Perot resonator coupled laser, use two waveguides to constitute Fabry Perot resonator, have big Free Spectral Range, can realize the single longitudinal mode running of laser.

The technical scheme that the present invention adopts is:

Technical scheme 1:

It comprises an active waveguide that gain is provided the present invention, a Fabry Perot resonator and a speculum that produces the pectination reflectance spectrum.Said Fabry Perot resonator by one with active waveguide tilt be 30 °～70 °, the inside fill air or low refractive index dielectric, be used for air groove Fabry Perot resonator, that do not lost by the light partial reflection of transmission is advanced in the light part transmission that produces in the active waveguide; First waveguide; Second waveguide, first high reflective mirror and second high reflective mirror are formed; First waveguide and the coaxial placement of active waveguide lay respectively at the both sides of air groove; Angle equates between second waveguide and first waveguide and the air groove, is positioned at the air groove homonymy; The connectivity port of the connectivity port of second waveguide and air groove and first waveguide and air groove partially overlaps; First high reflective mirror and second high reflective mirror are arranged at the place, non-NULL air drain connectivity port of first waveguide and second waveguide respectively.

Said first waveguide, thus all or part of being coated with of second waveguide can change the tuning electrode that its optical length changes the one of reflection peak position output wavelength; The active waveguide subregion is coated with the phase matched electrode.

Thereby all or part of being coated with of said second waveguide can change the tuning electrode of second waveguide that its optical length changes reflection peak position output wavelength; The optical length sum of the optical length sum of first waveguide and second waveguide and active waveguide and first waveguide is unequal.

Technical scheme 2:

It comprises an active waveguide that gain is provided the present invention, a Fabry Perot resonator that produces the pectination reflectance spectrum, and another produces the Fabry Perot resonator and the output waveguide of pectination reflectance spectrum.Said Fabry Perot resonator by one with active waveguide tilt be 30 °～70 °, the inside fill air or low refractive index dielectric, be used for air groove Fabry Perot resonator, that do not lost by the light partial reflection of transmission is advanced in the light part transmission that produces in the active waveguide; First waveguide; Second waveguide, first high reflective mirror and second high reflective mirror are formed; First waveguide and the coaxial placement of active waveguide lay respectively at the both sides of air groove; Angle equates between second waveguide and first waveguide and the air groove, is positioned at the air groove homonymy; The connectivity port of the connectivity port of second waveguide and air groove and first waveguide and air groove partially overlaps; First high reflective mirror and second high reflective mirror lay respectively at the place, non-NULL air drain connectivity port of first waveguide and second waveguide; Angle equates between said output waveguide and active waveguide and the air groove, is positioned at the air groove homonymy; Output waveguide and air groove connectivity port and active waveguide and air groove connectivity port partially overlap; Said another Fabry Perot resonator is positioned at the other end of active waveguide and Fabry Perot resonator connectivity port; Said another Fabry Perot resonator by one with active waveguide tilt be 30 °～70 °, the inside fill air or low refractive index dielectric, be used for another air groove another Fabry Perot resonator, that do not lost by the light partial reflection of transmission is advanced in the light part transmission that produces in the active waveguide; The 3rd waveguide; The 4th waveguide, the 3rd high reflective mirror and the 4th high reflective mirror are formed; The 3rd waveguide and the coaxial placement of active waveguide lay respectively at the both sides of another air groove; Angle equates between the 4th waveguide and the 3rd waveguide and another air groove, is positioned at another air groove homonymy; The 3rd waveguide and another air groove connectivity port and the 4th waveguide and another air groove connectivity port partially overlap; The 3rd high reflective mirror and the 4th high reflective mirror lay respectively at the place, non-NULL air drain connectivity port of the 3rd waveguide and the 3rd waveguide; Said first waveguide, the second waveguide optical length sum and the 3rd waveguide, the 4th waveguide optical length sum are unequal.

More than in two kinds of technical schemes, all be coated with highly reflecting films on said first high reflective mirror, second high reflective mirror, the 3rd high reflective mirror and the 4th high reflective mirror minute surface.

The beneficial effect that the present invention has is:

The present invention carries out beam splitting through air groove to reflection of light and transmission, has replaced the 3dB multi-mode interference coupler, has simple in structure and easily manufactured advantage.Constitute Fabry Perot resonator through additional two waveguides and carry out modeling, replaced ring shape resonator, have the advantage that Free Spectral Range is big and manufacture difficulty is low.Through regulating the optical length of waveguide, can be tuning on a large scale to laser output wavelength.But this laser single longitudinal mode running.

Description of drawings

Fig. 1 is the structural representation of the Crossed Circle resonance-cavity laser of a prior art.

Fig. 2 is the interval cursor effect sketch map of free spectrum.

Fig. 3 is first kind of execution mode structural representation of the present invention.

Fig. 4 is the reflectance spectrum sketch map of the Fabry Perot resonator that utilizes repeatedly interference theory to derive to obtain.

Fig. 5 is second kind of execution mode structural representation of the present invention.

Fig. 6 is the third execution mode structural representation of the present invention.

Fig. 7 is the 4th kind of execution mode structural representation of the present invention.

Among the figure: 1, active waveguide, 2, Fabry Perot resonator, 3, Fabry Perot resonator, 4, output waveguide; 5, speculum, 7, first ring resonator, 8, second ring resonator, 11, the phase matched electrode; 21, air groove, 23, first waveguide, 24, second waveguide, 25, first high reflective mirror; 26, second high reflective mirror, 27, tuning electrode, the tuning electrode of 28, second waveguide, 32, air groove; 33, the 3rd waveguide, the 34, the 4th waveguide, the 35, the 3rd high reflective mirror, the 36, the 4th high reflective mirror.

Embodiment

According to accompanying drawing and embodiment the present invention is further described below.

As shown in Figure 3, be first kind of execution mode structural representation of semiconductor laser of the present invention.This air groove beam splitting Fabry Perot resonator coupled laser comprises 1, one Fabry Perot resonator 2 and speculum 5 that produces the pectination reflectance spectrum of active waveguide that gain is provided.Said Fabry Perot resonator 2 by one with active waveguide 1 tilt be 30 °～70 °, the inside fill air or low refractive index dielectric, be used for air groove 21 Fabry Perot resonator 2, that do not lost by the light partial reflection of transmission is advanced in the light part transmission that produces in the active waveguide 1; First waveguide 23; Second waveguide, 24, the first high reflective mirrors 25 and second high reflective mirror 26 are formed; First waveguide 23 and active waveguide 1 coaxial placement lay respectively at the both sides of air groove 21; Angle equates between second waveguide 24 and first waveguide 23 and the air groove 21, is positioned at air groove 21 homonymies; Second waveguide 24 partially overlaps with the connectivity port of air groove 21 and the connectivity port of first waveguide 23 and air groove 21; First high reflective mirror 25 and second high reflective mirror 26 are arranged at the place, non-NULL air drain connectivity port of first waveguide 23 and second waveguide 24 respectively.

The light that produces in the active waveguide 1 comes back reflective between air groove 21 and speculum 5.In this process, part light gets into first waveguide 21 through air groove 21 transmissions, then in air groove 21, first high reflective mirror 25 and 26 repeatedly reflections of second high reflective mirror.Each light does not have light to pass through air groove 21 transmissions and gets into active waveguide 1 when reflection takes place for second waveguide 24 and air groove 21 interfaces.Each light all has part light to get into active waveguide 1 through air groove 21 transmissions when reflection takes place for first waveguide 23 and air groove 21 interfaces, forms feedback.

In order to analyze light after more than 2 reflection of Fabry Perot resonator, transmission gets into the feedback spectrum of active waveguide 1, and establishing initial incident light amplitude from active waveguide 1 directive air groove 21 directions is A ⁽ⁱ⁾ Process air groove 21 is t from the transmissivity of active waveguide 1 to first waveguide 23 directions; Through the transmissivity of air groove 21 from first waveguide, 23 directions to active waveguide 1 is t '; Through the air groove 21 sidewalls reflectivity from first waveguide 23 or second waveguide 24 to active waveguide 1 direction is r ', and the reflectivity of first high reflective mirror 25 is r ₁', the reflectivity of second high reflective mirror 26 is r ₂'.Obtain through after getting into first waveguide 23 after air groove 21 transmissions, the light beam vibration amplitude that active waveguide 1 is returned in transmission for the first time is tt ' r ₁' A ⁽ⁱ⁾With respect to the amplitude of this transmission for the first time, after this each time complex amplitude is respectively:

tt′r′ ²r ₁′ ²r ₂′e ^iδA ⁽ⁱ⁾、tt′r′ ⁴r ₁′ ³r ₂′ ²e ^i2δA ⁽ⁱ⁾、tt′r′ ⁶r ₁′ ⁴r ₂′ ³e ^i3δA ⁽ⁱ⁾、tt′r′ ⁸r ₁′ ⁵r ₂′ ⁴e ^i4δA ⁽ⁱ⁾...

Wherein δ is the phase difference that the optical path difference between adjacent twice transmitted light causes

l ₁, l ₂Be respectively the optical length of first waveguide 23 and second waveguide 24,

Be respectively the phase change that first waveguide 23 and second waveguide, 24 terminal high reflective mirror reflections cause, c is a light propagation velocity in a vacuum, and f is a light frequency.

To the complex amplitude summation of transmitted light repeatedly, obtain synthetic complex amplitude and be:

${\tilde{A}}^{\left(t\right)}=\underset{p=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{{\tilde{A}}_p}^{\left(t\right)}={\mathrm{tt}}^{\&prime;}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}^{\&prime;}{A}^{\left(i\right)}+{\mathrm{tt}}^{\&prime;}{r}^{\&prime;2}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}^{\&prime;2}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}^{\&prime;}{e}^{\mathrm{i\&delta;}}{A}^{\left(i\right)}+{\mathrm{tt}}^{\&prime;}{r}^{\&prime;4}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}^{\&prime;3}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}^{\&prime;2}{\mathrm{<figure-callout\; id="2"\; label="e\; i"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">e</figure-callout>}}^i{A}^{\left(i\right)}+\&CenterDot;\&CenterDot;\&CenterDot;$ (2)

$=\frac{{\mathrm{tt}}^{\&prime;}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}^{\&prime;}}{1-r^{\&prime;2}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}^{\&prime;}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}^{\&prime;}{e}^{\mathrm{i\&delta;}}}{A}^{\left(i\right)}$

So, the light intensity that feeds back to active waveguide 1 from Fabry Perot resonator 2 does

$I^{\left(t\right)}={\tilde{A}}^{\left(t\right)}\&CenterDot;{\tilde{A}}^{{\left(t\right)}^{*}}$

$=\frac{{\left({\mathrm{tt}}^{\&prime;}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}^{\&prime;}\right)}^2}{{(1-r^{\&prime;2}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}^{\&prime;}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}^{\&prime;})}^2+{4r}^{\&prime;2}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}^{\&prime;}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}^{\&prime;}{\sin }^2\frac{\mathrm{\&delta;}}{2}}{I}^{\left(i\right)}---\left(3\right)$

$=\frac{1}{{(\frac{1}{{\mathrm{tt}}^{\&prime;}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}^{\&prime;}}-\frac{r^{\&prime;2}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}^{\&prime;}}{{\mathrm{tt}}^{\&prime;}})}^2+\frac{{4r}^{\&prime;2}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}^{\&prime;}}{t^2{t}^{\&prime;2}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}^{\&prime;}}{\sin }^2\frac{\mathrm{\&delta;}}{2}}{I}^{\left(i\right)}$

According to formula (1) and (3), can obtain I ^(t)/ I ⁽ⁱ⁾With the sketch map 4 of the variation of frequency f, reflectance spectrum is pectination and distributes.Adjacent two peak-to-peak frequency-splittings of reflection are:

$\mathrm{\&Delta;f}=\frac{c}{2({\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">l</figure-callout>}}_1+l_2)}---\left(4\right)$

Only with the optical length total value l of first waveguide 23 and second waveguide 24 ₁+ l ₂Relevant (c is the light velocity in the vacuum).

And Free Spectral Range is:

$\mathrm{FSR}=\frac{{\mathrm{\&lambda;}}^2}{{2n}_d({\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">l</figure-callout>}}_1+l_2)}---\left(5\right)$

N wherein _dBe effective group index of waveguide, λ is a centre wavelength.

Can know that by above derivation Fabry Perot resonator 2 can be regarded the filtering speculum of a pectination reflectance spectrum as.And the Free Spectral Range only optical length with first waveguide 23 and second waveguide 24 is relevant.Through reducing the optical length total value of first waveguide 23 and second waveguide 24, can increase Free Spectral Range.

In addition, through on first high reflective mirror 25 and second high reflective mirror, 26 minute surfaces, plating highly reflecting films, can increase the reflectivity r of first high reflective mirror 25 ₁' with the reflectivity r of second high reflective mirror 26 ₂'.Can know by formula (3), as the reflectivity r of first high reflective mirror 25 ₁' or the reflectivity r of second high reflective mirror 26 ₂' increase after, I ^(t)/ I ⁽ⁱ⁾Variation to phase difference δ is more responsive.Can know that by formula (1) phase difference δ depends on frequency f.Comprehensively can get the reflectivity r of first high reflective mirror 25 ₁' or the reflectivity r of second high reflective mirror 26 ₂' increase, can cause the reflectance spectrum of Fabry Perot resonator 2 more sharp-pointed, improved the model selection characteristic of laser.

As shown in Figure 5, be second kind of execution mode structural representation of the present invention.It also comprises a tuning electrode 27 and a phase matched electrode 11 except comprising an active waveguide 1, a Fabry Perot resonator 2 and a speculum 5 that produces the pectination reflectance spectrum.Tuning electrode 27 covers first waveguide, 23, the second waveguides, 24 all or part of zones, can change the optical length of waveguide through the adjusting injection current, thereby changes the position of reflection peak.Phase matched electrode 11 covers the subregion of active waveguide 1.

Because in running order semiconductor laser need satisfy the laser condition of resonance:

2k ₀l _a+2k ₀l _p+φ＝2mπ，m＝1，2，3... (6)

K wherein ₀Be this output wavelength wave vector in a vacuum, l _aBe the optical length of active waveguide 1, l _pBe that phase matched electrode 11 covers the optical length of waveguide down, φ is because the phase change that Fabry Perot resonator 2 reflections cause changes along with the variation of first waveguide, 23, the second waveguides, 24 optical lengths.

When regulating tuning electrode 27 change Fabry Perot resonators 2 reflection peak positions, first waveguide, 23, the second waveguides, 24 optical lengths have changed, and cause the variation of reflected phase will φ, and the laser condition of resonance is destroyed.In this execution mode, regulate l through phase matched electrode 11 _pLength, the change of compensatory reflex phase for different output wavelengths, can both be satisfied the laser condition of resonance.After regulating the injection current of tuning electrode 27 and phase matched electrode 11 at the same time, just can realize the tuning of noise spectra of semiconductor lasers output wavelength.

As shown in Figure 6, be the third execution mode structural representation of the present invention.It is except comprising an active waveguide 1, a Fabry Perot resonator 2 and a speculum 5 that produces the pectination reflectance spectrum; Also comprise one and cover second waveguide, 24 all or part of zones, can be through regulating the tuning electrode 28 of second waveguide that injection current changes the optical length of waveguide.

Can know that by formula (4) spectrum intervals of Fabry Perot resonator 2 is:

${\mathrm{\&Delta;<figure-callout\; id="1"\; label="f"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1=\frac{c}{2({\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">l</figure-callout>}}_1+l_2)}---\left(7\right)$

L wherein ₁, l ₂Be respectively the optical length of first waveguide 23 and second waveguide 24, c is the light velocity in the vacuum.

First waveguide 23, active waveguide 1, first high reflective mirror 25 and speculum 5 be common to constitute an active Fabry Perot resonator.This active Fabry Perot resonator gets spectrum intervals:

${\mathrm{\&Delta;f}}_e=\frac{c}{2({\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">l</figure-callout>}}_1+l_a)}---\left(8\right)$

L wherein ₁, l _aBe respectively the optical length of first waveguide 23 and active waveguide 1, c is the light velocity in the vacuum.

Because the optical length sum of first waveguide and second waveguide and the optical length sum of the active waveguide and first waveguide are unequal, make Δ f ₁With Δ f _eThere is minute differences.At this moment, laser only in reflection peak coincidence place of two Fabry Perot resonators, just can obtain enough feedbacks, thereby satisfies the laser threshold condition at this wavelength.As shown in Figure 2, after two resonant cavity series connection, the peak-to-peak spacing of adjacent reflection is on the reflectance spectrum:

${{\mathrm{\&Delta;f}}_c}^{\&prime;}=\frac{{\mathrm{\&Delta;<figure-callout\; id="1"\; label="f"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1{\mathrm{\&Delta;f}}_e}{|{\mathrm{\&Delta;f}}_1-{\mathrm{\&Delta;f}}_e|}---\left(9\right)$

Because amplification factor Δ f _e/ | Δ f ₁-Δ f _e| existence, two Fabry Perot resonator semiconductor lasers are bigger than the Free Spectral Range of single Fabry Perot resonator.In the gain ranging of active waveguide, can guarantee that two Fabry Perot resonators have only a reflection peak to overlap, the running of semiconductor laser single longitudinal mode.Through regulating the injection current of the tuning electrode 28 of second waveguide, change the optical length of Fabry Perot resonator, thereby change Δ f ₁, at amplification factor Δ f _e/ | Δ f ₁-Δ f _e| effect under, can realize the tuning of laser output wavelength on a large scale.

As shown in Figure 7, be the 4th kind of execution mode structural representation of the present invention.It comprises 1, one Fabry Perot resonator 2 that produces the pectination reflectance spectrum of active waveguide that gain is provided, and another produces the Fabry Perot resonator 3 and output waveguide 4 of pectination reflectance spectrum.Said Fabry Perot resonator by one with active waveguide 1 tilt be 30 °～70 °, the inside fill air or low refractive index dielectric, be used for air groove 21 Fabry Perot resonator 2, that do not lost by the light partial reflection of transmission is advanced in the light part transmission that produces in the active waveguide 1; First waveguide 23; Second waveguide, 24, the first high reflective mirrors 25 and second high reflective mirror 26 are formed; First waveguide 23 and active waveguide 1 coaxial placement lay respectively at the both sides of air groove 21; Angle equates between second waveguide 24 and first waveguide 23 and the air groove 21, is positioned at air groove 21 homonymies; Second waveguide 4 partially overlaps with the connectivity port of air groove 21 and the connectivity port of first waveguide 23 and air groove 21; First high reflective mirror 25 and second high reflective mirror 26 lay respectively at the place, non-NULL air drain connectivity port of first waveguide 23 and second waveguide 24; Angle equates between said output waveguide 4 and active waveguide 1 and the air groove 21, is positioned at air groove 21 homonymies; Output waveguide 4 partially overlaps with air groove 21 connectivity ports with air groove 21 connectivity ports and active waveguide 1; Said another Fabry Perot resonator 3 is positioned at the other end of active waveguide 1 and Fabry Perot resonator 2 connectivity ports; Said another Fabry Perot resonator 3 by one with active waveguide 1 tilt be 30 °～70 °, the inside fill air or low refractive index dielectric, be used for another air groove 31 another Fabry Perot resonator 3, that do not lost by the light partial reflection of transmission is advanced in the light part transmission that produces in the active waveguide 1; The 3rd waveguide 33; The 4th waveguide 34, the three high reflective mirrors 35 and the 4th high reflective mirror 36 are formed; The 3rd waveguide 33 and active waveguide 1 coaxial placement lay respectively at the both sides of another air groove 31; Angle equates between the 4th waveguide 34 and the 3rd waveguide 33 and another air groove 31, is positioned at another air groove 31 homonymies; The 3rd waveguide 33 partially overlaps with another air groove 31 connectivity ports with another air groove 31 connectivity ports and the 4th waveguide 34; The 3rd high reflective mirror 35 and the 4th high reflective mirror 36 lay respectively at the place, non-NULL air drain connectivity port of the 3rd waveguide 33 and the 4th waveguide 34.Said first waveguide 23, second waveguide, 24 optical length sums and the 3rd waveguide 33, the 4th waveguide 34 optical length sums are unequal, and the Fabry Perot resonator 2 that obtains like this distributes different with the reflectance spectrum of another Fabry Perot resonator 3.

Can know that by formula (4) spectrum intervals of Fabry Perot resonator 2 is:

${\mathrm{\&Delta;<figure-callout\; id="1"\; label="f"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1=\frac{c}{2({\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">l</figure-callout>}}_1+l_2)}---\left(10\right)$

L wherein ₁, l ₂Be respectively the optical length of first waveguide 23 and second waveguide 24, c is the light velocity in the vacuum.

The spectrum intervals of another Fabry Perot resonator 3 is:

${\mathrm{\&Delta;<figure-callout\; id="2"\; label="f"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">f</figure-callout>}}_2=\frac{c}{2(l_3+l_4)}---\left(11\right)$

L wherein ₃, l ₄Be respectively the optical length of the 3rd waveguide 33 and the 4th waveguide 34.

Through selecting first waveguide 23, the second waveguides, the 24 optical length sums and the 3rd waveguide 33, the four waveguides 34 optical length sums different, make Δ f ₁With Δ f ₂There is difference.At this moment, laser only in reflection peak coincidence place of two Fabry Perot resonators, just can obtain enough feedbacks, thereby satisfies the laser threshold condition at this wavelength.As shown in Figure 2, after two resonant cavity series connection, the peak-to-peak spacing of adjacent reflection is on the reflectance spectrum:

${\mathrm{\&Delta;f}}_c=\frac{{\mathrm{\&Delta;<figure-callout\; id="1"\; label="f"\; filenames="HSA00000287752400011.png,HSA00000287752400021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1{\mathrm{\&Delta;<figure-callout\; id="2"\; label="f"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">f</figure-callout>}}_2}{|{\mathrm{\&Delta;f}}_1-{\mathrm{\&Delta;<figure-callout\; id="2"\; label="f"\; filenames="HSA00000287752400021.png,HSA00000287752400022.png"\; state="\{\{state\}\}">f</figure-callout>}}_2|}---\left(12\right)$

Because amplification factor Δ f ₂/ | Δ f ₁-Δ f ₂| existence, two Fabry Perot resonator semiconductor lasers are bigger than the Free Spectral Range of single Fabry Perot resonator.In the gain ranging of active waveguide, can guarantee that two Fabry Perot resonators have only a reflection peak to overlap, the running of semiconductor laser single longitudinal mode.Through changing the optical length of one of them or two Fabry Perot resonators, can realize the tuning of laser output wavelength on a large scale.

The foregoing description is used for the present invention that explains, rather than limits the invention, and in the protection range of spirit of the present invention and claim, any modification and change to the present invention makes all fall into protection scope of the present invention.

Claims (6)

1. air groove beam splitting Fabry Perot resonator coupled laser, it comprises an active waveguide (1) that gain is provided, a Fabry Perot resonator (2) and a speculum (5) that produces the pectination reflectance spectrum; It is characterized in that: said Fabry Perot resonator (2) be by a slanted angle with active waveguide (1) be 30 °～70 °, the inside fill air or low refractive index dielectric, be used for air groove (21) Fabry Perot resonator (2), that do not lost by the light partial reflection of transmission is advanced in the light part transmission that produces in the active waveguide (1); First waveguide (23); Second waveguide (24), first high reflective mirror (25) and second high reflective mirror (26) are formed; First waveguide (23) and the coaxial placement of active waveguide (1) lay respectively at the both sides of air groove (21); Angle equates between second waveguide (24) and first waveguide (23) and the air groove (21), is positioned at air groove (21) homonymy; Second waveguide (24) partially overlaps with the connectivity port of air groove (21) and the connectivity port of first waveguide (23) and air groove (21); First high reflective mirror (25) and second high reflective mirror (26) are arranged at the place, non-NULL air drain connectivity port of first waveguide (23) and second waveguide (24) respectively.

2. a kind of air groove beam splitting Fabry Perot resonator coupled laser according to claim 1; It is characterized in that: said first waveguide (23), second waveguide (24) thereby all or part of are coated with and can change the tuning electrode (27) that its optical length changes the one of reflection peak position output wavelength; Active waveguide (1) subregion is coated with phase matched electrode (11).

3. a kind of air groove beam splitting Fabry Perot resonator coupled laser according to claim 1 is characterized in that: said second waveguide (24) thereby all or part of is coated with and can changes the tuning electrode of second waveguide (28) that its optical length changes reflection peak position output wavelength; First waveguide (23) is unequal with the optical length sum of first waveguide (21) with the optical length sum and the active waveguide (1) of second waveguide (24).

4. a kind of air groove beam splitting Fabry Perot resonator coupled laser according to claim 1 is characterized in that: all be coated with highly reflecting films on said first high reflective mirror (25) and second high reflective mirror (26) minute surface.

5. air groove beam splitting Fabry Perot resonator coupled laser; It comprises an active waveguide (1) that gain is provided; A Fabry Perot resonator (2) that produces the pectination reflectance spectrum, another produces the Fabry Perot resonator (3) and the output waveguide (4) of pectination reflectance spectrum; It is characterized in that: said Fabry Perot resonator (2) be by a slanted angle with active waveguide (1) be 30 °～70 °, the inside fill air or low refractive index dielectric, be used for air groove (21) Fabry Perot resonator (2), that do not lost by the light partial reflection of transmission is advanced in the light part transmission that produces in the active waveguide (1); First waveguide (23); Second waveguide (24), first high reflective mirror (25) and second high reflective mirror (26) are formed; First waveguide (23) and the coaxial placement of active waveguide (1) lay respectively at the both sides of air groove (21); Angle equates between second waveguide (24) and first waveguide (23) and the air groove (21), is positioned at air groove (21) homonymy; Second waveguide (24) partially overlaps with the connectivity port of air groove (21) and the connectivity port of first waveguide (23) and air groove (21); First high reflective mirror (25) and second high reflective mirror (26) lay respectively at the place, non-NULL air drain connectivity port of first waveguide (23) and second waveguide (24); Angle equates between said output waveguide (4) and active waveguide (1) and the air groove (21), is positioned at air groove (21) homonymy; Output waveguide (4) partially overlaps with air groove (21) connectivity port with air groove (21) connectivity port and active waveguide (1); Said another Fabry Perot resonator (3) is positioned at the other end of active waveguide (1) and Fabry Perot resonator (2) connectivity port; Said another Fabry Perot resonator (3) be by a slanted angle with active waveguide (1) be 30 °～70 °, the inside fill air or low refractive index dielectric, be used for another air groove (31) another Fabry Perot resonator (3), that do not lost by the light partial reflection of transmission is advanced in the light part transmission that produces in the active waveguide (1); The 3rd waveguide (33); The 4th waveguide (34), the 3rd high reflective mirror (35) and the 4th high reflective mirror (36) are formed; The 3rd waveguide (33) and the coaxial placement of active waveguide (1) lay respectively at the both sides of another air groove (31); Angle equates between the 4th waveguide (34) and the 3rd waveguide (33) and another air groove (31), is positioned at another air groove (31) homonymy; The 3rd waveguide (33) partially overlaps with another air groove (31) connectivity port with another air groove (31) connectivity port and the 4th waveguide (34); The 3rd high reflective mirror (35) and the 4th high reflective mirror (36) lay respectively at the place, non-NULL air drain connectivity port of the 3rd waveguide (33) and the 4th waveguide (34); Said first waveguide (23), second waveguide (24) optical length sum and the 3rd waveguide (33), the 4th waveguide (34) optical length sum are unequal.

6. a kind of air groove beam splitting Fabry Perot resonator coupled laser according to claim 5 is characterized in that: all be coated with highly reflecting films on said first high reflective mirror (25), second high reflective mirror (26), the 3rd high reflective mirror (35) and the 4th high reflective mirror (36) minute surface.

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