CN1115916A - Wave guide laser apparatus in which wave length is changable - Google Patents
Wave guide laser apparatus in which wave length is changable Download PDFInfo
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- CN1115916A CN1115916A CN 95103587 CN95103587A CN1115916A CN 1115916 A CN1115916 A CN 1115916A CN 95103587 CN95103587 CN 95103587 CN 95103587 A CN95103587 A CN 95103587A CN 1115916 A CN1115916 A CN 1115916A
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Abstract
A semiconductor laser emits semiconductor laser light with TM-mode oscillation. The emitted semiconductor laser light is collimated by a first collimating lens, passes through a Brewster plate that is arranged so that the direction of Brewster plane's p-polarized light is in alignment with the direction of polarization of the emitted semiconductor laser light, and is coupled to an incident portion of a wavelength-conversion waveguide by means of a focusing lens. While being guided through the waveguide, the emitted semiconductor laser light is converted into second-harmonic light by means of a polarization inversion region. Semiconductor laser light emanating from an emitting portion of the waveguide reflects from an output mirror towards a diffraction grating, for modulation in wavelength. Second-harmonic light emanating from the emitting portion of the waveguide is outputted from the output mirror.
Description
The present invention relates to have on one side the wavelength conversion waveguide type laser aid that semiconductor laser is transformed to the wavelength conversion waveguide that second harmonic light propagates on one side, particularly relate to and can be used for CD recording and playing device, laser printer or laser and use the wavelength conversion waveguide type laser aid that goes in measurement mechanism or the like.
For the densification of CD and the high-gradeization of laser printer, people need short wavelength's semiconductor laser light resource.Now, the semiconductor laser light resource of practicability, its emission wavelength reaches till the redness of the about 630nm of wavelength, and the further short wavelengthization of single semiconductor laser light resource (green, blue, ultraviolet) is a problem from now on.
On the other hand, as the short wavelength laser device of using semiconductor laser, people have proposed a kind of like this mode: the near-infrared semiconductor laser that emits from semiconductor laser is transformed to the laser that 2 subharmonic light make it to launch blueness or ultraviolet light.
In general, in order to produce second harmonic expeditiously, the first-harmonic propagation constant is equated with the propagation constant of second harmonic with nonlinear optical material.For this reason, must pay the refractive index N ω of first-harmonic and refractive index N second harmonic
2ω equates, and is still, under the situation of whole (bulk) material, common because the wavelength dispersion of refractive index; So N
2ω＞N ω can not satisfy the generation condition of second harmonic light.
Yet under the situation of wavelength conversion waveguide, the light that advances in the wavelength conversion waveguide will become the natural mode with specific propagation constant.The propagation constant of this communication mode is relevant with the size of wavelength conversion waveguide, so by changing the width or the degree of depth of wavelength conversion waveguide, just can satisfy 2 times of the propagation constant B ω that the makes first-harmonic B with second harmonic
2The condition that ω equates.Under the situation of using the wavelength conversion waveguide, first-harmonic and second harmonic overlapping big more and power density first-harmonic in the wavelength conversion waveguide is high more, and then conversion efficiency is high more, so wish to utilize the low order pattern.
A kind of mode is that semiconductor laser is coupled at the LiNbO with high non-linearity optical constant
3Substrate, LiTaO
3Substrate or KTiOPO
4In the wavelength conversion waveguide that forms on (below be referred to as KTP) substrate, and it is transformed into second harmonic light.Because a kind of like this mode can obtain high conversion efficiency; So being subjected to people recently payes attention to.
Bottom describes existing wavelength conversion waveguide type laser aid with reference to Figure 13.
As shown in figure 13, the semiconductor laser of the wavelength 860nm that is emitted by semiconductor laser 50 sees through collimating lens 51 and collector lens 52 and is coupled to and is formed at the LiTaO with Z shaft section
3The plane of incidence of the wavelength conversion waveguide 54 on the substrate 53 gets on.The semiconductor laser of wavelength 860nm is being formed at LiTaO when propagating in the wavelength conversion waveguide
3Be transformed into the second harmonic light of wavelength 430mm in the plate reversal zone 55 on the substrate 53.
In the cycle of the polarization inversion region 55 that forms with proton exchange, usually design load is had and depart from, so adopted the method that the wavelength of semiconductor laser is adjusted into the wavelength that can obtain maximum conversion efficiency.Because the wavelength of semiconductor laser depends on temperature and power, so will seek out high conversion efficiency, the mechanism that just needs certain that wavelength is adjusted.
The second harmonic light that emits from wavelength conversion waveguide 54, after collimated lens 56 are processed into directional light, penetrate from output reflector 57, but be to adjust wavelength by the diffraction reflection light from diffraction grating 58 is fed back to the way of going in the semiconductor laser 50 in the method shown in Figure 13.By adjusting the incidence angle of semiconductor laser, can adjust the oscillation wavelength of semiconductor laser to diffraction grating 58.As for the reason that polariscope 59 is set between collimating lens 51 and condenser lens 52, will tell about afterwards.
Owing to constitute external resonator with semiconductor laser 50 and outgoing mirror 57, so on the outgoing plane of semiconductor laser 50, apply, make it semiconductor laser is formed areflexia (AR), on outgoing mirror 57, also apply, make it semiconductor laser is high reflection (HR), and second harmonic light is become areflexia.In addition, on the end face at two of wavelength conversion waveguide 54, carried out the areflexia coating to reduce the loss of semiconductor laser.
, be formed at LiNbO
3Substrate, LiTaO
3In the wavelength conversion waveguide on substrate or the RTP substrate,, must import to semiconductor laser in the wavelength conversion waveguide 54 and go with the TM mode oscillation for obtaining high conversion efficiency.
In existing wavelength conversion waveguide type laser aid, the semiconductor laser that emits from semiconductor laser 50 is with TE (Transverse Electric Wave: the mode oscillation light wave of direction of polarized light in selecting aspect).Therefore, shown in Figure 15 (a), semiconductor laser 50 and LiTaO
3 Substrate 53 is disposed under the situation on the plane parallel to each other, and then shown in Figure 15 (b), the direction of polarized light of semiconductor laser and second harmonic polarisation of light light direction text can not get phase matched, so semiconductor laser can not be transformed into second harmonic light.On the other hand, shown in Figure 16 (a), semiconductor laser 50 and LiTaO
3 Substrate 53 is disposed at mutually perpendicular plane when getting on, then shown in Figure 16 (b), though the direction of polarized light of semiconductor laser is consistent with second harmonic polarisation of light light direction, but owing to be that the long axis direction of semiconductor laser of oval in shape is consistent with the short-axis direction of the second harmonic light of oval in shape, so the coupling efficiency step-down, conversion efficiency reduces.
So, for the beam shape that makes semiconductor laser consistent with the distribution shape of second harmonic light, usually the method that adopts is: the semiconductor laser that shoots out from semiconductor laser 50 is become TM (Transverse Magnetic Wave: direction of polarized light is at the light wave of Z-direction) pattern from the TE pattern, and the plane of incidence that is coupled to wavelength conversion waveguide 54 then gets on.Semiconductor laser is become the TM pattern from the TE pattern following method is arranged, as shown in figure 13, configuration polariscope 59 between collimating lens 51 and condenser lens 52, perhaps as shown in figure 14, between collimating lens 51 and condenser lens 52, insert λ/2 wavelength plates 60, make semiconductor laser that 2 λ/2 phase differences be arranged.
Yet, insertion polariscope 59 as shown in figure 13 is so that semiconductor laser becomes the method for TM pattern from the TE pattern, to produce the semiconductor laser of TM pattern when the TE pattern composition of giving semiconductor laser brings high loss, the problem that it brings is: increase considerably the oscillation threshold current of semiconductor laser 50 and reduce differential efficiency.
On the other hand, insertion λ as shown in figure 14/2 wavelength plates 60 make semiconductor laser become the method for TM pattern from the TE pattern, because externally exist λ/2 wavelength plates 60 in the resonator, so the problem that exists is: the oscillation threshold current increase and the differential efficiency reduction that will cause semiconductor laser light resource lost in seeing through of λ/2 wavelength plates 60.
The increase of the oscillation threshold current of semiconductor laser and the reduction of differential efficiency, will cause that the operating current of semiconductor laser increases, so can not meet the demands.
In view of the foregoing, the purpose of this invention is to provide a kind of like this wavelength conversion waveguide type laser aid, this device can obtain short wavelength's second harmonic light and can not cause the oscillating current that increases semiconductor laser and reduce differential efficiency.
To achieve these goals, the present invention is being used as semiconductor laser light resource with TM mode oscillation and the polarization direction semiconductor laser consistent with the TM pattern direction of wavelength conversion waveguide.
The 1st kind of wavelength conversion waveguide type laser aid of the present invention has wavelength conversion waveguide, semiconductor laser light resource, collector lens and external resonator.Above-mentioned wavelength conversion waveguide is propagated this laser when semiconductor laser is transformed into second harmonic light.The configuration of above-mentioned semiconductor laser light resource can make the semiconductor laser that penetrates from the surface of emission with the TM mode oscillation, and the direction of polarized light of the semiconductor laser that vibrates is consistent with the TM pattern direction of above-mentioned wavelength conversion waveguide.Above-mentioned collector lens is gathered in the semiconductor laser that emits from above-mentioned semiconductor laser light resource on the plane of incidence of above-mentioned wavelength conversion waveguide.The said external resonator can make the semiconductor laser resonance that penetrates from above-mentioned semiconductor laser light resource.
If use the 1st kind of wavelength conversion waveguide type laser aid, then owing to do not need to make semiconductor laser to become the TM pattern from the TE mode conversion, so can the suppression mode conversion with loss, can obtain short wavelength's second harmonic light (for example Lan Se laser) and not increase the operating current of semiconductor laser light resource.
Above-mentioned semiconductor light sources preferably adopts the semiconductor laser that semiconductor laser is vibrated with the TM pattern.
Like this, because self-oscillatory semiconductor laser is used as semiconductor laser light resource, thus also can not use oscillator supply, in order to avoid form unwanted radiation, so no longer need those to be used to cut off the shielding body of oscillating circuit and unwanted radiation.Therefore, can realize small-sized wavelength conversion waveguide type laser aid.
In the said external resonator, wish to have Bu Liusite plate fully.The Bu Liusite plate will dispose like this: make the P direction of polarized light of Bu Liusite face consistent with the direction of polarized light of the semiconductor laser that shoots out from above-mentioned semiconductor laser light resource.
Because the Bu Liusite plate is 100% to the transmitance of the semiconductor laser of P polarised light, even so the Bu Liusite plate is disposed in the external resonator, also can obtain high efficiency short wavelength laser, because it can not cause the increase of semiconductor laser light resource oscillation threshold current and the reduction of differential efficiency, the operating current of semiconductor laser light resource increases hardly.
In the 1st kind of wavelength conversion waveguide type laser aid, preferably possesses band pass filter.This filter configuration has the arrowband bandpass characteristics for the wavelength of the semiconductor laser that penetrates from semiconductor laser light resource in external resonator.Like this, just can adjust to narrow zone to the wavelength of the semiconductor laser that penetrates from semiconductor laser light resource.
Can be not yet equipment band pass filter and replace on a face of Bu Liusite plate a band pass filter layer is set in the resonator externally.This filter layer has the bandpass characteristics of arrowband to the wavelength of the semiconductor laser that penetrates from semiconductor laser light resource.Like this, owing to can realize that oscillation threshold current to semiconductor laser light resource increases and the inhibition of differential efficiency reduction reaches adjustment to semiconductor laser wavelength with device, so can reduce the volume of wavelength conversion waveguide type laser aid.
In the 1st kind of wavelength conversion waveguide type laser aid, it is desirable to configuring semiconductor LASER Light Source in this wise: the semiconductor laser that penetrates from this semiconductor laser light resource is incided on the plane of incidence of above-mentioned wavelength conversion waveguide with the Bu Liusite angle.Like this, just can suppress the reduction of the increase of semiconductor laser light resource oscillation threshold current and differential efficiency and the Bu Liusite plate need be set.
In the 1st kind of wavelength conversion waveguide type laser aid, it is desirable to collector lens is that the hemispheric lens of Bu Liusite face constitute by its tabular surface, and should dispose like this: make the P direction of polarized light of Bu Liusite face consistent with the direction of polarized light of the semiconductor laser that penetrates from semiconductor laser light resource.So, because collector lens has the effect of Bu Liusite plate, just can suppress the increase of semiconductor laser light resource oscillation threshold current and the reduction of differential efficiency so need not to be provided with the Bu Liusite plate.
In the 1st kind of wavelength conversion waveguide type laser aid, the ideal situation of collector lens is: collector lens is a sphere lens, and it is that the 2nd packaged lens of the 1st packaged lens of the Bu Liusite face tabular surface relative with the tabular surface with the 1st packaged lens therewith constitutes by tabular surface.Collector lens should dispose like this: make the P direction of polarized light of Bu Liusite face consistent with the direction of polarized light of the semiconductor laser that penetrates from above-mentioned semiconductor laser light resource.On the tabular surface of the 2nd packaged lens, be provided with band pass filter.This filter has the bandpass characteristics of arrowband to the wavelength of the semiconductor laser that penetrates from semiconductor laser light resource.
Because collector lens has the function of Bu Liusite plate and band pass filter, the compact so the wavelength conversion waveguide becomes.In addition, because collector lens is a sphere lens, and, even make of the optical axis rotation of this spherical lens with respect to semiconductor laser, the focal position can not departed from yet and come, so can adjust, make the P direction of polarized light of Bu Liusite face consistent with the polarization direction of light of the semiconductor laser that penetrates from semiconductor laser light resource in that semiconductor laser is concentrated under the state of wavelength conversion waveguide, and can adjust the wavelength of semiconductor laser, make these operations be easy to carry out.
In the 1st kind of wavelength conversion waveguide type laser aid, semiconductor laser light resource preferably have the active layer of actual refractive index Waveguide structure semiconductor laser, to active layer be added with strain semiconductor laser, send semiconductor laser or dfb semiconductor laser by receiving from the outside with the semiconductor laser of TM mode oscillation with the incident of the semiconductor laser of the direction of polarized light vibration parallel with the TM pattern.If this situation then can be produced the semiconductor laser light resource of launching the semiconductor laser that vibrates with the TM pattern from exit facet reliably.
The 2nd kind of wavelength conversion waveguide type semicondcutor laser unit that the present invention relates to possesses wavelength conversion waveguide, semiconductor laser light resource, collector lens and external resonator, wherein, above-mentioned wavelength conversion waveguide is propagated when semiconductor laser is transformed into second harmonic light; Above-mentioned semiconductor laser light resource is made of surface luminous semiconductor laser, and the configuration of this surface luminous semiconductor laser will make the direction of polarized light of the semiconductor laser that vibrates consistent with the TM pattern direction of above-mentioned wavelength conversion waveguide; Above-mentioned collector lens focuses on the plane of incidence of above-mentioned wavelength conversion waveguide the semiconductor laser that penetrates from above-mentioned semiconductor laser light resource.The said external resonator makes the semiconductor laser resonance that penetrates from above-mentioned semiconductor laser light resource.
If adopt the 2nd kind of wavelength conversion waveguide type laser aid, then owing to no longer needing semiconductor laser is become the TM pattern from the TE mode conversion, so but the loss that the suppression mode conversion is followed.Can under the situation of the operating current that does not increase semiconductor laser light resource, obtain short wavelength's second harmonic light (for example Lan Se laser).
Fig. 1 is the pie graph of the wavelength conversion waveguide type laser aid that relates to of the 1st embodiment of the present invention.
Fig. 2 is the pie graph of the wavelength conversion waveguide type laser aid that relates to of the 2nd embodiment of the present invention.
Fig. 3 is the pie graph of the wavelength conversion waveguide type laser aid that relates to of the 3rd embodiment of the present invention.
Fig. 4 is the pie graph of the wavelength conversion waveguide type laser aid that relates to of the 4th embodiment of the present invention.
Fig. 5 is the exploded perspective view of microsphere lens among above-mentioned the 4th embodiment.
Fig. 6 shows the transmitance of Bu Liusite plate used among the 1st～the 4th embodiment of the present invention to the P polarised light.
Fig. 7 shows the input-output characteristic of the wavelength conversion waveguide type laser aid that the 4th embodiment of the present invention relates to.
Fig. 8 is the pie graph of the wavelength conversion formula laser aid that relates to of the 5th embodiment of the present invention.
Fig. 9 is the pie graph of the wavelength conversion formula laser aid that relates to of the 6th embodiment of the present invention.
Figure 10 is the pie graph of the wavelength conversion formula laser aid that relates to of the 7th embodiment of the present invention.
Figure 11 shows the optical output waveform of the semiconductor laser of the used autoexcitation vibration of above-mentioned the 5th～the 7th embodiment.
Figure 12 shows the wavelength conversion waveguide type laser aid of having used the autoexcitation vibration semiconductor laser that above-mentioned the 5th embodiment relates to and the input-output characteristic of having used the wavelength conversion waveguide type laser aid of the semiconductor laser that does not carry out the autoexcitation vibration.
Figure 13 is the pie graph of existing wavelength conversion waveguide type laser aid.
Figure 14 is the pie graph of existing wavelength conversion waveguide type laser aid.
Figure 15 (a) is the pie graph of existing wavelength conversion waveguide type laser aid; Figure 15 (b) shows semiconductor laser and second harmonic polarisation of light light direction in the laser aid of wavelength conversion waveguide type shown in (a).
Figure 16 (a) is the pie graph of existing wavelength conversion waveguide type laser aid.Figure 16 (b) shows shown in Figure 16 (a) semiconductor laser and second harmonic polarisation of light light direction in the wavelength conversion waveguide type laser aid.
Bottom describes embodiments of the invention with reference to accompanying drawing.
Fig. 1 shows the formation of the wavelength conversion waveguide type laser aid that the 1st embodiment of the present invention relates to.Among Fig. 1, the 10th, as the semiconductor laser of semiconductor laser light resource, it is to have the active layer that oscillation wavelength is the real refractive index Waveguide structure of 860nm, and launches the semiconductor laser of TM mode oscillation from exit facet.11 is the 1st collimating lenses, and it becomes directional light to the semiconductor laser that penetrates from semiconductor laser 10.The 12nd, the Bu Liusite plate, it is made of thick 0.5 millimeter BK7 glass and is configured to make the P direction of polarized light of Bu Liusite face consistent with the direction of polarized light of the semiconductor laser that penetrates from semiconductor laser 10.The 13rd, collector lens, it is concentrated on the semiconductor laser that sees through Bu Liusite plate 12 on the plane of incidence of wavelength conversion waveguide 14.Wavelength conversion waveguide 14 is formed at LiTaO
3 Substrate 15 tops, and in wavelength conversion waveguide 14, formed polarization inversion region 16, polarization inversion region 16 is used for the semiconductor laser of wavelength 860nm is transformed into second harmonic light (wavelength 460nm).In addition, 17 among Fig. 1 is the 2nd collimating lenses, and it becomes directional light to the semiconductor laser that the exit facet from wavelength conversion waveguide 14 penetrates.18 is output reflectors.It exports second harmonic light when semiconductor laser being reflexed on the diffraction grating 19.
In general, in semiconductor laser, the gain of the ratio of gains TM pattern of TE pattern is much higher, so will be with the TE mode oscillation.Yet, in high state of the current density of active layer or active layer, having under the state of response, the gain of TM pattern will uprise.So the TM pattern also can with TE pattern one oscillates.Therefore, when giving the TE pattern, can only make the TM mode oscillation with loss.
Therefore, in the 1st embodiment, by configuration Nei Liusite plate 12 in the resonator externally and give the TE pattern of semiconductor laser that produces vibration from semiconductor laser 10, then can realize the TM mode oscillation with loss.It is Bu Liusite angle (being about 56 ° under the situation of BK7 glass) that Bu Liusite plate 12 is configured to make the incidence angle of semiconductor laser; With this, make the P direction of polarized light of Bu Liusite plate 12 consistent with the direction of polarized light of the semiconductor laser that penetrates from semiconductor laser 10.
In addition, also can be configured to semiconductor laser 10 make the plane of incidence that incides wavelength conversion waveguide 14 with the Bu Liusite angle from the semiconductor laser of this semiconductor laser 10 ejaculations to get on, and the Bu Liusite plate 12 among above-mentioned the 1st embodiment is not set.
Fig. 2 shows the formation of the wavelength conversion waveguide type laser aid that the 2nd embodiment of the present invention relates to.In the 2nd embodiment, the inscape identical with the 1st embodiment all is marked with the symbol identical with the 1st embodiment, Therefore, omited explanation.
Feature as the 2nd embodiment, in order to adjust the wavelength of semiconductor laser, disposing wavelength between Bu Liusite plate 12 and collector lens 13 is the band pass filter 20 that the semiconductor laser of 860nm has the bandpass characteristics of arrowband, to replace the diffraction grating 19 among the 1st embodiment.Band pass filter 20 is to make like this: form the dielectric multilayer-film that semiconductor Wavelength of Laser (about 860nm) is had the arrowband bandpass characteristics on the one side of BK7 glass, the unreflected coating of coating on the another side of this BK7 glass.The concrete way of semiconductor laser wavelength adjustment is that the adjustment semiconductor laser incides the angle on the band pass filter 20.
In the 2nd embodiment, owing to constitute external resonator with semiconductor laser 10 and output reflector 18, so on the exit facet of semiconductor laser 10, applied to the unreflected coating of semiconductor laser, simultaneously, having formed on output reflector 18 semiconductor laser is reflected for high, is unreflected coating to second harmonic light.
Fig. 3 shows the formation of the wavelength conversion waveguide type laser aid that the 3rd embodiment of the present invention relates to.In the 3rd embodiment, the inscape identical with the 1st embodiment or the 2nd embodiment all is marked with the identical symbol with the 1st or the 2nd embodiment, Therefore, omited explanation.
The feature of the 3rd embodiment is for optical system is oversimplified and miniaturization, at the LiTaO of Bu Liusite plate 12
3The face of substrate 15 1 sides is provided with band pass filter layer 21.That is, the face of semiconductor laser 10 1 sides of Bu Liusite plate 12 is a blank, and at LiTaO
3On the face of substrate 15 1 sides, formed dielectric multilayer-film, dielectric multilayer-film has the bandpass characteristics of arrowband to semiconductor Wavelength of Laser (about 860nm) like this.As shown in Figure 6, the characteristic that sees through of Bu Liusite plate 12 is: in closely being close to of Bu Liusite angle, the transmitance of P polarised light being bordering on 100% substantially, but the S polarised light is had tens percentage points loss.Thereby, in closely being close to of Bu Liusite angle,, just can obtaining best bandpass characteristics and do not damage the function of Bu Liusite plate 12 by a little way that changes the semiconductor laser incidence angle.So an available device guarantees to be close to 100% the transmitance to the P polarised light, wavelength that again can semiconductor laser is adjusted simultaneously.
In the 3rd embodiment, because the exit facet 15a with semiconductor laser 10 and wavelength conversion waveguide 14 constitutes external resonator, so, on the exit facet of semiconductor laser 10, apply with to the unreflected coating of semiconductor laser, simultaneously, on the exit facet 15a of wavelength conversion waveguide 14, apply serving as that high reflection is unreflected coating to second harmonic light to semiconductor laser.
Fig. 4 shows the formation of the wavelength conversion waveguide type laser aid that the 4th embodiment of the present invention relates to.In the 4th embodiment, the inscape identical with the 1st embodiment or the 2nd embodiment also is marked with the identical symbol with the 1st or the 2nd embodiment, thereby omitted explanation.
The feature of the 4th embodiment is, thereby for optical system being done to such an extent that oversimplify more and make the further simple compact function that does not influence the 2nd embodiment again of wavelength conversion waveguide type laser aid, be provided with a spherical lenticule 22, lenticule 22 has the 1st collimating lens 11 among the 2nd embodiment, Bu Liusite plate 12 simultaneously, sees through the multiple function of filter 20 and condenser lens 13.
The drawn decomposition structure of spherical lenticule 22 of Fig. 5.This lenticule 22 is that the pad 22C of the annular of 0.1mm makes an integral body to the 1st packaged lens 22a and the 2nd packaged lens 22b that the BK7 glass by diameter 5mm constitutes by thickness.In addition, lenticule 22 forms a round as a ball sphere by the 1st and the 2nd packaged lens 22a, 22b and pad 22c.The tabular surface of the 1st packaged lens 22a is the Bu Liusite face that the state by the blank of BK7 glass constitutes.Be coated with on the tabular surface of the 2nd half-sphere mirror 22b and applied dielectric multilayer-film, this film has the bandpass characteristics of arrowband to semiconductor Wavelength of Laser (about 800nm).Lenticule 22 is configured to make the P direction of polarized light of tabular surface (Bu Liusite face) of the 1st packaged lens 22a consistent with the direction of polarized light of the semiconductor laser that penetrates from semiconductor laser light resource 10.
For the semiconductor laser that penetrates from semiconductor laser 10 is concentrated in the wavelength conversion waveguide 14, lenticule 22 is configured on such position: make the tabular surface of the 1st packaged lens 22a and the tabular surface of the 2nd packaged lens 22b all form the Bu Liusite angle to above-mentioned semiconductor laser.In addition, adjust the wavelength of above-mentioned semiconductor laser by rotation lenticule 22.In the 4th embodiment, owing to used the lenticule 22 of spherical shape, so even this lenticule is rotated with respect to the optical axis of semiconductor laser, the focal position of lenticule 22 can not be offset yet.So, can under the state on the plane of incidence that the semiconductor laser that penetrates from semiconductor laser 10 is focused on wavelength conversion waveguide 14, adjust wavelength.
Fig. 7 shows the input and output power characteristic of the wavelength conversion waveguide type laser aid of related wavelength conversion waveguide type laser aid of the 4th embodiment and prior art.If adopt the related wavelength conversion waveguide type laser aid of the 4th embodiment, then in operating current 100mA, can obtain the blue laser of 3.5mW.
Also having, is LiTaO in above-mentioned the 1st～the 4th embodiment
3Substrate 15 uses LiNbO as the substrate that forms wavelength conversion waveguide 14 but also can replace
3Other the substrate that constitutes by nonlinear optical crystal such as substrate or KTP substrate.
In above-mentioned the 1st～the 4th embodiment, used the semiconductor laser 10 that drives by the pulse power, but be about among the 5-the 7 embodiment of explanation in bottom, but used by DC (direct current) power drives and produce the semiconductor laser of impulse hunting (autoexcitation vibration).
In general, because the conversion efficiency that is transformed to second harmonic light is directly proportional with the power density of first-harmonic, so that first-harmonic is the power output of semiconductor laser is big more, resulting conversion efficiency is just high more.In semiconductor laser, drive the power height that obtains not as with pulsed drive with CW (continuous wave).Therefore, if the repetition rate of pulse enough high (more than the hundreds of MHz), then from the average output power of second harmonic light, with the semiconductor laser of pulsed drive than the resulting power output height of semiconductor laser that drives with CW.
, for obtaining high-power semiconductor laser, just must use the current drives semiconductor laser of large amplitude from semiconductor laser.Yet, driving the oscillator supply of semiconductor laser with the electric current of high frequency and large amplitude, its unnecessary radiation is just big, so must remove unnecessary radiation.But this is unusual difficulty to making it the consumer complete machine that unwanted radiation has enough shield effectivenesses in limited space.
So, in the 5-the 7 following embodiment, do not adopt the semiconductor laser that carries out pulsed drive by oscillator supply as semiconductor laser light resource, replace employing by the go forward side by side semiconductor laser of horizontal pulse vibration (autoexcitation vibration) of DC power drives.
Fig. 8 shows the structure of the related wavelength conversion waveguide type laser aid of the 5th embodiment of the present invention.In the 5th embodiment, for the 1st embodiment or the identical inscape of the 2nd embodiment, be marked with identical symbol with the 1st or the 2nd embodiment, omit explanation.
The feature of the 5th embodiment is: the semiconductor laser 30 that adopts the autoexcitation vibration is as semiconductor laser light resource.So, owing to also can not adopt noise spectra of semiconductor lasers to carry out the oscillator supply of pulsed drive, so can solve the problem of above-mentioned unnecessary radiation.And, owing to no longer need pierce circuit, so can realize small-sized wavelength conversion waveguide type laser aid.
Have the autoexcitation oscillatory type semiconductor laser of the gain waveguide structure of the light source that is used as CD-audio player etc., in general, (pulse peak power is 20mW to be lower than about 5mW in average power.) time be in the autoexcitation state, if but average power when becoming greater than about 5mW will become and not carry out the autoexcitation vibration.Yet, in the present embodiment,, before average power becomes hundreds of mW, will proceed the autoexcitation vibration owing to used semiconductor laser 30 with real refractive index Waveguide structure.(when average power was hundreds of mW, pulse peak power was about 1W.)。As previously mentioned, because being transformed to the conversion efficiency of second harmonic light is directly proportional with the power density of first-harmonic, so as the light source of wavelength conversion waveguide type laser aid, the semiconductor laser with the real refractive index Waveguide structure that can obtain high pulse power is suitable.Semiconductor laser 30 in the present embodiment has the active layer of the real refractive index Waveguide structure of oscillation wavelength 860nm.
Figure 11 shows the luminous power waveform of autoexcitation vibration semiconductor laser 30, and peak pulse power is that (average power is 100mW to 1W.), pulse frequency is 2GHz.
In the 5th embodiment, the way formation of ion of periodically replacing the Ka of KTP substrate 32 with the Rb ion is adopted in wavelength conversion waveguide 31.In addition, in KTP substrate 32, what carry out is the ion-exchange of Ka → Rb, but at LiNbO
3Substrate or LiTaO
3In the substrate, what carry out is the ion-exchange of Li → H.Be higher than the X-axis that is parallel to real estate or the diffusion velocity on the Y direction in order to make, so wavelength conversion waveguide 31 is formed on the Z face of KTP substrate 31 perpendicular to ions diffusion on the Z-direction of real estate.Because the crystal of KTP substrate 31 has positive birefringence, the refractive index height of rate so the folding of Z-direction looses than X-axis or Y direction.In addition, the crystal of the KTP substrate 31 nonlinear optical constant height relevant with the Z axle.
In the 5th embodiment, because semiconductor laser 30 and wavelength conversion waveguide 31 constitutes external resonators, so deposited with to the unreflected coating of semiconductor laser on the exit facet of semiconductor laser 30.Coating is high reflection to semiconductor laser on the plane of incidence 31a of wavelength conversion waveguide 31, to the unreflected coating of second harmonic light.
The same with the 2nd embodiment, semiconductor laser 30 is configured to make the direction of polarized light of the TM pattern semiconductor laser that produces from its exit facet consistent with the TM pattern direction of wavelength conversion waveguide 31.
In addition, Bu Liusite plate 12 is configured to make the incident angle of semiconductor laser to become the Bu Liusite angle, thereby the P direction of polarized light of Bu Liusite plate 12 is consistent with the direction of polarized light of the semiconductor laser that penetrates from semiconductor laser 30.
The oscillatory regime of the semiconductor laser 30 of autoexcitation vibration is many longitudinal modes formula, but as the 5th embodiment, externally establish the band pass filter 20 with the arrowband in the resonator, then semiconductor laser 30 will be to be carried out the single-vertical mode vibration by band filter 20 selected wavelength.
Figure 12 shows the input-output characteristic (zero mark) of the related wavelength conversion waveguide type laser aid of the 5th embodiment.Shown in the abscissa is as the input P that is sent to wavelength conversion waveguide 31
ωThe average power of semiconductor laser 30, ordinate is represented the average power from the second harmonic light of wavelength conversion waveguide 31.In Figure 12, in order to compare, the input and output power characteristic when also having drawn the semiconductor laser of CW vibration as light source (● mark).
The semiconductor laser of non-autoexcitation vibration as under the situation of light source, when the power output of semiconductor laser is 100mW, be 5mW from the power of the second harmonic light of wavelength conversion waveguide 31.On the other hand, as the 5th embodiment, the semiconductor laser of autoexcitation vibration as under the situation of light source, when the average power of semiconductor laser is 100mW, be 50mW from the power of the second harmonic light of wavelength conversion waveguide 31.Hence one can see that, by the way of the semiconductor laser of autoexcitation vibration as the light source of wavelength conversion waveguide type laser aid, can obtain 10 times conversion efficiency.
Have, when the semiconductor laser as light source carried out the autoexcitation vibration, then second harmonic light also can be modulated with the frequency (several GHz) identical with the autoexcitation frequency of oscillation of semiconductor laser again.But, when the related wavelength conversion waveguide type laser aid of present embodiment is used as the light source of optical disc apparatus, because the second harmonic light frequency is more much higher than the signal frequency (tens MHz) of optical disc apparatus, so not influence.
Wanting the light source of wavelength conversion waveguide type device as optical disc apparatus or the like, just must be small-sized device.
Fig. 9 shows making optical system simplification and miniaturization and don't damaging the structure of wavelength conversion waveguide type laser aid of the function of the 5th embodiment of the 6th embodiment.Because the 6th embodiment is the structure that the 3rd embodiment and the 5th embodiment are lumped together, thus to the 3rd embodiment or the identical inscape of the 5th embodiment, employing is marked with the way of same-sign to omit explanation.
Figure 10 shows the formation of the related wavelength conversion waveguide type laser aid of the 7th embodiment, and the purpose of this device is to make optical system simpler, further miniaturization, and the while is not damaged the function of the 5th embodiment again.
In the 7th embodiment, be provided with the spherical lenticule 33 of diameter 5mm, it has the function of the 1st collimating lens 11, Bu Liusite plate 12, band pass filter 20 and collector lens 13 among the 5th embodiment simultaneously.The spherical microlens 33 among the 7th embodiment and the difference of the spherical microlens 22 among the 4th embodiment have 2 points, a bit are that pad 22C is not set, and on the other hand only form the ball shape with the 1st packaged lens 33a and the 2nd packaged lens 33b.In the lenticule 33 of the 7th embodiment, the same with the lenticule 22 of the 4th embodiment, the tabular surface of the 1st packaged lens 33a also is with the Bu Liusite face of the blank state formation of BK7 glass, is coated with this dielectric multilayer-film of dielectric multilayer-film has the arrowband to semiconductor Wavelength of Laser (about 860nm) bandpass characteristics on the tabular surface of the 2nd packaged lens 33b.
In the related wavelength conversion waveguide type laser aid of the 6th embodiment and the 7th embodiment, also can obtain the equal performance of wavelength conversion waveguide type laser aid with the 5th embodiment.
In the various embodiments described above, the material of Bu Liusite plate 12, band pass filter 20 and lenticule 22,23 has adopted BK7 glass, but adopts other optical glass, optical resin or organic material also can reach same effect.
Moreover, in the various embodiments described above, the semiconductor laser of the active layer with real refractive index Waveguide structure has been used as semiconductor laser 10,30, but in the semiconductor laser 10 and 30 of this real refractive index Waveguide structure, owing on current blocking layer, used the low lossization that the material of semiconductor laser-light transparent is realized light, so the gain inequality between TE pattern and the TM pattern is little, so can obtain the TM mode oscillation.
The semiconductor laser 10,30 that also can have the active layer of real refractive index Waveguide structure, and with give active layer in addition strain semiconductor laser, inject the semiconductor laser or the DFB (distributed feed-back: formula semiconductor laser Distributed Feedback) of TM Mode for Laser from the outside.
The semiconductor laser that is added with strain on the active layer because of to active layer in addition strain changed and can be with structure, so can increase the gain of TM pattern, and obtain the TM mode oscillation thus.
If adopt the semiconductor laser that injects the laser of TM pattern from the outside, then the gain of TM pattern uprises, so can obtain the TM mode oscillation.
The dfb semiconductor laser application be designed to improve the gain of TM pattern to the grating that the TM pattern is fed back, thereby can obtain the TM mode oscillation.
Moreover, in the 1st～the 4th embodiment, also can be surface luminous semiconductor laser as semiconductor laser 10.In this case, can be configured like this: make that to produce the direction of polarized light of semiconductor laser of vibration from this surface luminous semiconductor laser consistent with the TM pattern direction of wavelength conversion waveguide 14.
Claims (13)
1. wavelength conversion waveguide type laser aid, it possesses has:
The wavelength conversion waveguide is used for propagating when making semiconductor laser be transformed into second harmonic light;
Semiconductor laser light resource is configured such that from exit facet it consistent with the TM pattern direction of above-mentioned wavelength conversion waveguide with the direction of polarized light of TM mode producing semiconductor laser vibration and the semiconductor laser that vibrates;
Collector lens is used for the plane of incidence that a semiconductor laser from above-mentioned semiconductor laser light resource ejaculation is concentrated on above-mentioned wavelength conversion waveguide;
External resonator is used to make the semiconductor laser resonance that penetrates from above-mentioned semiconductor laser light resource.
2. wavelength conversion waveguide type laser aid as claimed in claim 1, wherein:
Above-mentioned semiconductor laser light resource is to make semiconductor laser carry out the semiconductor laser of autoexcitation vibration with the TM pattern.
3. wavelength conversion waveguide type laser aid as claimed in claim 1,
Also have the Bu Liusite plate in the said external resonator, this Bu Liusite plate is configured to make the P direction of polarized light of Bu Liusite face consistent with the direction of polarized light of the semiconductor laser that penetrates from above-mentioned semiconductor laser light resource.
4. wavelength conversion waveguide type laser aid as claimed in claim 3, also possessing has band pass filter, this band pass filter is configured in the said external resonator, and the wavelength of the semiconductor laser that penetrates from above-mentioned semiconductor laser light resource is had the bandpass characteristics of arrowband.
5. wavelength conversion waveguide type laser aid as claimed in claim 3, wherein,
Be provided with the band pass filter layer on a face of above-mentioned Bu Liusite plate, this band pass filter layer has the bandpass characteristics of arrowband to the wavelength of the semiconductor laser that penetrates from above-mentioned semiconductor laser light resource.
6. wavelength conversion waveguide type laser aid as claimed in claim 1, wherein,
Above-mentioned semiconductor laser light resource is configured to make the semiconductor laser that penetrates from this semiconductor laser light resource to incide on the plane of incidence of above-mentioned wavelength conversion waveguide with the Bu Liusite angle.
7. wavelength conversion waveguide type laser aid as claimed in claim 1, wherein;
Above-mentioned collector lens is that the hemispherical lens of Bu Liusite face is formed and is configured to make the P direction of polarized light of above-mentioned Bu Liusite face consistent with the P direction of polarized light of the semiconductor laser that penetrates from above-mentioned semiconductor laser light resource by its tabular surface.
8. wavelength conversion waveguide type laser aid as claimed in claim 1, wherein,
Above-mentioned collector lens is made of globe lens, this globe lens is that the 1st packaged lens of Bu Liusite face constitutes with the 2nd packaged lens with tabular surface relative with the tabular surface of the 1st packaged lens by tabular surface, and its collocation method will make the P direction of polarized light of above-mentioned Bu Liusite face consistent with the direction of polarized light of the semiconductor laser that penetrates from above-mentioned semiconductor laser light resource;
Be provided with the band pass filter layer on the tabular surface of above-mentioned the 2nd packaged lens, this band pass filter layer has the bandpass characteristics of arrowband to the wavelength of the half-wave volumetric laser that penetrates from above-mentioned semiconductor laser light resource.
9. wavelength conversion waveguide type laser aid as claimed in claim 1, wherein;
Above-mentioned semiconductor laser light resource is the semiconductor laser with active layer of real refractive index Waveguide structure.
10. wavelength conversion waveguide type laser aid as claimed in claim 1, wherein;
Above-mentioned semiconductor laser light resource is the semiconductor laser that is added with strain in the active layer.
11. wavelength conversion waveguide type laser aid as claimed in claim 1, wherein;
Above-mentioned semiconductor laser light resource is a kind of like this semiconductor laser, and it is received in the incident of the semiconductor laser that the direction of polarized light parallel with the TM pattern vibrate from the outside, penetrate the semiconductor laser that vibrates with the TM pattern then.
12. wavelength conversion waveguide type laser aid as claimed in claim 1, wherein;
Above-mentioned semiconductor laser light resource is the dfb semiconductor laser.
13. a wavelength conversion waveguide type laser aid has:
The wavelength conversion waveguide is used for propagating when semiconductor laser is transformed to second harmonic light;
Semiconductor laser light resource, it is made of surface luminous semiconductor laser and is configured to make the direction of polarized light of the semiconductor laser that vibrates consistent with the TM pattern direction of above-mentioned wavelength conversion waveguide;
Collector lens is used for the plane of incidence that a semiconductor laser from above-mentioned semiconductor laser light resource ejaculation is concentrated on above-mentioned wavelength conversion waveguide;
External resonator is used to make the semiconductor laser resonance that penetrates from above-mentioned semiconductor laser light resource.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP057541/94 | 1994-03-28 | ||
| JP057541/1994 | 1994-03-28 | ||
| JP5754194 | 1994-03-28 |
Publications (2)
| Publication Number | Publication Date |
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| CN1115916A true CN1115916A (en) | 1996-01-31 |
| CN1116724C CN1116724C (en) | 2003-07-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 95103587 Expired - Fee Related CN1116724C (en) | 1994-03-28 | 1995-03-27 | Wave guide laser apparatus in which wave length is changable |
Country Status (2)
| Country | Link |
|---|---|
| KR (1) | KR0174775B1 (en) |
| CN (1) | CN1116724C (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1305189C (en) * | 2003-06-30 | 2007-03-14 | 三星电子株式会社 | Wavelength-tunable laser apparatus |
| CN101779161B (en) * | 2007-07-20 | 2012-10-03 | 康宁股份有限公司 | Optical configurations for wavelength-converted laser sources |
| CN101765950B (en) * | 2007-07-30 | 2012-11-28 | 三菱电机株式会社 | Wavelength conversion laser device |
| CN105264726A (en) * | 2013-06-06 | 2016-01-20 | 三菱电机株式会社 | Waveguide-type laser device |
| CN106505280A (en) * | 2016-11-17 | 2017-03-15 | 山东省科学院海洋仪器仪表研究所 | A kind of millimeter wave multi-frequency multi-mode mode excitation device |
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| KR100734831B1 (en) * | 2005-07-28 | 2007-07-03 | 한국전자통신연구원 | Wavelength conversion device using TM-mode laser diode and fabricating method thereof |
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| KR101424601B1 (en) * | 2014-01-27 | 2014-08-01 | 주식회사 엘티에스 | Apparatus for transforming laser beam using optical waveguide film |
-
1995
- 1995-02-28 KR KR1019950004102A patent/KR0174775B1/en not_active IP Right Cessation
- 1995-03-27 CN CN 95103587 patent/CN1116724C/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1305189C (en) * | 2003-06-30 | 2007-03-14 | 三星电子株式会社 | Wavelength-tunable laser apparatus |
| CN101779161B (en) * | 2007-07-20 | 2012-10-03 | 康宁股份有限公司 | Optical configurations for wavelength-converted laser sources |
| CN101765950B (en) * | 2007-07-30 | 2012-11-28 | 三菱电机株式会社 | Wavelength conversion laser device |
| CN105264726A (en) * | 2013-06-06 | 2016-01-20 | 三菱电机株式会社 | Waveguide-type laser device |
| CN106505280A (en) * | 2016-11-17 | 2017-03-15 | 山东省科学院海洋仪器仪表研究所 | A kind of millimeter wave multi-frequency multi-mode mode excitation device |
| CN108321670A (en) * | 2018-03-22 | 2018-07-24 | 华南理工大学 | A kind of micro-cavity laser of cascaded pump |
| CN108321670B (en) * | 2018-03-22 | 2023-12-01 | 华南理工大学 | Cascaded pumped microcavity laser |
| CN109638640A (en) * | 2019-01-08 | 2019-04-16 | 惠州学院 | Semiconductor laser |
| CN109638640B (en) * | 2019-01-08 | 2020-08-14 | 惠州学院 | Semiconductor laser device |
| CN111244758A (en) * | 2020-01-22 | 2020-06-05 | 上海交通大学 | Silicon-based narrow-linewidth high-power external cavity laser based on transverse magnetic mode |
| CN112630876A (en) * | 2020-12-04 | 2021-04-09 | 西安电子科技大学 | Microsphere lens for generating and focusing columnar polarized light |
Also Published As
| Publication number | Publication date |
|---|---|
| KR0174775B1 (en) | 1999-04-01 |
| CN1116724C (en) | 2003-07-30 |
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