CN101615763B - Semiconductor laser with wideband wavelength locking - Google Patents

Abstract

The invention relates to the laser field, in particular to a semiconductor laser which carries out wavelength locking in the wider wavelength range and is especially applicable to as pumping source for pumping laser gain medium with wider absorption bandwidth. In the semiconductor laser with wideband wavelength locking, the output wavelength thereof is locked in the absorption bandwidth of the laser gain medium; the semiconductor laser comprises output light thereof, which is collimated by an optical collimating system, feedbacks resonance by a feedback output system and outputs pumping laser. Mainly, a wideband length locking component is added for locking the output wavelength range. By adopting the above technical proposal, the semiconductor laser is different from the existing semiconductor laser which uses a narrow band filter plate to manufacture narrow band wavelength locking, has wider working temperature range and is characterized by simple and reasonable, easy realization and the like.

Description

A kind of semiconductor laser of wideband wavelength locking

Technical field

The present invention relates to laser field, relate in particular to the semiconductor laser that carries out wavelength locking in a kind of broad wave-length coverage, pumping has the gain medium wide than broad absorption band to particularly suitable as pumping source.

Background technology

For semiconductor laser, people engrave arrowband feedback grating in the laser side, perhaps in the chamber, add chromatic dispersion elements such as grating, prism, add that perhaps narrow band pass filter makes the wavelength locking semiconductor laser.This type of wavelength locking semiconductor laser can with the output wavelength of laser in certain temperature range lock in very narrow wave-length coverage. and semiconductor laser is along with variation of temperature; The ability interband is at a distance from changing; And then gain band center drifts about, and along with the drift of temperature, the wavelength that the gain misalignment of laser locks is increasing; And because the narrow-band filtering effect of narrowband wavelength locked plug-in unit; After temperature exceeded certain amplitude, the gain at the wavelength locking place of semiconductor laser diminished, and the feedback that whole system provides also can die down; Just be difficult to reach the effect of exocoel feedback wavelength locking after arriving to a certain degree; Wavelength locking was lost efficacy, and the operating temperature range of its wavelength locking of semiconductor laser of this type wavelength locking generally has only 20 ℃-30 ℃, the requirement that it can not satisfy wide temperature working range far away or not have temperature controlling range.And all have certain wavelength absorption bandwidth for semiconductor pumping sources for most of gain mediums; Absorption bandwidth like Nd:YAG is 5nm; Nd:YVO4 is 11nm; Like this for the used semiconductor laser light source of these gain mediums, just will wavelength locking in very narrow wave-length coverage, but can be in the wave-length coverage of broad relatively (as: 5-11nm) with wavelength locking.In addition; The semiconductor laser of some visible light wave ranges such as red light semiconductor laser, if when variations in temperature is big, its wavelength can drift about in a big way; Thereby make change color clearly, this just need be in bigger temperature range with its wavelength restriction within the specific limits.

Summary of the invention

The present invention just is based on certain wavelength absorption bandwidth of characteristics most of gain mediums all have to(for) semiconductor pumping sources; Proposition is locked in gain medium with semiconductor laser wavelength and absorbs within the bandwidth; Thereby make semiconductor laser serviceability temperature scope obtain bigger raising, and can be applicable to laser color with the very sensitive visible laser field of variations in temperature.

The present invention adopts following technical scheme:

The semiconductor laser of wideband wavelength locking of the present invention, its output wavelength are locked in gain medium and absorb within the bandwidth, and gain medium absorbs bandwidth and is meant that semiconductor laser is from λ ₁Change to λ ₂Bandwidth, λ ₁For gain medium absorption spectra shortwave can be accepted absorbing wavelength, λ ₂For gain medium absorption spectra long wave can be accepted absorbing wavelength; Semiconductor laser output light; Through optical alignment system collimation; By feedback output system feedback resonance and output pumping laser, also add the broad band wavelength transmission member again, the lock-in range of this broad band wavelength transmission member is that single-point wavelength locking temperature range bandwidth adds that semiconductor laser is from λ ₁Change to λ ₂The temperature bandwidth, insert in the exterior resonant cavity, the feedback output system is to adopt the structure that feedback is provided by exocoel, in order to be locked in λ ₁To λ ₂Between the output wavelength scope.

Further, described wideband wavelength locking member is the broad band wavelength transmission member, inserts in the exterior resonant cavity, adopts the structure that feedback is provided by exocoel.

Further, described broad band wavelength transmission member is broad band pass filter or the optical element that plates the broadband filter coating.

Further, described wideband wavelength locking member is the broad band wavelength reflecting member, inserts in the exterior resonant cavity, adopts the structure that feedback is provided by exocoel.

Further, described broad band wavelength reflecting member is broadband reflection grating or the optical element that plates the broadband reflection film.Perhaps, described broad band wavelength reflecting member is to carve broadband feedback grating or directly on the mirror of chamber, plate the broadband reflection film at the semiconductor laser side face.

Further, the described feedback output system Effect of Back-Cavity Mirror that is a partial reflection constitutes or is that a partial reflection sheet and a total reflection Effect of Back-Cavity Mirror constitute.

Further, described total reflection Effect of Back-Cavity Mirror can be plane reflection chip architecture or miniature pyramidal structure.

Aforesaid laser can be applicable to pumping has the gain medium wide than broad absorption band; Can be applicable to laser color with the very sensitive visible laser of variations in temperature; Can be applicable to allow in the laser acquisition field of certain optical maser wavelength bandwidth.

The present invention adopts as above technical scheme, is different from the wavelength-locked laser that existing use narrow band pass filter is made, and has wideer operating temperature range, and simple and reasonable, is easy to realize.

Description of drawings

Fig. 1 (a) absorbs spectrogram for gain medium;

Fig. 1 (b) is that the semiconductor laser of wideband wavelength locking of the present invention is exported the optical maser wavelength curve chart in the different temperatures scope;

Fig. 2 is embodiment one structure chart of the semiconductor laser of wideband wavelength locking of the present invention;

Fig. 3 is embodiment two structure charts of the semiconductor laser of wideband wavelength locking of the present invention;

Fig. 4 is the Effect of Back-Cavity Mirror structure chart of miniature pyramid;

Fig. 5 is embodiment three structure charts of the semiconductor laser of wideband wavelength locking of the present invention;

Fig. 6 is embodiment four structure charts of the semiconductor laser of wideband wavelength locking of the present invention;

Fig. 7 is embodiment five structure charts of the semiconductor laser of wideband wavelength locking of the present invention.

Embodiment

Combine accompanying drawing and embodiment that the present invention is further specified at present.

The present invention changes traditional wavelength locked laser diode and attempts the thinking with the narrow wavelength locking of laser; The filter or wide grating or the wide reflectance coating of width reflection belt of width reflection belt that adopt wide bandwidth to see through add in the semiconductor laser; Make LD in the certain temperature range of low-temperature end, can be locked in gain medium absorption spectra shortwave and can accept absorbing wavelength; In the temperature end certain temperature range, make semiconductor laser wavelength be locked in gain medium absorption spectra long wave and can accept wavelength; And between two cut-off wavelengths, the wavelength of semiconductor laser can free move with temperature.

The semiconductor laser of wideband wavelength locking of the present invention, its output wavelength are locked in gain medium and absorb within the bandwidth, comprise semiconductor laser output light, through optical alignment system collimation, again by feedback output system feedback resonance and output pumping laser.Main, also add the wideband wavelength locking member in order to locking output wavelength scope.

Consult shown in Fig. 1 (a) for the gain medium absorption spectra.λ ₀Be the gain medium peak absorbtivity wavelength, its corresponding temperature is T ₀, Δ λ ₁For gain medium absorption spectra shortwave direction can be accepted the absorbing wavelength bandwidth, Δ λ ₂For gain medium absorption spectra long wave direction can be accepted the absorbing wavelength bandwidth, the semiconductor laser of the wideband wavelength locking that the present invention proposes is locked in λ with the output wavelength of laser ₁To λ ₂Between.

If the semiconductor laser lockable temperature range for traditional single-point wavelength locking is Δ T ₁And general non-wavelength locking semiconductor laser wavelength is d λ/dT with the drift velocity of temperature, but wideband wavelength locking semiconductor laser working temperature bandwidth deltaf T then of the present invention is that single-point wavelength locking temperature range bandwidth adds that semiconductor laser is from λ ₁Change to λ ₂Temperature bandwidth (λ ₁For gain medium absorption spectra shortwave can be accepted absorbing wavelength, λ ₂For gain medium absorption spectra long wave can be accepted absorbing wavelength), promptly

$\mathrm{\&Delta;T}=\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="H2009101122005E00024.png"\; state="\{\{state\}\}">T</figure-callout>}}_1+\frac{{\mathrm{\&lambda;}}_2-{\mathrm{\&lambda;}}_1}{\frac{\mathrm{d\&lambda;}}{\mathrm{dT}}}$

For example if semiconductor laser single-point lockable temperature bandwidth is 30 ℃; But it be effective absorbing wavelength bandwidth that Nd:YVO4 selects 802nm-814nm, is 0.3nm/ ℃ as if LD wavelength translational speed, but then total working temperature bandwidth be 30+12/0.3=70 (℃).

Consult the semiconductor laser shown in Fig. 1 (b) and export the optical maser wavelength curve in the different temperatures scope for wideband wavelength locking of the present invention.Δ T=T ₂-T ₁, for the semiconductor laser of wideband wavelength locking of the present invention with wavelength locking at λ ₁To λ ₂Between the time, the temperature bandwidth that can work.At T＜T ₁And T＞T ₂In the temperature range, this laser wavelength lockout, laser wavelength jumps to the wavelength X that changes to the drift velocity d λ/dT of temperature according to normal wavelength ₃=λ ₀-(* (the T of d λ/dT) ₀-T ₁), λ ₄=λ ₀+ (* (the T of d λ/dT) ₂-T ₀) (T ₀Be gain medium peak absorbtivity wavelength λ ₀The temperature that the place is corresponding).

Consult and shown in Figure 2 carry out the semiconductor laser structure of wideband wavelength locking for the present invention uses broad band pass filter.Wherein, 201 is the ordinary semiconductor laser, and 202 is the optical alignment system of laser; The laser that noise spectra of semiconductor lasers 201 is sent collimates, and 203 is the wideband wavelength locking member, and embodiment adopts broad band pass filter first; It inserts in the chamber at a certain angle; Angle changing can be adjusted the logical optical wavelength in center of this broad band pass filter 203 among a small circle, and 204 are the partial reflection Effect of Back-Cavity Mirror, in order to the part feedback light to be provided and to realize the effect that laser is exported.

Consult the structure of embodiments of the invention two that is shown in Figure 3.Wherein, 201 is the ordinary semiconductor laser, and 202 is the optical alignment system of laser, and the laser that noise spectra of semiconductor lasers 201 is sent collimates, and 203 is broad band pass filter, and 304 are the partial reflection sheet, and 305 are the total reflection Effect of Back-Cavity Mirror.Tilting partial reflection sheet 304 part transmissions provide feedback and bidirectional reflectance that laser output is provided, and its laser is output as both direction.

Consult shown in Figure 4ly, the total reflection Effect of Back-Cavity Mirror 305 of the embodiment two among Fig. 3 can also be that miniature pyramidal structure 401 as shown in Figure 4 replaces.Its surface is made up of a lot of miniature right-angle prisms; Angle between the adjacently situated surfaces is 90 °; The advantage of the miniature pyramidal structure 401 of this kind is; The light of any direction incident can realize all that through its reflection original optical path returns, and can reduce the sensitivity requirement of total reflection Effect of Back-Cavity Mirror 305 debugging of embodiment two like this, makes that the making of device is simpler.

Consult the structure of embodiments of the invention three that is shown in Figure 5.Wherein, 201 is the ordinary semiconductor laser; 202 is the optical alignment system of laser, and the laser that noise spectra of semiconductor lasers 201 is sent collimates, and 304 are the partial reflection sheet; The 304 part transmissions of partial reflection sheet provide feedback and bidirectional reflectance that laser output is provided, and its laser is output as both direction.504 is the broadband reflection Effect of Back-Cavity Mirror, realizes laser output wavelength is locked in the purpose in λ 1-λ 2 scopes through it.

Broadband reflection Effect of Back-Cavity Mirror 504 among the embodiment three shown in Figure 5 also can be a kind of grating of broadband reflection.Can also directly this grating be engraved on the semiconductor laser luminescence chip to be implemented in the purpose that realizes wavelength locking in the wide wave-length coverage.For example, consult the structure of embodiments of the invention four that is shown in Figure 6.Wherein 601 is semiconductor laser chip, and 602 is the broadband reflection grating that is carved with, and is engraved in semiconductor laser chip 601 sides, and 603 is heat sink, is used for heat conduction.The present invention can carve broadband feedback grating 602 by semiconductor laser chip 601 sides and realize wideband wavelength locking.

Similarly, be the structure of embodiments of the invention five shown in Fig. 7.601 is semiconductor laser chip, and 603 is heat sink, is used for heat conduction, and S1, S2 are the semiconductor chip reflecting cavity mirror, and one of them of chamber mirror S1 or chamber mirror S2 is coated with the broadband reflection film into wavelength locking according to the invention.

The applicable grating of the present invention, prism, filter or output film make laser broadband work laser cavity system.The present invention is applied to semiconductor pump laser especially and is applied to as in the pumping source laser; The wavelength locking range lambda 1-λ 2 that is mentioned among the present invention can be according to concrete application demand, changes through the performance index to broad band pass filter or broadband reflection sheet or broadband reflection grating and controls.

Although specifically show and introduced the present invention in conjunction with preferred embodiment; But the those skilled in the art should be understood that; In the spirit and scope of the present invention that do not break away from appended claims and limited; Can make various variations to the present invention in form with on the details, be protection scope of the present invention.

Claims (3)

1. the semiconductor laser of a wideband wavelength locking is characterized in that: its output wavelength is locked in gain medium and absorbs within the bandwidth, and gain medium absorbs bandwidth and is meant that semiconductor laser is from λ ₁Change to λ ₂Bandwidth, λ ₁For gain medium absorption spectra shortwave can be accepted absorbing wavelength, λ ₂For gain medium absorption spectra long wave can be accepted absorbing wavelength; Semiconductor laser output light; Through optical alignment system collimation; By feedback output system feedback resonance and output pumping laser, also add the broad band wavelength transmission member again, the lock-in range of this broad band wavelength transmission member is that single-point wavelength locking temperature range bandwidth adds that semiconductor laser is from λ ₁Change to λ ₂The temperature bandwidth, insert in the exterior resonant cavity, the feedback output system is to adopt the structure that feedback is provided by exocoel, in order to be locked in λ ₁To λ ₂Between the output wavelength scope, Effect of Back-Cavity Mirror that described feedback output system is a partial reflection constitutes or is that a partial reflection sheet and a total reflection Effect of Back-Cavity Mirror constitute.

2. the semiconductor laser of wideband wavelength locking according to claim 1 is characterized in that: described broad band wavelength transmission member is broad band pass filter or the optical element that plates the broadband filter coating.

3. the semiconductor laser of wideband wavelength locking according to claim 2, it is characterized in that: described total reflection Effect of Back-Cavity Mirror is plane reflection chip architecture or miniature pyramidal structure.

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