The electric pump micro cavity laser of integrated straight wave guide output
Technical field: the invention belongs to the photoelectron technology field, is a kind of integrated electric pump micro cavity laser of full light that is used for.
Background technology:
Semiconductor whispering gallery mode micro-cavity laser have volume little, swash and to penetrate that threshold values is low, the integrated level advantages of higher.Whispering gallery mode laser is propagated on the device inside direction parallel with device surface, can realize that on-chip interconnect is integrated with photo-detector, optical coupler etc., satisfying extensive integrated optical circuit needs, is key in application devices such as light is integrated, photometry calculation, optical communication.
The basic structure of the whispering gallery mode micro-cavity laser of report is little dish-like or little annular both at home and abroad at present.Rely on the edge and the refringence between the air of little dish or little annular micro-cavity that the light of propagating in it is formed total reflection.Be able to set up vibration by this total reflection effect, form feedback and amplify at device inside.Because this whispering gallery mode is based on the total reflection principle of light, determined that therefore the laser that produces in little dish or the little ring is limited in the inside of micro chamber device consumingly, the very difficult directional light power output that obtains along certain direction.
According to the slab guide mode coupling theory, two at a distance of the coupling transmission that energy can take place between the parallel waveguide of a determining deviation.The luminous power of propagating in a waveguide produces vibration in another waveguide by the resonance coupling effect, coupling efficiency is by two waveguide spacings and coupling length decision.Based on this theory, Northwestern Univ USA has reported U type structured light pumping micro-cavity laser.Its architectural feature is to be several microns U type curved waveguide around width of little dish or little ring preparation, 1 micron of little dish or little ring and U type curved waveguide gap less than.Laser produces in little dish or little ring and vibrates, and coupling is delivered in the U type curved waveguide then, by two port outputs of U type waveguide.This structure is owing to need to make the U type waveguide of 1 micron of gap less than, required precision height, complex process.
Summary of the invention
Luminous power is difficult to the directed shortcoming of exporting in the prior art in order to overcome, and solution U type structured light pumping micro-cavity laser required precision height, problems such as complex process, the present invention discloses a kind of electric pump micro cavity laser of integrated straight wave guide output, can be with the port output of the laser in the micro-cavity laser by integrated straight wave guide output, this device is based on the micro-cavity laser that the whispering gallery mode principle produces laser generation.Device is made up of tube core and heat sink two parts, by scolder both is welded together.Heat sinkly both tube core was provided support, also be connected with additional power source as bottom electrode.
Tube core is the micro-cavity laser chip of finishing after complex devices technologies such as process photoetching, burn into oxidation and electron beam evaporation on the quantum well semiconductor laser device epitaxial wafer.The center of tube core is a little dish or little ring, and its diameter is between tens microns-tens of microns, and thickness is several microns, and the width of little ring also is several microns.Tangentially connect a straight wave guide at the edge of little dish or little ring, width is several microns, and length is tens of-hundreds of microns, the consistency of thickness of thickness and little dish or little ring.Surface preparation at little dish or little ring has the metal ohmic contact film.Adopt scolder with tube core and the heat sink making that welds together the electric pump micro cavity laser of finishing integrated straight wave guide output.
Its operation principle is as follows:
On the metal ohmic contact film of little dish or little ring surface, draw top electrode with gold ball bonding.Draw bottom electrode in heat sink surface.At upper and lower electrode two ends biasing, positive pole is added in and powers on extremely.Negative pole is added in the bottom electrode end.After the electric current by tube core surpassed the laser lasing threshold, the light emission that the quantum well active area in tube core inside produces formed stable vibration with whispering gallery mode in little dish or little ring, produce laser.Because straight wave guide output and little dish or little ring integrate, the laser generation in little dish or little ring has certain proportion to be coupled in the straight wave guide output, and exports by the port of straight wave guide.Adjusting the size of injection current can control from the intensity of the laser of straight wave guide port output.
Advantage of the present invention is the U type waveguide that does not need to make 1 micron of gap less than, have simple in structure, the output couple efficiency height, the needs of extensive optical integrated device research have been satisfied in the directed output of luminous power.
Description of drawings:
Fig. 1 is the electric pump micro cavity laser schematic diagram of little dish-like integrated straight wave guide output, also is Figure of abstract.
Fig. 2 is the electric pump micro cavity laser schematic diagram of little ring-like integrated straight wave guide output
Fig. 3 is that the electric pump micro cavity laser of little dish-like integrated straight wave guide output prepares schematic diagram
Wherein heat sink 1, substrate 2, straight wave guide 3, with the figure 7 of little dish 4, ohmic contact film 5, little ring 6, laser.
Embodiment:
Below in conjunction with drawings and Examples the present invention is further specified.
Fig. 1 is the electric pump micro cavity laser schematic diagram of little dish-like integrated straight wave guide output.Form by heat sink (1) and tube core two parts.Tube core is formed by being produced on the straight wave guide (3) on the substrate (2), little dish (4) and metal ohmic contact film (5).Straight wave guide (3) is connected with little dish (4), and tangentially prolongs.
Fig. 2 is the electric pump micro cavity laser schematic diagram of little ring-like integrated straight wave guide output.With Fig. 1 difference is to replace little dish (4) among Fig. 1 with little ring (6).
Embodiment 1:
Fig. 3 is that the electric pump micro cavity laser of little dish-like integrated straight wave guide output prepares schematic diagram.
(1), figure (a) is that the thickness of quantum-well laser material is the 2-3 micron at the last sample with MOCVD or the intact quantum well semiconductor laser device material of MBE technology growth of substrate (2).
(2), make the reticle that photoetching is used according to the structural design of little dish and straight wave guide output.The diameter of little dish can be designed as 50 microns in this example, and the width of straight wave guide is that 5 microns, length are 100 microns.Figure (b) adopts the figure (7) of the laser that photoetching method will prepare with photoresist to transfer to the surface of figure (a) sample.
(3), figure (c) figure (b) the sample employing chemical corrosion method that will shift the laser figure carves straight wave guide (3) and little dish (4), corrosion depth is to be as the criterion the whole corrosion of quantum-well laser material thoroughly.Photoresist protection straight wave guide (3) and little dish (4) are not corroded in corrosion process.
(4), figure (d) proceeds photoetching to figure (c) sample also with photoresist the part beyond little dish (4) surface to be covered; then with thermal evaporation in the high vacuum coating unit or with the method for radio frequency sputtering at superficial growth AuGeNi/Au film; adopt stripping means that the AuGeNi/Au film beyond little dish (4) surface is peeled off the back again and remove remaining photoresist; make surfaces A uGeNi/Au film form good ohmic contact film (5) 40 seconds at 400 ℃ of quick alloys of following nitrogen protection, finish the making of laser tube core.
(5), heat sink (1) can be with the material preparations such as oxygen-free copper, diamond or aluminium nitride of high heat conduction.Above-mentioned material is cut into 1 millimeter of the length of side, thick 500 microns thin slice.The back polishing is ground on the surface.The method that adopts vacuum evaporation or sputter is finished the metallization of heat sink (1) at superficial growth TiPtAu/Au film.
(6), vacuum evaporation or plated metal indium scolder film on metallization heat sink (1) surface.The laser tube core that Fig. 3 (d) is finished closely contacts with heat sink (1), is heated to 200 ℃ then with tube core and heat sinkly weld together by scolder under nitrogen protection.
Embodiment 2:
The electric pump micro cavity laser of little ring-like integrated straight wave guide output shown in Figure 2 is identical with the manufacturing process of embodiment 1.Difference is only carried out figure transfer and needed in Fig. 3 (b) reticle is changed the reticle that work is made according to the structural design of little ring and straight wave guide output.The external diameter of little ring can be designed as 50 microns in this example, and internal diameter is 30 microns, and the width of straight wave guide is that 5 microns, length are 100 microns.