Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
  • H01S5/042—Electrical excitation ; Circuits therefor
  • H01S5/0421—Electrical excitation ; Circuits therefor characterised by the semiconducting contacting layers
  • H01S5/0422—Electrical excitation ; Circuits therefor characterised by the semiconducting contacting layers with n- and p-contacts on the same side of the active layer
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
  • H01S5/042—Electrical excitation ; Circuits therefor
  • H01S5/0421—Electrical excitation ; Circuits therefor characterised by the semiconducting contacting layers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
  • H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
  • H01S5/06226—Modulation at ultra-high frequencies
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
  • H01S5/18—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities
  • H01S5/183—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
  • H01S5/18305—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL] with emission through the substrate, i.e. bottom emission
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
  • H01S5/18—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities
  • H01S5/183—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
  • H01S5/18341—Intra-cavity contacts
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
  • H01S5/22—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure
  • H01S5/2205—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure comprising special burying or current confinement layers
  • H01S5/2222—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure comprising special burying or current confinement layers having special electric properties
  • H01S5/2224—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure comprising special burying or current confinement layers having special electric properties semi-insulating semiconductors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
  • H01S5/22—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure
  • H01S5/227—Buried mesa structure ; Striped active layer
  • H01S5/2275—Buried mesa structure ; Striped active layer mesa created by etching
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/30—Structure or shape of the active region; Materials used for the active region
  • H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
  • H01S5/343—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
  • H01S5/34306—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/30—Structure or shape of the active region; Materials used for the active region
  • H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
  • H01S5/343—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
  • H01S5/3434—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser with a well layer comprising at least both As and P as V-compounds

Definitions

• the present invention relates to a semiconductor laser device used as a transmission light source in technical fields such as optical communication and optical measurement.
• a transmission system with a data rate of about 10 Gb / s has been proposed as a next-generation large-capacity trunk system for optical communication.Soliton transmission systems that do not affect the dispersion characteristics of fibers have been proposed. Possibilities are being pursued.
• the semiconductor laser element used in sled ton transmission method in order to pulse width generating the following ultra-short optical pulses 1 X 1 0- 12 seconds (1 picosecond), high-speed modulation of more than 20 GH z Is required.
• the modulation characteristics of a semiconductor laser device are theoretically based on the following rate equations [la] and [lb] for the photon density S and carrier density N in the active layer, as described in Reference 1 below. Studies are being conducted.
• ⁇ is expressed by the following equation (3).
• ⁇ corresponds to the linear differential gain and the saturation constant of the gain when G (S, N) is expressed as in the following equation (4), where N t is the threshold carrier density.
• Specific means for reducing ⁇ ⁇ include shortening the cavity length of the semiconductor laser device and reducing the end face reflectivity of the semiconductor laser device.
• the active layer is made p-type by doping.
• ⁇ is fixed as a constant, and ⁇ also has a lower limit from the correlation with the threshold current density, making it difficult to reduce ⁇ by these means.
• the quantum well structure also greatly degrades the modulation characteristics of the semiconductor laser device.In other words, as a unique problem of the multiple quantum well structure, the time required for carrier injection into the quantum well is delayed. Ref.
• the rate equation of a semiconductor laser device having a quantum well structure is as follows by modifying the above equation [la] [lb].
• N w is the carrier density in the quantum well layer
• N b is the carrier density in the barrier layer
• V w is the volume of the quantum well layer
• V b is the volume in the barrier layer.
• J w (t) is the carrier density injected directly into the quantum well layer
• J b (t) is the carrier density injected into the barrier layer
• r is the carrier density in the barrier layer
• the other one is that most of the quantum well structures used in the active layer of the semiconductor laser device have a thickness of the optical confinement layer of 100 A or more for the purpose of lowering the threshold and increasing the output, and a quantum well layer. Since the thickness of the metal is set to 50 A or less, the value of r increases and the value of e decreases.
• the surface emitting semiconductor laser device is pointed out roughly in the following documents 3 and 4 as follows.
• the present invention has been made in view of such technical problems, and has as its object to provide a semiconductor laser device having excellent high-speed modulation or high-speed response.
• the present invention includes: a lower light confinement layer, an active layer, and an upper light confinement layer on a slim substrate to achieve an intended purpose, wherein the active layer is a lower light confinement layer and an upper light confinement.
• Semiconductor sandwiched between layers In the laser device an electron injection path for injecting electrons into the active layer via the optical confinement layer and a hole injection path for injecting holes into the active layer without passing through the optical confinement layer are formed. It is characterized by having.
• the semiconductor laser device according to the present invention is, for example, of a quantum well type
• the lower optical confinement layer, the active layer, and the upper optical confinement layer are formed in a mesa shape, and the upper side of the mesa shape portion is covered with a p-type layer. Both sides of the mesa are covered with n-type layers.
• the active layer consists of a barrier layer and a quantum well layer, but the lower optical confinement layer and the upper optical confinement layer consist of a single semiconductor layer.
• a quantum well semiconductor laser device has, as basic components, an electron injection path for injecting electrons into the active layer via the optical confinement layer, and a hole for injecting holes into the active layer without passing through the optical confinement layer.
• an n-electrode is provided above the P-type layer covering the upper side of the mesa-shaped portion, and above the n-type layer covering both sides of the mesa-shaped portion.
• a p-electrode is provided.
• the ⁇ means that the modulation characteristics are improved compared to the conventional device because there is no first-order roll-off term, ie, (1 + j cu ⁇ ⁇ ⁇ 1 ).
• the other is to increase the relaxation frequency by bringing the parameter ⁇ closer to 1. Therefore, the width of the quantum well layer and the width of the optical confinement layer can be designed to be small, which leads to a large improvement in the modulation speed.
• quantum well semiconductor laser device In such a quantum well semiconductor laser device, electrons are injected into the quantum well layer via the optical confinement layer and the barrier layer, and holes are injected into the quantum well layer without passing through the optical confinement layer and the barrier layer. In this case, the carrier density in the quantum well layer is directly modulated, so that the modulation characteristics of the semiconductor laser device are improved.
• the active layer on the lower light confinement layer is formed in a mesa shape, and the upper side of the mesa shape portion is the P-type layer and the upper light confinement thereabove. And both sides of the mesa are covered with n-type layers.
• the lower optical confinement layer and the upper optical confinement layer are composed of a semi-insulating multilayer film.
• Such a surface-emitting type semiconductor laser device also has, as a basic configuration, an electron injection path for injecting electrons into the active layer through a light confinement layer, and injects holes into the active layer without passing through the light confinement layer.
• an n-electrode is provided above the upper optical confinement layer
• a p-electrode is provided above the n-type layer covering both sides of the mesa-shaped portion.
• FIG. 1 is a cross-sectional view showing one embodiment of a quantum well semiconductor laser device according to the present invention.
• FIG. 2 is an explanatory diagram showing the results of a simulation on the modulation characteristics of the quantum well semiconductor laser device.
• FIG. 4 is a sectional view and a plan view showing one embodiment of the surface emitting semiconductor laser device according to the present invention.
• FIG. 1 shows an embodiment of a quantum well semiconductor laser device according to the present invention.
• the quantum well type semiconductor laser device of this embodiment is manufactured as follows as an example.
• a non-doped InP layer 2 with a thickness of 1000 A and a non-doped InP layer 2 with a thickness of 300 A, a non-gap wavelength; ixm InGaA s P Lower optical confinement layer 31 1, 900A thick active layer 3 including multiple quantum well layers, 300A thick, bandgap wavelength ln g ll / um
• the s P upper optical confinement layer 34 and the non-doped InP layer 4 having a thickness of 1000 A are sequentially stacked through the first organic metal vapor deposition (MOCVD) method.
• MOCVD organic metal vapor deposition
• a A P quantum well layer 33 and a force s are alternately stacked, and include six barrier layers 32 and seven quantum well layers 33.
• the non-dove I n P layer 4 was The SiO 2 film formed at this time is processed into a strip shape by photolithography technology, and becomes a mask for preventing etching.
• portions outside the mask that is, both sides of each layer from the non-doped InP layer 4 to the InP semi-insulating substrate 1 are chemically etched and processed into a mesa shape.
• the p-type InP layer 5, the p-type InGaP layer 6, and the semi-insulating InP layer 7 were formed on both sides of the mesa through the second metalorganic vapor phase epitaxy.
• both sides of the mesa are covered with a P-type InP layer 5, and around the mesa, a p-type InGaP layer 6 and a semi-insulating InP layer 7 are stacked. Is done.
• n-type electrode 10 is provided on the n-type InGaAs P layer 9 and a mesa is formed by chemical etching using the n-type electrode 10, a p-type InGaAs Since the P layer 6 is exposed as an etching stop layer, a P-type electrode 11 is provided on the surface thereof.
• r is determined by the thickness of the optical confinement layer and the mobility of holes, and is assumed to be about 50 psec.
• electrons are injected into the quantum well layer via the optical confinement layer and the barrier layer, and holes are injected into the quantum well layer without passing through the optical confinement layer and the barrier layer. Since the carrier is injected, the carrier density in the quantum well layer is directly modulated to improve the modulation characteristics.
• 3 and 4 show an embodiment of the surface emitting semiconductor laser device according to the present invention.
• the surface-emitting type semiconductor laser device of this embodiment is manufactured as follows as an example.
• the layers are sequentially stacked by epitaxial growth via the long method (M0CVD method).
• the lower cladding layer 43 of the P-type implant InP has a thickness of 1 m and is doped with Zn to about 5 ⁇ 10 17 cnr 3 .
• the thickness of the non-doped I ⁇ ⁇ upper cladding layer 45 is 0.5 jum.
• an SiO 2 film is formed on the non-doped InP upper cladding layer 45 via a plasma CVD method, and is processed into a circular shape with a diameter of 4 / ⁇ ⁇ ⁇ ⁇ ⁇ by a photolithography technique. It becomes a mask for preventing etching.
• the P-type InP peripheral side cladding layer 46, the p-type InGaAs P contact layer 47, and the current confinement half-layer were used.
• the insulating InP layer 48 is formed on the upper surface, the peripheral side surface of the circular mesa, and when formed around the circular mesa, the circular mesa is covered with these layers.
• the P-type InP peripheral side cladding layer 46 is doped with Zn to about 5 ⁇ 10 17 cnT 3 .
• the semi-insulating I! 1 layer 48 for current constriction is doped with Fe.
• n-type semi-insulating multilayer film (multilayer reflective film) 50 is sequentially laminated.
• the n-type InP layer 49 has a carrier concentration of about 1 ⁇ 10 18 cm— 3 .
• the n-type semi-insulating multilayer film 50 has substantially the same configuration as the semi-insulating multilayer film 42 except that the n-type semi-insulating multilayer film 50 is about 1 ⁇ 10 18 cm ⁇ 3 and is n-type doped.
• an n-type electrode 51 is provided on the n-type semi-insulating multilayer film 50.
• the P-type InGaAs P contact layer is formed. Since 47 is exposed, a P-type electrode 52 having a circular hole is provided on the exposed surface of the p-type InGaAsP contact layer 47.
• the injection current from the P-type electrode 52 does not pass through the semi-insulating multilayer film 42, but the p-type doped InP lower cladding layer 43;
• the non-doped InGaAsP active layer 44 is injected into the inside of the non-doped InGaAsP active layer 44 through the mold InP peripheral side cladding layer 46 through the side surface and lower surface thereof.
• the injection is performed uniformly in the active layer 44.
• the n-type electrode 51 and the p-type electrode 52 are narrowed by the semi-insulating InP layer 48 when they are not opposed to each other, so that the high-speed response is not impaired.
• the hole injection path disclosed by the present invention is not limited to the quantum well semiconductor laser device and the surface emitting semiconductor laser device of each of the above-described embodiments.
• an n-type electrode and a p-type electrode are formed on the upper surface of a semiconductor wafer.
• the present invention can also be applied to a semiconductor laser device having a structure other than that of the embodiment as long as it is provided on the evening.
• a known or well-known semiconductor substrate (semi-insulating substrate) containing GaAs as well as InP is used.
• the active layer may be either a single quantum well type or a multiple quantum well type
• the optical confinement layer may have an SCH structure or a GRIN-SCH structure.
• a p-type layer, an n-type layer, a doped layer, a non-doped layer, and a combination thereof, of a group V-V containing a mixed crystal are used in an appropriate place.
• n-type electrode and the p-type electrode any known or well-known ones in this kind of technical field may be used.
• the present invention provides a semiconductor device comprising a lower optical confinement layer, an active layer, and an upper optical confinement layer on a semiconductor substrate, wherein the active layer is sandwiched between the lower optical confinement layer and the upper optical confinement layer.
• a semiconductor device comprising a lower optical confinement layer, an active layer, and an upper optical confinement layer on a semiconductor substrate, wherein the active layer is sandwiched between the lower optical confinement layer and the upper optical confinement layer.
• an electron injection path for injecting electrons into the active layer through the optical confinement layer Since a hole injection path for injecting holes into the active layer without passing through the confining layer is formed, it is self-evident that electrons are injected into the active layer through the optical confinement layer, and The holes are injected into the active layer without passing through the optical confinement layer, and thus the modulation characteristics or response of the device are improved in terms of high speed.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
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• Semiconductor Lasers (AREA)

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• 1992
  • 1992-03-31 JP JP4105388A patent/JPH05283802A/ja active Pending
• 1993
  • 1993-03-31 WO PCT/JP1993/000405 patent/WO1993020604A1/ja not_active Ceased
  • 1993-03-31 EP EP93906859A patent/EP0587911A1/en not_active Withdrawn
  • 1993-03-31 US US08/157,099 patent/US5544189A/en not_active Expired - Lifetime

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