US20020158266A1 - Optoelectronic waveguiding device and optical modules - Google Patents

Optoelectronic waveguiding device and optical modules Download PDF

Info

Publication number
US20020158266A1
US20020158266A1 US09/916,286 US91628601A US2002158266A1 US 20020158266 A1 US20020158266 A1 US 20020158266A1 US 91628601 A US91628601 A US 91628601A US 2002158266 A1 US2002158266 A1 US 2002158266A1
Authority
US
United States
Prior art keywords
optoelectronic
optical
mqw
waveguiding
layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US09/916,286
Other languages
English (en)
Inventor
Hiroshi Sato
Akira Taike
Kazunori Shinoda
Shinji Tsuji
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Assigned to HITACHI, LTD. reassignment HITACHI, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SATO, HIROSHI, SHINODA, KAZUNORI, TAIKE, AKIRA, TSUJI, SHINJI
Publication of US20020158266A1 publication Critical patent/US20020158266A1/en
Priority to US10/614,779 priority Critical patent/US6973226B2/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/12007—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/1228—Tapered waveguides, e.g. integrated spot-size transformers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4215—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers
    • 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
    • H01S5/02—Structural details or components not essential to laser action
    • H01S5/026—Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers
    • H01S5/0265—Intensity modulators
    • 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
    • H01S5/12—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 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B2006/12035—Materials
    • G02B2006/12078—Gallium arsenide or alloys (GaAs, GaAlAs, GaAsP, GaInAs)
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4256—Details of housings
    • G02B6/4262—Details of housings characterised by the shape of the housing
    • G02B6/4265—Details of housings characterised by the shape of the housing of the Butterfly or dual inline package [DIP] type
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4274—Electrical aspects

Definitions

  • the present invention relates to integrated semiconductor optical devices, and more specifically, the present invention relates to semiconductor optoelectronic waveguiding devices including an optical waveguide comprising a plurality of multiple quantum wells and to optical modules utilizing such devices.
  • optical transmission apparatuses for optical communication of a trunk line in which a plurality of communication lines are bundled should support high-speed (10 Gbit/s class) and long-distance transmission. Consequently, a semiconductor laser capable of operating at a transmission speed as high as at least 10 Gbit/s is preferred as the light source to be built into such optical transmission apparatuses.
  • a promising light source that enables high-speed, long-distance transmission whose speed is equal to at least 10 Gbit/s is a laser device manufactured by integrating an EA (electro absorption) type optical modulator and a DFB (distributed feedback) semiconductor laser on a single substrate (“EA/DFB laser”). Because the operating principles and availability of the EA/DFB laser are known, a detailed explanation is omitted and only the basic structure, advantages, and potential disadvantages thereof will now be described.
  • EA/DFB laser areas of the DFB laser and of the EA modulator are monolithically formed on the same semiconductor substrate.
  • a multiple quantum well (MQW) structure of the laser and that of the modulator are formed to have different materials, compositions, layer thicknesses, and other properties so that an energy gap of the MQW layer of the modulator part is larger than that of the MQW layer of the laser part.
  • Typical methods whereby the MQW structures having mutually different energy gaps are formed on the same semiconductor substrate include (1) a selective area growth method and (2) a butt-joint formation method.
  • the modulator and the laser may be formed by single crystal growth; this method has the advantage of a simple manufacturing process.
  • the materials, the compositions, and the total numbers of layers of the laser part and of the modulator are inevitably the same, and the method has little or no room for independent optimization of these device elements.
  • the laser part and the modulator can be formed by independent processes. Therefore, the modulator and the laser may be optimized independently in terms of their materials, compositions, layer thicknesses, the numbers of layers, and other properties. For 10 Gbit/s-and-higher high-speed and long-distance transmission, where both the modulator and the laser part preferably each achieve high end characteristics respectively, integration of the modulator and the laser by the butt-joint method appears promising.
  • a laser having the optical modulator integral therewith is generally formed through the following processes.
  • a device element structure of the DFB laser is formed on a semiconductor substrate.
  • the DFB laser area is protected with a dielectric film such as silicon oxide or silicon nitride.
  • the MQW layer in the DFB laser area is selectively etched away to expose the semiconductor substrate.
  • a MQW structure that is desired for use as the EA modulator and that will act as an absorption layer (“EA-MQW”) is re-grown.
  • the present invention provides a semiconductor optoelectronic waveguiding device with as small an optical loss as possible in the optical waveguide and that can respond to high-speed modulation that is desired for high-speed transmission.
  • the present invention may also provide a semiconductor optoelectronic waveguiding device that is manufactured by integrating device elements of the optical modulator and the semiconductor laser, each of which is optimized in terms of several characteristics thereof.
  • the basic structure of the present invention comprises an optoelectronic waveguiding device having at least two optoelectronic device element parts each comprising an optical waveguide.
  • the optical waveguides possessed by the above-mentioned at least two optoelectronic device element parts are preferably connected to each other with an optical waveguide such that at least a core portion thereof is made of a bulk crystal.
  • Examples of the above-mentioned at least two optoelectronic device element parts may include: a semiconductor laser part; an optical modulator part; and an optical amplifier part. Further, optical device elements other than these enumerated device elements may be used as the need arises. Moreover, in accordance with particular embodiments of the optoelectronic waveguiding device of the present invention, a configuration in which a plurality of pairs each having two of these optical device elements are arranged side by side may be adopted.
  • the present invention preferably comprises a structure such that the crystal defect between the DFB laser and the EA modulator is removed and a waveguide whose optical absorption is extremely low is inserted into this area. Consequently, the basic structure according to at least one embodiment of the present invention includes an optical waveguide of a bulk crystal formed at a connection part between the MQW of the laser part and the MQW of the modulator part.
  • the form according to the present invention may be a structure whose quantum effect is extremely small by using the above-mentioned bulk crystal area as the optical waveguide.
  • the MQW of the above-mentioned laser part to be connected to the MQW of the above-mentioned modulator part is preferably formed by a first butt-joint formation.
  • the bulk crystal waveguide is then formed by a second butt-joint formation so as to have a desirable refractive index distribution.
  • the present invention preferably realizes the one or more of the following: (1) the optical absorption can be reduced as low as possible by suppressing the shifting of the absorption edge that may occur in the MQW structure and (2) a further decrease in the optical absorption and improvement of the reliability of the device may be achieved by not providing a crystal defect of poor crystallinity in the device.
  • FIG. 1 is a perspective view of a device according to a first embodiment of the present invention
  • FIG. 2 is a cross section of a device according to the first embodiment of the present invention, taken along a plane parallel to the travelling direction of light therein;
  • FIG. 3 is a cross section of a device according to the first embodiment of the present invention, taken along a plane intersecting the travelling direction of light therein;
  • FIG. 4 shows cross sections of a device according to the first embodiment of the present invention, illustrating a manufacturing process in a processing order
  • FIG. 5 is a characteristic diagram illustrating the shift of the absorption edge in a crystal defect of poor crystallinity
  • FIG. 6 is a diagram in which cumulative distributions of slope efficiency for the present invention and for the conventional example are shown for comparison;
  • FIG. 7 is a perspective view of a device according to a second embodiment of the present invention.
  • FIG. 8 is a cross section of a device according to the second embodiment of the present invention, taken along a plane parallel to the travelling direction of light therein;
  • FIG. 9 is a cross section of a device according to the second embodiment of the present invention, taken along a plane intersecting the travelling direction of light therein;
  • FIG. 10 shows cross sections of a device according to the second embodiment of the present invention, illustrating the manufacturing process in a processing order
  • FIG. 11 is a cross section of a device according to a third embodiment of the present invention, taken along a plane parallel to the travelling direction of light therein;
  • FIG. 12 is a view showing an example of a mask pattern to be used to form a bulk crystal waveguide of a device according to the third embodiment of the present invention shown in FIG. 11;
  • FIG. 13 is a cross section of a device according to a fourth embodiment of the present invention, taken along a plane parallel to the travelling direction of light therein;
  • FIG. 14 is a view showing an example of a mask pattern to be used to form a bulk crystal waveguide of a device according to the fourth embodiment of the present invention shown in FIG. 13;
  • FIG. 15 is a top view of an embodiment that has an array of light emitting device element parts
  • FIG. 16 is a cross section of an embodiment that has an array of the light emitting device element parts, taken along a plane parallel to the travelling direction of light therein;
  • FIG. 17 is a top view of an embodiment that has an array of light emitting device element parts and an optical multiplexer
  • FIG. 18 is a cross section of an embodiment that has an array of light emitting device element parts and an optical multiplexer, taken along a plane parallel to the travelling direction of light therein;
  • FIG. 19 is a top view showing an optical module that uses the optoelectronic waveguiding device according to the present invention.
  • FIG. 20 illustrates the relation between radiation loss in the device and the distance between the laser part and the optical modulator
  • FIG. 21 is a cross section showing a basic concept of the present invention.
  • FIG. 22 is a cross section showing a comparative example where the same single crystal is used to bury a gap between the laser part and the optical modulator as well as the laser part and the modulator.
  • the above-mentioned crystal defect is removed, and hence, the absorption loss of light in the device is significantly reduced. Because the bulk crystal waveguide has no MQW structure, there may occur little shift of the bad-gap energy (absorption edge) in the vicinity of the mask pattern edge in this butt-joint formation process. Therefore, the absorption arising from the bulk crystal waveguide that is introduced into the structure is decreased significantly as compared to that of the original MQW structure.
  • the present invention may be differentiated from the methods in the above-mentioned Japanese Patent Application Laid-Open No. 8-335745. Note that, in the above-mentioned Japanese Patent Application Laid-Open No. 8-335745, the absorption edge of the crystal defect is shifted toward a shorter wavelength by ion implantation to achieve reduction in the absorption loss. In this case, although it is possible that the absorption edge is shifted, the crystal defect itself cannot be removed.
  • the crystal defect is preferably replaced with the optical waveguide of the bulk crystal, not only can the absorption edge be shifted from the absorption edge of the crystal having the crystal defect to a desired absorption edge, but also the crystal defect itself may be removed.
  • the removal of the crystal defect in the optical waveguide additional effects such as an improvement in reliability of the device may also be expected. That is, the service life of an apparatus into which the present device is built may be improved.
  • FIG. 20 is a diagram showing a relation between the magnitude of the radiation loss and the distance between the optical modulator and the laser part.
  • the horizontal axis denotes the distance between the optical modulator and the laser part; the vertical axis denotes the radiation loss in the device.
  • the case where InP exists between the modulator and the laser part is marked with “buried with InP” and the case of the present invention is marked with “present invention.”
  • the radiation loss increases exponentially with an increase in distance between the modulator and the laser.
  • the EA modulator and the laser part are separated by at least a few tens of ⁇ m, there occurs a radiation loss equal to at least approximately 1 dB, and the loss may become a large obstacle to an increase of the optical output from the device.
  • FIG. 21 details a DFB laser part 501 , tan optical modulator part 502 , and an area of the optical waveguide of the bulk crystal formed by new crystal growth 503 .
  • a first optical confinement layer 514 , an active layer 515 , a second optical confinement layer 516 , and a grating 517 are preferably formed on a semiconductor substrate 500 .
  • a first optical confinement layer 511 For the optical modulator part 502 , a first optical confinement layer 511 , an optical waveguide part 512 , and a second optical confinement layer 513 are preferably formed. Thereafter, a second cladding layer 518 is formed over these two parts 501 , 502 .
  • FIG. 22 is a cross section showing an example where an area of the crystal defect that existed between the optical modulator 502 and the laser part 501 is buried with a second cladding layer 518 by crystal growth.
  • the laser part includes a first light confinement layer 514 , an active layer area 515 , a second optical confinement layer 516 , and a grating 517 are formed on the semiconductor substrate 500 .
  • the optical modulator includes a first optical confinement layer 511 , an optical waveguide part 512 , and a second optical confinement layer 513 formed on the substrate 500 . Further, a second cladding layer 518 is again formed over these parts 501 , 502 . It should be noted in this example that a gap between the optical modulator 502 and the laser part 501 is buried with the second cladding layer 518 .
  • FIG. 21 and FIG. 22 are schematic, conceptual diagrams, and there may be many structural variants that can be carried out in manufacturing actual devices according to these diagrams.
  • the loss may be reduced by at least an order of magnitude as compared to the structure illustrated in FIG. 22 where the gap between the modulator and the laser is buried with InP, and a structure suitable to increase the optical output of a device may be provided.
  • This improvement may be more fully understood with respect to the comparison of characteristics shown in FIG. 20 and described above.
  • optical modulator and the laser part it is preferred in the present invention to establish an optical connection between the optical modulator and the laser part with the optical waveguide of a bulk crystal. If the optical modulator and the laser part, which are placed with a gap, are connected using the same material as the cladding layer, one or more of the above desired effects may not be obtainable.
  • the present invention may be effective for semiconductor optoelectronic waveguiding devices, especially for semiconductor optoelectronic waveguiding devices that use compound semiconductor materials.
  • semiconductor materials to be used for said semiconductor optoelectronic waveguiding devices include InGaAlAs, InGaAsP, and similar compounds.
  • the MQW structure may be composed of one of these enumerated materials. In this case, one material selected from a group consisting of InGaAsP, InGaAlAs, and InAlAs is preferable for the bulk part for connecting these MQW structures.
  • InP is used as the substrate for various device applications.
  • this invention may be effective for optoelectronic waveguiding devices that use compound semiconductor materials containing N.
  • the optoelectronic waveguiding device may use an InGaNAs system compound semiconductor material as a material for the MQW structure formed on a GaAs substrate.
  • EA modulator integrated semiconductor laser device A first exemplary embodiment of the present invention as applied to a semiconductor laser device into which a 1.55 ⁇ m band EA modulator is integrated (“EA modulator integrated semiconductor laser device”) will now be described.
  • the feedback of light in the present laser may be achieved by distributed feedback (DFB).
  • DFB distributed feedback
  • FIG. 1 is a perspective view of a first exemplary embodiment according to the present invention
  • FIG. 2 is a cross section of the optical waveguide part taken along a plane parallel to the travelling direction of light therein.
  • FIG. 3 is a cross section of the device taken along a plane intersecting the travelling direction of light therein, and FIG. 4 illustrates cross sections of the device during various stages of the manufacturing process.
  • the device is comprised of two device elements, a laser part 26 and a modulator 27 .
  • a laser electrode 23 and a modulator electrode 24 were formed independently.
  • a groove 21 is preferably formed for electrically isolating both device elements 26 , 27 .
  • An optical waveguide part 31 of the device is formed as a stripe shape with a buried hetero (BH) structure as is generally known in the art.
  • the sides of the stripe optical waveguide in the buried hetero structure are preferably buried with an Fe-doped high-resistance InP 32 (see FIG. 3).
  • each of the laser part 26 and the EA modulator part 27 is of an optimal structure independently. Therefore, each element has a different layered structure.
  • the substrate is preferably common to both device elements and is a compound semiconductor substrate made of, for example, n-type InP
  • the laser part 26 preferably comprises an n-type InGaAsP optical confinement layer 2 , a strained MQW layer 3 , and a p-type InGaAsP optical confinement layer 4 .
  • the MQW layer that will act as the active layer region, may consist of seven pairs (cycles) of a 6 nm thick well layer and a 10 nm thick barrier layer which are deposited sequentially, with the intention of achieving sufficient characteristics as a laser.
  • a grating layer 5 made of an InGaAsP material exists on top of these layers.
  • the active layer region and a structure of the grating layer may be formed so that the emission wavelength of the DFB laser at room temperature (25 degree C.) is approximately 1550 nm.
  • the optical confinement layers provided to sandwich the MQW layer are layers for enhancing the optical confinement of the above-mentioned MQW layer.
  • the optical waveguiding function is effected by sandwiching the core region with cladding layers whose refractive indexes are lower than that of the core region. That is, the optical waveguiding function is achieved by a layered structure of cladding layer/MQW layer/cladding layer.
  • the optical confinement layers sandwiching the MQW layer are provided to further enhance the optical confinement in the MQW layer. Therefore, the refractive indexes of the cladding layers are set to be lower than the refractive indexes of the above-mentioned optical confinement layers.
  • the optical waveguiding function is preferably enhanced by the layered structure of the cladding layer/optical confinement layer/MQW layer/optical confinement layer/cladding layer.
  • a form may also be adopted in which the cladding layer of the substrate side is the substrate itself. It may also be possible to provide the cladding layer of the substrate side independently on the semiconductor substrate.
  • the polarity of the grating layer 5 may be either n type or p type.
  • the DFB laser preferably becomes a refractive index coupling type where only the refractive index varies periodically in the propagation direction of light.
  • the n-type grating polarity gives rise to a gain coupling type DFB laser.
  • the grating functions as a periodically varying current-blocking layer, as is well known in the art. Therefore, not only the refractive index but also the gain in the active layer suffers periodic changes.
  • a grating that was uniformly formed over the whole area of the DFB laser is described.
  • the EA modulator area 27 is preferably comprised of an n-type InGaAsP optical confinement layer 11 , an undoped optical absorption layer 12 , and an undoped InGaAsP optical confinement layer 13 .
  • the optical absorption layer 12 may be formed of an InGaAsP system strained multiple quantum well (strained MQW) structure.
  • the thickness of a quantum well is preferably set at approximately 7 nm, and the thickness of a barrier layer is set at approximately 5 nm. These layers may be deposited for 10 cycles.
  • T barrier layer in the modulator part is preferably thinner than its counterpart in the laser part because the drift of the carriers is facilitated in the absorption layer to improve the modulation characteristics.
  • an InGaAsP optical waveguide layer may be formed in this area by butt-joint formation.
  • An exemplary method of forming the waveguides of the modulator part and the butt-joint waveguide layer will now be described with reference to FIG. 4.
  • an n-type InGaAsP optical confinement layer 2 , a strained MQW layer 3 , and a p-type InGaAsP optical confinement layer 4 are preferably deposited on an n-type InP substrate 1 .
  • a layered structure including the grating layer 5 made of an InGaAsP system material is thereafter formed (FIG. 4A).
  • SiN Silicon nitride
  • SiN Silicon nitride
  • RIE reactive ion etching
  • an absorption layer area of the EA modulator is formed by a first butt-joint process (FIG. 4C).
  • the absorption layer area is preferably formed by sequentially depositing an n-type InGaAsP optical confinement layer 11 , a MQW optical absorption layer 12 , a p-type optical confinement layer 13 , and a p-type InP cladding layer 15 .
  • the strained-MQW layer 12 may be comprised of ten cycles of a 7 nm thick quantum well layer and a 5 nm thick barrier layer. The absorption edge thereof is designed to be approximately 1490 nm. To achieve improved modulation characteristics, crystal compositions of the quantum well and of the barrier well are preferably chosen so that the former is given with compression strain whereas the latter is given with tensile strain.
  • FIG. 5 shows an example of a shift amount of the absorption edge of the EA part when the EA part is grown with the butt-joint method.
  • the horizontal axis denotes the distance from the edge of the protection mask in the laser part
  • the vertical axis denotes the shift amount of the absorption edge of the EA modulator part.
  • the shift of the absorption edge is caused in the area adjacent to the protection mask in the laser part within the range of at least approximately 100 ⁇ m from a mask edge, and the wavelength shift of the absorption edge is larger as the distance from the protection mask in the laser part decreases.
  • the absorption edge has moved to the longer wavelength side by as much as about 30 nm.
  • a mask 52 that has an opening only in the vicinity of the crystal defect (FIG. 4D) is formed, and the crystal defect is removed for a length of about 50 ⁇ m. Also in this process, in a similar manner to the first butt-joint process, the etching is selectively stopped at the surface of the n-type InP substrate 1 . Subsequent to this etching, an optical waveguide layer 14 preferably made of undoped InGaAsP and an undoped InP layer 18 are deposited thereon (FIG. 4E).
  • the p-type InP cladding layer 15 and a p-type InGaAs layer 16 may be formed.
  • An exemplary process for growing these crystals uses a metal-organic chemical vapor deposition (MOCVD) method.
  • MOCVD metal-organic chemical vapor deposition
  • the p-type InGaAs layer 16 may be formed to obtain an ohmic contact when the electrode is to be formed.
  • An exemplary process for growing the above-mentioned crystal uses a metal organic vapor phase epitaxy (MOVPE) method. It should be noted in the cross section of FIG. 3 that numerals for the p-type InP cladding layer 15 and the p-type InGaAs layer 16 on the layer 13 are omitted.
  • a buried hetero (BH) structure is preferably formed by a process of forming a mesa stripe through a normal dry etching process and a further process of regrowing a burying layer by the MOVPE method.
  • the BH structure is a structure where both sides of an optical waveguide, as viewed from the travelling direction of light, are buried with a material capable of confining the light.
  • the confining material normally is characterized by a high resistance.
  • a high-resistance InP 32 was used and Fe was doped therein to increase its resistivity.
  • FIG. 3 is a cross section of the BH laser part taken along a plane intersecting the travelling direction of light therein.
  • FIG. 3 may facilitate a better understanding of the BH structure.
  • the wafer surface is insulated with silicon oxide (“SiO 2 ”) 22 and the p-side electrode 24 and an nside electrode 25 are then formed.
  • SiO 2 silicon oxide
  • a low-reflection coating 40 and a high-reflection coating 41 are formed, respectively (see e.g., FIG. 2).
  • FIG. 6 a distribution of optical output efficiency per unit current (slope efficiency) obtained by evaluating the optical output versus current characteristics of exemplary devices is shown in FIG. 6.
  • the horizontal axis of FIG. 6 denotes the slope efficiency, and the vertical axis denotes the cumulative distribution for the measured samples.
  • FIG. 6 also shows the cumulative distribution of slope efficiency for devices that the present invention was not applied to (conventional device) and hence have crystal defects at the connection parts between the laser part and the modulator.
  • a group of solid squares designates samples according to the present invention
  • a group of open circles designates samples of conventional devices.
  • About 95 percent of the conventional devices are distributed below a slope efficiency of approximately 0.15 W/A.
  • less than about 25% of the devices according to the present invention have a slope efficiency of 0.15 W/A or less.
  • the devices according to the present invention improved the center value (almost equivalent to the average value) of the slope efficiency by a factor of about 1.3 (2 dB) over the conventional devices.
  • One reason for this changes is that because the devices of the present invention have no crystal defect in the optical waveguides, the absorption loss in the waveguide is reduced to an extremely small value as compared to the conventional butt-joint method.
  • FIG. 7 though FIG. 9 show devices according to a second exemplary embodiment of the present invention.
  • FIG. 7 is a perspective view of a device of the second embodiment
  • FIG. 8 is a cross section of the waveguide part of the device taken along a plane parallel to the travelling direction of light therein.
  • FIG. 9 is a cross section of the device taken along a plane intersecting the travelling direction of light therein, and
  • FIG. 10 shows cross sections illustrating an exemplary manufacturing process of the device.
  • This embodiment is preferably characterized in that the EA modulator part 27 is comprised of an InGaAlAs system MQW.
  • the laser part 26 is formed with an InGaAsP system MQW in a similar manner to the first exemplary embodiment.
  • the present exemplary embodiment has a basic configuration similar to that described with respect to the first embodiment. A detailed explanation for the similar features in the figures is omitted.
  • an EA modulator that uses an InGaAlAs system material has improved modulation efficiency and may achieve a larger extinction ratio than one that uses an InGaAsP system MQW.
  • the extinction ratio is a parameter which shows the ratio of the light outputs for ON and for OFF of the optical signal. In general, larger the extinction ratio are preferred for the transmission of light signals. Therefore, for an optical transmission system that requires a larger extinction ratio, the laser having the EA modulator made of the InGaAlAs system MQW integral therewith, as described in this embodiment, may be suitable.
  • an exemplary manufacturing process for the laser will be described with reference to FIG. 10.
  • the growth temperature of the InGaAlAs system material to be used for the EA modulator part in this embodiment is higher than the growth temperature of the InGaAsP system material to be used for the laser part. Therefore, if the MQW of the laser part is formed first, that MQW will be exposed to an elevated temperature above the growth temperature of the laser. When the laser part undergoes such a thermal hysteresis, minute defects in the crystals that constitute the MQW of the laser part move easily to easily effectuate a degradation of the crystals, and these defects cause a deterioration of the device characteristics. To circumvent this potential problem, the InGaAlAs-system MQW that requires the high temperature is preferably grown first in the present embodiment of the invention.
  • the optical absorption layer preferably comprises: an n-type InGaAlAs optical confinement layer 112 ; an MQW layer 113 ; and an undoped InGaAlAs optical confinement layer 114 formed on an n-type InP substrate 111 .
  • the MQW layer 113 may be manufactured by depositing a quantum well layer (thickness approximately 7 nm) and a barrier layer (thickness approximately 5 nm), both of which consist of the InGaAlAs system material, for ten cycles. On this optical absorption layer, a cladding layer of a p-type InP 115 is grown to a thickness of approximately 0.2 ⁇ m.
  • the semiconductor wafer that has this layered structure is clad with SiN, which is formed to a mask 116 that serves to protect the modulator part (FIG. 10A).
  • a mask 116 that serves to protect the modulator part
  • the p-InP cladding layer and the optical absorption layer are etched away (FIG. 10B).
  • the etching is allowed to proceed through the n-type InGaAlAs 112 and is selectively stopped at the n-type InP substrate 111 .
  • the etching may be either of: dry etching, for example, reactive ion etching (RIE); selective wet etching that uses a solution whose main constituent is phosphoric acid or sulfuric acid; or a combination of both of these processes.
  • RIE reactive ion etching
  • an InGaAsP system MQW structure that will act as a laser is formed by a first butt-joint process.
  • the MQW structure is manufactured, in a similar manner to the first embodiment, by depositing an n-type InGaAsP optical confinement layer 121 , an undoped active layer 122 , an undoped InGaAsP optical confinement layer 123 , and additional layers thereon. Then, a grating layer 124 made of an InGaAsP system material and a p-type InP cladding layer 125 are preferably formed (FIG. 10C).
  • a crystal defect 126 with poor crystallinity that was formed at the connection part between the modulator and the laser is removed using a SiN mask 130 (FIG. 10D).
  • dry etching such as the reactive ion etching (RIE) and selective wet etching using a solution whose main constituent is phosphoric acid or sulfuric acid are preferably used together. It should be noted that the etching is selectively stopped at the n-type InP substrate 111 .
  • an undoped bulk InGaAsP waveguide layer 131 and an undoped InP 132 are deposited thereon as a second butt-joint process (FIG. 10E).
  • a grating structure 141 is formed in the laser area by a conventional method (FIG. 10F) on which a p-type InP cladding layer 151 and a p-type InGaAs layer 152 are deposited (FIG. 10G).
  • FIG. 9 is a cross section of the device taken along a plane intersecting the travelling direction of light therein.
  • reference numerals for the p-type InP cladding layer 151 and for the p-type InGaAs layer 152 on the layer 114 are omitted.
  • Exemplary optoelectronic waveguiding devices according to this embodiment are evaluated for optical output versus current characteristics at an operating temperature of 25 degree C. The results of the tests show that an average threshold current was approximately 8 mA, and the average slope efficiency was 0.17 W/A. An example of the cumulative distribution of slope efficiency was shown in FIG. 6. From FIG. 6, it can be understood that the present invention preferably improves the slope efficiency as compared to conventional devices. Further, exemplary optoelectronic waveguiding devices according to this embodiment are tested in an optical transmission experiment using a single mode optical fiber of a length of 40-80 km, and sufficient transmission characteristics are achieved.
  • FIG. 11 and FIG. 13 show the potential problem of mode mismatching between the waveguides in cases where the EA modulator part and the laser part have different waveguide layer thicknesses, and therefore, the guided mode size of light in the respective areas differ from each other.
  • FIG. 11 is an example in which the length of the modulator is shortened with the intention of improving the operating frequency band thereof. That is, by shortening the modulator length of the modulator, the electric capacitance can be reduced, and the modulation bandwidth of the device can be improved.
  • the thicknesses of several layers that constitute the optical modulator are set to be larger than those of the corresponding layers of the laser part.
  • FIG. 11 is a cross section of the device taken along a plane parallel to the travelling direction of light therein
  • FIG. 12 is a top view showing locations and widths of patterns of the protection mask that are used to manufacture respective parts in this example.
  • FIG. 13 is a cross section of the device taken along a plane parallel to the travelling direction of light therein, and FIG. 14 is a top view showing locations and widths of patterns of a protection mask that are used to manufacture respective parts of this example.
  • the example of FIG. 11 will be described.
  • the number of the quantum well layers of the EA modulation part was increased, and the optical confinement coefficient in the absorption layer was made larger. Accordingly, the thickness of a waveguide 204 in an area near the EA modulator part is larger than that in an area near the laser part.
  • the modulator part is preferably comprised of the MQW structure of an InGaAlAs system material to realize desired modulation characteristics of the modulator.
  • an optical absorption layer comprises an n-type InGaAlAs optical confinement layer 201 , an MQW layer 202 , and an undoped InGaAlAs optical confinement layer 203 formed on an n-type InP substrate 111 .
  • the quantum well layer acting as a light absorbing layer is repeatedly deposited to approximately 14 cycles which is larger than that of the second embodiment. Accordingly, the absorption layer is thicker than that of the second embodiment by approximately 50 nm.
  • a cladding layer of p-type InP is grown to a thickness of about 0.2 ⁇ m.
  • a SiN mask for protecting the modulator part is formed using the same technique as the second embodiment.
  • the p-InP cladding layer and the optical absorption layer are etched away.
  • the etching is allowed to proceed through the n-type InGaAlAs 201 and is selectively stopped at the n-type InP substrate 111 .
  • the etching may be either of: dry etching, for example, reactive ion etching (RIE); selective wet etching that uses a solution whose main constituent is phosphoric acid or sulfuric acid; or a combination of these processes.
  • the surface of the n-type InP substrate 111 is exposed, and an active layer region of the laser is formed on this surface.
  • the structure of the active layer region is the same as in the first and second embodiments.
  • the n-type InGaAsP optical confinement layer 2 , the active layer 3 , the undoped InGaAsP optical confinement layer 4 are formed, On these layers, the grating layer 5 made of an InGaAsP system material and a p-type InP cladding layer are formed.
  • the crystal defect that was formed at the connection part between the optical modulator and the laser part is replaced with a bulk InGaAsP waveguide 204 by a second butt-joint process.
  • the mask pattern to be used in this second butt-joint process is such that the width of a mask stripe pattern on the optical modulator side is set to be larger than that on the laser side.
  • the dry etching such as the reactive ion etching (RIE) and the selective wet etching that uses a solution whose main constituent is phosphoric acid or sulfuric acid are used together.
  • the etching is selectively stopped at the n-type InP substrate 111 .
  • the undoped bulk InGaAsP waveguide layer 112 and an undoped InP are preferably deposited as a second butt-joint process.
  • the width of a mask 211 on the EA modulator side is set to be larger than the width of a mask 212 for protecting the laser part, the well-known effect of the selective area growth occurs. That is, since the quantity of the growth species supplied becomes large near the EA modulator side, the crystal that is grown there in the second butt-joint process becomes thicker than that near the laser side. Accordingly, the InGaAsP waveguide layer 204 tends to be thicker closer to the modulator side than at a point near the laser side.
  • the thickness of the waveguide can be varied in a taper manner so that the thickness of the waveguide near the laser side equals the thickness of the waveguide of the laser and the waveguide near the EA modulator side equals the thickness of the absorption layer.
  • any discontinuity of the waveguide thickness may be eliminated both at the connection part between the laser part and the InGaAsP bulk crystal waveguide and at the connection part between the optical modulator and the InGaAsP bulk crystal waveguide. Therefore, the propagation loss of light between the waveguides is decreased.
  • a grating structure is formed in the laser area by a conventional technique, and a p-type InP cladding layer 205 and a p-type InGaAs layer 206 are deposited thereon. Subsequently, the laser structure is formed through the same process that is described with respect to the first embodiment. Previously described details are again omitted.
  • the above-mentioned description is for the case where the waveguide thickness of the EA modulator portion is larger than that of the laser part, but the present invention can be applied to a converse case (shown in FIG. 13) where the waveguide thickness of the EA modulator part is smaller than that of the laser part.
  • an optical waveguide 251 of a bulk crystal that is provided between the laser part and the modulator is such that its thickness at the connection part to the laser part is thick and becomes thinner nearer to the modulator.
  • a mask pattern as shown in FIG. 14 may be used in the second butt-joint process. That is, the width of a SiN mask 261 (stripe pattern) for protecting the laser side is to be larger than the width of a SiN mask 262 (stripe pattern) for protecting the EA modulator part.
  • the reason that the taper waveguide is formed with such a mask pattern is the same as description of FIG. 12.
  • the device manufacturing process is basically the same as the first embodiment excluding alteration of the mask pattern.
  • FIG. 15 and FIG. 16 are examples of the present invention as applied to side-by-side arrangements of the device elements described in the first and/or second embodiments to compose an array of optoelectronic device elements.
  • FIG. 15 is a top view of the device according to this embodiment
  • FIG. 16 is a cross section of the device taken along a plane parallel to the travelling direction of light therein. Note that each figure shows only characteristic portions of the device, and portions common to the device according to the present invention (such as the electrodes) are omitted for clarity.
  • a device with a plurality of modulator-integrated lasers arranged side by side provides a plurality of optical signals to be used with a plurality of transmission channels. Therefore the present invention can provide light sources suitable to a further high-capacity optical transmission system such that the transmission capacity is proportional to a product of the transmission speed and the number of channels.
  • FIG. 15 shows a top view of the device with four pieces of DFB lasers each acting as a light emitting part arranged side by side, from a first channel laser 301 to a fourth channel laser 304 mounted on its surface. Further, four modulators, from a first channel modulator 311 to a fourth channel modulator 314 , are also formed in such a way that each modulator corresponds to one of the DFB lasers.
  • FIG. 16 shows a cross-sectional structure of the optical waveguide of the side-by-side arranged channel device. Each of the four channels has a laser area 321 and a modulator area 322 , and a bulk crystal waveguide 323 is formed between these two areas. The formation process for these waveguide structures is preferably the same as that described in the first embodiment.
  • FIG. 17 is an example of the device such that light emitted from one of a plurality of lasers arranged side by side is multiplexed to a single optical waveguide by a multiplexer and then modulated by a single optical modulator.
  • FIG. 17 includes a laser part 451 , an optical modulator part 452 , and an optical multiplexer part 411 , all of which are connected to one another with optical waveguides.
  • Four lasers for four channels, from a first channel laser 401 to a fourth channel laser 404 are arranged side by side. Light generated by any of the four channel lasers is preferably made to enter a single optical modulator 412 through the optical multiplexer 411 , and is modulated thereby.
  • a desired wavelength i.e., one of four wavelengths
  • emission wavelengths of the four channel lasers, from the first channel laser 401 to the fourth channel laser 404 are preferably set at different wavelengths with a spacing of approximately 2 nm.
  • a device with lasers at frequencies of 1550 nm, 1552 nm, 1554 nm, and 1556 nm, respectively was formed. Adoption of such a side-by-side structure makes it possible to obtain light having a desired wavelength by injecting current to a channel having the desired wavelength according to need.
  • the number of channels and wavelength separation between the channels are set at 4 and 2 nm, respectively, but by setting the number of channels and wavelength separation according to need, the number of selectable wavelengths and a wavelength region can be set in an almost unlimited variety of desired values.
  • FIG. 18 is an irregular section of the optoelectronic waveguiding device taken along a non-straight line that passes each optical waveguide layers.
  • both device elements preferably have MQW structures. As details of their layered structures are the same as in the first embodiment, further explanation is omitted.
  • an optical waveguide layer 453 is formed of a bulk crystal having a refractive index distribution desirable as the optical waveguide according to the present invention.
  • a multiplexer because the length of the whole device becomes longer, it may be important to limit the optical absorption per unit length in the path. If the light is absorbed in the optical waveguide, optical output emitted from the device becomes small. As a result, after the device is built into an optical transmission apparatus, there may occur a failure that results in deterioration of S/N characteristics of the transmission apparatus.
  • the optical multiplexer itself may be of a conventional structure, and many types of device elements may achieve a sufficient effect.
  • the structure according to the present invention where a bulk crystal waveguide is provided between the laser part and the EA modulator is preferably suitable.
  • the bulk crystal waveguide has an absorption edge that is far away from the guided wave wavelength as compared to the MQW waveguide, it is possible to control the waveguide absorption per unit length to be low value.
  • the number of channels is set at 4, if the present invention is applied to a device whose number of channels is other than four, the effect of reducing the loss when the light passes through the multiplexer is the same.
  • FIG. 19 A conceptual top view of a mounting form including an optoelectronic waveguiding device according to this embodiment is shown mounted on an optical module in FIG. 19.
  • An optoelectronic waveguiding device 603 is placed on a mount board 602 together with an optical lens 604 , and the prepared mount board 602 is then placed in a package 605 and a fiber 601 is connected thereto.
  • Current feed to the device may be accomplished from an electrode pad through a wire in a similar manner to conventional techniques.
  • a feed pad 611 for EA modulator there is shown a feed pad 611 for EA modulator; an n-electrode pad 612 for semiconductor laser; p-electrode feed pads 621 , 622 , 623 , and 624 for DFB laser; and a feed wire 631 .
  • a modulator-integrated laser that emits large optical output and enables high-speed optical communication can preferably be provided.
  • a high-speed optical transmission system capable of operating at low power consumption can be provided.
  • An optoelectronic waveguiding device in which a layered structure consisting of an optical waveguide layer having a refractive index desirable for light guiding and cladding layers each of which is made of a material having a refractive index lower than that of the optical waveguide layer that exist above or beneath the optical waveguide is formed on a semiconductor substrate.
  • the device is characterized in that (a) a plurality of optical waveguide layers each having the MQW structure exist in a direction of a light propagation axis of the optical waveguide layer each have layer structures or constituent materials that are mutually different, and (b) an optical waveguide made of a semiconductor bulk crystal that bears a small quantum effect and has a refractive index higher than those of the cladding layers exists at the connection part between these MQW structure waveguides.
  • An optoelectronic waveguiding device formed by depositing a first MQW structure on a semiconductor substrate, removing a part of the first MQW layer and subsequently forming a second MQW structure in that area. Further, an optical waveguide layer made of a semiconductor bulk crystal material that bears a small quantum effect and has a refractive index higher than those of the cladding layers is deposited thereon.
  • An optoelectronic waveguiding device characterized in that a plurality of optoelectronic waveguiding device elements each having a different function are formed in a direction of the light propagation axis on the same semiconductor substrate.
  • cladding layers are each made of a material having a refractive index lower than that of the optical waveguide layer being deposited above and beneath the optical waveguide layer, and some or all of the optoelectronic waveguiding device elements have the MQW structures.
  • an optical waveguide exists that is formed by depositing a semiconductor bulk crystal bearing an extremely small quantum effect.
  • An optoelectronic waveguiding device that has at least a semiconductor laser part and an optical modulator in a portion thereof, characterized in that both the optical modulator and the semiconductor laser part have the MQW structures, layer structures or constituent materials of these MQW structures are mutually different, and an optical waveguide made of a bulk crystal exists at the connection part between the optical modulator and the semiconductor laser part.
  • An optoelectronic waveguiding device characterized in that optoelectronic waveguiding device elements each of which is one optoelectronic waveguiding device element selected from a group consisting of at least a semiconductor laser, an optical modulator, and a semiconductor optical amplifier are formed on the same semiconductor substrate. These optoelectronic waveguiding device elements are arranged in a direction of the light propagation axis with at least the optical modulator and the semiconductor laser part having the MQW structures. Layer structures or constituent materials of these MQW structures are mutually different.
  • An optical waveguide that is formed by depositing a semiconductor bulk crystal bearing an extremely small quantum effect exists at the connection parts between two of the optical modulator, the semiconductor laser, and the semiconductor amplifier.
  • An optoelectronic waveguiding device characterized in that (a) a plurality of device element structures each comprising at least a semiconductor laser and an optical modulator are formed side by side in a direction parallel to the light propagation axis on the same semiconductor substrate, each device element structure capable of emitting light of the same or a mutually different wavelength. Both the optical modulator and the semiconductor part having the MQW structures, respectively, and layer structures or constituent materials of these MQW structures being mutually different.
  • An optical waveguide made of a bulk crystal may exist at the connection part between the modulator and the semiconductor laser part.
  • An optical module that has at least a semiconductor optoelectronic waveguiding device and an optical fiber as constituents in a portion thereof, characterized in that said semiconductor optoelectronic waveguiding device is a semiconductor optoelectronic waveguiding device such that a plurality of device element structures each comprising at least a semiconductor laser and an optical modulator are formed side by side in a direction parallel to the light propagation axis. Each device element structure being capable of emitting light of the same or a mutually different wavelength.
  • optical modulators and the semiconductor laser parts all having the MQW structures, and layer structures or constituent materials of these MQW structures of each device element structure are mutually different.
  • An optical waveguide made of a bulk crystal exists at the connection part between the modulator and the semiconductor laser of each device element structure.
  • An optoelectronic waveguiding device characterized in that a plurality of device element structures each having at least a semiconductor laser are formed side by side in a direction parallel to the light propagation axis on the same semiconductor substrate and at least an optical multiplexer and an optical modulator are arranged in the optical waveguide running from the semiconductor lasers up to a light facet of the device.
  • the semiconductor lasers, the optical multiplexer, and the optical modulator being configured so that light emitted from the lasers arranged side by side is multiplexed to one optical waveguide and subsequently made to enter the optical modulator.
  • An optical module comprising at least an optical fiber and a semiconductor optoelectronic waveguiding device capable of emitting single longitudinal mode light in a portion thereof, characterized in that (a) a plurality of device element structures each having at least a semiconductor laser are formed side by side in a direction parallel to the light propagation axis on the same semiconductor substrate, each device element structure in a side-by-side arrangement being capable of emitting light of the same or a mutually different wavelength, (b) at least an optical multiplexer and an optical modulator are arranged in the optical waveguides running from the semiconductor lasers up to a light emitting facet of the device, the optical multiplexer and the optical modulator being configured in such a way that light emitted from any of the lasers in a side-by-side arrangement is multiplexed by the optical multiplexer and then made to enter the optical modulator, and at least modulator part having the MQW structure, and (c) an optical waveguide made of a bulk crystal exists at least in a portion
  • An optoelectronic waveguiding device characterized in that the MQW structure made of an InGaAlAs system material and the MQW structure made of an InGaAsP system material exist on the light propagation axis of the optoelectronic waveguiding device, and an optical waveguide made of one crystal selected from among InGaAsP system, InGaAlAs system, and InAlAs system bulk crystals exist at the connection part between these two MQW structures.
  • An optoelectronic waveguiding device that has at least a semiconductor laser and an optical modulator (EA modulator) in a portion thereof, characterized in that a layered structure that constitutes the EA modulator comprises the MQW structure made of an InGaAlAs system material, a layered structure that constitutes the semiconductor laser comprises the MQW structure made of an InGaAsP system material, and an optical waveguide made of one material selected from among InGaAsP system, InGaAlAs system, and InAlAs system bulk crystals exists at the connection part between the modulator and the semiconductor laser.
  • EA modulator optical modulator
  • An optoelectronic waveguiding device that has at least a semiconductor laser and an optical modulator (EA modulator) in a portion thereof, characterized in that each of the EA modulator and the semiconductor laser has the MQW structure made of an InGaAsP system material, at least one of a thickness of the quantum well, a thickness of the barrier layer, and the number of cycles of the quantum wells which constitute the MQW structure of the modulator being different from a counterpart of the MQW structure of the laser part, and an optical waveguide made of one material selected from among InGaAsP system, InGaAlAs system, and InAlAs system bulk crystals exists at the connection part between the modulator and the semiconductor laser.
  • EA modulator optical modulator
  • An optoelectronic waveguiding device that has at least a semiconductor laser and an optical modulator (EA modulator) in a portion thereof, characterized in that each of the EA modulator and the semiconductor laser has a MQW structure made of an InGaAlAs system material, one of a thickness of the quantum well, a thickness of barrier layer, and the number of cycles of the quantum well which constitute the MQW structure of the modulator is different from a counterpart of the MQW structure of the laser part, and an optical waveguide made of one material selected from among InGaAsP system, InGaAlAs system, and InAlAs system bulk crystals exists at the connection part between the modulator and the semiconductor laser part.
  • EA modulator optical modulator

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Semiconductor Lasers (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
US09/916,286 2001-04-26 2001-07-30 Optoelectronic waveguiding device and optical modules Abandoned US20020158266A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US10/614,779 US6973226B2 (en) 2001-04-26 2003-07-09 Optoelectronic waveguiding device and optical modules

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2001129178A JP4105403B2 (ja) 2001-04-26 2001-04-26 半導体光集積素子の製造方法
JP2001-129178 2001-04-26

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US10/614,779 Division US6973226B2 (en) 2001-04-26 2003-07-09 Optoelectronic waveguiding device and optical modules

Publications (1)

Publication Number Publication Date
US20020158266A1 true US20020158266A1 (en) 2002-10-31

Family

ID=18977743

Family Applications (2)

Application Number Title Priority Date Filing Date
US09/916,286 Abandoned US20020158266A1 (en) 2001-04-26 2001-07-30 Optoelectronic waveguiding device and optical modules
US10/614,779 Expired - Lifetime US6973226B2 (en) 2001-04-26 2003-07-09 Optoelectronic waveguiding device and optical modules

Family Applications After (1)

Application Number Title Priority Date Filing Date
US10/614,779 Expired - Lifetime US6973226B2 (en) 2001-04-26 2003-07-09 Optoelectronic waveguiding device and optical modules

Country Status (2)

Country Link
US (2) US20020158266A1 (ja)
JP (1) JP4105403B2 (ja)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080291952A1 (en) * 2007-05-23 2008-11-27 Fujitsu Limited Optical semiconductor device
US20100142885A1 (en) * 2008-12-09 2010-06-10 Hitachi, Ltd. Optical module
US20120163405A1 (en) * 2009-12-07 2012-06-28 Emcore Corporation Low chirp coherent light source
US20130207140A1 (en) * 2012-02-13 2013-08-15 Hitachi, Ltd. Semiconductor Optical Element Semiconductor Optical Module and Manufacturing Method Thereof
US9306372B2 (en) 2013-03-14 2016-04-05 Emcore Corporation Method of fabricating and operating an optical modulator
US9306672B2 (en) 2013-03-14 2016-04-05 Encore Corporation Method of fabricating and operating an optical modulator
US9372306B1 (en) 2001-10-09 2016-06-21 Infinera Corporation Method of achieving acceptable performance in and fabrication of a monolithic photonic integrated circuit (PIC) with integrated arrays of laser sources and modulators employing an extended identical active layer (EIAL)
US9438007B2 (en) 2013-03-14 2016-09-06 Emcore Corporation Optical modulator
CN105981239A (zh) * 2014-02-13 2016-09-28 古河电气工业株式会社 集成型半导体激光器元件以及半导体激光器模块
US9564733B2 (en) 2014-09-15 2017-02-07 Emcore Corporation Method of fabricating and operating an optical modulator
US10012797B1 (en) 2002-10-08 2018-07-03 Infinera Corporation Monolithic photonic integrated circuit (PIC) with a plurality of integrated arrays of laser sources and modulators employing an extended identical active layer (EIAL)
US10074959B2 (en) 2016-08-03 2018-09-11 Emcore Corporation Modulated laser source and methods of its fabrication and operation
WO2020224775A1 (en) * 2019-05-08 2020-11-12 Huawei Technologies Co., Ltd. Compound optical device

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005175295A (ja) * 2003-12-12 2005-06-30 Hitachi Ltd 半導体光素子及び光モジュール
CN100384038C (zh) * 2004-09-16 2008-04-23 中国科学院半导体研究所 选择区域外延生长叠层电吸收调制激光器结构的制作方法
KR100620391B1 (ko) 2004-12-14 2006-09-12 한국전자통신연구원 집적형 반도체 광원
GB2430548B (en) * 2005-09-27 2011-08-10 Agilent Technologies Inc An integrated modulator-laser structure and a method of producing same
JP2008053501A (ja) 2006-08-25 2008-03-06 Opnext Japan Inc 集積光デバイスおよびその製造方法
JP5082414B2 (ja) * 2006-12-06 2012-11-28 株式会社日立製作所 光半導体装置および光導波路装置
US7539228B2 (en) * 2007-06-26 2009-05-26 Avago Technologies Fiber Ip (Singapore) Pte. Ltd. Integrated photonic semiconductor devices having ridge structures that are grown rather than etched, and methods for making same
JP4998238B2 (ja) * 2007-12-07 2012-08-15 三菱電機株式会社 集積型半導体光素子
JP5151532B2 (ja) * 2008-02-15 2013-02-27 住友電気工業株式会社 半導体光集積素子の製造方法
JP5382289B2 (ja) * 2008-03-26 2014-01-08 セイコーエプソン株式会社 発光装置
JP5534826B2 (ja) * 2010-01-19 2014-07-02 日本オクラロ株式会社 半導体光素子、光送信モジュール、光送受信モジュール、光伝送装置、及び、それらの製造方法
JP5691216B2 (ja) 2010-03-29 2015-04-01 富士通株式会社 光半導体集積素子及びその製造方法
JP5800466B2 (ja) * 2010-04-20 2015-10-28 日本電信電話株式会社 多チャネル光送信モジュール
JP2012084627A (ja) * 2010-10-08 2012-04-26 Anritsu Corp 半導体発光素子およびそれを用いた光パルス試験器
EP2442165B1 (en) * 2010-10-15 2015-04-15 Huawei Technologies Co., Ltd. Coupling methods and systems using a taper
JP2012174700A (ja) * 2011-02-17 2012-09-10 Nippon Telegr & Teleph Corp <Ntt> 多チャネル光送信モジュール及びその作製方法
US9097846B2 (en) * 2011-08-30 2015-08-04 Skorpios Technologies, Inc. Integrated waveguide coupler
JP6423159B2 (ja) * 2014-02-27 2018-11-14 富士通株式会社 Ｇｅ系半導体装置、その製造方法及び光インターコネクトシステム
JP2016092124A (ja) * 2014-10-31 2016-05-23 三菱電機株式会社 光変調器集積半導体レーザ
JP6452451B2 (ja) * 2015-01-06 2019-01-16 古河電気工業株式会社 光集積素子およびその製造方法
JP6499268B2 (ja) * 2017-12-26 2019-04-10 日本オクラロ株式会社 半導体光素子及び光通信モジュール

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5816620B2 (ja) * 1977-08-29 1983-04-01 松下電器産業株式会社 光集積回路装置
US4480446A (en) * 1981-07-08 1984-11-06 Margulefsky Allen L Method and apparatus for rehabilitating refrigerant
JPS6215875A (ja) * 1985-07-12 1987-01-24 Matsushita Electric Ind Co Ltd 半導体装置およびその製造方法
JPS6371826A (ja) 1986-09-16 1988-04-01 Hitachi Ltd 光半導体装置
JPS63156388A (ja) * 1986-12-19 1988-06-29 Fujitsu Ltd 半導体発光素子の製造方法
DE69331979T2 (de) 1992-02-28 2003-01-23 Hitachi, Ltd. Optische integrierte Halbleitervorrichtung und Verfahren zur Herstellung und Verwendung in einem Lichtempfänger
KR100357787B1 (ko) 1994-01-31 2003-01-24 가부시끼가이샤 히다치 세이사꾸쇼 도파로형광소자의제조방법
GB9523731D0 (en) * 1995-11-20 1996-01-24 British Telecomm Optical transmitter
SE507376C2 (sv) * 1996-09-04 1998-05-18 Ericsson Telefon Ab L M Våglängdsavstämbar laseranordning
JPH10163568A (ja) * 1996-12-03 1998-06-19 Mitsubishi Electric Corp 変調器集積半導体レーザ
JPH10270793A (ja) * 1997-03-27 1998-10-09 Fujitsu Ltd 光半導体集積装置
JP2001085781A (ja) * 1999-09-17 2001-03-30 Mitsubishi Electric Corp 変調器集積半導体レーザ及び変調器集積半導体レーザを使用した半導体レーザ装置
JP2001142037A (ja) 1999-11-17 2001-05-25 Oki Electric Ind Co Ltd 電界効果型光変調器および半導体光素子の製造方法
JP4547765B2 (ja) * 2000-03-30 2010-09-22 三菱電機株式会社 光変調器及び光変調器付半導体レーザ装置、並びに光通信装置
JP2002148575A (ja) 2000-11-15 2002-05-22 Mitsubishi Electric Corp 光変調器および光変調器集積型レーザーダイオード

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9372306B1 (en) 2001-10-09 2016-06-21 Infinera Corporation Method of achieving acceptable performance in and fabrication of a monolithic photonic integrated circuit (PIC) with integrated arrays of laser sources and modulators employing an extended identical active layer (EIAL)
US10012797B1 (en) 2002-10-08 2018-07-03 Infinera Corporation Monolithic photonic integrated circuit (PIC) with a plurality of integrated arrays of laser sources and modulators employing an extended identical active layer (EIAL)
US20080291952A1 (en) * 2007-05-23 2008-11-27 Fujitsu Limited Optical semiconductor device
US20100142885A1 (en) * 2008-12-09 2010-06-10 Hitachi, Ltd. Optical module
US20120163405A1 (en) * 2009-12-07 2012-06-28 Emcore Corporation Low chirp coherent light source
US20130207140A1 (en) * 2012-02-13 2013-08-15 Hitachi, Ltd. Semiconductor Optical Element Semiconductor Optical Module and Manufacturing Method Thereof
US9306672B2 (en) 2013-03-14 2016-04-05 Encore Corporation Method of fabricating and operating an optical modulator
US9438007B2 (en) 2013-03-14 2016-09-06 Emcore Corporation Optical modulator
US9564734B2 (en) 2013-03-14 2017-02-07 Emcore Corporation Method of fabricating and operating an optical modulator
US9306372B2 (en) 2013-03-14 2016-04-05 Emcore Corporation Method of fabricating and operating an optical modulator
CN105981239A (zh) * 2014-02-13 2016-09-28 古河电气工业株式会社 集成型半导体激光器元件以及半导体激光器模块
US20160336719A1 (en) * 2014-02-13 2016-11-17 Furukawa Electric Co., Ltd. Integrated semiconductor laser device and semiconductor laser module
US9564733B2 (en) 2014-09-15 2017-02-07 Emcore Corporation Method of fabricating and operating an optical modulator
US10074959B2 (en) 2016-08-03 2018-09-11 Emcore Corporation Modulated laser source and methods of its fabrication and operation
WO2020224775A1 (en) * 2019-05-08 2020-11-12 Huawei Technologies Co., Ltd. Compound optical device

Also Published As

Publication number Publication date
US20050078904A1 (en) 2005-04-14
JP2002324936A (ja) 2002-11-08
US6973226B2 (en) 2005-12-06
JP4105403B2 (ja) 2008-06-25

Similar Documents

Publication Publication Date Title
US6973226B2 (en) Optoelectronic waveguiding device and optical modules
US7577319B2 (en) Semiconductor optical device and manufacturing method thereof
EP0627798B1 (fr) Composant intégré monolithique laser-modulateur à structure multi-puits quantiques
US7809038B2 (en) Electro-absorption optical modulator integrated with a laser to produce high speed, uncooled, long distance, low power, 1550 nm optical communication device with optimized parameters
US6455338B1 (en) Method of manufacturing an integrated semiconductor laser-modulator device
US20040179569A1 (en) Wavelength tunable DBR laser diode
US20080291952A1 (en) Optical semiconductor device
US7340142B1 (en) Integrated optoelectronic device and method of fabricating the same
US5151818A (en) Semiconductor optical amplifier
US7859745B2 (en) Semiconductor optical amplifying device, semiconductor optical amplifying system and semiconductor optical integrated element
US20070297475A1 (en) Semiconductor optical device and optical transmission module
US5703974A (en) Semiconductor photonic integrated circuit and fabrication process therefor
US8179592B2 (en) Semiconductor optical amplifier, method for manufacturing the same, and semiconductor optical integrated device
EP0672932B1 (en) Semiconductor optical modulator
JP3284994B2 (ja) 半導体光集積素子及びその製造方法
US20100245987A1 (en) Semiconductor optical amplifier
JP5243901B2 (ja) 同軸型半導体光モジュール
JP2019008179A (ja) 半導体光素子
JP2012002929A (ja) 半導体光素子の製造方法、レーザモジュール、光伝送装置
JP2003133638A (ja) 分布帰還型半導体レーザ素子及びレーザモジュール
JPH07231144A (ja) 光機能素子、これを含む光集積素子およびそれらの製造方法
JP4243506B2 (ja) 半導体レーザ及びそれを用いた光モジュール
JP2003234541A (ja) 分布帰還型半導体レーザ素子
JP2907234B2 (ja) 半導体波長可変装置
JP2019007997A (ja) 半導体光素子

Legal Events

Date Code Title Description
AS Assignment

Owner name: HITACHI, LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SATO, HIROSHI;TAIKE, AKIRA;SHINODA, KAZUNORI;AND OTHERS;REEL/FRAME:012398/0824

Effective date: 20010808

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION