WO2000072383A1 - Improved optoelectronic device - Google Patents

Improved optoelectronic device Download PDF

Info

Publication number
WO2000072383A1
WO2000072383A1 PCT/GB2000/002112 GB0002112W WO0072383A1 WO 2000072383 A1 WO2000072383 A1 WO 2000072383A1 GB 0002112 W GB0002112 W GB 0002112W WO 0072383 A1 WO0072383 A1 WO 0072383A1
Authority
WO
WIPO (PCT)
Prior art keywords
modulator
optical
optoelectronic device
resonant tunnelling
rtd
Prior art date
Application number
PCT/GB2000/002112
Other languages
French (fr)
Inventor
Charles Norman Ironside
Colin Roy Stanley
Jose Longras Figueiredo
Original Assignee
The University Court Of The University Of Glasgow
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 The University Court Of The University Of Glasgow filed Critical The University Court Of The University Of Glasgow
Priority to CA002398287A priority Critical patent/CA2398287A1/en
Priority to EP00935379A priority patent/EP1183736A1/en
Priority to AU50925/00A priority patent/AU5092500A/en
Publication of WO2000072383A1 publication Critical patent/WO2000072383A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/015—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on semiconductor elements with at least one potential jump barrier, e.g. PN, PIN junction
    • G02F1/025—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on semiconductor elements with at least one potential jump barrier, e.g. PN, PIN junction in an optical waveguide structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/86—Types of semiconductor device ; Multistep manufacturing processes therefor controllable only by variation of the electric current supplied, or only the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched
    • H01L29/861—Diodes
    • H01L29/88—Tunnel-effect diodes
    • H01L29/882—Resonant tunneling diodes, i.e. RTD, RTBD
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/0352—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/015—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on semiconductor elements with at least one potential jump barrier, e.g. PN, PIN junction
    • G02F1/0155—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on semiconductor elements with at least one potential jump barrier, e.g. PN, PIN junction modulating the optical absorption
    • G02F1/0157—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on semiconductor elements with at least one potential jump barrier, e.g. PN, PIN junction modulating the optical absorption using electro-absorption effects, e.g. Franz-Keldysh [FK] effect or quantum confined stark effect [QCSE]

Definitions

  • This invention relates generally to optoelectronic devices .
  • One aspect of the present invention relates to the use of quaternary III-V semiconductor alloys in the fabrication of optoelectronic devices, and in particular - though not exclusively - to the use of quaternary III-V semiconductor alloys in optoelectronic components integrated with resonant tunnelling divides (RTDs) .
  • RTDs resonant tunnelling divides
  • Another aspect of the present invention relates to optical modulators, and in particular - though not exclusively - to an optical modulator controlled or switched by a resonant tunnelling diode.
  • (a) uses a quaternary III-V semiconductor alloy (compound) which does not include Phosphorous (P) and is, therefore, particularly suitable for fabrication by Molecular Beam Epitaxy (MBE) ;
  • modulators such as Electro Absorption modulators are employed in optical communication systems where they switch light from a laser source on and off according to an applied electrical signal, i.e. they convert information from electrical to optical form. Key performance factors are the power used by the device and the speed of the device .
  • a device according to another aspect of the present invention may be used in telecommunications.
  • an optical fibre connection is required to each base station in a mobile network, and in future generations of mobile network there may be many more base stations; the next generation is the picocell network with a base only covering a range of a few tens of meters.
  • the information from each of these stations may be encoded on to optical fibres, e.g. using electro absorption modulators.
  • a device according to the another aspect of the present invention may also be used in Wavelength Division
  • WDM Wave Division Multiplexing
  • an optoelectronic device at least partially made from a quaternary III-V semiconductor alloy, the device including at least one resonant tunnelling diode
  • the quaternary III-V semiconductor alloy may advantageously be Indium Gallium Aluminium Arsenide (InGaAsAs) .
  • the quaternary III-V semiconductor alloy may be Indium Gallium Arsenide
  • a quaternary III-V semiconductor alloy layer may be provided on at least one side, and preferably both sides of the RTD.
  • the RTD may act as an electrically controlled optical device, eg. an optical modulator or alternatively as an optical switch.
  • the RTD may act as an optically controlled electrical device, eg. an optical detector.
  • a base station of a communication network including at least one optoelectronic device according to the first aspect.
  • a communication network including at least one optoelectronic device according to the first aspect .
  • a quaternary III-V semiconductor alloy in the fabrication of an optoelectronic device, the optoelectronic device including a resonant tunnelling diode
  • an optical modulator for modulation of electro-magnetic radiation in a wavelength region 1000 to 1600 nanometres (nm) , wherein the modulator includes a resonant tunnelling diode (RTD) for modulating the radiation.
  • RTD tunnelling diode
  • the modulator may include means for guiding the radiation, e.g. a waveguide.
  • the modulator is fabricated at least partially from Indium Gallium Aluminium Arsenide (InGaAlAs) .
  • the RTD is fabricated at least partially from InGaAlAs.
  • a unipolar electro-optical and/or electro-absorption modulator for operation in a wavelength region 1000-1600nm, the modulator being made at least partly from InGaAlAs, modulation being based on electric fields switched by an RTD.
  • the RTD peak to valley transition may increase the electric field across the waveguide, which shifts the core material absorption band- edge to longer wavelengths via the Franz-Keldysh effect thus changing the light guiding characteristics of the waveguide.
  • Low-frequency characterisation of a device has shown modulation up to 28 dB at 1565nm.
  • NDR negative differential resistance
  • a base station of a communication network the station including at least one optical modulator according to the fifth aspect.
  • a communication network including at least one optical modulator according to the first aspect.
  • Figure 1 (A) a schematic diagram of a wafer structure for use in fabrication of a device according to an embodiment of the present invention
  • Figure 1 (B) a perspective view of • a resonant tunnelling diode (RTD) optical modulator according to an embodiment of the present invention made from the wafer of Figure 1 (A) ;
  • RTD tunnelling diode
  • Figure 2 an experimental I-V characteristic of a 2 ⁇ m active area RTD optical waveguide, showing a PVCR around 7 and a peak current density of 17.5kA/cm 2 ;
  • Figure 3 modulation depth enhancement as a function of wavelength, induced by the RTD peak-to-valley transition.
  • an optoelectronic device 5 comprising part of an optical modulator, generally designed 10, according to an embodiment of the present invention.
  • the modulator 10 is intended to modulate light in the wavelength region 1000- 1600nm, and preferably at around 1550nm, by use of a resonant tunnelling diode (RTD) 12 formed in the modulator 10.
  • RTD tunnelling diode
  • the modulator 10 includes a waveguide 15 operatively associated with the RTD 12.
  • the modulator 10 according to this embodiment of the invention may, therefore, be termed a resonant tunnelling diode electro-absorption modulator
  • RTD-EAM RTD-EAM
  • RTD's are advantageous due to their high speed response and potential for electrical gain over a wide bandwidth.
  • the operation of the device 5 is based on the RTD 12 within the optical waveguide 15 which introduces a non- uniform electric field distribution across a core of the waveguide 15.
  • the electric field becomes strongly dependent on the bias voltage due to accumulation and depletion of electrons in the emitter and collector sides of the RTD 12, respectively.
  • a small high frequency AC signal ⁇ 1V
  • the high-frequency and large modulation depth characteristics of the RTD-EAM are a direct consequence of the carrier transport mechanisms across the RTD 12 and a depletion region of the waveguide 15. They are closely related to the material system and the specific device structure. High-speed performance can be improved by increasing the differential negative resistance (NDR) , R n , or decreasing the series resistance, R s .
  • NDR differential negative resistance
  • R n the differential negative resistance
  • R s series resistance
  • the velocity of the carriers, v, and hence the carriers transit time across the whole structure are material and structure dependent .
  • To obtain a larger value of R n it is necessary to achieve a high peak current density, J p , and a low valley current,
  • the InGaAs-InAlAs material system has improved tunnelling characteristics with a superior peak-to-valley current ratio evident in the dc current-voltage characteristics.
  • a specific contact resistivity less than 10 "7 ⁇ cm 2 and a saturation velocity higher than 10 7 cm/s can be achieved.
  • GaAs/AlGaAs typical metal to n + - GaAs contacts have a specific contact resistivity of about 10 ⁇ 6 ⁇ cm 2 , and the saturation velocity of electrons in GaAs layers is less than 10 7 cm/s.
  • RTDs can present higher peak current density and smaller valley current density, higher- speed operation can be expected.
  • the use of the InGaAs/AlAs system shifts the wavelengths of operation to optical communication wavelengths, and also gives a significant improvement in the electrical characteristics of the devices compared to the GaAs/AlAs system.
  • the InGaAlAs RTD optical waveguide structure may be grown by Molecular Beam Epitaxy (MBE) in a Varian Gen II system, on a n + InP substrate 20 (see Fig. 1(A)) . It consists of two 2 nm thick AlAs barriers separated by a 6nm wide InGaAs quantum well, sandwiched between two 500nm thick moderately doped (Si: 5xl0 16 cm "3 ) InGaAs spacer layers 25,30 which form the waveguide core.
  • MBE Molecular Beam Epitaxy
  • the InP substrate and a top heavily doped (Si: 2xl0 18 cm “3 ) InAlAs region 35 provide the waveguide cladding layers, which confine the light in a direction parallel to the double barrier plane, thus increasing the interaction length between the electric and the optical fields.
  • a ⁇ -doped InGaAs cap layer 40 is provided for formation of Au-Ge-Ni ohmic contacts.
  • Ridge waveguides (2 to 6 ⁇ m wide) and large-area mesas in each side of the ridges may be fabricated by wet- etching.
  • Ohmic contacts (100 to 400 ⁇ m long) may then be deposited on top of the ridges and mesas.
  • the waveguide width and the ohmic contact length define the device 5 active area.
  • a Si0 2 layer may be deposited, and access contact windows etched on the ridge and the mesa electrodes [Fig. 1(B)], allowing contact to be made to high frequency bonding pads (coplanar waveguide transmission line, CPW 45) .
  • the device 5 may be. die bonded on packages allowing light coupling into the waveguide 15 by a microscope objective end-fire arrangement.
  • the DC I-V characteristics of packaged devices 5 have been measured using a HP 4145 parametric analyser and show typical RTD behaviour. From the I-V characteristics one can estimate the electric field change across the depleted portion of the waveguide core due to RTD peak-to-valley switching.
  • Figure 2 shows the I-V characteristic of a 2 ⁇ m x lOO ⁇ m active area RTD 12.
  • Typical devices 5 have peak current density around 20 kA/cm 2 , with a peak-to-valley current ratio (PVCR) of 4.
  • Typical GaAs/AlAs devices show a PVCR around 1.5, J p ⁇ 13 kA/cm 2 , ⁇ V ⁇ 0.4V, and ⁇ J ⁇ 5 kA/cm 2
  • the modulator bandwidth which is related to the 10%-90% switching time, t R , of the RTD 12 between the peak and valley points, and the modulation depth, which is related to the peak-to-valley current ratio.
  • the applied electric field enhancement is given by:
  • ⁇ E is approximately 47kV/cm.
  • Figure 3 shows modulation depth as a function of the wavelength for peak-to-valley switching induced by a low- frequency, i.e. ⁇ 10kHz square wave signal with IV amplitude for a 4 ⁇ m x 200 ⁇ m active area.
  • a maximum modulation depth of 28 dB was obtained at 1565nm.
  • the device disclosed may have an operational speed limited by its packaging of around 8GHz bandwidth.
  • a device according to the invention may have a much large bandwidth, e.g. it is envisaged that up to 60 Ghz is possible.
  • the optoelectronic device 5 has hereinbefore been described as an electrically controlled optical device, eg. an optical modulator 10 or switch, wherein an input signal in the form of an applied electrical signal modulates an output signal in the form of an optical signal
  • the device 5 may also be used in reverse, ie. as an optically controlled electrical device eg. as an optical detector wherein the input signal is in the form of an applied optical signal which controls an output signal in the form of an electrical signal.
  • an optical detector will act, in use, as if it were provided with a built-in amplifier.

Abstract

There is disclosed an optoelectronic device (5) at least partially made from a quaternary III - V semiconductor alloy, the device (5) including at least one resonant tunnelling diode (RTD) (12). In a preferred embodiment the quaternary alloy is Indium Gallium Aluminium Arsenide (InGaAlAs). There is also disclosed an optical modulator (10) for modulation of electro-magnetic radiation in the wavelength region 1000 to 1600 nm, wherein the modulator (10) includes an RTD (12) for modulating the radiation.

Description

IMPROVED OPTOELECTRONIC DEVICE
Background of the Invention
This invention relates generally to optoelectronic devices .
One aspect of the present invention relates to the use of quaternary III-V semiconductor alloys in the fabrication of optoelectronic devices, and in particular - though not exclusively - to the use of quaternary III-V semiconductor alloys in optoelectronic components integrated with resonant tunnelling divides (RTDs) .
Another aspect of the present invention relates to optical modulators, and in particular - though not exclusively - to an optical modulator controlled or switched by a resonant tunnelling diode.
Regarding the aforementioned one aspect, it is among the objects of one or more embodiments of the one aspect of the present invention to provide an optoelectronic device which:
(a) uses a quaternary III-V semiconductor alloy (compound) which does not include Phosphorous (P) and is, therefore, particularly suitable for fabrication by Molecular Beam Epitaxy (MBE) ;
(b) provides for band-gap tuning and lattice matching to substrate;
(c) which at least when used as an optical detector provides for built-in amplification. Regarding the aforementioned another aspect, modulators such as Electro Absorption modulators are employed in optical communication systems where they switch light from a laser source on and off according to an applied electrical signal, i.e. they convert information from electrical to optical form. Key performance factors are the power used by the device and the speed of the device .
It is an object of the another aspect of the present invention to obviate or mitigate one or more problems/disadvantages in known modulators.
It is a further object of at least one embodiment of the another aspect of the present invention to provide an optical modulator which uses less electrical power and/or operates at a higher speed than known modulators .
It is a yet further object of at least one embodiment of the another aspect of the present invention to provide an optical modulator which operates at a very low voltage, e.g. which can be switched on and off with an applied signal of less than 1 volt.
A device according to another aspect of the present invention may be used in telecommunications.
With the expansion of mobile communications, an optical fibre connection is required to each base station in a mobile network, and in future generations of mobile network there may be many more base stations; the next generation is the picocell network with a base only covering a range of a few tens of meters. The information from each of these stations may be encoded on to optical fibres, e.g. using electro absorption modulators.
A device according to the another aspect of the present invention may also be used in Wavelength Division
Multiplexing (WDM) , wherein separate wavelengths are used for each channel, and a modulator is required for each channel.
Summary of Invention
According to a first aspect of the present invention there is provided an optoelectronic device at least partially made from a quaternary III-V semiconductor alloy, the device including at least one resonant tunnelling diode
(RTD) .
The quaternary III-V semiconductor alloy may advantageously be Indium Gallium Aluminium Arsenide (InGaAsAs) . Alternatively, the quaternary III-V semiconductor alloy may be Indium Gallium Arsenide
Phosphide (InGaAsP) . A quaternary III-V semiconductor alloy layer may be provided on at least one side, and preferably both sides of the RTD.
In one embodiment the RTD may act as an electrically controlled optical device, eg. an optical modulator or alternatively as an optical switch. In another embodiment the RTD may act as an optically controlled electrical device, eg. an optical detector.
According to a second aspect of the present invention there is provided a base station of a communication network, the station including at least one optoelectronic device according to the first aspect.
According to a third aspect of the present invention there is provided a communication network including at least one optoelectronic device according to the first aspect .
According to a fourth aspect of the present invention there is provided use of a quaternary III-V semiconductor alloy in the fabrication of an optoelectronic device, the optoelectronic device including a resonant tunnelling diode
(RTD) .
According to a fifth aspect of the present invention there is provided an optical modulator for modulation of electro-magnetic radiation in a wavelength region 1000 to 1600 nanometres (nm) , wherein the modulator includes a resonant tunnelling diode (RTD) for modulating the radiation.
Advantageously, the modulator may include means for guiding the radiation, e.g. a waveguide. Advantageously, the modulator is fabricated at least partially from Indium Gallium Aluminium Arsenide (InGaAlAs) .
Advantageously, the RTD is fabricated at least partially from InGaAlAs. In one embodiment of the fifth aspect of the present invention there is provided a unipolar electro-optical and/or electro-absorption modulator for operation in a wavelength region 1000-1600nm, the modulator being made at least partly from InGaAlAs, modulation being based on electric fields switched by an RTD.
According to a preferred form of the fifth aspect of the present invention there is provided an electro- absorption modulator of light at around 155Onm in wavelength in a unipolar InGaAlAs optical waveguide containing an InGaAs/AlAs double-barrier resonant tunnelling diode (DB-RTD) . The RTD peak to valley transition may increase the electric field across the waveguide, which shifts the core material absorption band- edge to longer wavelengths via the Franz-Keldysh effect thus changing the light guiding characteristics of the waveguide. Low-frequency characterisation of a device has shown modulation up to 28 dB at 1565nm. When DC biased close to the negative differential resistance (NDR) region, the RTD optical waveguide behaves as an electro-absorption modulator integrated with a wide bandwidth electrical amplifier, offering a potential advantage over conventional pn modulators.
According to a sixth aspect of the present invention there is provided a base station of a communication network, the station including at least one optical modulator according to the fifth aspect. According to a seventh aspect of the present invention there is provided a communication network including at least one optical modulator according to the first aspect.
Brief Description of the Drawings An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, which are:
Figure 1 (A) a schematic diagram of a wafer structure for use in fabrication of a device according to an embodiment of the present invention;
Figure 1 (B) a perspective view of • a resonant tunnelling diode (RTD) optical modulator according to an embodiment of the present invention made from the wafer of Figure 1 (A) ;
Figure 2 an experimental I-V characteristic of a 2μm active area RTD optical waveguide, showing a PVCR around 7 and a peak current density of 17.5kA/cm2; and
Figure 3 modulation depth enhancement as a function of wavelength, induced by the RTD peak-to-valley transition.
Detailed Description of Drawings
Referring to Figures 1 (A) and (B) , there is shown an optoelectronic device 5 comprising part of an optical modulator, generally designed 10, according to an embodiment of the present invention. The modulator 10 is intended to modulate light in the wavelength region 1000- 1600nm, and preferably at around 1550nm, by use of a resonant tunnelling diode (RTD) 12 formed in the modulator 10. The modulator 10 includes a waveguide 15 operatively associated with the RTD 12. The modulator 10 according to this embodiment of the invention may, therefore, be termed a resonant tunnelling diode electro-absorption modulator
(RTD-EAM) . RTD's are advantageous due to their high speed response and potential for electrical gain over a wide bandwidth. The operation of the device 5 is based on the RTD 12 within the optical waveguide 15 which introduces a non- uniform electric field distribution across a core of the waveguide 15. The electric field becomes strongly dependent on the bias voltage due to accumulation and depletion of electrons in the emitter and collector sides of the RTD 12, respectively. Depending on the DC bias operating point, a small high frequency AC signal (<1V) can induce high-speed switching. This produces substantial high-speed modulation of the wavegui&e optical absorption coefficient at a given wavelength near the material band- edge via the Franz-Keldysh effect and, therefore, modulates light at photon energies lower than the waveguide core band-gap energy. The modulation depth can be considered because, under certain conditions, the RTD operation point switches well into the two positive differential resistance portions of the current-voltage I-V characteristic, with a substantial part of the terminal voltage dropped across the depleted region in the collector side. The advantage of RTD-EAM compared to the conventional pn modulators is that, when DC biased close to the negative differential resistance (NDR) region, the device 5 behaves as an optical waveguide electro-absorption modulator integrated with a wide bandwidth electrical amplifier.
The high-frequency and large modulation depth characteristics of the RTD-EAM are a direct consequence of the carrier transport mechanisms across the RTD 12 and a depletion region of the waveguide 15. They are closely related to the material system and the specific device structure. High-speed performance can be improved by increasing the differential negative resistance (NDR) , Rn, or decreasing the series resistance, Rs. The velocity of the carriers, v, and hence the carriers transit time across the whole structure are material and structure dependent . To obtain a larger value of Rn, it is necessary to achieve a high peak current density, Jp, and a low valley current,
The demonstration and development of this new modulator concept in the InGaAs-InAlAs material system lattice matched to InP appear to be a promising route towards high speed, low radio frequency (rf) power consumption, optoelectronic converters (rf-optical and optical-rf) , because it can cover the waveguide range 1.0 to 1.6 μm where optical fibres have the lowest loss and chromatic dispersion. This disclosure teaches modulation of light at wavelengths around 1550nm in a unipolar InGaAlAs optical waveguide containing a InGaAs/AIAs double- barrier resonant tunnelling diode (RTD) . Furthermore, due to a smaller effective mass for the electrons in InGaAs (0.045mo compared to 0.067mo for GaAs) , and a larger r InGaAs -XaiAs barrier height (0.65 eV compared to 0.20 eV GaAs/AlAs) which will reduce the parasitic F-X mediated transport, the InGaAs-InAlAs material system has improved tunnelling characteristics with a superior peak-to-valley current ratio evident in the dc current-voltage characteristics. In addition, by changing the material to InGaAs/AlAs, a specific contact resistivity less than 10"7 Ωcm2 and a saturation velocity higher than 107 cm/s can be achieved. For GaAs/AlGaAs, typical metal to n+- GaAs contacts have a specific contact resistivity of about 10~6 Ωcm2, and the saturation velocity of electrons in GaAs layers is less than 107 cm/s. In GaAs/AlAs RTDs can present higher peak current density and smaller valley current density, higher- speed operation can be expected. The use of the InGaAs/AlAs system shifts the wavelengths of operation to optical communication wavelengths, and also gives a significant improvement in the electrical characteristics of the devices compared to the GaAs/AlAs system. The InGaAlAs RTD optical waveguide structure may be grown by Molecular Beam Epitaxy (MBE) in a Varian Gen II system, on a n+ InP substrate 20 (see Fig. 1(A)) . It consists of two 2 nm thick AlAs barriers separated by a 6nm wide InGaAs quantum well, sandwiched between two 500nm thick moderately doped (Si: 5xl016 cm"3) InGaAs spacer layers 25,30 which form the waveguide core. The InP substrate and a top heavily doped (Si: 2xl018 cm"3) InAlAs region 35 provide the waveguide cladding layers, which confine the light in a direction parallel to the double barrier plane, thus increasing the interaction length between the electric and the optical fields. A δ-doped InGaAs cap layer 40 is provided for formation of Au-Ge-Ni ohmic contacts.
Ridge waveguides (2 to 6 μm wide) and large-area mesas in each side of the ridges may be fabricated by wet- etching. Ohmic contacts (100 to 400 μm long) may then be deposited on top of the ridges and mesas. The waveguide width and the ohmic contact length define the device 5 active area. A Si02 layer may be deposited, and access contact windows etched on the ridge and the mesa electrodes [Fig. 1(B)], allowing contact to be made to high frequency bonding pads (coplanar waveguide transmission line, CPW 45) . After cleaving, the device 5 may be. die bonded on packages allowing light coupling into the waveguide 15 by a microscope objective end-fire arrangement.
The DC I-V characteristics of packaged devices 5 have been measured using a HP 4145 parametric analyser and show typical RTD behaviour. From the I-V characteristics one can estimate the electric field change across the depleted portion of the waveguide core due to RTD peak-to-valley switching. Figure 2 shows the I-V characteristic of a 2μm x lOOμm active area RTD 12. Typical devices 5 have peak current density around 20 kA/cm2, with a peak-to-valley current ratio (PVCR) of 4. The difference between the valley and peak voltages, ΔV, is around 0.8V, and the difference between the peak and valley current densities, ΔJ=JP(1-PVCR"1) , is about 15kA/cm2. (Typical GaAs/AlAs devices show a PVCR around 1.5, Jp ~ 13 kA/cm2, ΔV ~ 0.4V, and ΔJ ~ 5 kA/cm2) .
Two important figures of merit of the modulator 10 can be estimated from the RTD DC characteristics, and for a given material system they can be tailored by structural design. They are the modulator bandwidth, which is related to the 10%-90% switching time, tR, of the RTD 12 between the peak and valley points, and the modulation depth, which is related to the peak-to-valley current ratio. The switching time of the RTD 12 can be estimated from tR = 4.4 (ΔV/ΔJ) Cv, where C,, is the capacitance at the valley point per unit area (Cv=ε/W, where ε is the dielectric constant, and W is the depletion region width) . For the present device 5 W=0.5 μm and ε=13ε0, tR=5 ps . From this switching time, one can expect devices 5 with a bandwidth larger than 60 GHz. Experimental optical characterisation of the modulator
10 employed light from a Tunics diode laser, tuneable in the wavelength region around the absorption edge of the InGaAlAs waveguide (1480-1580nm) . The laser light was coupled into the waveguide 15 by a microscope objective end-fire arrangement. To measure the change in the optical absorption spectrum induced by the peak-to-valley transition, a low frequency rf signal was injected to switch the RTD 12 between the extremes of the NDR region, and a photodetector was used to measure the transmitted light. The applied electric field enhancement is given by:
ΔV W ΔE ~ + ΔJ
W 2εvsat
Taking ε=13ε0 and v=lxl07 cm/s (electron saturation velocity in the depletion region) , and assuming the depletion region to be 500nm wide, we have ΔE=47 kV/cm (for the GaAs based device we obtained ΔE=20kV/cm) . The shift in the transmission spectrum due to electric field enhancement in the InGaAlAs depletion region, as a result of the Franz-Keldysh effect, is given approximately by:
λ2g / e'h'
Δλg ~ V ΔE2 he 2mr
where mr is the electron-hole system reduced effective mass, h is Planck's constant, c is the light velocity, e is the electron charge, and λg is the wavelength corresponding to the waveguide transmission edge at zero bias, which is around 1520nm. The observed band edge shift associated with peak-to-valley switching is approximately Δλg = 3Onm, which agrees with the expression above and confirms that ΔE is approximately 47kV/cm.
Figure 3 shows modulation depth as a function of the wavelength for peak-to-valley switching induced by a low- frequency, i.e. < 10kHz square wave signal with IV amplitude for a 4μm x 200μm active area. A maximum modulation depth of 28 dB was obtained at 1565nm.
In conclusion, optical modulation up to 28 dB has been demonstrated in InGaAlAs optical waveguides containing an InGaAs/AlAs double-barrier resonant tunnelling diode (RTD) , due to peak-to-valley switching. Integration of a RTD with an optical waveguide, which combines a wide bandwidth electrical amplifier with an electro-absorption modulator, opens up the possibility for a variety of operation modes (such as modulation due to self-oscillation and relaxation oscillation) .
It will be appreciated that the embodiment of the present invention hereinbefore described is given by way of example only, and is not meant to limit the scope thereof in any way.
Particularly, it will be appreciated that the device disclosed may have an operational speed limited by its packaging of around 8GHz bandwidth. However, it will be understood that a device according to the invention may have a much large bandwidth, e.g. it is envisaged that up to 60 Ghz is possible.
It will further be appreciated that although the optoelectronic device 5 has hereinbefore been described as an electrically controlled optical device, eg. an optical modulator 10 or switch, wherein an input signal in the form of an applied electrical signal modulates an output signal in the form of an optical signal, the device 5 may also be used in reverse, ie. as an optically controlled electrical device eg. as an optical detector wherein the input signal is in the form of an applied optical signal which controls an output signal in the form of an electrical signal. It will be appreciated that such an optical detector will act, in use, as if it were provided with a built-in amplifier.

Claims

1. An optoelectronic device at least partially made from a quaternary III - V semiconductor alloy, the device including at last one resonant tunnelling diode.
2. An optoelectronic device as claimed in claim 1, wherein the quaternary III - V semiconductor alloy is Indium Gallium Aluminium Arsenide (InGaAlAs) .
3. An optoelectronic device as claimed in claim 1, wherein the quaternary III - V semiconductor alloy is Indium Gallium Arsenide Phosphide (InGaAsP) .
4. An optoelectronic diode as claimed in any of claims 1 to 3 , wherein a quaternary III - V semiconductor alloy layer is provided on at least one side of the at least one resonant tunnelling diode.
5. An optoelectronic device as claimed in claim 4, wherein quaternary III - V semiconductor layers are provided on both sides of the at least one resonant tunnelling diode.
6. An optoelectronic device as claimed any of claims 1 to 5, wherein the resonant tunnelling diode acts as an optical modulator or switch.
7. An optoelectronic device as claimed in any of claims 1 to 5 , wherein the resonant tunnelling diode acts as an optical detector.
8. A base station of a communication network, the station including at least one optoelectronic device according to any of claims 1 to 7.
A communication network including at least one optoelectronic device according to any of claims 1 to 7.
10. An optical modulator for modulation of electromagnetic radiation in a wavelength region 1000 to 1600 nanometres (nm) , wherein the modulator includes a resonant tunnelling diode for modulating the radiation.
11. An optical modulator as claimed in claim 10, wherein the modulator includes means for guiding the radiation.
12. An optical modulator as claimed in either of claims 10 or 11, wherein the modulator is fabricated at least partially from Indium Gallium Aluminium Arsenide (InGaAlAs) .
13. An optical modulator as claimed in either of claims 10 or 11, wherein the resonant tunnelling diode is fabricated at least partially from Indium Gallium Aluminium Arsenide (InGaAlAs) .
14. An optical modulator comprising a unipolar electro- optical and/or electro-absorption modulator for operation in a wavelength region 1000-1600 nm, the modulator being made at least partly from Indium
Gallium Aluminium Arsenide (InGaAlAs) , modulation being based on electric fields switched by a resonant tunnelling diode (RTD) .
15. A modulator as claimed in claim 14, wherein the modulator is an electro-absorption modulator of radiation at around 1550 nm in wavelength the modulator including a unipolar InGaAlAs optical waveguide containing an Indium Gallium Arsenide/Aluminium Arsenide (InGaAs/AlAs) double- barrier resonant tunnelling diode (DB-RTD) .
16. A modulator as claimed in claim 15, wherein in use, the resonant tunnelling diode peak to valley transition increases an electric field across the waveguide thereby shifting a core material absorption band-edge to longer wavelengths via the Franz-Keldysh effect thus changing radiation guiding characteristics of the waveguide .
17. A modulator as claimed in either of claims 15 or 16, wherein, in use, when DC biassed close to a negative differential resistance (NDR) region the waveguide and resonant tunnelling diode act as an electro-absorption modulator integrated with a wide band electrical amplifier.
18. A base station of a communication network, the station including at least one optical modulator according to any of claims 10 to 17.
19. A communication network including at least one optical modulator according to any of claims 10 to 17.
PCT/GB2000/002112 1999-05-25 2000-05-25 Improved optoelectronic device WO2000072383A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CA002398287A CA2398287A1 (en) 1999-05-25 2000-05-25 Improved optoelectronic device
EP00935379A EP1183736A1 (en) 1999-05-25 2000-05-25 Improved optoelectronic device
AU50925/00A AU5092500A (en) 1999-05-25 2000-05-25 Improved optoelectronic device

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9912178.2 1999-05-25
GBGB9912178.2A GB9912178D0 (en) 1999-05-25 1999-05-25 Improved optical modulator

Publications (1)

Publication Number Publication Date
WO2000072383A1 true WO2000072383A1 (en) 2000-11-30

Family

ID=10854150

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2000/002112 WO2000072383A1 (en) 1999-05-25 2000-05-25 Improved optoelectronic device

Country Status (5)

Country Link
EP (1) EP1183736A1 (en)
AU (1) AU5092500A (en)
CA (1) CA2398287A1 (en)
GB (1) GB9912178D0 (en)
WO (1) WO2000072383A1 (en)

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002088834A2 (en) * 2001-04-25 2002-11-07 The University Court Of The University Of Glasgow Optoelectronic device
WO2010052481A1 (en) * 2008-11-07 2010-05-14 The University Court Of The University Of Glasgow Interfaces and method for wireless-optical and optical-wireless conversion
US8847279B2 (en) 2006-09-07 2014-09-30 Taiwan Semiconductor Manufacturing Company, Ltd. Defect reduction using aspect ratio trapping
US8860160B2 (en) 2006-09-27 2014-10-14 Taiwan Semiconductor Manufacturing Company, Ltd. Quantum tunneling devices and circuits with lattice-mismatched semiconductor structures
US8878243B2 (en) 2006-03-24 2014-11-04 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures and related methods for device fabrication
US8981427B2 (en) 2008-07-15 2015-03-17 Taiwan Semiconductor Manufacturing Company, Ltd. Polishing of small composite semiconductor materials
US8987028B2 (en) 2005-05-17 2015-03-24 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures with reduced dislocation defect densities and related methods for device fabrication
US8994070B2 (en) 2008-07-01 2015-03-31 Taiwan Semiconductor Manufacturing Company, Ltd. Reduction of edge effects from aspect ratio trapping
US9040331B2 (en) 2007-04-09 2015-05-26 Taiwan Semiconductor Manufacturing Company, Ltd. Diode-based devices and methods for making the same
US9105549B2 (en) 2008-09-24 2015-08-11 Taiwan Semiconductor Manufacturing Company, Ltd. Semiconductor sensor structures with reduced dislocation defect densities
US9299562B2 (en) 2009-04-02 2016-03-29 Taiwan Semiconductor Manufacturing Company, Ltd. Devices formed from a non-polar plane of a crystalline material and method of making the same
US9365949B2 (en) 2008-06-03 2016-06-14 Taiwan Semiconductor Manufacturing Company, Ltd. Epitaxial growth of crystalline material
US9508890B2 (en) 2007-04-09 2016-11-29 Taiwan Semiconductor Manufacturing Company, Ltd. Photovoltaics on silicon
US9780190B2 (en) 2007-06-15 2017-10-03 Taiwan Semiconductor Manufacturing Company, Ltd. InP-based transistor fabrication
US9853176B2 (en) 2007-04-09 2017-12-26 Taiwan Semiconductor Manufacturing Company, Ltd. Nitride-based multi-junction solar cell modules and methods for making the same
US9859381B2 (en) 2005-05-17 2018-01-02 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures with reduced dislocation defect densities and related methods for device fabrication
US9934967B2 (en) 2008-09-19 2018-04-03 Taiwan Semiconductor Manufacturing Co., Ltd. Formation of devices by epitaxial layer overgrowth
US9984872B2 (en) 2008-09-19 2018-05-29 Taiwan Semiconductor Manufacturing Company, Ltd. Fabrication and structures of crystalline material
US10002981B2 (en) 2007-09-07 2018-06-19 Taiwan Semiconductor Manufacturing Company, Ltd. Multi-junction solar cells
US10468551B2 (en) 2006-10-19 2019-11-05 Taiwan Semiconductor Manufacturing Company, Ltd. Light-emitter-based devices with lattice-mismatched semiconductor structures

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0545692A (en) * 1991-08-15 1993-02-26 Kokusai Denshin Denwa Co Ltd <Kdd> Semiconductor optical function element
EP0689250A1 (en) * 1994-06-22 1995-12-27 Kokusai Denshin Denwa Kabushiki Kaisha Semiconductor element with a triangular barrier diode structure
EP0706225A1 (en) * 1994-08-19 1996-04-10 Texas Instruments Incorporated Optical communication system comprising a resonant tunneling diode

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0545692A (en) * 1991-08-15 1993-02-26 Kokusai Denshin Denwa Co Ltd <Kdd> Semiconductor optical function element
EP0689250A1 (en) * 1994-06-22 1995-12-27 Kokusai Denshin Denwa Kabushiki Kaisha Semiconductor element with a triangular barrier diode structure
EP0706225A1 (en) * 1994-08-19 1996-04-10 Texas Instruments Incorporated Optical communication system comprising a resonant tunneling diode

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
FIGUEIREDO J M L ET AL: "Integration of a RTD with an optical waveguide to form a high speed electroabsorption modulator", IEE COLLOQUIUM ON OPTOELECTRONIC INTEGRATION AND SWITCHING (REF. NO.1997/372), IEE COLLOQUIUM ON OPTOELECTRONIC INTEGRATION AND SWITCHING (REF. NO.1997/372), GLASGOW, UK, 13 NOV. 1997, 1997, London, UK, IEE, UK, pages 6/1 - 6, XP002151207 *
FIGUEIREDO J M L ET AL: "Self-oscillation in a resonant tunnelling diode electroabsorption modulator", TECHNICAL DIGEST. SUMMARIES OF PAPERS PRESENTED AT THE CONFERENCE ON LASERS AND ELECTRO-OPTICS. POSTCONFERENCE EDITION. CLEO '99. CONFERENCE ON LASERS AND ELECTRO-OPTICS (IEEE CAT. NO.99CH37013), TECHNICAL DIGEST. SUMMARIES OF PAPERS PRESENTED AT THE, 1999, Washington, DC, USA, Opt. Soc. America, USA, pages 125 - 126, XP002151208, ISBN: 1-55752-595-1 *
PATENT ABSTRACTS OF JAPAN vol. 017, no. 338 (P - 1564) 25 June 1993 (1993-06-25) *

Cited By (41)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002088834A2 (en) * 2001-04-25 2002-11-07 The University Court Of The University Of Glasgow Optoelectronic device
WO2002088834A3 (en) * 2001-04-25 2003-04-17 Univ Glasgow Optoelectronic device
US11251272B2 (en) 2005-05-17 2022-02-15 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures with reduced dislocation defect densities and related methods for device fabrication
US9219112B2 (en) 2005-05-17 2015-12-22 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures with reduced dislocation defect densities and related methods for device fabrication
US9431243B2 (en) 2005-05-17 2016-08-30 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures with reduced dislocation defect densities and related methods for device fabrication
US9859381B2 (en) 2005-05-17 2018-01-02 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures with reduced dislocation defect densities and related methods for device fabrication
US10522629B2 (en) 2005-05-17 2019-12-31 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures with reduced dislocation defect densities and related methods for device fabrication
US8987028B2 (en) 2005-05-17 2015-03-24 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures with reduced dislocation defect densities and related methods for device fabrication
US10074536B2 (en) 2006-03-24 2018-09-11 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures and related methods for device fabrication
US8878243B2 (en) 2006-03-24 2014-11-04 Taiwan Semiconductor Manufacturing Company, Ltd. Lattice-mismatched semiconductor structures and related methods for device fabrication
US9318325B2 (en) 2006-09-07 2016-04-19 Taiwan Semiconductor Manufacturing Company, Ltd. Defect reduction using aspect ratio trapping
US9818819B2 (en) 2006-09-07 2017-11-14 Taiwan Semiconductor Manufacturing Company, Ltd. Defect reduction using aspect ratio trapping
US8847279B2 (en) 2006-09-07 2014-09-30 Taiwan Semiconductor Manufacturing Company, Ltd. Defect reduction using aspect ratio trapping
US8860160B2 (en) 2006-09-27 2014-10-14 Taiwan Semiconductor Manufacturing Company, Ltd. Quantum tunneling devices and circuits with lattice-mismatched semiconductor structures
US9105522B2 (en) 2006-09-27 2015-08-11 Taiwan Semiconductor Manufacturing Company, Ltd. Quantum tunneling devices and circuits with lattice-mismatched semiconductor structures
US9559712B2 (en) 2006-09-27 2017-01-31 Taiwan Semiconductor Manufacturing Company, Ltd. Quantum tunneling devices and circuits with lattice-mismatched semiconductor structures
US10468551B2 (en) 2006-10-19 2019-11-05 Taiwan Semiconductor Manufacturing Company, Ltd. Light-emitter-based devices with lattice-mismatched semiconductor structures
US9853118B2 (en) 2007-04-09 2017-12-26 Taiwan Semiconductor Manufacturing Company, Ltd. Diode-based devices and methods for making the same
US9231073B2 (en) 2007-04-09 2016-01-05 Taiwan Semiconductor Manufacturing Company, Ltd. Diode-based devices and methods for making the same
US9040331B2 (en) 2007-04-09 2015-05-26 Taiwan Semiconductor Manufacturing Company, Ltd. Diode-based devices and methods for making the same
US9853176B2 (en) 2007-04-09 2017-12-26 Taiwan Semiconductor Manufacturing Company, Ltd. Nitride-based multi-junction solar cell modules and methods for making the same
US9508890B2 (en) 2007-04-09 2016-11-29 Taiwan Semiconductor Manufacturing Company, Ltd. Photovoltaics on silicon
US9543472B2 (en) 2007-04-09 2017-01-10 Taiwan Semiconductor Manufacturing Company, Ltd. Diode-based devices and methods for making the same
US10680126B2 (en) 2007-04-09 2020-06-09 Taiwan Semiconductor Manufacturing Company, Ltd. Photovoltaics on silicon
US9780190B2 (en) 2007-06-15 2017-10-03 Taiwan Semiconductor Manufacturing Company, Ltd. InP-based transistor fabrication
US10002981B2 (en) 2007-09-07 2018-06-19 Taiwan Semiconductor Manufacturing Company, Ltd. Multi-junction solar cells
US10961639B2 (en) 2008-06-03 2021-03-30 Taiwan Semiconductor Manufacturing Company, Ltd. Epitaxial growth of crystalline material
US9365949B2 (en) 2008-06-03 2016-06-14 Taiwan Semiconductor Manufacturing Company, Ltd. Epitaxial growth of crystalline material
US9640395B2 (en) 2008-07-01 2017-05-02 Taiwan Semiconductor Manufacturing Company, Ltd. Reduction of edge effects from aspect ratio trapping
US8994070B2 (en) 2008-07-01 2015-03-31 Taiwan Semiconductor Manufacturing Company, Ltd. Reduction of edge effects from aspect ratio trapping
US9356103B2 (en) 2008-07-01 2016-05-31 Taiwan Semiconductor Manufacturing Company, Ltd. Reduction of edge effects from aspect ratio trapping
US8981427B2 (en) 2008-07-15 2015-03-17 Taiwan Semiconductor Manufacturing Company, Ltd. Polishing of small composite semiconductor materials
US9607846B2 (en) 2008-07-15 2017-03-28 Taiwan Semiconductor Manufacturing Company, Ltd. Polishing of small composite semiconductor materials
US9287128B2 (en) 2008-07-15 2016-03-15 Taiwan Semiconductor Manufacturing Company, Ltd. Polishing of small composite semiconductor materials
US9984872B2 (en) 2008-09-19 2018-05-29 Taiwan Semiconductor Manufacturing Company, Ltd. Fabrication and structures of crystalline material
US9934967B2 (en) 2008-09-19 2018-04-03 Taiwan Semiconductor Manufacturing Co., Ltd. Formation of devices by epitaxial layer overgrowth
US9105549B2 (en) 2008-09-24 2015-08-11 Taiwan Semiconductor Manufacturing Company, Ltd. Semiconductor sensor structures with reduced dislocation defect densities
US9455299B2 (en) 2008-09-24 2016-09-27 Taiwan Semiconductor Manufacturing Company, Ltd. Methods for semiconductor sensor structures with reduced dislocation defect densities
WO2010052481A1 (en) * 2008-11-07 2010-05-14 The University Court Of The University Of Glasgow Interfaces and method for wireless-optical and optical-wireless conversion
US9576951B2 (en) 2009-04-02 2017-02-21 Taiwan Semiconductor Manufacturing Company, Ltd. Devices formed from a non-polar plane of a crystalline material and method of making the same
US9299562B2 (en) 2009-04-02 2016-03-29 Taiwan Semiconductor Manufacturing Company, Ltd. Devices formed from a non-polar plane of a crystalline material and method of making the same

Also Published As

Publication number Publication date
EP1183736A1 (en) 2002-03-06
CA2398287A1 (en) 2000-11-30
AU5092500A (en) 2000-12-12
GB9912178D0 (en) 1999-07-28

Similar Documents

Publication Publication Date Title
WO2000072383A1 (en) Improved optoelectronic device
US7711214B2 (en) Semiconductor optical modulator
EP0135582B1 (en) Semiconductor device for controlling light using multiple quantum wells
US5680411A (en) Integrated monolithic laser-modulator component with multiple quantum well structure
Dagli Wide-bandwidth lasers and modulators for RF photonics
US8538206B1 (en) Hybrid silicon electro-optic modulator
JP2606079B2 (en) Optical semiconductor device
Jasmin et al. Diluted-and distributed-absorption microwave waveguide photodiodes for high efficiency and high power
US20010053165A1 (en) Apparatuses and methods for generating optical signals
US8179585B2 (en) Coupled quantum well structure
Figueiredo et al. Optical modulation at around 1550 nm in an InGaAlAs optical waveguide containing an InGaAs/AlAs resonant tunneling diode
Chen Development of an 80 Gbit/s InP-based Mach-Zehnder modulator
US20050225828A1 (en) Electro-optic modulators incorporating quantum dots
Walker et al. Gallium arsenide modulator technology
US5689357A (en) Nonlinear optical element for extremely high bit rates
Figueiredo et al. Ultralow voltage resonant tunnelling diode electroabsorption modulator
US20210184421A1 (en) Semiconductor Optical Element
US20240006844A1 (en) Semiconductor Optical Device
JP2001013472A (en) Optical semiconductor element and optical communication equipment
Knodl et al. Integrated 1.3-µm InGaAlAs-InP laser-modulator with double-stack MQW layer structure
EP0385638A2 (en) Semiconductor superlattice self-electrooptic effect device
EP1849037B1 (en) Optical modulator
JP2670051B2 (en) Quantum well type optical modulator
US7425726B2 (en) Electroabsorption modulators and methods of making the same
JP2734214B2 (en) Nonlinear optical element

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY CA CH CN CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
WWE Wipo information: entry into national phase

Ref document number: 2000935379

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 2000935379

Country of ref document: EP

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

WWE Wipo information: entry into national phase

Ref document number: 09979417

Country of ref document: US

WWE Wipo information: entry into national phase

Ref document number: 2398287

Country of ref document: CA

NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Ref document number: 2000935379

Country of ref document: EP