Inter-band and inter-sub-band hybrid TM electric absorption modulator

Abstract

The utility model discloses an inter-band and inter-sub-band hybrid TM electric absorption modulator, which comprises a quantum well structure. The quantum well structure comprises at least one quantum well and at least one barrier; the quantum well is provided with a conduction band bottom energy level and at least one conduction band high-order energy level; the conduction band high-order energy level and the conduction band bottom energy level have the same energy difference as the designed absorbed photons. On the basis of conventional inter-band absorption, the width of the quantum well and the height of the barrier are ingeniously designed and adjusted, a plurality of conduction band energy levels are increased, modulatable sub-band absorption with the same absorption energy as that of inter-band absorption is achieved, the quantum efficiency upper limit of the electro-absorber can be increased, and the quantum efficiency of the electro-absorber can be improved. The utility model provides that inter-band and inter-band absorption is simultaneously used in a semiconductor quantum well to realize electro-absorption modulation on the same operating wavelength for the first time in the industry and academic circles, and has extremely high requirements on accurate calculation and design of an energy band.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of electric absorption modulator especially relates to a mixed TM electric absorption modulator between band and subband. BACKGROUND

[0002] The existing common electric absorption modulator mainly depends on the interband absorption of electrons, that is, the transition of electrons from the valence band to the conduction band absorbs photons. The conventional absorption mode design is relatively simple, which is limited by the band gap energy range of the material itself, and each electron in each quantum well corresponds to the absorption of one photon, so the maximum quantum absorption efficiency is limited. SUMMARY

[0003] The utility model discloses a mixed TM electric absorption modulator between band and subband, which is based on the conventional interband absorption. By skillfully designing the quantum well width and barrier height, multiple conduction band levels are added to realize the modulatable subband absorption with the same absorption energy as the interband absorption, which can increase the upper limit of the quantum efficiency of the electric absorption modulator.

[0004] To achieve the above object, the following technical scheme is adopted:

[0005] A mixed TM electric absorption modulator between band and subband includes a quantum well structure. The quantum well structure includes at least one quantum well and at least one barrier. The quantum well has a conduction band bottom level and at least one conduction band high-order level. The conduction band high-order level has the same energy difference as the designed photon absorption as the conduction band bottom level.

[0006] Further, the quantum well is designed such that under zero bias, the interband and subband of the quantum well have little absorption of the designed wavelength of photons, and under operating bias, the interband and subband have peak absorption of the operating wavelength.

[0007] Further, it also includes an n-doped substrate, a p-doped substrate, and a transition layer arranged on the n-doped substrate. The quantum well structure includes a highest barrier, a high-energy quantum well, an intermediate barrier, and a narrow-bandwidth quantum well. The highest barrier, the high-energy quantum well, the intermediate barrier, and the narrow-bandwidth quantum well are arranged in sequence from top to bottom between the transition layer and the p-doped substrate.

[0008] Further, the highest barrier is made of AlGaAs material, with a thickness of 4 nm and a band width of 2.13 eV.

[0009] Further, the high-energy quantum well is made of Al 0.5 Ga 0.1 In 0.4 As material, with a thickness of 6.5 nm and a band width of 1.9268 eV.

[0010] Further, the intermediate barrier is made of Al 0.8 Ga 0.1 In 0.1 As material, with a thickness of 1nm and a band width of 2.01086eV.

[0011] Further, the narrow-band quantum well is made of Al 0.175 Ga 0.095 In 0.73 As material, with a thickness of 5nm and a band width of 0.800eV.

[0012] With the above scheme, the utility model has the beneficial effects that:

[0013] The utility model discloses on the basis of conventional band absorption, through the ingenious design adjustment quantum well width and barrier height, increase multiple conduction band energy level, realize adjustable sub-band absorption with same absorption energy of band absorption, can increase electric absorber quantum efficiency upper limit. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 For the structure schematic diagram of one embodiment of the utility model,

[0015] Figure 2 For the band structure and absorption characteristic diagram under low bias voltage in one embodiment of the utility model,

[0016] Figure 3 For the band structure diagram under operating voltage in one embodiment of the utility model,

[0017] Figure 4 For the band absorption characteristic curve diagram in one embodiment of the utility model,

[0018] Figure 5 For the sub-band absorption characteristic curve diagram in one embodiment of the utility model.

[0019] Among them, the drawing mark explanation is:

[0020] 1, highest barrier;2, high-energy quantum well;3, intermediate barrier;4, narrow-band quantum well. DETAILED DESCRIPTION

[0021] The utility model will be explained in detail in combination with the drawings and specific embodiment.

[0022] Refer to Figures 1 to 5As shown, the utility model provides a kind of interband and inter-subband hybrid TM electric absorption modulator, in an embodiment, including quantum well structure;The quantum well structure includes at least one quantum well and at least one barrier;The quantum well has a conduction band bottom energy level, and at least one conduction band high-order energy level;The conduction band high-order energy level has the same energy difference with the conduction band bottom energy level as design absorption photon.

[0023] In order to solve the performance constraints of the lower upper limit of electronic utilization efficiency of conventional interband electric absorption modulator, in the embodiment, the utility model designs interband and inter-subband absorption hybrid electric absorption modulator, by combining interband and inter-subband two kinds of chain absorption reaction to increase electronic utilization efficiency, to improve the upper limit of performance, the quantum well of the utility model contains higher multiple conduction band energy levels in addition to bottom energy level, while, adjustable conduction band high-order energy level has the same energy difference with the conduction band bottom energy level as design absorption photon, in addition, interband and inter-subband photon absorption of design wavelength is small under zero bias voltage, while inter-subband and interband absorption of operating wavelength reaches peak value under operating bias voltage, the combination can improve quantum efficiency, increase dynamic ER and reduce current.

[0024] As Figure 1 Shown, in an embodiment, a specific design and the way of epitaxial growth connection with other epitaxial layers are provided, including n-doped substrate, p-doped substrate and transition layer arranged on the n-doped substrate;The quantum well structure can be repeatedly and periodically arranged multiple, and the quantum well structure includes highest barrier 1, high-energy quantum well 2, intermediate barrier 3 and narrow-bandwidth quantum well 4;The highest barrier 1, high-energy quantum well 2, intermediate barrier 3 and narrow-bandwidth quantum well 4 are arranged between the transition layer and the p-doped substrate in turn from top to bottom;The highest barrier 1 is made of AlGaAs material, and the thickness is 4nm, and the energy band width is 2.13eV;The high-energy quantum well 2 is made of Al 0.5 Ga 0.1 In 0.4 As material, and the thickness is 6.5nm, and the energy band width is 1.9268eV;The intermediate barrier 3 is made of Al 0.8 Ga 0.1 In 0.1 As material, and the thickness is 1nm, and the energy band width is 2.01086eV;The narrow-bandwidth quantum well 4 is made of Al 0.175 Ga 0.095 In 0.73 As material, and the thickness is 5nm, and the energy band width is 0.800eV.

[0025] As Figure 2As shown, under low bias, the quantum well formed by conduction band (curve a) has three energy levels of curve b, curve c and curve d, and the quantum well formed by valence band (curve f) has the bottom energy level of curve e, wherein the interband absorption occurs between curve e and curve f, and the energy spacing is 0.9537eV, as shown in curve j in FIG. Figure 4 As shown in curve j in FIG. Figure 5 As shown in curve m in FIG. Figure 3 As shown in curve i in FIG. Figure 4 As shown in curve i in FIG. Figure 5 As shown in curve L in FIG.

[0026] The key parameters such as band gap, under zero bias, the energy spacing between curve e and curve d should be greater than the operating energy as much as possible, and the energy spacing between curve d and curve b should be less than the operating photon energy; under operating voltage, the energy spacing between curve e and curve d and the energy spacing between curve d and curve b should be close to the operating photon energy to achieve maximum extinction ratio; the designed structure should make the wave function overlap rate between curve d and curve b be small under low bias and reach a large overlap rate under operating voltage.

[0027] In summary, the utility model can be used in various modulation optical chips in combination with TM polarized laser to realize high-efficiency, large-extinction-ratio optical modulation, and can also be used as TM polarization modulator alone, and has strong versatility.

[0028] The above is only a preferred embodiment of the utility model, and is not used for limiting the utility model, and any modification, equivalent replacement and improvement within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A hybrid inter-band and sub-band inter-band TM electroabsorption modulator, characterized in that, The invention includes a quantum well structure; the quantum well structure includes at least one quantum well and at least one barrier; the quantum well has a conduction band bottom level and at least one conduction band higher level; the conduction band higher level and the conduction band bottom level have the same energy difference as designed to absorb photons.

2. The hybrid inter-band and sub-band inter-band TM electroabsorption modulator according to claim 1, characterized in that, The quantum well is designed such that, under zero bias, the inter-band and inter-sub-band absorption of photons at the designed wavelength is very small, while under operating bias, the absorption of photons at the operating wavelength by the inter-sub-band and inter-band reaches its peak simultaneously.

3. The hybrid inter-band and sub-band inter-band TM electroabsorption modulator according to claim 1, characterized in that, It also includes an n-doped substrate, a p-doped substrate, and a transition layer disposed on the n-doped substrate; the quantum well structure includes a highest barrier, a high-energy quantum well, an intermediate barrier, and a narrow-bandwidth quantum well; the highest barrier, the high-energy quantum well, the intermediate barrier, and the narrow-bandwidth quantum well are arranged from top to bottom between the transition layer and the p-doped substrate.

4. The hybrid inter-band and sub-band inter-band TM electroabsorption modulator according to claim 3, characterized in that, The highest barrier is made of AlGaAs material with a thickness of 4 nm and a band width of 2.13 eV.

5. The hybrid inter-band and sub-band inter-band TM electroabsorption modulator according to claim 3, characterized in that, The high-energy quantum well is made of Al 0.5 Ga 0.1 In 0.4 Made of As material, it has a thickness of 6.5 nm and a band width of 1.9268 eV.

6. The hybrid inter-band and sub-band inter-band TM electroabsorption modulator according to claim 3, characterized in that, The intermediate barrier is composed of Al 0.8 Ga 0.1 In 0.1 Made of As material, with a thickness of 1 nm and a band width of 2.01086 eV.

7. The hybrid inter-band and sub-band inter-band TM electroabsorption modulator according to claim 3, characterized in that, The narrow bandwidth quantum well is composed of Al 0.175 Ga 0.095 In 0.73 Made of As material, with a thickness of 5nm and a band width of 0.800eV.

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