An adjustable electrically controlled and all-optical dual-controlled electro-optic modulator and control method

Abstract

The application provides an adjustable electric control and all-optical double control photoelectric modulator and a control method, realizes phase modulation and amplitude under all-optical and electric double modulation, and adopts a cadmium oxide layer on the surface of a silicon single groove structure of the modulator, so that the extinction ratio of the modulator is obviously improved, and the phase modulation depth and modulation range are large; the insertion loss of the structure can be adjusted through an external voltage or a pumping light irradiation mode, so that the extinction ratio of different wavelengths is adjusted, and thus corresponding adjustment can be made according to actual conditions; the modulator works at a communication wavelength, and has a wide application prospect; the manufacturing process of the modulator is simple, is compatible with an existing CMOS process, can be produced on a large scale by using an integrated process, and reduces production cost; has a nanoscale integrated size, and is convenient for technicians to carry out integrated application; one metal electrode is arranged on the cadmium oxide thin layer, and the other electrode is arranged on a silicon substrate, so that the device structure is simplified.

Description

Technical Field

[0001] This invention belongs to the field of optical micro-nano optoelectronic device technology, specifically relating to an adjustable electrically controlled and all-optical dual-control optoelectronic modulator and its control method. Background Technology

[0002] As an indispensable component of high-speed optical networks and integrated optical devices, optoelectronic modulators have wide applications in optical communication. Optoelectronic modulators possess superior performance characteristics such as low loss, high efficiency, high extinction ratio, ultrafast response speed, and small integrated size, which are unmatched by traditional electronic modulators. Currently, classic optical modulation structures mainly include double-arm Mach-Zehnder interferometer structures, micro-ring resonator structures, and straight waveguide structures. However, the challenges faced by optoelectronic modulators in application mainly stem from the materials themselves, including the untunability of the materials, narrow spectral application range, high propagation loss, and incompatibility with current CMOS processes, which limit the further development of optoelectronic modulators.

[0003] In recent years, the unique optical properties of materials with near-zero dielectric constants have brought new opportunities for the development of new technologies. Among many man-made and natural materials with near-zero dielectric constants, the transparent conductive oxide cadmium oxide stands out. Under the modulation of an applied voltage, the carrier concentration of cadmium oxide supports 10-1... 19 Up to 10 21 cm -3 The modulation range provides modulated optical effects from the ultraviolet to the near-infrared. Furthermore, cadmium oxide, with its near-zero dielectric constant, exhibits a large nonlinear optical response, achieving femtosecond-level optical response speeds under pump light. In addition, cadmium oxide is characterized by low cost, simple fabrication process, and CMOS process compatibility.

[0004] Based on the above, the introduction of cadmium oxide with near-zero dielectric constant into integrated photonic devices has become a research hotspot in recent years. However, current research on cadmium oxide with near-zero dielectric constant mainly focuses on its electrical properties, with less attention paid to all-optical response devices based on nonlinear optical responses, limiting their practical operating conditions. Therefore, existing technologies still need further improvement. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an adjustable electronically controlled and all-optically controlled dual-control optoelectronic modulator and control method, which can operate under both applied voltage and pump light irradiation conditions, and has the characteristics of low cost, simple manufacturing process, tunability, and CMOS process compatibility.

[0006] A tunable electronically controlled and all-optically controlled dual-control optoelectronic modulator includes a silicon substrate (6), a cadmium oxide nanofilm (2), a metal electrode (3), and a hafnium dioxide nanofilm (4);

[0007] A silicon single-groove structure consisting of two protrusions is formed on a silicon substrate (6); the surface of the silicon single-groove structure is a hafnium dioxide nanofilm (4), and the surface of the hafnium dioxide nanofilm (4) is a cadmium oxide nanofilm (2); the cadmium oxide nanofilm (2) on one side of the silicon single-groove structure extends to the surface of the silicon substrate (6); one metal electrode (3) is disposed on the cadmium oxide nanofilm (2) on the surface of the silicon substrate (6), and the other metal electrode (3) is disposed on the surface of the silicon substrate (6) on the other side of the silicon single-groove structure;

[0008] A gate voltage (5) is set between the two metal electrodes (3) to electrically modulate the modulator.

[0009] Preferably, the widths of the cadmium oxide nanofilm (2), the metal electrode (3), the hafnium dioxide nanofilm (4), and the silicon single-groove structure (6) are all 1000 nm.

[0010] Preferably, the thickness of the cadmium oxide nanofilm (2) is 15 nm.

[0011] Preferably, the metal electrode (3) is made of gold, with a length of 15 nm and a thickness of 10 nm.

[0012] Preferably, the thickness of the hafnium dioxide layer (4) is 5 nm.

[0013] Preferably, the two cuboid silicon sections of the single-slot silicon structure are 25 nm apart along their length.

[0014] A control method for an adjustable electrically controlled and all-optically dual-controlled optoelectronic modulator involves injecting pump light and probe light into the modulator via a silicon waveguide; adjusting the gate voltage (5) thereby changing its complex dielectric constant and achieving the shift of the near-zero dielectric constant point of cadmium oxide.

[0015] A control method for an adjustable electronically controlled and all-optically dual-controlled optoelectronic modulator involves coupling pump light into a cadmium oxide nanofilm (2); adjusting the intensity of the pump light to achieve extinction ratio and phase modulation.

[0016] A control method for an adjustable electronically controlled and all-optical dual-control photoelectric modulator, wherein when a probe light is coupled to an incident modulator at a selected working wavelength, the gate voltage (5) is adjusted to change the carrier concentration of cadmium oxide, and the adjustable dual-control photoelectric modulator (1) is continuously irradiated with pump light, thereby modulating the extinction ratio and phase.

[0017] The present invention has the following beneficial effects:

[0018] This invention provides an adjustable electrically and all-optically dual-controlled optoelectronic modulator and its control method, realizing phase modulation and amplitude modulation under both all-optical and electrical modulation. The silicon single-slot structure of the modulator has a cadmium oxide layer on its surface, which significantly improves the extinction ratio of the modulator and has a large phase modulation depth and modulation range. The insertion loss of the structure can be adjusted by applying an external voltage or pump light irradiation, thereby adjusting the extinction ratio of different wavelengths, so it can be adjusted according to actual conditions. The modulator operates at communication wavelengths and has broad application prospects. The fabrication process of the modulator is simple and compatible with existing CMOS processes, enabling large-scale production using integrated processes and reducing production costs. It has a nanometer-scale integrated size, which facilitates integrated applications by technicians. By placing one metal electrode on a cadmium oxide thin layer and the other electrode on a silicon substrate, the device structure is simplified. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a tunable electrically and all-optically dual-controlled optoelectronic modulator based on cadmium oxide with near-zero dielectric constant.

[0020] Figure 2 A schematic diagram of the pump and probe light coupled to an incident tunable electrically controlled and all-optical dual-control optoelectronic modulator based on near-zero dielectric constant cadmium oxide;

[0021] Figure 3 The graph shows the change of the dielectric constant of cadmium oxide with wavelength under electrical modulation of the modulator.

[0022] Figure 4 The graph shows the phase modulation and extinction ratio curves of the modulator under electrical control.

[0023] Figure 5 The graph shows the refractive index and refractive index change of cadmium oxide as a function of wavelength under pump light illumination.

[0024] Figure 6 This is a graph showing the phase modulation and extinction ratio of the modulator under pump light illumination.

[0025] Among them, 1-modulator, 2-cadmium oxide nanofilm, 3-metal electrode, 4-hafnium dioxide nanofilm, 5-gate voltage, 6-silicon substrate, 7-pump optical silicon waveguide, 8-probe optical silicon waveguide. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] This invention provides a tunable electrically controlled and all-optically controlled dual-control optoelectronic modulator 1 based on cadmium oxide with near-zero dielectric constant, such as... Figure 1As shown, it includes a silicon substrate 6, a cadmium oxide nanofilm 2, a metal electrode 3, and a hafnium dioxide nanofilm 4.

[0028] A silicon single-groove structure consisting of two protrusions is formed on the silicon substrate 6; the surface of the silicon single-groove structure is a hafnium dioxide nanofilm 4, and the surface of the hafnium dioxide nanofilm 4 is a cadmium oxide nanofilm 2; the cadmium oxide nanofilm 2 on one side of the silicon single-groove structure extends to the surface of the silicon substrate 6; one metal electrode 3 is disposed on the cadmium oxide nanofilm 2 on the surface of the silicon substrate 6, and the other metal electrode 3 is disposed on the surface of the silicon substrate 6 on the other side of the silicon single-groove structure.

[0029] An electrode gate voltage 5 is set between the two metal electrodes 3 to electrically modulate the modulator.

[0030] Traditional modulators typically place the driving metal electrodes on a silicon substrate to facilitate better contact between the metal electrodes, silicon waveguides, and the silicon substrate. This requires extending the silicon substrate by hundreds of nanometers on both sides, which is detrimental to integration. This invention places the metal electrode on one side directly on cadmium oxide, not only reducing the device size but also allowing carrier concentration to accumulate in the metal-oxide-semiconductor capacitor structure under the driving force of the metal electrode. This results in a near-zero dielectric constant effect with high loss, further enhancing the modulation depth.

[0031] In this embodiment, the widths of the cadmium oxide nanofilm 2, the metal electrode 3, the hafnium dioxide nanofilm 4, and the silicon single-cell structure 6 are all 1000 nm; the thickness of the cadmium oxide nanofilm 2 is 15 nm; the metal electrode 3 is made of gold, has a length of 15 nm, and a thickness of 10 nm; the thickness of the hafnium dioxide layer 4 is 5 nm; and the two cuboid silicon sections of the silicon single-cell structure are 25 nm apart along their length.

[0032] The thickness of the cadmium oxide nanolayer 2 at any location is a fixed value. The thickness of the hafnium dioxide nanolayer 4 at any location is a fixed value.

[0033] Example 1:

[0034] like Figure 2 As shown, the pump light of the modulator of the present invention is coupled into the silicon waveguide 7, and the probe light is coupled into the silicon waveguide 8. When linearly polarized light with a center wavelength of 1550 nm is coupled into the tunable electrically controlled and all-optical dual-control optoelectronic modulator 1 based on near-zero dielectric constant cadmium oxide through the silicon waveguide 8, the carrier concentration of the cadmium oxide nanolayer 2 can be adjusted by applying an external voltage. Figure 1 As shown, the carrier concentration of cadmium oxide is changed by altering the gate voltage 5, thereby changing its complex dielectric constant and shifting the near-zero dielectric constant point of cadmium oxide. The role of the hafnium dioxide nanofilm 4 is to enrich the carriers of the cadmium oxide nanofilm 2 near its surface. Figure 3 As shown, regardless of whether a voltage is applied, the real part of the dielectric constant of cadmium oxide decreases with increasing wavelength, while the imaginary part of the dielectric constant increases with increasing wavelength and is always less than zero. Figure 3 As shown, when no external voltage is applied, the near-zero dielectric constant point of the cadmium oxide nanofilm is around 3600 nm. With increasing applied voltage, the near-zero dielectric constant point of the cadmium oxide nanofilm gradually blue-shifts. When the voltage reaches 8.8825V, the near-zero dielectric constant point of the cadmium oxide nanofilm moves to the communication wavelength of 1550 nm, which is the center wavelength of the coupled incident linearly polarized light. Technicians can also select different operating wavelengths based on actual needs.

[0035] In this embodiment, the near-zero dielectric constant point of cadmium oxide is shifted by changing the applied voltage to adjust the carrier concentration. The fundamental purpose is to utilize the large nonlinear optical response of cadmium oxide. Under applied voltage modulation, the complex dielectric constant of cadmium oxide changes, and its optical response also changes accordingly, thereby altering its absorption properties. For example... Figure 4 As shown, the adjustable dual-control photoelectric modulator 1 uses a working wavelength of 1.55 μm as the incident light. By changing the gate voltage 5, as the applied voltage 5 gradually increases from 0 V, the phase change gradually increases, peaking at around 8.5 V, achieving a phase modulation of 25π / cm, which is also a good phase modulation effect. With the increase of the applied voltage, the extinction ratio gradually increases. When the voltage reaches 8.8825 V, the near-zero dielectric constant point of the cadmium oxide nanofilm shifts to the 1550 nm communication wavelength, achieving a depth of 13 dB / μm, indicating good performance of the photoelectric modulator. Considering both the phase change and the extinction ratio, the photoelectric modulator in this operating state achieves a superior modulation level using an applied voltage of 8.5 V. Furthermore, technicians can select different modulator extinction ratios and working wavelengths according to actual application requirements.

[0036] Example 2:

[0037] This embodiment provides a method for all-optical modulation of a tunable electrically controlled and all-optically controlled dual-control optoelectronic modulator 1 based on near-zero dielectric constant cadmium oxide under pump light irradiation. With linearly polarized probe light coupled into the cadmium oxide nanolayer 2 at a center wavelength of 1550 nm, the pump light is coupled into the nanolayer 2. At this time, due to the large optical nonlinear effect of cadmium oxide, the transmittance spectrum changes, thereby realizing the function of the optoelectronic modulator. Figure 5 As shown, under pump light irradiation of different intensities, the increase in pump energy flow will cause the refractive index n in cadmium oxide materials to increase and the absorption coefficient k to decrease. Figure 5The changes in refractive index and absorption coefficient of cadmium oxide under different pump currents were also shown. It can be observed that near the near-zero dielectric constant region, i.e., at the communication wavelength of ~1.55 μm, cadmium oxide exhibits peaks in both the n and k changes. As mentioned earlier, cadmium oxide, as a highly mobile transparent conductive oxide, can exhibit a sufficiently low absorption coefficient in the communication window, demonstrating its potential in switching and modulator applications. Figure 6 As shown, as the energy intensity of the pump light gradually increases, the phase change gradually increases, and the extinction ratio gradually increases. When the pump power reaches 0.0350 J / cm², the phase change and extinction ratio increase. 2 At this point, the extinction ratio increases to a relatively stable value, achieving a depth of 10 dB / μm, indicating that the photoelectric modulator performs well. When the pump power reaches 0.0569 J / cm²... 2 When the phase change increases to a relatively stable value of 25π / cm, the phase modulation effect is also good. Considering both the phase change and the extinction ratio, the photoelectric modulator operates at 0.0569 J / cm in this state. 2 By performing all-optical modulation on the pump light, a superior modulation level can be achieved.

[0038] Example 3:

[0039] The tunable electrically controlled and all-optical dual-control optoelectronic modulator 1 based on near-zero dielectric constant cadmium oxide provided in this embodiment can also operate simultaneously under both electrically controlled and pump light irradiation conditions according to actual needs. When the carrier concentration of cadmium oxide is changed by applying an external gate voltage 5 at a selected operating wavelength to realize the function of the optoelectronic modulator, the tunable dual-control optoelectronic modulator 1 can continue to be pumped to obtain a larger extinction ratio and phase modulation depth, thus making up for the shortcomings in practical applications.

[0040] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tunable electronically controlled and all-optically controlled dual-control optoelectronic modulator, characterized in that, It includes a silicon substrate (6), a cadmium oxide nanofilm (2), a metal electrode (3), and a hafnium dioxide nanofilm (4); A silicon single-groove structure consisting of two protrusions is formed on a silicon substrate (6); the surface of the silicon single-groove structure is a hafnium dioxide nanofilm (4), and the surface of the hafnium dioxide nanofilm (4) is a cadmium oxide nanofilm (2); the cadmium oxide nanofilm (2) on one side of the silicon single-groove structure extends to the surface of the silicon substrate (6); one metal electrode (3) is disposed on the cadmium oxide nanofilm (2) on the surface of the silicon substrate (6), and the other metal electrode (3) is disposed on the surface of the silicon substrate (6) on the other side of the silicon single-groove structure. A gate voltage (5) is set between the two metal electrodes (3) for electrically modulating the modulator; Pump light and probe light are injected into the modulator through a silicon waveguide; the gate voltage (5) is adjusted to change the complex dielectric constant of the cadmium oxide nanofilm (2), thereby achieving the shift of the near-zero dielectric constant point of cadmium oxide; Pump light was coupled into the cadmium oxide nanofilm (2); the intensity of the pump light was adjusted to achieve extinction ratio and phase modulation; When the probe light is coupled to the incident modulator at the selected working wavelength, the gate voltage (5) is adjusted to change the carrier concentration of cadmium oxide, and the pump light continues to irradiate the tunable dual-control photoelectric modulator (1), thereby modulating the extinction ratio and phase.

2. The adjustable electronically controlled and all-optically dual-controlled optoelectronic modulator as described in claim 1, characterized in that, The widths of the cadmium oxide nanofilm (2), the metal electrode (3), the hafnium dioxide nanofilm (4), and the silicon single-groove structure are all 1000 nm.

3. The adjustable electronically controlled and all-optically controlled dual-control optoelectronic modulator as described in claim 1, characterized in that, The thickness of the cadmium oxide nanofilm (2) is 15 nm.

4. The adjustable electronically controlled and all-optically dual-controlled optoelectronic modulator as described in claim 1, characterized in that, The metal electrode (3) is made of gold, with a length of 15 nm and a thickness of 10 nm.

5. The adjustable electrically controlled and all-optical dual-control optoelectronic modulator as described in claim 1, characterized in that, The thickness of the hafnium dioxide layer (4) is 5 nm.

6. The adjustable electronically controlled and all-optically controlled dual-control optoelectronic modulator as described in claim 1, characterized in that, The two rectangular silicon sections of the single-slot silicon structure are 25 nm apart along their length.

Images