Modulator chip assembly for high-speed optical signal generation

Abstract

The present invention discloses a modulator chip assembly for high-speed optical signal generation, including a modulator chip, at least one high-speed signal transmission line, at least one ground line, a capacitor, a resistor and at least two sections of gold wire; wherein the length of the first gold wire is L1, 0.05 mm < L1 ≤ 1 mm; or, the length of the first gold wire L1 ≤ 0.05 mm; and also includes a first inductor, one end of the first inductor is connected to the first gold wire, and the other end of the first inductor is connected to the capacitor via the high-speed signal transmission line; the first inductor is located between the modulator chip and the capacitor; the first inductor is connected in series with the modulator chip. The present invention further improves the bandwidth of the modulator chip by adding a parallel capacitor and a series inductor between the microwave signal line and the modulator chip, so that the low-bandwidth modulator can be applied to the modulation of 50G and above signals, so as to achieve low-cost and convenient increase in the bandwidth of the modulator chip assembly.

Description

Technical Field

[0001] The invention relates to a signal modulation device in the communication field, and in particular to a modulator chip assembly for generating high-speed optical signals. Background Art

[0002] With the construction of large-scale data centers, 100G / 400G / 800G transmission technology has become inevitable. However, there are many challenges in the process of upgrading from traditional 10G networks to 100G / 400G / 800G and above networks, one of which is the demand for high-bandwidth, low-cost modulator chips for high-speed optical signals.

[0003] At present, the core modulation chip for achieving single-wave 100G and four-channel 400G transmission is a 50Gb / s semiconductor electroabsorption modulated laser. As a key chip for generating high-speed optical signals, the bandwidth of the semiconductor electroabsorption modulator is mainly limited by the junction capacitance and parasitic capacitance of the chip. Therefore, to improve the modulation bandwidth of the electroabsorption modulator, the most direct way is to reduce the length of the electroabsorption modulator to reduce the junction capacitance of the detector chip, while reducing the area of ​​the electrode, increasing the thickness of the dielectric material and using special low dielectric constant materials to reduce the parasitic capacitance, thereby increasing the 3dB bandwidth of the modulation chip. However, reducing the length of the electroabsorption chip will reduce the extinction ratio of the modulator and increase the operating voltage required by the electroabsorption modulator; and the area of ​​the electrode is limited by the requirements of wire bonding, and the diameter is generally difficult to be less than 50 microns, and the process difficulty of low dielectric constant materials (such as BCB, benzocyclobutene) is greatly increased, and the cost is also increased. Therefore, there are great limitations in reducing the junction capacitance and parasitic capacitance of the chip. At present, the junction capacitance of general electro-absorption modulators is about 0.1pF, the parasitic capacitance is about 0.2pF, and its RC bandwidth is less than 30GHz, which cannot meet the modulation requirements of 50Gbit / s signals. If electro-absorption modulators with high junction capacitance and parasitic capacitance can be used, and the modulation bandwidth of the modulator can be improved through peripheral circuits, it will have great practical significance.

[0004] The packaging structure of the traditional electro-absorption modulated laser is as follows: Figure 1As shown, it comprises an electro-absorption modulated laser 1 and a ceramic substrate 2, wherein the electro-absorption modulated laser 1 comprises an electro-absorption modulator 1a and a semiconductor laser 1b, and an electrical signal is applied to the electro-absorption modulator 1a to modulate the DC light generated by the semiconductor laser to generate a high-speed optical signal output. The ceramic substrate 2 comprises a plurality of microwave transmission lines and electrodes for connecting an external circuit with the electro-absorption modulated laser 1 (3a, 3b, 3c are signal transmission lines for connecting the electro-absorption modulator 1a with transmission lines 13a, 13b, 13c for transmitting electrical signals of an external circuit, wherein 3b and 13b are high-speed signal lines, and 3a, 3c and 13a, 13c are ground lines) and a resistor 6 (generally 50 ohms) for impedance matching with an external RF driver. The transmission lines 3a, 3b, 3c and the transmission lines 13a, 13b, 13c are connected through gold wires 12a, 12b and 12c. The signal line 3b is connected to the electro-absorption modulator 1a through the first gold wire 9. The current driving the DC semiconductor laser 1b is applied to the semiconductor laser 1b through the electrode 15 of the external packaging circuit, the electrode 4 on the ceramic substrate 2, and the gold wire 10. The first end electrode 7 of the matching resistor 6 is connected to the external ground electrode 14 through the gold wire 11, and the second end electrode 5 of the matching resistor 6 is connected to the electrode of the electro-absorption modulator 1a through the second gold wire 8. Figure 1 The decoupling capacitor that may be required for the external drive current of the semiconductor laser 1b is not shown, and the specific wiring position can be adjusted. In general, in order to minimize the parasitic effects introduced by the package, the first gold wire 9 and the second gold wire 8 connecting the electro-absorption modulator 1a with the signal line 3b and the matching resistor 6 need to be as short as possible to reduce the self-induced inductance generated by the gold wire itself.

[0005] like Figure 2 Shown is a small signal S21 curve simulated based on an electro-absorption modulator chip with a junction capacitance of 0.1 pF and a parasitic capacitance of 0.2 pF. The figure is calculated based on the equivalent circuit of the modulator chip and a 50 ohm load resistor. Figure 2 The 3dB bandwidth is 22.4GHz, which can meet the modulation requirements of 25Gb / s signals, but it is still far from the bandwidth of 35GHz or more required by 50Gb / s signals. Increasing the bandwidth by significantly reducing the junction capacitance and parasitic capacitance poses great challenges to chip performance and process.

[0006] Research has found that, under the premise of minimizing the parasitic effects introduced by the package, adding a suitable inductor between the electro-absorption modulator 1a and the matching resistor 6 will be able to increase the modulation bandwidth of the electro-absorption modulator to a certain extent. Based on this idea, the following can be adopted: Figure 3The package structure of the electro-absorption modulated laser shown in the figure adds an inductor 16 between the electro-absorption modulator 1a and the matching resistor 6 to increase the modulation bandwidth of the modulator chip. The electro-absorption modulator 1a is connected to the inductor 16 through the second gold wire 8, and the inductor 16 is connected to the second terminal electrode 5 of the matching resistor 6. If a separate inductor is used, the inductor 16 and the second terminal electrode 5 can be connected through another gold wire. According to tests, adding an inductor can generally increase the bandwidth of the modulator chip by about 50%. Figure 4 The following table shows the theoretically calculated small signal bandwidth under different inductance values. When the inductance 16 is 0.25nH, the 3dB bandwidth increases from 22.4GHz without inductance to 32GHz; when the inductance 16 increases to 0.5nH, the 3dB bandwidth increases to 33GHz; when the inductance 16 is 0.75nH, the 3dB bandwidth is 32.4GHz; if the inductance is further increased, the bandwidth will begin to decrease. Although the modulator bandwidth can be increased from 22.4GHz to about 33GHz by introducing inductance, to modulate a 50Gb / s signal, the 3dB bandwidth of the modulator is generally required to be above 35GHz. Therefore, simply adding inductance to the modulator's intrinsic bandwidth of 22GHz is still not enough to ensure the modulation of a 50Gb / s signal. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a modulator chip assembly for generating high-speed optical signals, which can improve the modulation bandwidth of the semiconductor electro-absorption modulator, thereby enabling the low-bandwidth modulator chip to be applied to the generation of high-speed optical signals.

[0008] In order to solve the above technical problems, the technical solution of the modulator chip assembly for high-speed optical signal generation of the present invention is:

[0009] The invention comprises a modulator chip, at least one high-speed signal transmission line, at least one ground line, a capacitor, a resistor and at least two sections of gold wire; the high-speed signal transmission line is used to realize connection with an external circuit; the capacitor is located between the high-speed signal transmission line and the ground line; one end of the capacitor is connected to the high-speed signal transmission line, and the other end is grounded with the modulator chip; the capacitor is connected in parallel with the modulator chip; the resistor is located between the modulator chip and the ground electrode, and the resistor is connected in series with the modulator chip for impedance matching with an external radio frequency driver; a first gold wire connects the modulator chip with the high-speed signal transmission line and the capacitor, and a second gold wire connects the modulator chip with the resistor; wherein the length of the first gold wire is L1, 0.05 mm<L1≤1 mm; or the length of the first gold wire L1≤0.05 mm; and a first inductor is also included, one end of the first inductor is connected to the first gold wire, and the other end of the first inductor is connected to the capacitor via the high-speed signal transmission line; the first inductor is located between the modulator chip and the capacitor; the first inductor is connected in series with the modulator chip.

[0010] In another embodiment, the inductance value of the first inductor is between 0.01 nH and 1 nH.

[0011] In another embodiment, the inductance value of the first inductor is between 0.05 nH and 1 nH.

[0012] In another embodiment, the length of the second gold wire is L2, 0.1 mm<L2≤1 mm.

[0013] In another embodiment, the length L2 of the second gold wire is ≤0.1 mm; a second inductor is also included, one end of the second inductor is connected to the second gold wire, and the other end of the second inductor is connected to the resistor; the second inductor is located between the modulator chip and the resistor; the second inductor is connected in series with the detector chip.

[0014] In another embodiment, the inductance of the second inductor is between 0.05 nH and 1 nH.

[0015] In another embodiment, the inductance of the second inductor is between 0.1 nH and 1 nH.

[0016] In another embodiment, the modulator chip is an electro-absorption modulated laser.

[0017] In another embodiment, the length of the first gold wire is L1, 0.05 mm < L1 ≤ 1 mm, and the self-inductive inductance generated by the first gold wire is between 0.01 nH and 1 nH; and / or the length of the second gold wire is L2, 0.1 mm < L2 ≤ 1 mm, and the self-inductive inductance generated by the second gold wire is between 0.05 nH and 1 nH.

[0018] In another embodiment, the capacitance value of the capacitor is between 0.01 pF and 0.6 pF.

[0019] The technical effects that can be achieved by the present invention are:

[0020] The present invention further improves the bandwidth of the modulator chip by adding a parallel capacitor and a series inductor between the microwave signal line and the modulator chip, so that the low-bandwidth modulator can be applied to the modulation of 50G and above signals, thereby achieving low-cost and convenient increase in the bandwidth of the modulator chip component.

[0021] The modulator chip of the present invention converts an external high-speed electrical signal into a high-speed optical signal, and the high-speed electrical signal is input to the modulator chip through a capacitor and an inductor, thereby generating a required high-speed modulated optical signal. By selecting appropriate inductors and capacitors, the present invention can greatly increase the modulation bandwidth of the modulator chip, thereby realizing the generation of high-speed optical signals using a low-cost and low-bandwidth modulator chip.

[0022] The present invention utilizes a low-cost peripheral circuit and a low-bandwidth modulator chip to achieve the improvement of modulator bandwidth and the generation of high-speed optical signals without the need to develop a high-bandwidth modulator chip with huge technical difficulty. This will solve the limitation of the shortage of high-bandwidth modulator chips in the current market.

[0023] The present invention is compatible with existing modulator chip packaging technology, and does not require the development of new packaging processes or the increase of chip packaging size, and can be applied to all optical devices and optical modules. Therefore, the technical solution of the present invention can ensure large-scale production, and at the same time, compared with high-bandwidth modulator chips, the cost is lower.

[0024] The present invention can overcome the bandwidth limitation of existing semiconductor modulator chips used for generating high-speed optical signals of 50G and above, and use low-bandwidth modulator chips for generating high-speed optical signals of 50G and above, thereby being able to utilize existing mature low-cost and high-reliability modulator chips and assembly manufacturing processes to achieve high-speed optical signal generation of 50G and above. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] It should be understood by those skilled in the art that the following description is only intended to schematically illustrate the principles of the present invention, which can be applied in a variety of ways to achieve many different alternative embodiments. These descriptions are only intended to illustrate the general principles of the teachings of the present invention and are not intended to limit the inventive concepts disclosed herein.

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description above and the detailed description of the drawings that follow, serve to explain the principles of the invention.

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments in order to more clearly understand its structure and working principle, but this shall not be used to limit the protection scope of the present invention.

[0028] Figure 1 It is a structural schematic diagram of a modulator chip assembly in the prior art;

[0029] Figure 2 yes Figure 1 The intrinsic small signal response curve S21 of the chip shown in the figure, the horizontal axis is the frequency (unit GHz), and the vertical axis is the small signal response S21 (unit dB);

[0030] Figure 3 It is a structural schematic diagram of a modulator chip assembly with an inductor in the prior art;

[0031] Figure 4 yes Figure 3 The small signal response curve S21 of the chip simulated after adding different inductors;

[0032] Figure 5 1 is a schematic structural diagram of Embodiment 1 of a modulator chip assembly for generating a high-speed optical signal according to the present invention;

[0033] Figure 6 FIG21 is a signal response curve of Example 1 of the present invention when there is no capacitor and the second inductance value is 0.5 nH and different first inductances are added;

[0034] Figure 7 FIG21 is a signal response curve of Example 1 of the present invention when there is no first inductance and the second inductance value is 0.5 nH and different capacitors are added;

[0035] Figure 8 It is a signal response curve S21 of Example 1 of the present invention after adding different first inductors when the capacitance value is 0.1 pF and the second inductance value is 0.5 nH;

[0036] Fig. 9 It is a signal response curve S21 of Example 1 of the present invention after adding different second inductors when the capacitance value is 0.1 pF and the first inductance value is 0.1 nH;

[0037] Fig.10 Graph S21 is a signal response curve of Embodiment 1 of the present invention after adding different capacitors when the first inductance value is 0.1nH and the second inductance value is 0.5nH;

[0038] Fig.11FIG21 is a signal response curve of different modulator chips without capacitors, the first inductor and the second inductor and with capacitors, the first inductor and the second inductor according to Embodiment 1 of the present invention;

[0039] Fig.12 is a schematic structural diagram of Embodiment 2 of the modulator chip assembly for generating high-speed optical signals according to the present invention, in which the second inductor is replaced by a second gold wire;

[0040] Fig.13 It is a schematic structural diagram of Example 3 of the modulator chip assembly for generating high-speed optical signals of the present invention, in which the first inductor is replaced by the first gold wire, and the second inductor is replaced by the second gold wire.

[0041] Description of reference numerals in the figures:

[0042] 1 is an electro-absorption modulated laser, 2 is a ceramic substrate,

[0043] 1a is an electroabsorption modulator, 1b is a semiconductor laser,

[0044] 3a, 3b, 3c are signal transmission lines, 4 is an electrode,

[0045] 5 is the second terminal electrode of the resistor, 6 is the matching resistor,

[0046] 7 is the first terminal electrode of the resistor, 8 is the second gold wire,

[0047] 9 is the first gold line,

[0048] 10 is a gold wire connecting the electrode of the external packaging circuit and the semiconductor laser,

[0049] 11 is the gold wire connecting the matching resistor and the ground electrode,

[0050] 12a, 12b and 12c are gold wires that connect high-speed signal lines to external circuits.

[0051] 13a, 13b, and 13c are signal transmission lines for transmitting signals to external circuits.

[0052] 14 is an external ground electrode,

[0053] 15 is an electrode of an external packaging circuit, used to power the semiconductor laser.

[0054] 16 is the second inductor,

[0055] 17 is a capacitor,

[0056] 18 is a first inductor. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work belong to the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in this article do not indicate any order, quantity or importance, but are only used to distinguish different components. "Including" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", etc. are only used to indicate relative position relationships. When the absolute position of the described object changes, the relative position relationship may also change accordingly.

[0058] The core idea of ​​the present invention is to combine an external circuit based on inductance and capacitance with a modulator chip to increase the bandwidth of the modulator chip assembly to achieve the generation of a high-speed optical signal higher than the intrinsic bandwidth of the modulator chip. The semiconductor modulator chip changes the absorption intensity of the passing DC light through an external high-speed electrical signal (generally a reverse bias voltage) to convert the high-speed electrical signal into a high-speed optical signal.

[0059] Although in theory the chip's junction capacitance and parasitic capacitance can be reduced to increase the chip's bandwidth to meet the requirements of 50G or even 100G bandwidth, the junction capacitance and parasitic capacitance are closely related to the chip size and the process used. Reducing capacitance generally requires reducing the chip size and using special dielectric materials. However, due to the limitations of semiconductor materials and chip processes, the physical size cannot be reduced infinitely. The more serious problem is that the reduction in chip length will limit the intensity of light that the modulator can absorb, greatly reducing the extinction ratio of high-speed optical signals, which is not conducive to the transmission and detection of high-speed optical signals. In addition, the introduction of special dielectric materials in the chip process will complicate the chip manufacturing process, increase the cost of the chip and reduce the chip's interest rate. All of these will increase the packaging and manufacturing costs of high-bandwidth modulator chips.

[0060] The present invention can appropriately adjust the overall performance of the circuit through the addition of inductors and capacitors, thereby increasing the modulation bandwidth of the modulator chip assembly. The following will take the 50G modulator chip assembly as an example to explain in detail how the present invention uses a low-bandwidth modulator chip to achieve high-speed 50Gbps optical signal generation. Obviously, the technical solution of the present invention is also applicable to the bandwidth improvement of high-speed modulator chips above 50G.

[0061] Based on the above-mentioned inventive concept, the present invention combines a modulator chip with a compensation circuit composed of a capacitor and an inductor to form a modulator chip assembly. The high-speed electrical signal is not directly added to the modulator chip, but first passes through the compensation circuit and then added to the modulator chip, thereby realizing the generation of high-speed optical signals.

[0062] The modulator chip component for generating high-speed optical signals of the present invention mainly comprises a modulator chip (such as a semiconductor electroabsorption modulated laser), a capacitor, an inductor and a resistor, a TIA (transimpedance amplifier), and gold wires for connecting components and leads for connecting external circuits, wherein the leads are used for inputting high-speed electrical signals; wherein the capacitor is located between an external high-speed signal line and the inductor, and is connected in parallel with the inductor and the modulator; and the inductor is located between the capacitor and the modulator, and is connected in series with the modulator chip.

[0063] The modulator chip assembly of the present invention first passes the input high-speed electrical signal through a circuit composed of an inductor and a capacitor before adding it to the modulator chip. The modulator chip can modulate the frequency response of the entire circuit by selecting appropriate inductor and capacitor values, thereby improving the bandwidth of the entire modulator chip assembly.

[0064] In order to achieve the above-mentioned purpose of realizing high-speed optical signal generation based on a low-bandwidth modulator chip, the present invention is described through the following embodiments.

[0065] Example 1

[0066] like Figure 5 As shown, the modulator chip assembly for high-speed optical signal generation of the present invention comprises an electro-absorption modulated laser 1, a capacitor 17, a second inductor 16, a first inductor 18 and a matching resistor 6; wherein the electro-absorption modulated laser 1 comprises an electro-absorption modulator 1a and a semiconductor laser 1b, and a high-speed electrical signal is applied to the electro-absorption modulator 1a to modulate the direct current light emitted by the semiconductor laser 1b to generate a high-speed optical signal output; all these components (including the electro-absorption modulated laser 1, the capacitor 17, the second inductor 16, the first inductor 18 and the matching resistor 6) are located on the same substrate 2;

[0067] The substrate 2 also includes a plurality of microwave transmission lines and electrodes for connecting an external circuit with the electro-absorption modulated laser and a resistor 6 (generally 50 ohms) for impedance matching with an external RF driver; 3a, 3b, 3c are transmission lines for connecting the electro-absorption modulator 1a with transmission lines 13a, 13b, 13c for transmitting external high-speed electrical signals, wherein 3b and 13b are high-speed signal lines, and 3a, 3c and 13a, 13c are ground lines; the transmission lines 3a, 3b, 3c are connected to 13a, 13b, 13c through gold wires 12a, 12b, 12c;

[0068] The other end of the high-speed signal line 3b is connected to one end of the first inductor 18, and the other end of the first inductor 18 is connected to the electro-absorption modulator 1a through the first gold wire 9; the capacitor 17 is located between the high-speed signal line 3b and the first inductor 18; one end of the capacitor 17 is connected to the high-speed signal line 3b, and the other end is connected to the ground line 3c; one end of the second inductor 16 is connected to the second end electrode 5 of the matching resistor 6, and the other end is connected to the electro-absorption modulator 1a through the second gold wire 8; the current driving the DC semiconductor laser 1b is applied to the semiconductor laser 1b through the electrode 15 of the external packaging circuit, the electrode 4 on the ceramic substrate 2, and the gold wire 10; the first end electrode 7 of the matching resistor 6 is connected to the external ground electrode 14 through the gold wire 11.

[0069] As a preferred embodiment, the capacitor 17, the first inductor 18, the second inductor 16, the matching resistor 6 and the electrical signal transmission lines 3a, 3b, 3c can be made by thin film technology and integrated on the substrate 2 to facilitate packaging and save costs;

[0070] Preferably, the electro-absorption modulated laser 1, the capacitor 17, the second inductor 16, the first inductor 18, the matching resistor 6 and the substrate 2 are packaged in a TO-CAN (package component).

[0071] Based on a large number of experiments, the present invention overcomes the technical prejudice that the first gold wire 9 and the second gold wire 8 need to be as short as possible to reduce the self-induced inductance generated by the gold wire itself. As long as the inductance is increased by using a suitable inductance value, the modulation bandwidth of the modulator can be increased. Obviously, the values ​​of capacitance and inductance directly determine the performance of the modulator chip packaging component.

[0072] The capacitor 17 may be a planar capacitor, the capacitance of which is controlled by the area and / or the thickness of the dielectric layer.

[0073] The inductance values ​​of the first inductor 18 and the second inductor 16 are controlled by the size of the film;

[0074] The specific values ​​of the capacitor 17, the first inductor 18 and the second inductor 16 can be optimized based on the performance of the modulator chip 1a and the signal rate to be achieved; preferably, the value of the capacitor 17 is between 0.01pF and 0.6pF; the value of the first inductor 18 is between 0.01nH and 1nH; the value of the second inductor 16 is between 0.05nH and 1nH. Within this range, the purpose of the invention of increasing the bandwidth can be achieved.

[0075] Furthermore, the value of the first inductor 18 is between 0.05 nH and 1 nH, and the value of the second inductor 16 is between 0.1 nH and 1 nH. Within this range, the performance of the modulator chip assembly is optimal.

[0076] Preferably, the substrate 2 may be a ceramic substrate. Of course, substrates of other suitable materials may also be used, such as aluminum nitride, aluminum oxide, quartz or silicon-based substrates.

[0077] The following is an example to illustrate how the present invention uses capacitor 17, first inductor 18 and second inductor 16 to use a low-bandwidth modulator chip for 50Gbps optical signal generation. The junction capacitance of the modulator chip is 0.1pF, the parasitic capacitance is 0.2pF, and the corresponding intrinsic bandwidth is 22.4GHz; when a second inductor 16 with an inductance value of 0.5nH is added, the modulation bandwidth will increase to 33GHz, but it still cannot fully meet the modulation bandwidth requirements for generating 50Gbps optical signals; when the capacitor 17 and the first inductor 18 in Example 1 are added, by selecting appropriate inductors and capacitors, the 3dB bandwidth of the modulator chip assembly can be further improved.

[0078] like Figure 6 The figure shows the corresponding small signal bandwidth when the second inductor 16 is 0.5nH, the capacitor 17 is not added, and the first inductor 18 is 0, 0.25nH and 0.5nH respectively; Figure 6 As shown in FIG. 1 , when the second inductor 16 is 0.5 nH, only the first inductor 18 is added, and the 3 dB bandwidth is reduced from 33 GHz to 31.4 GHz (the first inductor 18 is 0.25 nH) and 25.2 GHz (the first inductor 18 is 0.5 nH). Obviously, the shorter the gold wire from the high-speed signal line 3b to the modulator chip 1a, the better. Figure 7 The figure shows that when the second inductor 16 is 0.5nH, the first inductor 18 is not added, and the capacitor 17 is 0, 0.05pF and 0.1pF, the corresponding 3dB bandwidth is 33GHz, 29.6GHz and 26GHz respectively. Therefore, if only the capacitor 17 is added, the bandwidth of the modulator component will be greatly reduced, which is why the traditional packaging needs to reduce the external capacitance as much as possible. However, after a large number of experimental studies, the present invention has found that after adding the capacitor 17 and the first inductor 18 at the same time, the 3dB bandwidth of the signal will be significantly increased.

[0079] like Figure 8 The small signal response curves shown are when the second inductance 16 is 0.5 nH, the capacitance 17 is 0.1 pF, and the first inductance 18 is 0, 0.1, 0.2, and 0.3 nH, respectively, and the corresponding bandwidths are 33, 58.4, 42.4, and 35.2 GHz, respectively. Figure 8 It is shown in the figure that the bandwidth will be improved when a capacitor and another inductor are added at the same time. When the capacitance value is 0.1pF, the modulation bandwidth can be increased from 33GHz to greater than 58GHz, far exceeding the modulation requirements of a 50Gbps signal. Therefore, the addition of capacitor 17 and the first inductor 18 will increase the high-frequency response and greatly improve the bandwidth of the modulator chip component. When the first inductor 18 increases from 0.1nH to 0.2nH or 0.3nH, although the frequency response decreases, it is still much higher than the original intrinsic bandwidth of the modulator chip 22GHz. Although the bandwidth is lower than that of the first inductor 18 of 0.1nH, the flatness of the frequency response is significantly improved, which is also very important for the quality of high-speed modulated signals. Therefore, the bandwidth can be increased and the flatness of the frequency response can be improved by adjusting the value of the first inductor 18. After adding capacitor 17 and the first inductor 18, the sensitivity of the value of the second inductor 16 to the bandwidth is significantly reduced, but the flatness of the bandwidth can also be improved to a certain extent by adjusting the value of the second inductor 16. Fig. 9 The response curves are shown when the capacitor 17 is 0.1 pF and the first inductor 18 is 0.1 nH with different second inductor values ​​(0.25 nH, 0.5 nH and 0.75 nH). It can be seen that the change in 3 dB bandwidth is less than 1 GHz, but it has a greater impact on the flatness of the response curve. Fig.10 It is the response curve under different capacitance values ​​(0.1pF, 0.15pF and 0.2pF) when the first inductance value is 0.1nH and the second inductance value is 0.5nH. As the capacitance value increases, the bandwidth decreases to a certain extent, but it is still greater than 50GHz, which is sufficient to meet the modulation requirements of 50Gb / s signals. Therefore, the combination of capacitor 17, the second inductor 16 and the first inductor 18 will not only greatly improve the 3dB bandwidth of the modulator chip component, but also adjust the flatness of the signal response and improve the quality of the generated high-speed optical signal. This technology can also be applied to the modulation of 100Gb / s high-speed optical signals. Fig.11 This is a signal response curve for a modulator with an intrinsic bandwidth of 32.6GHz (corresponding to a junction capacitance of 0.1pF and a parasitic capacitance of 0.1pF) before and after adding a 0.1pF capacitor 17, a 0.08nH first inductor 18, and a 0.25nH second inductor 16. It can be seen that the 3dB bandwidth is increased from 32.6GHz to 76.2GHz, which can meet the bandwidth requirements of a 100Gb / s high-speed optical modulator.

[0080] In Example 1, the second inductor 16 and the first inductor 18 are made by thin film technology and are located on the same substrate 2 as the capacitor 17; the modulator chip 1a is connected to the second inductor 16 and the first inductor 18 respectively through the first gold wire 9 and the second gold wire 8. Since the diameter of the gold wire used for chip connection is generally about 25 microns, it will generate self-induced inductance, so the second inductor 16 and the first inductor 18 in Example 1 can be replaced by gold wires to form Examples 2 and 3 of the present invention.

[0081] Example 2

[0082] like Fig.12 As shown, the first inductor 18 originally located on the same substrate 2 as the capacitor 17 is replaced by a first gold wire 91 of a certain length; the first gold wire 91 not only provides a connection between the signal line 3b and the modulator chip 1a, but also acts as the first inductor 18. Compared with Example 1, Example 2 replaces the first inductor 18 with a gold wire, which not only reduces the cost, but also because the length of the gold wire can be adjusted during chip packaging, the inductance value also changes accordingly, so gold wires of different lengths will be able to play the role of adjustable inductance. Since the parameters of modulator chips from different suppliers are different, adjusting the inductance value by changing the length of the first gold wire 91 will greatly facilitate adjusting the resonance characteristics for different modulator chips to obtain the best response performance. Under the premise of considering parasitic effects, the size of the first gold wire 91 can be adjusted according to the performance of the modulator chip to obtain the best receiving bandwidth and response curve.

[0083] Example 3

[0084] Furthermore, Fig.13 As shown, the first inductor 18 originally located on the same substrate 2 as the capacitor 17 is replaced by a first gold wire 92 of a certain length, and the second inductor 16 is replaced by a second gold wire 82. The first gold wire 92 not only provides a connection between the signal line 3b and the modulator chip 1a, but also serves as the first inductor 18, and the second gold wire 82 serves as the second inductor 16. Compared with Example 1, Example 3 replaces the first inductor 18 and the second inductor 16 with two first gold wires 92 and second gold wires 82 of different lengths, which can not only further reduce the cost, but also because the length of the gold wire can be adjusted during chip packaging, the inductance value also changes accordingly, so the gold wires of different lengths will be able to play the role of adjustable inductance. Under the premise of considering parasitic effects, the sizes of the first gold wire 92 and the second gold wire 82 can be adjusted according to the performance of the modulator chip to obtain the best receiving bandwidth and response curve.

[0085] In the above embodiment, the capacitor 17 is located between the signal line 3b and the ground line 3c, but it can also be located in the signal lines 3b and 3a, or other grounded electrodes or transmission lines. There can be only one ground line 3a and 3c.

[0086] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.

Claims

1. A modulator chip assembly for high-speed optical signal generation, characterized in that: include: a modulator chip; at least one high-speed signal transmission line, used to achieve connection with an external circuit, connecting an external high-speed electrical signal to the modulator chip; At least one ground wire; a capacitor, located between the high-speed signal transmission line and the ground line; one end of the capacitor is connected to the high-speed signal transmission line, and the other end is connected to the ground line; the capacitor is connected in parallel with the modulator chip; a resistor, located between the modulator chip and the ground electrode, the resistor being connected in series with the modulator chip for impedance matching with an external RF driver; as well as At least two gold wires, a first gold wire connecting the modulator chip with the high-speed signal transmission line and the capacitor, and a second gold wire connecting the modulator chip with the resistor; The length of the first gold wire is L1, 0.05 mm<L1≤1 mm; or, the length of the first gold wire is L1≤0.05 mm; it also includes a first inductor, one end of the first inductor is connected to the first gold wire, and the other end of the first inductor is connected to the capacitor via the high-speed signal transmission line; the first inductor is located between the modulator chip and the capacitor; the first inductor is connected in series with the modulator chip.

2. The modulator chip assembly for high-speed optical signal generation according to claim 1, characterized in that: The inductance value of the first inductor is between 0.01nH and 1nH.

3. The modulator chip assembly for high-speed optical signal generation according to claim 1, characterized in that: The inductance value of the first inductor is between 0.05nH and 1nH.

4. The modulator chip assembly for high-speed optical signal generation according to claim 1, characterized in that: The length of the second gold wire is L2, 0.1 mm<L2≤1 mm.

5. The modulator chip assembly for high-speed optical signal generation according to claim 1, characterized in that: The length L2 of the second gold wire is ≤0.1 mm; it also includes a second inductor, one end of the second inductor is connected to the second gold wire, and the other end of the second inductor is connected to the resistor; the second inductor is located between the modulator chip and the resistor; the second inductor is connected in series with the modulator chip.

6. The modulator chip assembly for high-speed optical signal generation according to claim 5, characterized in that: The inductance value of the second inductor is between 0.05nH and 1nH.

7. The modulator chip assembly for high-speed optical signal generation according to claim 5, characterized in that: The inductance value of the second inductor is between 0.1 nH and 1 nH.

8. The modulator chip assembly for high-speed optical signal generation according to claim 1, characterized in that: The modulator chip is an electro-absorption modulated laser.

9. The modulator chip assembly for high-speed optical signal generation according to claim 1, characterized in that: The length of the first gold wire is L1, 0.05 mm < L1 ≤ 1 mm, and the self-inductive inductance generated by the first gold wire is between 0.01 nH and 1 nH; and / or the length of the second gold wire is L2, 0.1 mm < L2 ≤ 1 mm, and the self-inductive inductance generated by the second gold wire is between 0.05 nH and 1 nH.

10. The modulator chip assembly for high-speed optical signal generation according to claim 1, characterized in that: The capacitance value of the capacitor is between 0.01 pF and 0.6 pF.

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