High-frequency ceramic substrate and laser packaging structure

Abstract

The utility model discloses a high-frequency ceramic substrate which comprises a bottom plate. The RF transmission line is arranged on the bottom plate and is used for transmitting a radio frequency signal; the at least one chip inductor Lm is arranged on the bottom plate and is positioned on one side of the tail end of the RF transmission line; the chip inductor Lm is electrically connected with the RF transmission line and is used for impedance matching; the at least one matching resistor Rm is arranged on the bottom plate and is connected in series with the chip inductor Lm; one side of the tail end of the RF transmission line is grounded through the chip inductor Lm and the matched resistor Rm, and the other side of the tail end of the RF transmission line is used for being connected with the EML optical chip. After the ceramic substrate and the EML chip are packaged and integrated, resonance can be formed at 30GHz under the combined action of the chip inductor Lm and the parasitic capacitance of the EML chip, and the resonance can reduce high-frequency signal reflection, so that the 1dB bandwidth of a system is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of optoelectronic device microwave packaging, in particular to a high-frequency ceramic substrate and a laser packaging structure. Background Art

[0002] The EML electro-absorption modulator, fully known as the Electro-Absorption Modulated Laser (EML), is an optoelectronic device integrating an electro-absorption modulator (EAM) and a distributed feedback laser (DFB Laser, LD). It has a wide range of applications in the fields of communication and optical fiber communication and is an ideal light source for information transmission carriers in high-speed optical fiber transmission networks.

[0003] In actual product deployment, since the EAM electro-absorption modulator is a high-frequency device, for specific application requirements, a precise optoelectronic coupling packaging process needs to be implemented for the EML chip to ensure efficient and stable optical signal output and distortion-free modulation signal conversion, thereby meeting the transmission performance indicators of the communication system. For the latter, issues such as transmission line matching, microwave reflection, and high-frequency transmission loss must be considered during the packaging design process to achieve a flat response, minimum jitter, and sufficient 1dB and 3dB bandwidths within the entire frequency response bandwidth range.

[0004] Among them, the 3dB bandwidth is a key indicator for measuring the high-frequency performance of a device. However, a large amount of simulation and measured data have proven that the 1dB bandwidth is also an important indicator that cannot be ignored and is an effective bandwidth for evaluating the signal transmission quality of a system or device within a specific frequency band. Increasing the 1dB bandwidth is of great significance for improving the transmission rate and signal transmission quality. A larger 1dB bandwidth means that the system has a wider frequency band to transmit signals while maintaining low power loss.

[0005] In the design and application of EML lasers, bandwidth and extinction ratio ER (extinction ratio) are a pair of key performance indicators that restrict each other and often need to be balanced and optimized. When pursuing a higher extinction ratio ER to meet strict signal quality requirements, it is often accompanied by a reduction in bandwidth. To make up for this bandwidth loss and improve the high-frequency response characteristics of the entire device, advanced packaging technologies and compensation strategies need to be adopted to finely adjust the packaging structure to effectively enhance the performance of the EML laser in the high-frequency band, thereby reducing the requirements for the bandwidth of the optical chip and relaxing the mutual restraint between bandwidth and extinction ratio. Summary of the Utility Model

[0006] The purpose of the utility model is to provide a high-frequency ceramic substrate and a laser packaging structure to improve the 1dB bandwidth of the device while maintaining the 3dB bandwidth of the device.

[0007] To achieve the above object, the following technical solutions are adopted:

[0008] A high-frequency ceramic substrate, comprising

[0009] A bottom plate;

[0010] An RF transmission line, which is arranged on the bottom plate and used for transmitting radio frequency signals;

[0011] At least one chip inductor Lm, which is arranged on the bottom plate and located on one side of the end of the RF transmission line; the chip inductor Lm is electrically connected to the RF transmission line and used for impedance matching;

[0012] At least one matching resistor Rm, which is arranged on the bottom plate and in series with the chip inductor Lm; one side of the end of the RF transmission line is grounded through the chip inductor Lm and the matching resistor Rm, and the other side of the end of the RF transmission line is used for connecting to an EML optical chip;

[0013] The chip inductor Lm and the matching resistor Rm are also used to act together with the parasitic capacitance of the EML optical chip to form a resonance at 30 GHz, so as to reduce high-frequency signal reflection and increase the 1 dB bandwidth of the device.

[0014] Further, the bottom plate is made of AIN material.

[0015] Further, the other side of the end of the RF transmission line is connected to the EML optical chip through high-frequency wire bonding.

[0016] There is also provided a laser packaging structure, which includes the above-mentioned high-frequency ceramic substrate and also includes an EML optical chip; the EML optical chip is integrated with an impedance matching structure; the impedance matching structure includes a matching inductor Lload and a matching resistor Rload connected in series with the matching inductor Lload; the EML optical chip is arranged on the bottom plate and connected to one side of the end of the RF transmission line through high-frequency wire bonding.

[0017] Adopting the above scheme, the beneficial effects of the present utility model are:

[0018] After the ceramic substrate of the present utility model is packaged and integrated with the EML chip, the combined action of the chip inductor Lm and the parasitic capacitance of the EML optical chip will form a resonance at 30 GHz. This resonance can reduce high-frequency signal reflection, thereby increasing the 1 dB bandwidth of the system. At the same time, the present utility model breaks through the limitations of traditional substrate design. While increasing the bandwidth, it effectively optimizes the reflection phenomenon in the link and reduces the signal noise caused by signal interference and loss. Description of the Drawings

[0019] Figure 1It is a structural schematic diagram of the present utility model;

[0020] Figure 2 It is a perspective view of the present utility model;

[0021] Figure 3 It is a circuit schematic diagram of the impedance matching design of the present utility model;

[0022] Figure 4 It is a parameter frequency response comparison diagram of the substrate of the present utility model and a traditional substrate;

[0023] Figure 5 It is an eye diagram performance comparison diagram of the substrate of the present utility model and a traditional substrate;

[0024] Among them, the description of the attached drawing signs:

[0025] 1. Bottom plate; 11. RF transmission line; 12. EML optical chip; 13. Chip inductor Lm; 14. Matching resistor Rm. Specific implementation manners

[0026] The following will describe the present utility model in detail in conjunction with the attached drawings and specific embodiments.

[0027] Referring to Figures 1 to 5 as shown, the present utility model provides a high-frequency ceramic substrate. In one embodiment, it includes

[0028] Bottom plate 1;

[0029] RF transmission line 11, the RF transmission line 11 is arranged on the bottom plate 1 and is used for transmitting radio frequency signals;

[0030] At least one chip inductor Lm 13, the chip inductor Lm 13 is arranged on the bottom plate 1 and is located on one side of the end of the RF transmission line 11; the chip inductor Lm 13 is electrically connected to the RF transmission line 11 and is used for impedance matching;

[0031] At least one matching resistor Rm 14, the matching resistor Rm 14 is arranged on the bottom plate 1 and is connected in series with the chip inductor Lm13; one side of the end of the RF transmission line 11 is grounded through the chip inductor Lm 13 and the matching resistor Rm 14, and the other side of the end of the RF transmission line 11 is used for connecting to the EML optical chip 12;

[0032] The chip inductor Lm 13 and the matching resistor Rm 14 are also used to act together with the parasitic capacitance of the EML optical chip 12 to form resonance at 30 GHz, so as to reduce high-frequency signal reflection and increase the 1 dB bandwidth of the device.

[0033] The traditional concept holds that after device packaging, the device performance will always decline compared to the performance of the optical chip. However, this is not the case in reality. During the device packaging process, certain parasitic parameters will inevitably be introduced. When the parasitic parameters introduced by packaging and the parasitic parameters of the optical chip itself can effectively generate high-frequency resonance, this resonance can compensate for the frequency response characteristics of the device, thereby improving the high-frequency response characteristics and enabling the device performance to exceed the performance of the optical chip itself. And the present utility model precisely utilizes this resonance to correct the high-frequency response characteristics of the optical chip in order to improve the yield of the optical chip.

[0034] Specifically, as Figures 1 to 3 shown, in this embodiment, a high-performance high-frequency ceramic substrate is designed to improve the 1dB bandwidth of the device on the premise of maintaining the 3dB bandwidth of the device. Among them, the bottom plate 1 of the ceramic substrate is made of AIN (a ceramic material, full name aluminum nitride, with high thermal conductivity, low thermal expansion coefficient, good electrical insulation and excellent mechanical properties). At the end of the RF transmission line 11, on the left side, it is connected to the EML optical chip 12 through high-frequency wire bonding, and on the right side, it is grounded through the chip inductance Lm13 and the matching resistor Rm 14.

[0035] At the same time, a laser packaging structure is also provided, including the above-mentioned high-frequency ceramic substrate and also including the EML optical chip 12; the EML optical chip 12 is integrated with an impedance matching structure; the impedance matching structure includes a matching inductance Lload and a matching resistor Rload connected in series with the matching inductance Lload; the EML optical chip 12 is disposed on the bottom plate 1 and is connected to one side of the end of the RF transmission line 11 through high-frequency wire bonding.

[0036] In this embodiment, before the RF signal enters the EML optical chip 12, a second impedance matching design is additionally added to the ceramic substrate, which is composed of a chip inductance Lm 13 and a matching resistor Rm 14 connected in series, realizing efficient support and performance enhancement for the EML chip. At the same time, the first impedance matching design, that is, the traditional matching inductance Lload and the matching resistor Rload are integrated with the EML chip. When the substrate and the EML chip are completed with packaging and integration, the combined action of the matching inductance Lm and the parasitic capacitance Cea of the EML optical chip 12 will form a resonance at 30GHz, and this resonance can reduce the high-frequency signal reflection, thereby improving the 1dB bandwidth of the system (as Figure 4 shown).

[0037] The present utility model breaks through the limitations of the traditional substrate design. Moreover, while the bandwidth is increased, the reflection phenomenon in the link is effectively optimized, reducing the signal noise caused by signal interference and loss. In addition, referring to Figure 5As shown in the figure, during the high-speed data transmission test, the eye diagram quality has been significantly improved: the height of the eye diagram has increased and the noise has decreased, which fully verifies the excellent performance of this high-frequency ceramic substrate in enhancing the high-frequency response characteristics of the EML chip, and enhancing signal integrity and stability. Moreover, this utility model not only opens up a new path for improving production yield and reducing production costs, but also provides strong technical support for high-speed, efficient, and high-quality transmission in the field of optical communication.

[0038] The above are only the preferred embodiments of this utility model and are not used to limit this utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of this utility model shall be included within the protection scope of this utility model.

Claims

1. A high-frequency ceramic substrate, characterized in that, including a bottom plate; an RF transmission line disposed on the bottom plate for transmitting radio frequency signals; at least one chip inductor Lm disposed on the bottom plate and on one side of the end of the RF transmission line; the chip inductor Lm is electrically connected to the RF transmission line for impedance matching; at least one matching resistor Rm disposed on the bottom plate and connected in series with the chip inductor Lm; one side of the end of the RF transmission line is grounded through the chip inductor Lm and the matching resistor Rm, and the other side of the end of the RF transmission line is used to connect to an EML optical chip; the chip inductor Lm and the matching resistor Rm are further used to cooperate with the parasitic capacitance of the EML optical chip to form resonance at 30 GHz to reduce high-frequency signal reflection and increase the 1 dB bandwidth of the device.

2. The high-frequency ceramic substrate according to claim 1, wherein The bottom plate is made of AIN material.

3. The high-frequency ceramic substrate according to claim 1, characterized in that, The other side of the end of the RF transmission line is connected to the EML optical chip through high-frequency wire bonding.

4. A laser packaging structure, comprising the high-frequency ceramic substrate according to any one of claims 1 to 3, characterized in that, It further includes an EML optical chip; the EML optical chip is integrated with an impedance matching structure; the impedance matching structure includes a matching inductor Lload and a matching resistor Rload connected in series with the matching inductor Lload; the EML optical chip is disposed on the bottom plate and connected to one side of the end of the RF transmission line through high-frequency wire bonding.

Images