A differential drive EML light assembly

Abstract

The application belongs to the technical field of optical communication, and specifically provides a differential driving EML optical assembly, which comprises an isolation capacitor C, a matching resistor R and a carrier, wherein an electro-absorption modulator EAM and a DFB laser are arranged on the carrier; one end of the matching resistor R is electrically connected with the electro-absorption modulator EAM, and the other end is electrically connected with the carrier; and the isolation capacitor C is electrically connected with the positive electrode and the negative electrode of the DFB laser respectively. Based on the high-speed optical module of the differential driving EML optical assembly, CDR or DSP can be directly used for differential driving, and no additional driver is needed, especially in the multi-channel scheme, which can significantly reduce the power consumption and cost of the optical module. In addition, the differential driving EML optical assembly only optimizes the peripheral circuit to realize differential driving, has no special requirement for the design of the EML chip itself, does not need to change the existing EML laser design, has strong universality, and can share the existing EML industrial chain without additional cost increase.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and more specifically, to a differentially driven EML optical component. Background Technology

[0002] In 2019, my country officially launched the commercial use of fifth-generation mobile communication (5G) technology. In 2020, 5G networks and data centers were identified as key components of new infrastructure construction. The 2021 Government Work Report explicitly stated the need to "increase investment in the construction of 5G networks and gigabit optical networks, and enrich application scenarios." This has accelerated the development of related technologies and industries such as 5G, data centers, and all-optical access networks. Optical modules are fundamental building blocks of 5G bearer networks, data center interconnects, and all-optical access networks. They primarily perform photoelectric / electro-optical conversion. In recent years, with the gradual increase in speed, their cost share in system equipment has been continuously rising, making them a key element for high bandwidth, wide coverage, low cost, and low energy consumption in various application fields.

[0003] With the rapid development of cloud computing, big data, ultra-high-definition video, artificial intelligence, and 5G industry applications, network access frequency and access methods are constantly increasing, and network data traffic is growing rapidly, posing greater challenges to data center interconnection. Internal data center interconnection accounts for a large proportion of the overall traffic distribution in data centers, and typical requirements for optical modules show development trends such as high speed, low power consumption, low cost, and intelligence.

[0004] From 100G, 200G, 400G to 800G optical modules, the module package size remains basically unchanged, but the module operating speed increases exponentially. This requires that, while maintaining the same number of channels, the speed of each individual channel must increase exponentially to achieve higher transmission rates. Currently, traditional low-cost direct-modulation lasers are commercially viable, but due to their inherent low bandwidth characteristics, they cannot meet the requirements for applications with speeds ≥100G. Therefore, currently commercially available high-speed optical modules all adopt the EML (Electronic Lens Modulation) solution, and it can be predicted that the EML solution will remain the mainstream solution for a long time to come.

[0005] Current high-speed optical modules used in data centers and 5G bearer networks all require multiple channels, high density, high speed, and low power consumption. Several types of lasers / modulators are used in high-speed optical modules: 1. Directly modulated laser (DFB): Low cost and low power consumption, but inherently insufficient bandwidth, making it unsuitable for high-speed transmission; 2. Lithium niobate modulator: High bandwidth, suitable for high-speed transmission, but high cost and large size, preventing small-size, high-density applications; 3. Silicon photonics MZ modulator: Low cost and small size, suitable for multi-channel, high-density, small-size applications, but high insertion loss, limiting its application scenarios. Furthermore, current production yield is low, resulting in high overall costs for large-scale commercial use; 4. Electro-absorption modulator (EML): High bandwidth and small size, suitable for high-density, high-speed applications, but with slightly higher cost and power consumption. In summary, the EML solution better meets the current market demand for optical modules. Traditional EML chips are more suited to single-ended driving in terms of chip structure. Traditional clock recovery chips (CDRs) or DSPs, due to material limitations, have insufficient single-ended driving capability, requiring an additional driver circuit after the CDR or DSP to achieve higher driving capability. In multi-channel optical modules, this results in high power consumption and increased cost. Developing an EML optical component suitable for differential driving based on traditional EML chips can eliminate the need for a driver circuit, allowing direct differential driving using a CDR or DSP, thus reducing power consumption and saving costs. In conclusion, using differential-driven EML components to realize high-speed optical modules is of great significance. Summary of the Invention

[0006] This invention addresses the technical problem of how to develop a suitable differential-driven EML optical component in the prior art.

[0007] This invention provides a differential-driven EML optical component, comprising: an isolation capacitor C, a matching resistor R, and a carrier, wherein an electro-absorption modulator (EAM) and a DFB laser are disposed on the carrier;

[0008] One end of the matching resistor R is electrically connected to the electroabsorption modulator EAM, and the other end is electrically connected to the carrier.

[0009] The two ends of the isolation capacitor C are electrically connected to the positive and negative terminals of the DFB laser, respectively.

[0010] Preferably, the EML optical component further includes a filter inductor, one end of which is electrically connected to the positive terminal of the DFB laser, and the other end is grounded.

[0011] Preferably, the filter inductor exhibits low impedance to high-frequency signals.

[0012] Preferably, the carrier is an aluminum nitride ceramic carrier.

[0013] Preferably, the resistance of the matching resistor is 50Ω.

[0014] Preferably, the electroabsorption modulator (EAM) is provided with a first bias-T circuit, which includes an inductor and a high-frequency ferrite bead connected in series, and the high-frequency ferrite bead is connected to the electroabsorption modulator (EAM).

[0015] Preferably, after the high-frequency magnetic bead is connected to the electroabsorption modulator (EAM), it is then connected to the positive terminal of the radio frequency signal via a DC blocking capacitor.

[0016] Preferably, the EML optical component further includes a second Bias-T circuit, which includes an inductor and a high-frequency ferrite bead connected in series, the high-frequency ferrite bead being connected to the carrier.

[0017] Preferably, after the high-frequency magnetic bead is connected to the carrier, it is then connected to the negative terminal of the radio frequency signal through a DC blocking capacitor.

[0018] Preferably, the EML optical component further includes a heat sink, and the carrier is in contact with the heat sink for heat dissipation.

[0019] Beneficial Effects: This invention provides a differential-driven EML optical component, comprising: an isolation capacitor C, a matching resistor R, and a carrier. An electro-absorption modulator (EAM) and a DFB laser are mounted on the carrier. One end of the matching resistor R is electrically connected to the EAM, and the other end is electrically connected to the carrier. The two ends of the isolation capacitor C are respectively electrically connected to the positive and negative terminals of the DFB laser. High-speed optical modules based on this differential-driven EML optical component can directly use a CDR or DSP for differential driving without the need for additional drivers. Especially in multi-channel solutions, this significantly reduces the power consumption and cost of the optical module. Furthermore, the differential-driven EML optical component only optimizes the peripheral circuitry to achieve differential driving, requiring no special design of the EML chip itself and no modification to the existing EML laser design. It has strong versatility and can share the existing EML industry chain without incurring additional costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the differential-driven EML optical component structure provided by the present invention.

[0021] Figure 2 The schematic diagram of the electrical connection of the differential drive EML optical component provided by the present invention. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0023] Combination Figure 1 and Figure 2 As shown in the figure, a differential-driven EML optical component provided by an embodiment of the present invention includes: an isolation capacitor C, a matching resistor R, and a carrier. An electro-absorption modulator (EAM) and a DFB laser are disposed on the carrier. One end of the matching resistor R is electrically connected to the electro-absorption modulator EAM, and the other end is electrically connected to the carrier. The two ends of the isolation capacitor C are respectively electrically connected to the positive and negative terminals of the DFB laser.

[0024] Specifically, the carrier serves as the foundation, upon which the electroabsorption modulator (EAM) and the DFB laser are first fixedly mounted. Then, a matching resistor R is configured, with its two ends electrically connected to both the carrier and the EAM. This creates a series connection between the matching resistor R and the EAM. Connecting the matching resistor R, which is also the characteristic impedance R, in parallel with the EAM ensures that the equivalent resistance of the EAM matches the impedance of the high-speed transmission line, preventing reflections and signal distortion caused by impedance discontinuities.

[0025] On the other hand, the two ends of the isolation capacitor C are electrically connected to the positive and negative terminals of the DFB laser, respectively. The isolation capacitor C provides a low-impedance path for high-frequency signals, guiding the high-frequency modulation signal from the negative terminal of the DFB laser to the positive terminal. Similarly, the filter inductor provides a low-impedance path for high-frequency signals, guiding the high-frequency modulation signal flowing to the positive terminal of the DFB laser to GND, preventing interference from the high-frequency modulation signal to the DFB laser, which could lead to signal-to-noise ratio degradation and affect signal quality.

[0026] As a preferred embodiment, the EML optical component further includes a filter inductor, one end of which is electrically connected to the positive terminal of the DFB laser, and the other end is grounded. The carrier is equipped with an electro-absorption modulator (EAM) and a DFB laser; one end of a matching resistor R is electrically connected to the EAM, and the other end is electrically connected to the carrier; the two ends of an isolation capacitor C are electrically connected to the positive and negative terminals of the DFB laser, respectively.

[0027] By connecting a filter inductor in series between the positive electrode of the DFB laser and GND, and by selecting an appropriate inductor, the filter inductor can present a low impedance state for high-frequency signals, providing a low impedance transmission path for high-frequency signals. This allows the high-frequency signals transmitted from the isolation capacitor to be directly transmitted to GND, avoiding direct modulation to the positive electrode of the DFB laser, which would cause a deterioration in the signal-to-noise ratio and thus a deterioration in device performance.

[0028] A further refinement involves using an aluminum nitride ceramic carrier as the support, upon which an electro-absorption modulator (EAM) and a DFB laser are mounted. One end of a matching resistor R is electrically connected to the EAM, and the other end is electrically connected to the carrier. The two ends of an isolation capacitor C are electrically connected to the positive and negative terminals of the DFB laser, respectively. The aluminum nitride ceramic carrier possesses high thermal conductivity and a low dielectric constant, making it suitable for high-frequency signal transmission while exhibiting excellent heat dissipation performance. Gold plating on the surface of the aluminum nitride ceramic carrier is primarily used for high-speed electrical signal transmission. The high-speed transmission line requires a controlled characteristic impedance (matching resistor) R = 50Ω. The aluminum nitride ceramic carrier provides a support for the EML laser, resistors, capacitors, inductors, and ferrite beads, dissipating the large amount of heat generated by the EML laser during operation to an external heat sink, preventing excessively high laser operating temperatures that could lead to performance degradation or even damage to the laser.

[0029] As a preferred solution, the matching resistor R is connected in parallel with the electro-absorption modulator EAM. The equivalent resistance of the electro-absorption modulator EAM is approximately 200Ω, which does not match the characteristic impedance of the high-speed transmission line (50Ω). Therefore, by connecting a 50Ω resistor in parallel, the overall equivalent impedance of the electro-absorption modulator EAM and the matching resistor is brought close to 50Ω, matching the characteristic impedance of the high-speed transmission line and improving the signal integrity of the high-speed circuit. In other words, impedance matching is achieved by using the characteristic impedance R in parallel.

[0030] As a preferred embodiment, the carrier is equipped with an electroabsorption modulator (EAM) and a DFB laser; one end of the matching resistor R is electrically connected to the electroabsorption modulator (EAM), and the other end is electrically connected to the carrier; the two ends of the isolation capacitor C are electrically connected to the positive and negative terminals of the DFB laser, respectively.

[0031] In this design, the isolation capacitor is connected in parallel with the DFB laser. Structurally, the EAM cathode and the DFB laser cathode share the same substrate in the EML chip. When the EAM is differentially driven, the high-frequency modulation signal simultaneously modulates the EAM cathode, and at the same time, the high-frequency modulation signal also modulates the DFB laser cathode. The isolation capacitor presents a low impedance state for high-frequency signals, providing a low-impedance transmission path for high-frequency signals and avoiding signal-to-noise ratio degradation caused by the modulation of the DFB laser cathode by the high-frequency signal. At the same time, it presents a high impedance state for DC signals, allowing the DC signal to be applied to the DFB laser cathode, providing the bias voltage for the DFB laser to operate, thereby stimulating the emission of DC optical signals.

[0032] As a preferred embodiment, the carrier is equipped with an electroabsorption modulator (EAM) and a DFB laser; one end of the matching resistor R is electrically connected to the electroabsorption modulator (EAM), and the other end is electrically connected to the carrier; the two ends of the isolation capacitor C are electrically connected to the positive and negative terminals of the DFB laser, respectively.

[0033] The filter inductor is connected in series between the positive electrode of the DFB laser and GND. By selecting an appropriate inductor, the filter inductor presents a low impedance state for high-frequency signals, providing a low impedance transmission path for high-frequency signals. This allows the high-frequency signals transmitted from the isolation capacitor to be directly transmitted to GND, avoiding direct modulation to the positive electrode of the DFB laser, which would cause a deterioration in the signal-to-noise ratio and thus a deterioration in device performance.

[0034] A further embodiment includes a first bias-T circuit on the electroabsorption modulator (EAM), comprising an inductor and a high-frequency ferrite bead connected in series, the high-frequency ferrite bead being connected to the EAM. It also includes a second bias-T circuit, comprising an inductor and a high-frequency ferrite bead connected in series, the high-frequency ferrite bead being connected to the carrier.

[0035] One high-frequency ferrite bead is connected to the electro-absorption modulator (EAM) and then connected to the positive terminal of the radio frequency (RF) signal via a DC blocking capacitor. The other high-frequency ferrite bead is connected to the carrier and then connected to the negative terminal of the RF signal via a DC blocking capacitor.

[0036] Specifically, an EML laser comprises an electroabsorption modulator (EAM) and a DFB laser. The DFB laser emits a continuous light wave of a fixed wavelength upon stimulation, which is then output to the EAM. The EAM operates under suitable bias conditions, i.e., in the linear region, by applying a DC bias voltage. High-speed signals are modulated by applying a differential high-frequency modulation electrical signal, thus modulating the high-speed electrical signal into a higher-speed optical signal, making it more suitable for transmission in optical fibers.

[0037] By incorporating a Bias-T circuit consisting of an inductor and a high-frequency ferrite bead into the electroabsorption modulator (EAM), a high impedance state is achieved for high-frequency signals, preventing leakage of the high-frequency modulation signal to the DC bias circuit and thus avoiding crosstalk to the DC bias signal. Conversely, a low impedance state is achieved for low-frequency signals, allowing the DC bias signal to be applied to the EAM through the Bias-T circuit. This keeps the EAM biased in the linear region, preventing nonlinear distortion during high-frequency modulation. One end of the inductor is connected to the VEA, and the other end is connected in series with the high-frequency ferrite bead, which is electrically connected to the EAM.

[0038] The present invention has the following beneficial effects:

[0039] (1) High-speed optical modules based on differentially driven EML optical components can be directly driven by CDR or DSP without the need for additional drivers. In particular, multi-channel solutions can significantly reduce the power consumption and cost of optical modules.

[0040] (2) Differential drive EML optical components only optimize the peripheral circuit to achieve differential drive. There are no special requirements for the design of the EML chip itself. There is no need to change the existing EML laser design. It has strong versatility and can share the existing EML industry chain without additional cost increase.

[0041] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0042] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A differential-driven EML optical component, characterized in that, include: An isolation capacitor C, a matching resistor R, and a carrier, wherein an electroabsorption modulator EAM and a DFB laser are mounted on the carrier; One end of the matching resistor R is electrically connected to the electroabsorption modulator EAM, and the other end is electrically connected to the carrier. The two ends of the isolation capacitor C are electrically connected to the positive and negative terminals of the DFB laser, respectively. The electroabsorption modulator EAM is provided with a first Bias-T circuit, which includes an inductor and a high-frequency ferrite bead connected in series, and the high-frequency ferrite bead is connected to the electroabsorption modulator EAM. The EML optical component also includes a second Bias-T circuit, which includes an inductor and a high-frequency ferrite bead connected in series, and the high-frequency ferrite bead is connected to the carrier.

2. The differential-driven EML optical component according to claim 1, characterized in that, The EML optical component also includes a filter inductor, one end of which is electrically connected to the positive terminal of the DFB laser, and the other end is grounded.

3. The differential-driven EML optical component according to claim 2, characterized in that, The filter inductor exhibits low impedance to high-frequency signals.

4. The differential-driven EML optical component according to claim 1, characterized in that, The carrier is an aluminum nitride ceramic carrier.

5. The differential-driven EML optical component according to claim 1, characterized in that, The resistance of the matching resistor is 50Ω.

6. The differential-driven EML optical component according to claim 1, characterized in that, After the high-frequency magnetic bead is connected to the electroabsorption modulator (EAM), it is then connected to the positive terminal of the radio frequency signal via a DC blocking capacitor.

7. The differential-driven EML optical component according to claim 1, characterized in that, After the high-frequency magnetic bead is connected to the carrier, it is then connected to the negative terminal of the radio frequency signal through a DC blocking capacitor.

8. The differential-driven EML optical component according to claim 1, characterized in that, The EML optical component also includes a heat sink, and the carrier is in contact with the heat sink for heat dissipation.

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