A coupling method of an EML laser, an EML laser and an optical module

Abstract

The application discloses a coupling method of an EML laser, an EML laser and an optical module, and the method comprises the following steps: coupling a lens to the output light power maximum of the EML laser and keeping the lens position; scanning the output light power AOP of the electric absorption reverse bias voltage VEA in a preset voltage range; calculating the slope value of the output light power AOP to the electric absorption reverse bias voltage VEA, and determining the VEA corresponding to the maximum slope value; setting the VEA corresponding to the maximum slope value as the working voltage of the EML laser, and coupling the lens again; fixing the lens position; setting the VEA corresponding to the maximum slope value to the firmware of the EML laser and saving it. The lens coupling of the EML laser is combined with the adjustment and measurement of the electric absorption reverse bias voltage VEA, and through twice lens coupling and once VEA adjustment and measurement, the adjustment and measurement efficiency can be improved, the EML laser can be ensured to be in the best working state, and the output performance of the optical module product and the production efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, specifically to a coupling method for an EML laser, an EML laser, and an optical module. Background Technology

[0002] Electro-absorption modulated lasers (EMLs) integrate a DFB laser and an electro-absorption modulator (EAM), offering advantages such as high integration, high-speed modulation, and low chirp, and are currently widely used in high-speed optical modules. A key parameter of EML lasers is the voltage electro-absorption (VEA), which significantly affects parameters such as the output optical power (AOP), chirp, dispersion, and extinction ratio.

[0003] Due to the batch-specific nature of EML lasers, writing a fixed VEA value cannot adequately adapt to the operating state of each EML laser. Therefore, different VEAs must be set during the final module debugging stage. However, different VEAs correspond to different EA absorption efficiencies, resulting in poor consistency of the module's output power distribution, increasing the difficulty of front-end coupling calibration, and also increasing the debugging time of the back-end module. Summary of the Invention

[0004] The purpose of this invention is to provide a coupling method for an EML laser, an EML laser, and an optical module, in order to solve the problems that manually adjusting the optimal VEA value of the EML laser during the coupling process leads to low production efficiency and yield, while uniformly writing a fixed VEA value results in poor consistency of the optical module and makes it difficult to achieve the optimal operating point.

[0005] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0006] In a first aspect, the present invention provides a coupling method for an EML laser, which combines lens coupling of the EML laser with the adjustment of the electro-absorption reverse bias voltage VEA. The method includes:

[0007] Couple the lens to the point of maximum output power of the EML laser and maintain the lens position;

[0008] The output optical power (AOP) of the scanning electroabsorption reverse bias voltage VEA within a preset voltage range;

[0009] Calculate the slope of the output optical power AOP with respect to the electroabsorption reverse bias voltage VEA, and determine the VEA corresponding to the maximum slope value;

[0010] Set the VEA corresponding to the maximum slope value as the operating voltage of the EML laser, and couple the lens again;

[0011] Fix the lens position;

[0012] Set the VEA corresponding to the maximum slope value into the firmware of the EML laser and save it.

[0013] Furthermore, the method also includes:

[0014] Before fixing the lens position, record the output optical power AOPrefB at the optimal VEA and the maximum output optical power AOPmax when VEA is 0V, and determine whether the extinction ratio ER of the EML laser meets the requirements based on the ratio of optical power AOPmax to AOPrefB.

[0015] Furthermore, the extinction ratio (ER) of the EML laser is determined based on the ratio of AOPmax to AOPrefB optical power, including:

[0016] If the ratio of optical power of AOPmax to AOPrefB is greater than the first threshold, then EA is qualified;

[0017] If the ratio of optical power of AOPmax to AOPrefB is less than the second threshold, then EA fails; where the first threshold is greater than the second threshold.

[0018] If the ratio of optical power of AOPmax to AOPrefB is greater than or equal to the second threshold and less than or equal to the first threshold, then EA is abnormal.

[0019] Furthermore, if the EA is abnormal, the output optical power of the EML laser is reduced, the lens is recoupled to the maximum output optical power of the EML laser, the output optical power AOP of the electroabsorption reverse bias voltage VEA within the preset voltage range is scanned again, and the VEA corresponding to the maximum slope value is determined. The EML lasers with EA failure are screened according to the optical power ratio of AOPmax to AOPrefB until the EA is qualified or the EA fails.

[0020] Furthermore, the optical power ratio is determined by 10lg(AOPmax / AOPrefB); the first threshold is 3dB and the second threshold is 1dB.

[0021] Furthermore, the slope value is Slope = ΔAOP / ΔVEA, where ΔAOP is the difference in output optical power under scanning steps, and ΔVEA is the voltage step value.

[0022] Furthermore, the preset voltage range is -2.5V to 0V.

[0023] Furthermore, during the first lens coupling, the reverse bias voltage VEA of the electro-absorption is 0V, and during the second lens coupling, the lens is coupled again to the maximum output optical power.

[0024] Secondly, the present invention provides an EML laser, which performs lens coupling and adjusts the electro-absorption reverse bias voltage VEA using the coupling method of the EML laser described in any one of the first aspects.

[0025] Thirdly, the present invention provides an optical module comprising the EML laser described in the second aspect.

[0026] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0027] This invention combines lens coupling of an EML laser with the adjustment of the electro-absorption reverse bias voltage (VEA). Through two lens couplings and one VEA adjustment, adjustment efficiency is improved, ensuring the EML laser is in optimal operating condition, thereby enhancing the output performance and production efficiency of the optical module. Specifically, the first lens coupling determines the initial lens position for subsequent adjustments, improving efficiency. The VEA adjustment, based on the initial lens position, scans and calculates the optimal VEA value, ensuring the EML laser is in optimal operating condition and further improving the output performance and production efficiency of the optical module. The second lens coupling, based on the optimal VEA value, redetermines the optimal lens position to improve the yield of the optical module.

[0028] Furthermore, this invention combines the lens coupling of the EML laser with the adjustment and measurement of the electro-absorption reverse bias voltage (VEA), enabling an EA function test to be performed during the lens coupling stage. This allows for the early screening of EML lasers with EA defects, significantly improving production efficiency and the yield of optical modules. Attached Figure Description

[0029] Figure 1 This is a schematic flowchart illustrating a coupling method for an EML laser according to an embodiment of the present invention.

[0030] Figure 2 A flowchart illustrating a coupling method for an EML laser according to another embodiment of the present invention;

[0031] Figure 3 This is a diagram showing the relationship between reverse bias and output optical power according to an embodiment of the present invention;

[0032] Figure 4 This invention provides a diagram showing the relationship between reverse bias and slope value according to an embodiment of the present invention.

[0033] Figure 5This is a flowchart of a method for screening EML lasers with EA failure, provided as an embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0035] Obviously, the accompanying drawings described below are merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0036] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention may be combined with other embodiments without conflict.

[0037] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," "an," "the," and similar words used in this invention do not indicate quantity limitation and may indicate singular or plural. The terms "comprising," "including," "having," and any variations thereof used in this invention are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms "connected," "linked," "coupled," and similar words used in this invention are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "A plurality" used in this invention refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships may exist; for example, "A and / or B" can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects have an "or" relationship. The terms "first," "second," and "third" used in this invention are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0038] Manually adjusting the optimal VEA value of the EML laser during coupling results in lower production efficiency and yield, while uniformly writing a fixed VEA value leads to poor consistency of the optical module and makes it difficult to achieve optimal operating point. Furthermore, performing EA adjustment at the optical module stage inevitably results in the influx of EML lasers with EA failures.

[0039] To address the aforementioned issues, this invention provides a coupling method for an EML laser, an EML laser, and an optical module. By simultaneously coupling and adjusting the EML laser, it can solve the problems of low efficiency in manually adjusting the EVA value and poor consistency in optical power distribution when uniformly writing a fixed VEA value. It can also screen out EML lasers with failed EVA values ​​in advance, significantly improving production efficiency and the yield of optical modules.

[0040] like Figure 1 As shown, the coupling method for an EML laser provided by this invention combines lens coupling of the EML laser with the adjustment of the electro-absorption reverse bias voltage VEA. The method includes:

[0041] Step S101: Couple the lens to the location of the maximum output optical power of the EML laser and maintain the lens position;

[0042] Step S102: Scan the output optical power AOP of the electroabsorption reverse bias voltage VEA within a preset voltage range;

[0043] Step S103: Calculate the slope of the output optical power AOP with respect to the electroabsorption reverse bias voltage VEA, and determine the VEA corresponding to the maximum slope value;

[0044] Step S104: Set the VEA corresponding to the maximum slope value to the operating voltage of the EML laser, and couple the lens again;

[0045] Step S105: Fix the lens position;

[0046] Step S106: Set the VEA corresponding to the maximum slope value into the firmware of the EML laser and save it.

[0047] By combining lens coupling of the EML laser with the adjustment of the electro-absorption reverse bias voltage (VEA), the adjustment efficiency can be improved, ensuring that the EML laser is in optimal working condition, thereby enhancing the output performance and production efficiency of optical module products. Simultaneously, an EA functional test can be performed during the lens coupling stage, allowing for the early screening of EML lasers with EA defects.

[0048] Specifically, this invention scans the values ​​of the electro-absorption reverse bias voltage VEA and the output optical power AOP of the EML laser during lens coupling, and calculates the Max Slope value in the linear region using the formula Slope=ΔAOP / ΔVEA, thereby determining the optimal VEA value as the operating point of the EML laser.

[0049] like Figure 2 As shown, the coupling method for an EML laser according to an embodiment of the present invention involves scanning to obtain the VEA and AOP data of the EML laser during lens coupling, calculating the optimal VEA, and then coupling again. Specifically, it includes the following steps:

[0050] Step S201: The lens is coupled to the position of maximum output optical power and the current lens position is maintained.

[0051] Lens coupling involves shaping and focusing the diverging light from a semiconductor laser into an optical waveguide using a lens. The lens is adjusted to its optimal position to achieve the target optical power value, and then glue is applied to fix the lens in place, completing the lens coupling process. In this lens coupling, the electro-absorption reverse bias voltage VEA was 0V to determine the initial lens position and improve subsequent adjustment and testing efficiency.

[0052] Step S202: Scan the output power AOP of VEA from -2.5V to 0V.

[0053] The scanning output power AOP (in mW) is measured from the reverse bias voltage VEA (-2.5V to 0V). The preferred scanning step is 0.1V. The scanning results are as follows: Figure 3 As shown.

[0054] Step S203: Calculate the slope value Slope and find the VEA corresponding to the Max Slope.

[0055] based on Figure 2 The scan results are calculated using Slope = ΔAOP / ΔVEA. Figure 4 The slope curve is shown, and the VEA corresponding to the Max Slope is found (ΔAOP is the power difference under the Step).

[0056] Step S204: Set the VEA corresponding to Max Slope as the working VEA and recouple it to the target output optical power.

[0057] Set the VEA corresponding to the maximum slope value as the operating voltage of the EML laser, and couple the lens to the target output optical power again. The target output optical power is determined according to the optical power required by the optical waveguide, preferably the maximum output optical power, which is the output optical power AOPrefB at the maximum slope VEA.

[0058] Furthermore, after recoupling and determining the optimal lens position, the AOP at this point and the AOP when VEA=0V are recorded, i.e., the output optical power AOPrefB at the optimal VEA and the maximum output optical power AOPmax when VEA is 0V are recorded. Then, the extinction ratio ER of the EML laser is determined based on the ratio of AOPmax to AOPrefB to screen out EML lasers with EA failure. The optical power ratio is determined by 10lg(AOPmax / AOPrefB).

[0059] In this embodiment, the extinction ratio ER of the EML laser is determined to meet the requirements by checking whether the ratio of the maximum optical power AOPmax (when VEA=0) to the optimal optical power AOPrefB (when VEA=0) is greater than 3dB. Figure 5 As shown, the extinction ratio ER of the EML laser is determined based on the ratio of AOPmax to AOPrefB optical power, and EML lasers with EA failure are screened out, as detailed below:

[0060] If the ratio of optical power of AOPmax to AOPrefB is greater than the first threshold, then EA is qualified;

[0061] If the ratio of optical power of AOPmax to AOPrefB is less than the second threshold, then EA fails.

[0062] If the optical power ratio of AOPmax to AOPrefB is greater than or equal to the second threshold and less than or equal to the first threshold, then EA is abnormal. AOPmax should be reduced by 3dB and recalibrated to meet the requirements. The first threshold is preferably 3dB, and the second threshold is preferably 1dB.

[0063] Step S205: Apply adhesive to fix the lens.

[0064] After re-determining the optimal position of the lens, apply adhesive to fix the lens in place.

[0065] Step S206: Set the VEA corresponding to Max Slope into the firmware and save it.

[0066] Reset the VEA corresponding to Max Slope in the firmware and save the settings for later use.

[0067] Based on the coupling method of the EML laser in the above method embodiment, the present invention provides an EML laser, which performs lens coupling and adjusts the electro-absorption reverse bias voltage VEA using the coupling method of the EML laser in the above method embodiment.

[0068] The present invention also provides an optical module comprising an EML laser fabricated by the coupling method of the EML laser described in the above method embodiments.

[0069] In summary, this invention combines lens coupling of the EML laser with the adjustment of the electro-absorption reverse bias voltage (VEA). Through two lens couplings and one VEA adjustment, the adjustment efficiency is improved, ensuring the EML laser is in optimal operating condition, thus enhancing the output performance and production efficiency of optical module products. Simultaneously, an EA (Electrical Absorption) functional test can be performed during the lens coupling stage, allowing for the early screening of EML lasers with EA defects, significantly improving production efficiency and the yield of optical modules.

[0070] It should be noted that, depending on the implementation needs, the various steps / components described in this invention can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0071] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements 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 coupling method for an EML laser, characterized in that, The method combines lens coupling of the EML laser with the adjustment of the electro-absorption reverse bias voltage VEA, and includes: Couple the lens to the point of maximum output power of the EML laser and maintain the lens position; The output optical power (AOP) of the scanning electroabsorption reverse bias voltage VEA within a preset voltage range; Calculate the slope of the output optical power AOP with respect to the electroabsorption reverse bias voltage VEA, and determine the VEA corresponding to the maximum slope value; Set the VEA corresponding to the maximum slope value as the operating voltage of the EML laser, and couple the lens to the maximum output optical power value again; Fix the lens position; Set the VEA corresponding to the maximum slope value into the firmware of the EML laser and save it.

2. The coupling method for an EML laser according to claim 1, characterized in that, The method also includes: Before fixing the lens position, record the output optical power AOPrefB at the optimal VEA and the maximum output optical power AOPmax when VEA is 0V, and determine whether the extinction ratio ER of the EML laser meets the requirements based on the ratio of optical power AOPmax to AOPrefB.

3. The coupling method for an EML laser according to claim 2, characterized in that, Determine whether the extinction ratio (ER) of the EML laser meets the requirements based on the ratio of AOPmax to AOPrefB optical power, including: If the ratio of optical power of AOPmax to AOPrefB is greater than the first threshold, then EA is qualified; If the ratio of optical power of AOPmax to AOPrefB is less than the second threshold, then EA fails; where the first threshold is greater than the second threshold. If the ratio of optical power of AOPmax to AOPrefB is greater than or equal to the second threshold and less than or equal to the first threshold, then EA is abnormal.

4. The coupling method for an EML laser according to claim 3, characterized in that, If the EA is abnormal, reduce the output optical power of the EML laser, recouple the lens to the maximum output optical power of the EML laser, scan the output optical power AOP of the electroabsorption reverse bias voltage VEA within the preset voltage range again, and determine the VEA corresponding to the maximum slope value. Continue to screen EML lasers with EA failure based on the optical power ratio of AOPmax to AOPrefB until EA is qualified or EA fails.

5. The coupling method for an EML laser according to claim 3 or 4, characterized in that, The optical power ratio is determined by 10lg(AOPmax / AOPrefB); the first threshold is 3dB and the second threshold is 1dB.

6. The coupling method for an EML laser according to claim 1, characterized in that, The slope value is Slope = ΔAOP / ΔVEA, where ΔAOP is the difference in output optical power under scanning steps, and ΔVEA is the voltage step value.

7. The coupling method for an EML laser according to claim 1, characterized in that, The preset voltage range is -2.5V to 0V.

8. The coupling method for an EML laser according to claim 1, characterized in that, During the first lens coupling, the reverse bias voltage VEA of the electro-absorption is 0V.

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