Coupling method of EML laser, EML laser and optical module

Abstract

The invention discloses a coupling method of an EML laser, the EML laser and an optical module, and the method comprises the steps: enabling a lens to be coupled to the maximum value of the output optical power of the EML laser, and maintaining the position of the lens; scanning the output optical power AOP of the electric absorption reverse bias voltage VEA within a preset voltage range; the slope value of the output optical power AOP to the electric absorption reverse bias voltage VEA is calculated, and the VEA corresponding to the maximum slope value is determined; setting the VEA corresponding to the maximum slope value as the working voltage of the EML laser, and coupling the lens again; fixing the position of the lens; and setting the VEA corresponding to the maximum slope value in firmware of the EML and storing the VEA. According to the invention, the lens coupling of the EML and the adjustment and measurement of the electric absorption reverse bias voltage VEA are combined, through two times of lens coupling and one time of VEA adjustment and measurement, the adjustment and measurement efficiency can be improved, it is ensured that the EML is in the optimal working state, and the output performance and the production efficiency of an optical module product are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical communication technology, and particularly relates to a coupling method of an EML laser, an EML laser and an optical module. BACKGROUND

[0002] An electro-absorption modulated laser (EML) integrates a DFB laser and an electro-absorption modulator EAM, has advantages of high integration, high-speed modulation, low chirp and the like, and is widely used in high-speed optical modules at present. A key parameter of the EML laser is a voltage electro-absorption (VEA), which has a significant influence on parameters such as output optical power (AOP), chirp, dispersion and extinction ratio of the EML laser.

[0003] Because of batch problems of the EML laser, a fixed VEA value cannot be well adapted to a working state of each EML laser, and therefore different VEAs can only be set in a final module debugging stage. However, different VEAs correspond to different EA absorption efficiencies, which brings about poor consistency of module output power distribution, increases difficulty of front-end coupling calibration, and increases module debugging time at the back end. SUMMARY

[0004] The present application aims to provide a coupling method of an EML laser, an EML laser and an optical module, so as to solve the problem that manual adjustment of an optimal VEA value of the EML laser in a coupling process causes low production efficiency and yield, and uniform writing of a fixed VEA value causes poor consistency of the optical module and difficulty in being at an optimal working point.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: In a first aspect, the present application provides a coupling method of an EML laser, which combines lens coupling of the EML laser with adjustment of a voltage electro-absorption (VEA), and the method comprises the following steps: coupling the lens to a maximum output optical power of the EML laser, and keeping the lens position; scanning output optical power AOP of the voltage electro-absorption (VEA) in a preset voltage range; calculating a slope value of the output optical power AOP with respect to the voltage electro-absorption (VEA), and determining a VEA corresponding to a maximum slope value; setting the VEA corresponding to the maximum slope value as a working voltage of the EML laser, and coupling the lens again; fixing the lens position; Set the VEA corresponding to the maximum slope value into the firmware of the EML laser and save it.

[0006] Further, the method further comprises: Before fixing the lens position, record the output optical power AOPrefB when the optimal VEA and the maximum output optical power AOPmax when the VEA is 0V, and determine whether the extinction ratio ER of the EML laser meets the requirement according to the optical power ratio of AOPmax to AOPrefB.

[0007] Further, determining whether the extinction ratio ER of the EML laser meets the requirement according to the optical power ratio of AOPmax to AOPrefB comprises: If the optical power ratio of AOPmax to AOPrefB is greater than a first threshold value, then the EA is qualified; If the optical power ratio of AOPmax to AOPrefB is less than a second threshold value, then the EA is failed; wherein the first threshold value is greater than the second threshold value; If the optical power ratio of AOPmax to AOPrefB is greater than or equal to the second threshold value and less than or equal to the first threshold value, then the EA is abnormal.

[0008] Further, if the EA is abnormal, then reduce the output optical power of the EML laser, re-couple the lens to the maximum output optical power of the EML laser, scan the output optical power AOP of the electric absorption reverse bias voltage VEA in the preset voltage range again, determine the VEA corresponding to the maximum slope value, and continue to screen the EML laser with the EA failed according to the optical power ratio of AOPmax to AOPrefB until the EA is qualified or the EA is failed.

[0009] Further, the optical power ratio is determined by 10lg(AOPmax / AOPrefB); the first threshold value is 3dB, and the second threshold value is 1dB.

[0010] Further, the slope value Slope = ΔAOP / ΔVEA, wherein ΔAOP is the output optical power difference under the scanning step, and ΔVEA is the voltage step value.

[0011] Further, the preset voltage range is -2.5V to 0V.

[0012] Further, the electric absorption reverse bias voltage VEA is 0V when the lens is coupled for the first time, and the lens is coupled to the maximum output optical power again when the lens is coupled for the second time.

[0013] In the second aspect, the application provides an EML laser, which is coupled by the coupling method of the EML laser in any one of the first aspect and the EML laser is tested by the electric absorption reverse bias voltage VEA.

[0014] In a third aspect, the present application provides an optical module, comprising the EML laser of the second aspect.

[0015] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects: The present application combines the lens coupling of the EML laser with the adjustment of the electrical absorption reverse bias voltage VEA, and through two lens couplings and one VEA adjustment, the adjustment 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. The first lens coupling is used to determine the initial position of the lens for subsequent adjustment, so as to improve the subsequent adjustment efficiency; the VEA adjustment combines the initial position of the lens to scan and calculate the optimal VEA value, so as to ensure that the EML laser is in the best working state, and the output performance of the optical module product and the production efficiency are improved; the second lens coupling is based on the optimal VEA value to re-determine the optimal position of the lens, so as to improve the yield of the optical module.

[0016] In addition, the present application combines the lens coupling of the EML laser with the adjustment of the electrical absorption reverse bias voltage VEA, and can perform an EA function test in the lens coupling stage, so as to screen out EML lasers with EA failure in advance, and greatly improve the production efficiency and the yield of the optical module. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 A flowchart of a coupling method of an EML laser according to an embodiment of the present application is shown in the figure; Figure 2 A flowchart of a coupling method of an EML laser according to another embodiment of the present application is shown in the figure; Figure 3 A graph of the relationship between the reverse bias and the output optical power according to an embodiment of the present application is shown in the figure; Figure 4 A graph of the relationship between the reverse bias and the slope value Slope according to an embodiment of the present application is shown in the figure; Figure 5 A flowchart of a method for screening EML lasers with EA failure according to an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. Based on the embodiments provided by the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0019] It is apparent that the following description of the drawings is merely some examples or embodiments of the present application, and the present application can be applied to other similar situations without creative labor on the basis of these drawings for those skilled in the art. In addition, it can be understood that although the efforts made in this development process can be complex and lengthy, some designs, manufacturing or production changes based on the technical content disclosed in the present application are only routine technical means for those skilled in the art related to the disclosure of the present application, and should not be understood as insufficient disclosure of the present application.

[0020] In the present application, the term "embodiment" means that the specific features, structures or properties described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments without conflict.

[0021] Unless otherwise defined, the technical terms or scientific terms involved in the present application should be understood as the usual meaning by those skilled in the art in the technical field to which the present application belongs. The terms "one", "a", "an", "the" and the like similar words involved in the present application do not represent quantity limitation, but can represent singular or plural. The terms "include", "contain", "have" and any variations thereof involved in the present application are intended to cover non-exclusive inclusion; for example, the process, method, system, product or device including a series of steps or modules (units) is not limited to the listed steps or units, but can also include steps or units not listed, or can also include other steps or units inherent to these processes, methods, products or devices. The terms "connected", "connected", "coupled" and the like similar words involved in the present application are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The term "multiple" refers to two or more. The association between the associated objects described by "and / or" can represent three relationships, for example, "A and / or B" can represent three cases of A alone, A and B together, and B alone. The character " / " generally represents an "or" relationship between the associated objects. The terms "first", "second", "third" and the like involved in the present application are merely to distinguish similar objects, and do not represent a specific order for the objects.

[0022] The manual adjustment of the optimal VEA value of the EML laser during the coupling process will result in low production efficiency and yield, and the uniform writing of the fixed VEA value will result in poor consistency of the optical module and difficulty in reaching the optimal working point. Meanwhile, the EA adjustment in the optical module stage will inevitably result in the inflow of the EML laser with EA failure.

[0023] To solve the above problems, the application provides an EML laser coupling method, an EML laser and an optical module, which simultaneously perform the coupling and adjustment of the EML laser, can solve the problems of low efficiency of manual adjustment of the EVA value and poor consistency of the optical power distribution of the uniform writing of the fixed VEA value, and can also filter out the EML laser with EA failure in advance, thereby greatly improving the production efficiency and yield of the optical module.

[0024] As shown in Figure 1 The application provides an EML laser coupling method, which combines the lens coupling of the EML laser with the adjustment of the electrical absorption reverse bias voltage VEA, and the method comprises the following steps: Step S101: coupling the lens to the maximum output optical power of the EML laser and keeping the lens position; Step S102: scanning the output optical power AOP of the electrical absorption reverse bias voltage VEA in a preset voltage range; Step S103: calculating the slope value of the output optical power AOP with respect to the electrical absorption reverse bias voltage VEA and determining the VEA corresponding to the maximum slope value; Step S104: setting the VEA corresponding to the maximum slope value as the working voltage of the EML laser and coupling the lens again; Step S105: fixing the lens position; Step S106: setting the VEA corresponding to the maximum slope value to the firmware of the EML laser and saving.

[0025] By combining the lens coupling of the EML laser with the adjustment of the electrical absorption reverse bias voltage VEA, the adjustment efficiency can be improved, the EML laser can be ensured to be in the optimal working state, and the output performance and production efficiency of the optical module product are improved. Meanwhile, the EA function of the EML laser can be tested in the lens coupling stage, and the EML laser with EA failure can be filtered out in advance.

[0026] Specifically, the application scans the values of the electrical absorption reverse bias voltage VEA and the output optical power AOP of the EML laser during the lens coupling, calculates the Max Slope value in the linear region through the formula Slope=ΔAOP / ΔVEA, and determines the optimal VEA value as the working point of the EML laser.

[0027] As shown in Figure 2As shown, the coupling method of the EML laser of the embodiment of the application scans the VEA and AOP data of the EML laser in lens coupling, calculates the optimal VEA and performs coupling again, and specifically includes the following steps: Step S201: lens coupling is performed at the maximum output optical power, and the current lens position is kept.

[0028] Lens coupling is to shape and focus the divergent light of the semiconductor laser through the lens into the optical waveguide, adjust the lens to the optimal position to achieve the target optical power value, and complete lens coupling after fixing the lens position by dispensing. During this lens coupling, the electrical absorption reverse bias voltage VEA is 0 V, so as to determine the initial position of the lens and improve the subsequent adjustment and testing efficiency.

[0029] Step S202: scan the light output power AOP of VEA from -2.5 V to 0 V.

[0030] Scan the light output power AOP (unit: mW) of the electrical absorption reverse bias voltage VEA from -2.5 V to 0 V, and the scanning step Step is preferably 0.1 V. The scanning result is as shown in Figure 3 .

[0031] Step S203: calculate the slope value Slope and find the VEA corresponding to Max Slope.

[0032] Based on the scanning result Figure 2 , the Slope curve as shown in Figure 4 is calculated by Slope=ΔAOP / ΔVEA, and the VEA corresponding to Max Slope is found (ΔAOP is the power difference value under Step).

[0033] Step S204: set the VEA corresponding to Max Slope as the working VEA and couple again to the target output optical power.

[0034] Set the VEA corresponding to the maximum slope value as the working voltage of the EML laser, and couple the lens again to the target output optical power. The target output optical power is determined according to the required optical power of the optical waveguide, and is preferably the maximum output optical power, that is, the output optical power AOPrefB at the maximum slope VEA.

[0035] Further, after the lens optimal position is determined, the AOP at this time and the AOP when VEA=0V are recorded, that is, the output optical power AOPrefB when the optimal VEA is recorded and the maximum output optical power AOPmax when VEA is 0V. Then, whether the extinction ratio ER of the EML laser meets the requirement is determined according to the optical power ratio of AOPmax and AOPrefB, so as to screen the EML laser with failed EA. Wherein, the optical power ratio is determined by 10lg(AOPmax / AOPrefB).

[0036] In the embodiment, whether the extinction ratio ER of the EML laser meets the requirement is determined by whether the optical power ratio of the maximum optical power AOPmax when VEA=0V and the optical power value AOPrefB when the optimal VEA is greater than 3dB. As shown in FIG. 2, whether the extinction ratio ER of the EML laser meets the requirement is determined according to the optical power ratio of AOPmax and AOPrefB, and the EML laser with failed EA is screened, and the specific steps are as follows: Figure 5 If the optical power ratio of AOPmax and AOPrefB is greater than the first threshold value, the EA is qualified; If the optical power ratio of AOPmax and AOPrefB is less than the second threshold value, the EA is failed; If the optical power ratio of AOPmax and AOPrefB is greater than or equal to the second threshold value and less than or equal to the first threshold value, the EA is abnormal, and the AOPmax is reduced by 3dB to be re-calibrated to meet the requirement. Wherein, the first threshold value is preferably 3dB, and the second threshold value is preferably 1dB.

[0037] Step S205: dispensing and fixing the lens.

[0038] After the optimal position of the lens is determined again, the lens is fixed by dispensing Step S206: setting the VEA corresponding to Max Slope into the firmware and saving.

[0039] The VEA corresponding to Max Slope is reset into the firmware, and the setting value is saved for use.

[0040] Based on the coupling method of the EML laser according to the above method embodiment, the application provides an EML laser, which is coupled by the coupling method of the EML laser according to the above method embodiment and the tuning of the electric absorption reverse bias voltage VEA.

[0041] The application also provides an optical module, which comprises the EML laser prepared by the coupling method of the EML laser according to the above method embodiment.

[0042] ​In summary, the lens coupling of the EML laser is combined with the adjustment of the electric absorption reverse bias voltage VEA, and through twice lens coupling and once VEA adjustment, the adjustment efficiency can be improved, the EML laser can be ensured in the best working state, and the output performance of the optical module product and the production efficiency are improved. Meanwhile, the EA function test can be performed in the lens coupling stage, the EML laser with poor EA is screened out in advance, and the production efficiency and the yield of the optical module are greatly improved.

[0043] It should be noted that, according to the needs of implementation, each step / component described in the present application can be split into more steps / components, or two or more steps / components or part of the operation of the steps / components can be combined into a new step / component, so as to realize the purpose of the present application.

[0044] Those skilled in the art will readily understand that the above is only a preferred embodiment of the present application, and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A coupling method for an EML laser, characterized in that, The lens coupling of the EML laser is combined with the tuning of the electrical absorption reverse bias voltage VEA, and the method comprises the following steps: coupling the lens to the EML laser at the maximum output optical power, and keeping the lens position; scanning the output optical power AOP of the electrical absorption reverse bias voltage VEA in a preset voltage range; calculating the slope value of the output optical power AOP to the electrical 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 into the firmware of the EML laser and saving.

2. The method of coupling an EML laser of claim 1, wherein, The method further comprises the following steps: before fixing the lens position, recording the output optical power AOPrefB at the optimal VEA and the maximum output optical power AOPmax when the VEA is 0V, and determining whether the extinction ratio ER of the EML laser meets the requirements according to the optical power ratio of AOPmax to AOPrefB.

3. The method of coupling an EML laser of claim 2, wherein, determining whether the extinction ratio ER of the EML laser meets the requirements according to the optical power ratio of AOPmax to AOPrefB, comprising: if the optical power ratio of AOPmax to AOPrefB is greater than a first threshold value, then EA is qualified; if the optical power ratio of AOPmax to AOPrefB is less than a second threshold value, then EA is invalid; wherein the first threshold value is greater than the second threshold value; if the optical power ratio of AOPmax to AOPrefB is greater than or equal to the second threshold value and less than or equal to the first threshold value, then EA is abnormal.

4. The method of coupling an EML laser of claim 3, wherein, if EA is abnormal, then reducing the output optical power of the EML laser, coupling the lens to the EML laser at the maximum output optical power again, scanning the output optical power AOP of the electrical absorption reverse bias voltage VEA in a preset voltage range again, determining the VEA corresponding to the maximum slope value, and continuing to screen the EML laser with EA invalid according to the optical power ratio of AOPmax to AOPrefB until EA is qualified or EA is invalid.

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

6. The method of coupling an EML laser of claim 1, wherein, The slope value Slope=ΔAOP / ΔVEA, wherein ΔAOP is the output optical power difference under the scanning step, and ΔVEA is the voltage step value.

7. The method of coupling an EML laser of claim 1, wherein, The preset voltage range is -2.5V to 0V.

8. The method of coupling an EML laser of claim 1, wherein, The electrical absorption reverse bias voltage VEA is 0V when the lens is coupled for the first time, and the lens is coupled to the maximum output optical power again when the lens is coupled for the second time.

9. An EML laser, characterized by, The laser is lens-coupled and the electrical absorption reverse bias voltage VEA is tuned by the coupling method of the EML laser according to any one of claims 1 to 8.

10. An optical module characterized by comprising: The optical module comprises the EML laser according to claim 9.

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