Wavelength conversion module manufacturing method and manufacturing device

Abstract

This manufacturing method for a wavelength conversion module of the present disclosure provides an efficient procedure for operating a wavelength conversion element at a desired operating wavelength while simultaneously attaching an optical fiber to the module. By automating most of the processes under computer control, the problem of element temperature fluctuations that are unique to wavelength conversion elements during the manufacturing process can be addressed, and the mass productivity of pigtail modules can be improved. The manufacturing method for a wavelength conversion module of the present disclosure also has the aspect of a manufacturing device including a computer for the wavelength conversion module.

Description

[Technical Field]

[0001] The present invention relates to a method and an apparatus for manufacturing a wavelength conversion module. [Background technology]

[0002] Wavelength conversion technology is used in a variety of application fields, including optical signal wavelength conversion in optical communications, optical processing, medicine, and bioengineering. In optical communications systems, wavelength conversion technology is also used in wavelength conversion devices that perform wavelength conversion operations using difference frequency generation (described below) and amplification operations using the parametric effect. Focusing on the materials used for wavelength conversion, periodically poled lithium niobate (PPLN) waveguide elements made of lithium niobate (LiNbO3), a second-order nonlinear material with a large nonlinear constant, are widely used in light sources due to their high wavelength conversion efficiency.

[0003] The second-order nonlinear optical effect utilizes a wavelength conversion mechanism in which light of wavelength λ1 and light of wavelength λ2 are input into a second-order nonlinear medium to generate a new wavelength λ3. The wavelength conversion expressed by the following equation is called sum frequency generation (SFG). 1 / λ3=1 / λ1+1 / λ2Equation (1) Furthermore, wavelength conversion that satisfies the following equation, which is obtained by modifying equation (1) with λ1=λ2, is called second harmonic generation (SHG). λ3=λ1 / 2 Equation (2) Furthermore, wavelength conversion that satisfies the following equation is called difference frequency generation (DFG). 1 / λ3=1 / λ1-1 / λ2Equation (3) The wavelength λ1 used in difference frequency generation according to the above formula (3) is called the pump light, λ2 the signal light, and λ3 the idler light. Furthermore, it is possible to construct an optical parametric oscillator that generates λ2 and λ3 that satisfy formula (3) by inserting a nonlinear medium into the resonator and inputting only λ1.

[0004] In recent years, improvements in wavelength conversion efficiency have made it possible to achieve optical amplification using the second-order nonlinear effect in the field of communications. This type of optical amplifier, known as a phase-sensitive amplifier (PSA), is capable of amplifying input light without degrading the signal-to-noise ratio, and is expected to replace erbium-doped fiber amplifiers as an optical amplifier for long-distance transmission.

[0005] Two types of amplification operations are known for PSA. One uses degenerate parametric amplification, in which signal light and pump light with half the wavelength of the signal light are input to a second-order nonlinear medium and the signal light is amplified (Non-Patent Document 1). The other uses non-degenerate parametric amplification, in which a pair of signal light and idler light, together with pump light with a wavelength that is the sum frequency of the signal light and idler light, are input and the signal light and idler light are amplified (Non-Patent Document 2). The pair of signal light and idler light is generated by the DFG mechanism described above.

[0006] When wavelength conversion technology is used in the communications field, DFG and optical parametric amplification (OPA) are the two main types of mechanisms that utilize the second-order nonlinear effect mentioned above. In the DFG and OPA mechanisms, the signal light and idler light are in the 1.55 μm communications wavelength band, so the pump light is in the 0.78 μm band.

[0007] FIG. 1 shows the basic configuration of a wavelength conversion module. FIG. 1(b) shows a top view (xy plane) of the wavelength conversion module 100, and FIG. 1(a) shows a partially simplified cross-sectional view (yz plane) of the module 100 taken along line Ia-Ia parallel to the y axis. The wavelength conversion module 100 receives fundamental light through an optical window 105-1 and generates second harmonic generation (SHG) light, a type of sum frequency light, from an optical window 108-2. The wavelength conversion module 100 includes a wavelength conversion element 102, a temperature control element 103, and a metal plate 104 that supports the wavelength conversion element, all housed within a metal housing 101. The metal housing 101 is equipped with fundamental light optical windows 105-1 and 105-2 and SHG light optical windows 108-1 and 108-2. The wavelength conversion element 102 includes lenses 106 before and after the wavelength conversion element 102, as well as optical filters 107-1 and 107-2 and other filter elements for separating fundamental wave light and SHG light. The wavelength conversion element 102 is, for example, a PPLN element.

[0008] While FIG. 1 shows a configuration including a wavelength conversion element for generating SHG light, modules with mechanisms such as PSA and OPA can also be realized by inputting two light beams with different wavelengths into the wavelength conversion element through one of the modules, the fundamental wave optical window 105-1 and the SHG light optical window 108-2. In the wavelength conversion module 100 shown in FIG. 1, the arrows indicate the light propagation direction when the fundamental wave light is input through the optical window 105-1 and the SHG light is output through the optical window 108-2. However, SHG light can be generated from the fundamental wave light in the same way even if the light propagation direction is reversed from that shown in FIG. 1. It is also possible to input the fundamental wave light through the optical window 105-2 and output the SHG light through the optical window 108-2, and the wavelength conversion module 100 has a symmetrical structure between the input and output.

[0009] As shown in Figure 1, a wavelength conversion module 100 is designed to input and output multiple light beams with different wavelengths. Devices incorporating such modules have often been configured with spatial optical components using bulk optical components due to their availability. In recent years, advances in the development of optical fiber communication devices have led to widespread availability of optical fiber-type and optical waveguide-type components for communication wavelength bands. Devices incorporating wavelength conversion modules have also begun to adopt pigtail-type modules, which emphasize easy optical coupling with optical fibers. Pigtail-type modules are compact, do not require optical alignment, and are versatile enough to be used in wavelength conversion, PSA, and OPA configurations. To promote wider adoption, a manufacturing method and apparatus capable of producing pigtail-type modules at low cost are needed.

[0010] The PPLN element 102 in the wavelength conversion module 100 in Figure 1 utilizes quasi-phase matching (QPM). In a PPLN element with a single-period QPM structure, the phase-matched wavelength is determined once the period of the repeating structure is determined. Because the refractive index of nonlinear optical materials is temperature-dependent, the PPLN element must be set to and controlled at an optimal temperature to achieve highly efficient wavelength conversion. [Prior art documents] [Non-patent literature]

[0011] [Non-Patent Document 1] T. Umeki, O. Tadanaga, A. Takada, and M. Asobe, “Phase sensitive degenerate parametric amplification using directly-bonded PPLN ridge waveguides,” Optics Express Vol.19, No. 27, pp.6326-6332, 2011 [Non-patent document 2] T. Umeki, O. Tadanaga, M. Asobe, Y. Miyamoto, and H. Takenouchi, “First demonstration of high-order QAM signal amplification in PPLN-based phase sensitive amplifier,” Optics Express Vol.22, No. 3, pp.2473-2482, 2014 Summary of the Invention [Problem to be solved by the invention]

[0012] However, when modularizing PPLN elements, there is a problem of fluctuations in the phase-matched wavelength during various processes, from obtaining the characteristics of the element itself to fixing all the fibers to the module. The process of attaching the fibers to the module involves tedious and complicated steps that require skilled workers, making it insufficient for mass production. The present invention provides a manufacturing method and apparatus for a pigtailed module that is excellent for mass production. [Means for solving the problem]

[0013] One aspect of the present invention is a manufacturing method for an optical module including a wavelength conversion element and a temperature control element fixed to the wavelength conversion element via a metal plate, the manufacturing method comprising the steps of: setting the wavelength conversion element to an initial temperature; aligning an input fiber so that the transmitted light of fundamental wave light is maximized; correcting the current temperature of the wavelength conversion element, the step including: sweeping the wavelength of the fundamental wave light in a predetermined wavelength range to determine a peak wavelength at which the level of wavelength-converted light is maximized; calculating the corrected temperature of the wavelength conversion element based on the operating wavelength of the wavelength conversion element, the peak wavelength, the current temperature and a temperature dependence coefficient of a phase-matching wavelength; and resetting the wavelength conversion element to the corrected temperature; re-aligning the input fiber so that the level of the wavelength-converted light is maximized at the corrected temperature; and fixing the adjusted input fiber to a metal housing of the optical module.

[0014] Another aspect of the present invention is a manufacturing method for an optical module including a wavelength conversion element and a temperature control element fixed to the wavelength conversion element via a metal plate, and connected to a fundamental wave input fiber, the manufacturing method comprising: a step of setting the wavelength conversion element to an initial temperature; a step of aligning an output fiber so that the transmitted light of the fundamental wave light is maximized; a step of correcting a current temperature of the wavelength conversion element, the step including a step of sweeping the wavelength of the fundamental wave light in a predetermined wavelength range to determine a peak wavelength at which the level of the wavelength-converted light is maximized; a step of calculating the corrected temperature of the wavelength conversion element based on the operating wavelength of the wavelength conversion element, the peak wavelength, the current temperature and a temperature dependence coefficient of a phase-matching wavelength; and a step of resetting the wavelength conversion element to the corrected temperature; a step of re-aligning the output fiber so that the level of the wavelength-converted light is maximized at the corrected temperature; and a step of fixing the adjusted output fiber to a metal housing of the optical module. [Effects of the Invention]

[0015] A method and apparatus for manufacturing a pigtail-type wavelength conversion module that is suitable for mass production. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing the basic configuration of a wavelength conversion module using a PPLN element. [Figure 2] 1A to 1C are diagrams illustrating an outline of a manufacturing process for a wavelength conversion module including a PPLN element. [Figure 3] 10A and 10B are diagrams showing changes in phase matching curves before and after fixing a wavelength conversion element. [Figure 4] 10A and 10B are diagrams illustrating the temperature dependence of the phase-matched wavelength before and after fixing the element. [Figure 5] 10A to 10C are diagrams illustrating changes in operating wavelength through the manufacturing process of a wavelength conversion module. [Figure 6] 10A and 10B are diagrams illustrating a procedure for connecting four PTFs to a wavelength conversion module. [Figure 7] 1 is a diagram showing an apparatus for implementing a wavelength conversion module manufacturing method according to the present disclosure. [Figure 8] FIG. 2 is a flow chart illustrating the steps of a method for manufacturing a wavelength conversion module according to the present disclosure. [Figure 9] 1A and 1B are diagrams illustrating the principle of determining the corrected temperature of a wavelength conversion element. [Figure 10] 10 is a diagram showing another configuration of an apparatus for carrying out a wavelength conversion module manufacturing method. [Figure 11] 10 is a diagram showing another configuration of an apparatus for carrying out a wavelength conversion module manufacturing method. [Figure 12] FIG. 10 is a flowchart illustrating another procedure of the method for manufacturing the wavelength conversion module. [Figure 13] FIG. 10 is a diagram illustrating the configuration of initial data in the manufacturing method of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] The disclosed method for manufacturing a wavelength conversion module provides an efficient procedure for operating a PPLN element at a desired operating wavelength while simultaneously attaching an optical fiber to the module. By automating most of the processes through computer control, the problem of element temperature fluctuations specific to PPLN elements during the manufacturing process is addressed, improving the mass productivity of pigtailed modules. The disclosed method for manufacturing a wavelength conversion module also has the aspect of a wavelength conversion module manufacturing apparatus that includes a computer. Below, we will explain the specific problems associated with wavelength conversion modules that include PPLN elements, followed by a detailed description of the disclosed method for manufacturing a wavelength conversion module and the configuration, operation, and procedures of the manufacturing apparatus.

[0018] FIG. 2 is a diagram showing an overview of the manufacturing process for a wavelength conversion module including a PPLN element. The manufacturing process begins with a PPLN element chip selection process 11. In this process 11, chips that include a PPLN waveguide to be used for modularization and have wavelength conversion performance according to the intended function are selected. This chip selection process 11 includes a chip data acquisition process 15 in parallel. In this process 15, a predetermined operating wavelength λ corresponding to the phase matching wavelength is selected for each chip or each product type. init and the initial temperature T corresponding to the operating wavelength init The chip data includes at least the following: The operating wavelength is a different value for each product type depending on the intended function, and may be the same wavelength for products of the same type. Products of the same type may have different operating wavelengths λ within a certain wavelength range. init may be set.

[0019] For a given PPLN element, the operating wavelength λ init Once this is determined, the same operating wavelength λ will be achieved even after modularization. init The principle is to operate at the initial temperature T init is the operating wavelength λ init Therefore, in the chip data acquisition step 15, the operating wavelength λ init and the initial temperature T initThere is a one-to-one correspondence with

[0020] Following step 11 in Fig. 2, step 12 is carried out in which the chip is incorporated into the module housing and fixed. In order to stably hold the wavelength conversion element 102 and uniformly control the temperature of the entire element during modularization, the wavelength conversion element 102 is fixed to a metal plate 104 that serves as a support, as shown in Fig. 1. When the wavelength conversion element 102 such as a PPLN element is fixed to the metal plate 104, a stress change occurs inside the wavelength conversion element 102 due to the difference in thermal expansion coefficient between the element and the metal plate. Such a stress change causes a change in the refractive index of the wavelength conversion element 102 due to the photoelastic effect, piezoelectric effect, Pockels effect, etc. Therefore, the actual operating wavelength of the wavelength conversion element 102 after it has been mounted in the module in chip fixing step 12 varies depending on the initial temperature T init That is, after mounting the wavelength conversion element on the module in step 12, the initial temperature T init , the phase-matching condition is not achieved. The details of this problem are further explained in Figs. 3 and 4.

[0021] The chip fixing step 12 is followed by step 13 of setting a pigtail fiber (hereinafter abbreviated as PTF for simplicity) in the module, aligning it, and searching for and optimizing the chip temperature, and step 14 of fixing the PTF to the module. The manufacturing method of the wavelength conversion module of the present disclosure, which will be described later, corresponds to steps 13 and 14. In the manufacturing method of the wavelength conversion module of the present disclosure, chip data including the initial temperature and the like acquired in the chip selection step 11 is updated to the corrected temperature and the like in the PTF fixing step 16.

[0022] 3 is a diagram showing the change in the phase matching curve before and after fixing the wavelength conversion element. In FIG. 3, the horizontal axis represents the wavelength (nm) of the input fundamental light, while the vertical axis represents the transmitted light output spectrum 10 of the fundamental light and the SHG light output spectra 20, 21 in arbitrary units (au). The transmitted light output spectrum 10 of the fundamental light is obtained by inputting the fundamental light through the optical window 105-1 in FIG. 1 and outputting it from the optical window 105-2 on the opposite side of the module. The SHG light output spectrum is obtained as output from the optical window 108-1. The SHG light output spectra 20, 21 are respectively obtained by heating the chip alone at an initial temperature T init When the temperature was measured at the same initial temperature T init 2. That is, it corresponds to the phase matching curve 20 obtained in steps 11 and 15 in FIG. 2 and the phase matching curve 21 obtained after the chip fixing step 12 in FIG. 2 is completed. The peak wavelength of the phase matching curve 20 is the operating wavelength λ init This becomes:

[0023] As is clear from Figure 3, the initial temperature T init Even if the operating wavelength λ is set to λ , the phase matching curve changes significantly before and after the wavelength conversion element is fixed. init To achieve a phase-matched state with a peak at init It must be corrected from

[0024] FIG. 4 is a diagram illustrating the temperature dependence of the phase-matching wavelength before and after fixing the wavelength conversion element. The horizontal axis represents the set temperature (°C) of the chip, and the horizontal axis represents the peak wavelength of the SHG light, i.e., the phase-matching wavelength (nm). The phase-matching wavelength has a roughly linear temperature dependence, and before and after fixing the wavelength conversion element chip, it changes from the temperature dependence curve 22 obtained in the selection process 11 to the temperature dependence curve 23 after the completion of the chip fixing process 12. The slope of the temperature dependence curve corresponds to the temperature dependence coefficient (nm / °C), and the temperature dependence coefficient also changes before and after fixing the chip. Note that for the purpose of explanation, the change in temperature dependence before and after chip fixing in FIG. 4 is slightly exaggerated.

[0025] As described above, before and after fixing the wavelength conversion element to the module, the chip is heated to the initial temperature T init As shown in Figure 3, the phase-matching curve, which has a bandwidth of only about 0.5 nm, shifts, causing the operating wavelength λ init Even if the fundamental wave light of λ is input, SHG light of the desired wavelength cannot be obtained at all. Not only is the desired wavelength conversion function not realized, but if SHG light cannot be obtained, the PTF alignment work cannot be performed. Therefore, after fixing the wavelength conversion element to the module, init It is necessary to find the "corrected temperature" that will result in a phase-matched state in the wavelength conversion element in the most efficient way possible. To find the "corrected temperature" of the wavelength conversion element, the element temperature must be changed. To efficiently search for the "corrected temperature," it is also necessary to avoid prolonging the time it takes for the element's characteristics to stabilize. In addition, stress changes occurring inside the wavelength conversion element may also occur due to impacts during the fiber welding and fixing process. It is also necessary to consider the possibility that fluctuations similar to the fluctuations in the phase-matched wavelength when fixing the chip described above may occur each time the fiber is fixed to the module housing.

[0026] The method for manufacturing a wavelength conversion module of the present disclosure solves or at least alleviates the above-mentioned problems, and automates the module mounting process that has previously relied on skilled workers, thereby significantly improving mass productivity.

[0027] 5 is a diagram illustrating the variation of the phase-matched wavelength during the manufacturing process of the wavelength conversion module. In the chip selection step 31, the target operating wavelength λ is selected for a specific type of wavelength conversion element. init In the actual selection process, the operating wavelength λ init In the chip selection stage 31, the operating wavelength λ init The initial temperature T init In step 32 after the wavelength conversion element chip is fixed to the metal plate, the chip is heated to an initial temperature T initThe actual operating wavelength that achieves phase matching when the initial temperature T init When the wavelength is set to , the actual operating wavelength variation increases.

[0028] In the method for manufacturing a wavelength conversion module of the present disclosure, in the module assembly step 33, which includes attaching the PTF to the module, init By determining and readjusting the "corrected temperature" that achieves the phase-matching state in the laser, the actual operating wavelength can be adjusted to fit within a certain range.

[0029] In the following explanation, as shown in Figure 1, a wavelength conversion module having two optical windows on one side (input side) and two optical windows on the other side (output side) of the wavelength conversion element 102, with a total of four ports (two inputs and two outputs) will be explained. A fundamental wave in the 1535 nm band is input to the input port, and transmitted light of the input light and SHG light in the 775 nm band are output from the output port. Four PTFs are connected sequentially to the four ports to complete the pigtail-type module. Depending on the function to be realized, light of two different wavelengths may also be input from the input port.

[0030] 6 is a diagram illustrating an outline of the procedure for connecting four PTFs to a wavelength conversion module. The wavelength conversion module 100 is a simplified version of the wavelength conversion module in FIG. 1. Port 1 corresponds to the fundamental light port of the optical window 105-1, and port 3 corresponds to the fundamental light port of the optical window 105-2. Port 2 corresponds to the SHG light output port of the optical window 108-1, and port 4 corresponds to the SHG light output port of the optical window 106-2. In the manufacturing method described below, the fundamental port is used as the input port for the fundamental light and the output port for the transmitted light of the fundamental light.

[0031] 6(a) shows the stage of connecting the first input PTF 202-1 to port 1, where a detector 203 for the fundamental wave 212 and a detector 206 for the SHG light 213 are used. In the connection process of the first input PTF, the initial temperature T init The initial data including the following is used. The configuration of a specific manufacturing device is shown in FIG. 7, and the flow of the manufacturing method is explained in FIG.

[0032] FIG. 6(b) shows the stage of connecting the second input PTF 202-2 to port 3, while the input PTF 202-1 is already connected to port 1. A detector 210 for the fundamental light and a detector 206 for the SHG light 213 connected to the input PTF 202-1 are used. FIG. 10 shows the specific configuration of the manufacturing apparatus, and the flow of the manufacturing method is generally the same as FIG. 8. Note that in the process of connecting the second and subsequent PTFs, updated data including the corrected temperature obtained in the process of connecting the first input PTF is used.

[0033] Figure 6(c) shows the stage where the third output PTF 211-1 is connected to port 4, while two input PTFs 202-1 and 202-2 are already connected to ports 1 and 3. A wavelength swept light source (SW) 201 is connected to input PTF 202-1, and a fundamental light detector 210 is connected to input PTF 202-2. Figure 11 shows the configuration of a specific manufacturing apparatus, and the flow of the manufacturing method is explained in Figure 12. Updated data including the corrected temperature is used.

[0034] 6(d) shows the stage where the fourth output PTF 211-2 is connected to port 2, and three PTFs have already been connected to the wavelength conversion module 100. The wavelength swept light source 201 is connected to the input PTF 202-2, and the fundamental light detector 210 is connected to the input PTF 202-1. The manufacturing method flow is generally the same as that shown in FIG. 12. Updated data including the corrected temperature is used.

[0035] The manufacturing procedures will be explained in detail below, separately for the manufacturing method when connecting a PTF for fundamental wave light input and the manufacturing method when connecting a PTF for SHG light output.

[0036] FIG. 7 is a diagram showing the configuration of an apparatus for implementing the wavelength conversion module manufacturing method of the present disclosure. The manufacturing apparatus has a configuration for connecting a PTF to a wavelength conversion module 100 and searching for and determining a correct operating temperature for operating the wavelength conversion element at a target operating wavelength. The manufacturing apparatus includes a wavelength-sweepable light source 201 that supplies fundamental light, a detector 206 that detects SHG light 213 and converts it into an electrical signal, and a detector 207 that detects transmitted fundamental light 212 and converts it into an electrical signal. The manufacturing apparatus also includes an aligner 203 that adjusts the position of the PTF at the fiber connection point to align the optical axis between the waveguide in the chip and the PTF core, and a lens aligner 204 that adjusts the position of lens 205-1. The above-mentioned elements are controlled by a computer 208. Although not shown, the computer 208 includes a processor, memory, and an A / D converter that converts the electrical signals from the detectors 206 and 207 into digital data. The computer 208 can be connected to an external storage device or a network (not shown).

[0037] In the manufacturing method of the wavelength conversion module of the present disclosure, the initial data of the wavelength conversion element acquired in advance in the chip selection process is read from a memory or the like and used in the manufacturing method flow described below. The initial data is updated in the manufacturing method flow. The initial data can be stored in the memory of the computer 208, an external storage medium, or on a network.

[0038] FIG. 13 is a diagram illustrating the configuration of initial data for wavelength conversion elements in the manufacturing method of the present disclosure. (a) in FIG. 13 shows initial data acquired in the chip selection process. (b) shows data updated in the manufacturing method flow described below. For example, wavelength conversion element data may include an element identification number, operating wavelength, initial temperature, temperature dependence coefficient of phase matching wavelength, wavelength conversion efficiency, loss element characteristics, etc. A file in a format such as a table is saved in computer memory, and this file is read by the control program for the manufacturing method. The PTF installed in the module is identified by the element identification number, etc., and the wavelength of the light source 201 and the set temperature of the temperature control element (temperature regulator) inside the module are controlled.

[0039] Fig. 8 is a flow diagram illustrating the steps of the method for manufacturing a wavelength conversion module according to the present disclosure. The flow diagram shown in Fig. 9 corresponds to the flow for connecting the input PTF 202-1 for inputting the first fundamental wave light shown in Fig. 6(a). The explanation will be given with reference to the configuration of the apparatus in Fig. 7. Each step in the flow will be explained using step numbers S100 to S116. Please note that the description of each step in Fig. 8 is simplified.

[0040] In S100, the wavelength conversion module, the input PTF 202-1 to be connected, the aligners 203 and 204, etc. are set in the adjustment jig of the manufacturing equipment.

[0041] In S101, initial data is read into the computer 208, and the fundamental wave light from the light source 201 is set to an operating wavelength. init After a certain temperature stabilization time, the wavelength conversion element is set to the initial temperature T init reached, the initial temperature T init This is the "current temperature." The "current temperature" is updated each time the "step of correcting the current temperature" is repeated, as will be described later.

[0042] The detector 207 aligns the input PTF 202-1 so that the level of the transmitted light 212 of the fundamental light is maximized. The alignment to maximize the transmitted light level is performed by aligners 203 and 204, and can be controlled by a processor using an appropriate control algorithm. The fundamental light from the end face of the PTF 202-1 is optically coupled to the wavelength conversion element in the module housing via lens 205-1. As shown as transmitted light 10 in Figure 3, the transmitted light level of the fundamental light has almost no wavelength dependency and very little temperature dependency. It is sufficient to set the light source wavelength to a wavelength close to the operating wavelength. Note that this alignment step is performed on the fundamental light.

[0043] Next, in S102, the light source 201 is controlled to sweep the wavelength of the input light within a predetermined wavelength range centered on the fundamental light. The predetermined wavelength range can be determined so that the peak wavelength of the SHG light is observed, taking into account the phase-matched wavelength variation of the SHG light expected in the wavelength conversion element due to the chip fixing process. At this time, the SHG light detector 206 acquires data on the wavelength-dependent characteristics 21 of the SHG light level corresponding to the swept wavelength range, as shown in FIG.

[0044] Next, in S103, the peak wavelength λ P Determine the peak wavelength λ P corresponds to the actual phase-matching wavelength at the current temperature of the wavelength conversion element included in the module. This actual phase-matching wavelength is the operating wavelength λ at which the element is originally intended to operate. init The peak wavelength λ P and operating wavelength λ init In this step, the wavelength difference between the peak wavelength λ and the SHG optical output is determined by performing the wavelength sweep by the light source 201 multiple times to obtain the average value of the phase matching curve. P Get.

[0045] In the state of S103, the peak wavelength λ P and operating wavelength λ initSince the wavelength difference Δλ between the input PTF 202-1 and the output PTF 202-2 is large, in many cases an SHG optical output at a level that allows alignment cannot be obtained. It is difficult to align the input PTF 202-1 so that the SHG optical level is maximized. Therefore, the current temperature of the wavelength conversion element is corrected to find a "corrected temperature" that reduces the wavelength difference Δλ.

[0046] In S104, the "corrected temperature" is calculated from the wavelength difference Δλ. More specifically, the operating wavelength λ of the wavelength conversion element is calculated. init , the peak wavelength λ P A corrected temperature of the wavelength conversion element is calculated based on the current temperature and the temperature-dependent coefficient of the phase-matching wavelength included in the initial data.

[0047] FIG. 9 is a diagram for explaining the principle of determining the corrected temperature of a wavelength conversion element. (a) of FIG. 9 is a diagram for explaining the shift in phase-matched wavelength due to the chip fixing process, similar to FIG. 3. The wavelength difference Δλ is the wavelength difference 24 between the peaks of the two phase-matched curves 20 and 21. (b) of FIG. 9 shows a schematic diagram of the relationship between the phase-matched wavelength (horizontal axis) and the corresponding chip temperature (°C). The black dots 26 indicate the difference in the phase-matched wavelength from the operating wavelength λ init This state is the target state. The black circle 27 indicates that the phase matching wavelength is equal to the peak wavelength λ at the current temperature in S203. P To move from the current state of black circle 27 to the target state of black circle 26, the "current" chip temperature should be corrected by the temperature difference ΔT. By using the value of the temperature dependency coefficient (nm / °C) of the initial data shown in Figure 13, the operating wavelength λ init , peak wavelength λ P Based on the current temperature and the temperature-dependent coefficient of the phase-matching wavelength, a "corrected temperature" can be calculated. To avoid the hunting phenomenon, the state can be corrected to a state 28 that is closer to the target state 26. There are no restrictions on the specific algorithm for calculating the corrected temperature; a general control algorithm can be used. Returning to FIG. 9 again, following S104, the wavelength difference Δλ is compared with a reference value.

[0048] In S105, the wavelength difference Δλ is compared with a first threshold value, which is a reference value. Since the direction of wavelength shift from the initial temperature when the chip is fixed may differ depending on the type of wavelength conversion element, the absolute value of the wavelength difference Δλ can be compared with the first threshold value, which is a positive value. Here, under the condition that the wavelength difference Δλ is equal to or less than the first threshold value (Y), the actual phase-matched wavelength is equal to or less than the operating wavelength λ. init Since the wavelength difference Δλ is sufficiently close to the operating wavelength λ , the process proceeds to the realignment step of the input PTF in S108. init Since the wavelength conversion element is still far from the target temperature, in S106 the wavelength conversion element is set to a temperature corrected from the current temperature. After waiting for a certain temperature stabilization time, the manufacturing method returns to the step of sweeping the wavelength of the fundamental wave light in S102. When returning to S102, the "corrected temperature" becomes the "current temperature."

[0049] The entire process from S102 to S106 described above can be said to be a process of correcting the current temperature of the wavelength conversion element. The step of determining whether the temperature is equal to the reference value in S105 can be performed before S104, which calculates the corrected temperature. In addition, the temperature dependency coefficient can be updated in S107 in parallel with determining the "corrected temperature."

[0050] In S107, the temperature dependence coefficient is updated based on the operating wavelength, peak wavelength, current temperature, and corrected temperature. As shown in Fig. 9(b), the temperature dependence coefficient of the phase-matching wavelength can be calculated from the wavelength difference Δλ and the temperature difference ΔT. Therefore, the temperature dependence coefficient included in the initial data shown in Fig. 13 can be updated, and steps S102 to S106 can be performed using the new temperature dependence coefficient upon return.

[0051] In S108, the light source 201 is set to the operating wavelength, and the input PTF 202-1 is re-aligned using the electrical signal from the detector 206 so that the level of the SHG light 213 is maximized. The alignment to maximize the SHG light level is performed by the aligners 203 and 204, and can be performed under the control of the processor using an appropriate control algorithm. Although alignment to maximize the level of the transmitted light 212 of the fundamental wave light is performed in S101, the reason for performing re-alignment in S108 is as follows.

[0052] First, the alignment position at which the fundamental light output is maximized may differ from the alignment position at which the SHG output is maximized. The guided mode shape of the fundamental light and the guided mode shape of the SHG light may not match depending on the core size. Second, after the temperature is set to the corrected temperature in S106, if the temperature reaches S108 after repeating S102 to S105, the chip set temperature will have changed from the initial temperature. This may cause a slight change in the shape of the wavelength conversion element, which may deviate from the optimal position aligned with the fundamental light. For the above reasons, in addition to alignment to maximize the level of the transmitted light 212 of the fundamental light in S101, the input PTF 202-1 is realigned in S108 to maximize the SHG output.

[0053] Next, in S109, it is determined whether the SHG light level meets a reference value. The reference value is a second threshold value, which is a predetermined SHG light level. If the SHG light level is equal to or greater than the second threshold value (Y), the process proceeds to the next step, S111. If the SHG light level is less than the second threshold value (N), there is a high possibility that there is some kind of defect in the wavelength conversion element itself or in the module assembly process, so further processing is stopped.

[0054] In S111, the metal housing, lens 205-1, and input PTF 202-1 are fixed together by welding using a YAG laser 209 or other methods. The "corrected temperature" is calculated and updated by the above-described steps S102 to S107, or by repeating these steps. After the wavelength conversion element is fixed to the module, the phase-matched state of the wavelength conversion element is achieved at the operating wavelength. However, the YAG welding in S111 may change the charged state of the PPLN element or cause drift during alignment. Furthermore, the YAG welding and fixing of the input PTF 202-1 may cause the optical axis to shift, resulting in a decrease in the optical coupling rate.

[0055] Therefore, in S112, the fundamental wave light is swept, and the peak wavelength λ of the SHG light is P and calculates the corrected temperature. Furthermore, in S113, the wavelength difference Δλ is judged using a reference value (first threshold value), and if necessary, the current temperature is changed to the "corrected temperature," and the process returns to sweeping the fundamental light in S112. As explained in S107, the temperature dependency coefficient can also be updated. The steps of S112 and S113 are a simplified version of the series of steps from S102 to S107, and essentially the same steps as S102 to S107 can be performed.

[0056] If it is determined in S112 that the wavelength difference Δλ is equal to or less than the first threshold value, the procedure of the manufacturing method proceeds to S113, where the transmission spectrum of the fundamental light and the phase matching curve are obtained.

[0057] Next, in S114, the initial data read by the computer 208 is updated with the values ​​that have been changed up to the step S113 described above. Specifically, the initial temperature value is rewritten with the final value of the corrected temperature, as shown in FIG. 13(b). Also, the temperature dependence coefficient value is rewritten with the final value of the corrected temperature dependence coefficient. After the initial data is updated, the procedure for the method for manufacturing the wavelength conversion module in FIG. 8 ends in S116.

[0058] Therefore, the present invention can be implemented as a manufacturing method for an optical module 100 including a wavelength conversion element 102 and a temperature control element 103 fixed to the wavelength conversion element via a metal plate 104, the manufacturing method including the steps of: setting the wavelength conversion element to an initial temperature; aligning an input fiber so that the transmitted light of fundamental wave light is maximized; correcting the current temperature of the wavelength conversion element, which includes sweeping the wavelength of the fundamental wave light in a predetermined wavelength range to determine a peak wavelength at which the level of wavelength-converted light is maximized; calculating the corrected temperature of the wavelength conversion element based on the operating wavelength of the wavelength conversion element, the peak wavelength, the current temperature and the temperature dependence coefficient of the phase-matching wavelength; and resetting the wavelength conversion element to the corrected temperature; re-aligning the input fiber so that the level of the wavelength-converted light is maximized at the corrected temperature; and fixing the adjusted input fiber to a metal housing of the optical module in step S111.

[0059] The updated data can be used as the initial data for the process of connecting the second and subsequent PTFs to the same wavelength conversion element. That is, in the connection process of (b) to (d) of Figure 6, by using the "updated data" that reflects the result of the connection process of the first PTF, the operating wavelength λ init Optimization of the chip operating temperature can be started from a state very close to . The process of connecting the second and subsequent PTFs can be performed in a significantly shorter time than the process of connecting the first PTF shown in Figure 8.

[0060] FIG. 10 is a diagram showing another configuration of an apparatus for implementing the wavelength conversion module manufacturing method of the present disclosure. The apparatus configuration of FIG. 10 shows the stage where the second input PTF 202-2 shown in FIG. 6(b) is connected to the optical window 105-2 (port 3), with the input PTF 202-1 already connected to the optical window 105-1 (port 1). A connector-type fundamental light detector 210 and an SHG light detector 206 connected to the input PTF 202-1 are used. The manufacturing method flow for connecting the second input PTF using the manufacturing apparatus configuration of FIG. 10 is generally the same as that of FIG. 8. The differences are that the initial data read in S101 is not the initial data according to Table 1 of FIG. 13(a) but the updated data according to Table 2 of FIG. 13(b), and that the propagation directions of the fundamental light and SHG light are opposite to those of FIG. 7. Therefore, a description of the wavelength conversion module manufacturing method for connecting the second input PTF will be omitted.

[0061] Fig. 11 is a diagram showing yet another configuration of an apparatus for implementing the manufacturing method of a wavelength conversion module of the present disclosure. The apparatus configuration of Fig. 11 shows the stage of connecting the output PTF 202-2, which is the third fiber shown in Fig. 6(c), to the optical window 101-1 (port 4), and two input PTFs 202-1 and 202-2 have already been connected. A connector-type SHG light detector 212 is used on the opposite side of the connection point of the output PTF 211-1. The flow of the manufacturing method for connecting the output PTF using the manufacturing apparatus configuration of Fig. 11 is generally the same as Fig. 8, except that the fiber to be aligned is the output PTF.

[0062] Fig. 12 is a flow diagram illustrating the steps of the method for manufacturing a wavelength conversion module according to the present disclosure. The flow diagram shown in Fig. 12 corresponds to the flow for connecting the first output PTF 211-1, which is the third fiber shown in Fig. 6(c) and is used to output SHG light. The description will also refer to the configuration of the apparatus in Fig. 11. Each step of the flow will be explained using step numbers S200 to S216. The description of each step in Fig. 12 is simplified. As mentioned above, the steps in the flow diagram in Fig. 12 are generally the same as those in the flow diagram in Fig. 8, and therefore will be explained in a simplified manner.

[0063] In S200, the wavelength conversion module, the output PTF 211-1 to be connected, the aligners 203 and 204, etc. are set in the adjustment jig of the manufacturing equipment.

[0064] In S201, initial data is read into the computer 208, and the fundamental wave light from the light source 201 is set to an operating wavelength. init However, this initial temperature T init is the initial temperature updated in the splicing process of the first fiber. As in the flow of Figure 8, the initial temperature T init becomes the "current temperature." The "current temperature" is updated each time the "step of correcting the current temperature" is repeated, as will be described later.

[0065] Furthermore, in S201, the output PTF 211-1 is aligned so that the level of the SHG light detected by the detector 212 is maximized. The alignment to maximize the SHG light level is performed by aligners 203 and 204, and can be performed under the control of a processor using an appropriate control algorithm. The SHG light from the wavelength conversion element in the module housing is optically coupled to the end face of the output PTF 202-1 via a lens. Even in this flow of connecting the output PTF in Figure 12, at the current temperature, the phase matching curve is shifted as shown in Figure 3, but the input PTFs 202-1 and 202-2 for the fundamental wave light have already been aligned and fixed. Furthermore, the wavelength conversion element is adjusted to the initial temperature T init Therefore, in S201, SHG light sufficient for alignment can be obtained.

[0066] Next, in S202, the light source 201 is controlled to sweep the wavelength of the input light within a predetermined wavelength range centered on the fundamental wave light. At this time, the SHG light detector 212 acquires data on the wavelength-dependent characteristics 21 of the SHG light level corresponding to the swept wavelength range as shown in FIG.

[0067] Next, in S203, the peak wavelength λ P Determine the peak wavelength λ P corresponds to the actual phase-matching wavelength at the current temperature of the wavelength conversion element included in the module. This actual phase-matching wavelength is the operating wavelength λ at which the element is originally intended to operate. init The peak wavelength λ P and operating wavelength λ init In this step, the light source 201 performs a wave sweep multiple times to obtain the average value of the phase matching curve, and the peak wavelength λ at which the SHG light output is maximized is calculated. P Get.

[0068] In the state of S203, the peak wavelength λ P and operating wavelength λ init Since there is a wavelength difference Δλ between the wavelengths, the level of the SHG light is insufficient for accurate alignment. Therefore, the current temperature of the wavelength conversion element is corrected to find a "corrected temperature" that reduces the wavelength difference Δλ.

[0069] In S204, the "corrected temperature" is calculated from the wavelength difference Δλ. init , the peak wavelength λ P A corrected temperature of the wavelength conversion element is calculated based on the current temperature and the temperature-dependent coefficient of the phase-matching wavelength included in the initial data.

[0070] By using the updated initial data temperature dependence coefficient (nm / °C) shown in Figure 13(b), the operating wavelength λ init , peak wavelength λ P Based on the current temperature and the temperature-dependent coefficient of the phase-matching wavelength, a "corrected temperature" can be determined.

[0071] Next, in S205, the wavelength difference Δλ is compared with a first threshold value, which is a reference value. Since the direction of wavelength shift from the initial temperature when the chip is fixed may differ depending on the type of wavelength conversion element, the absolute value of the wavelength difference Δλ can be compared with the first threshold value, which is a positive value. Here, under the condition that the wavelength difference Δλ is equal to or less than the first threshold value (Y), the actual phase-matched wavelength is equal to or less than the operating wavelength λ. init Since the wavelength difference Δλ is sufficiently close to the operating wavelength λ , the process proceeds to the realignment step of the output PTF in S208. init Since the wavelength conversion element is still far from the target temperature, in S206 the wavelength conversion element is set to a temperature corrected from the current temperature. After waiting for a certain temperature stabilization time, the manufacturing method returns to the step of sweeping the wavelength of the fundamental wave light in S202. When returning to S202, the "corrected temperature" becomes the "current temperature."

[0072] The entire process from S202 to S206 described above can be said to be a process of correcting the current temperature of the wavelength conversion element. The comparison and determination process with the reference value in S205 can be performed before S204, which calculates the corrected temperature. In addition, in parallel with obtaining the "corrected temperature," the temperature dependency coefficient can also be updated in S207.

[0073] In S207, the temperature-dependent coefficients are updated based on the operating wavelength, peak wavelength, current temperature, and corrected temperature. The temperature-dependent coefficients included in the updated initial data shown in Fig. 13(b) are updated, and steps S202 to S206 can be performed using the new temperature-dependent coefficients upon returning.

[0074] In S208, the light source 201 is set to the operating wavelength, and the output PTF 211-1 is realigned using an electrical signal from the detector 212 to maximize the SHG light level. The alignment to maximize the SHG light level is performed by aligners 203 and 204, and can be controlled by a processor using an appropriate control algorithm. In addition to the alignment to maximize the SHG light level in S201, the output PTF is realigned in S208, similar to the flow for connecting the input PTF in FIG. 8. After the temperature is set to the corrected temperature in S206, when S208 is reached through the repeated steps S202 to S205, the chip set temperature has changed from the initial temperature. This is because the shape of the wavelength conversion element may change slightly, potentially causing the output PTF to deviate from the optimal position initially aligned in S201.

[0075] Next, in S209, it is determined whether the SHG light level meets a reference value. The reference value is a second threshold value, which is a predetermined SHG light level. If the SHG light level is equal to or greater than the second threshold value (Y), the process proceeds to the next step, S211. If the SHG light level is less than the second threshold value (N), there is a high possibility that there is some kind of defect in the wavelength conversion element itself or in the module assembly process, so further processing is stopped.

[0076] In S211, the fixing of the metal housing, lens, and output PTF 211-1 is completed by welding with a YAG laser 209 or the like. The "corrected temperature" is calculated by the above-mentioned steps S202 to S207, or by repeating these steps, and the current temperature is updated with the corrected temperature. By using the "corrected temperature", it is possible to determine the target operating wavelength λ even after the module is fixed. init However, the YAG welding process in S211 can change the charged (pyroelectric) state of the PPLN element and cause wavelength drift during alignment. Furthermore, the YAG welding and the process of fixing the output PTF 211-1 can shift the optical axis, reducing the optical coupling rate.

[0077] Therefore, in S212, the fundamental wave light is swept, and the peak wavelength λ of the SHG light is P and calculates the corrected temperature. Furthermore, in S213, the wavelength difference Δλ is compared with a reference value (first threshold value), and if necessary, the current temperature is changed to the "corrected temperature," and the process returns to sweeping the fundamental light in S212. As explained in S207, the temperature dependency coefficient can also be updated in S213. The steps of S212 and S213 are a simplified version of the series of steps from S202 to S207, and essentially the same steps as S202 to S207 can be performed.

[0078] If it is determined in S213 that the wavelength difference Δλ is equal to or less than the first threshold value, the procedure of the manufacturing method proceeds to S214, where the transmission spectrum of the fundamental light and the phase matching curve are obtained.

[0079] Next, in S215, the initial data read by the computer 208 is updated with the values ​​that have been changed up to the step S213 described above. Specifically, the value of the initial temperature is rewritten with the final value of the corrected temperature, as shown in (b) of Fig. 13. After the initial data is updated, the procedure for the method for manufacturing the wavelength conversion module in Fig. 12 ends in S216.

[0080] Therefore, the present invention provides a method for manufacturing an optical module 100 including a wavelength conversion element 102 and a temperature control element 103 fixed to the wavelength conversion element via a metal plate 104, and connected to a fundamental wave input fiber 211-1, the method comprising the steps of: setting the wavelength conversion element to an initial temperature; aligning an output fiber so that the transmitted light of the fundamental wave light is maximized; and correcting the current temperature of the wavelength conversion element by sweeping the wavelength of the fundamental wave light in a predetermined wavelength range and determining a peak wavelength at which the level of the wavelength-converted light is maximized. The manufacturing method can also be implemented as a correction step including a step S204 of calculating a corrected temperature of the wavelength conversion element based on the operating wavelength of the wavelength conversion element, the peak wavelength, the current temperature, and the temperature dependence coefficient of the phase matching wavelength, and a step S206 of resetting the wavelength conversion element to the corrected temperature, a step S208 of re-aligning the output fiber so that the level of the wavelength-converted light is maximized at the corrected temperature, and a step S211 of fixing the aligned output fiber to a metal housing of the optical module.

[0081] As described above in detail, the "corrected temperature" can be determined efficiently when an output PTF is attached to a wavelength conversion module, just as when an input PTF is attached to a wavelength conversion module. Once the module, fiber, and alignment member are set in the manufacturing equipment, all processes can be automated under computer control. This provides a method for manufacturing pigtail-type modules that is suitable for mass production, with all processes for attaching the fiber to the module.

[0082] As already mentioned, Figure 13 is a diagram explaining the data configuration of a wavelength conversion element. Table 1 in Figure 13(a) is the initial data acquired in the chip selection process. Figure 13(b) is the updated initial data after the connection procedure for the first PTF has been performed. In the procedure for connecting four PTFs to the wavelength conversion module described in Figure 6, the updated initial data is used in the connection procedures for the second and subsequent PTFs.

[0083] The initial data can be updated each time a PTF is connected, or the same updated initial data can be used for the second to fourth PTFs. When the first PTF is connected, the "corrected temperature" is roughly close to the temperature that achieves phase matching at the target operating wavelength. When the third and fourth PTFs are connected, the initial data used for the second PTF can be used as is.

[0084] The optical module manufacturing method of the present invention described above is not limited to wavelength conversion modules that output SHG light, but can also be used when connecting a PTF to an input light port and an output port for wavelength-converted light. It can also be applied to wavelength conversion modules that use a wavelength conversion element in only one direction. It goes without saying that it can also be applied when connecting a PTF to an OPA module that uses a DFG or OPA mechanism other than a wavelength conversion module.

[0085] As explained above in detail, a method for manufacturing a pigtail type module that is suitable for mass production can be realized. [Industrial Applicability]

[0086] The present invention can be used in the manufacture of devices for optical signal processing.

Claims

1. A method for manufacturing an optical module including a wavelength conversion element and a temperature control element fixed to the wavelength conversion element via a metal plate, comprising: setting the wavelength conversion element to an initial temperature; aligning the input fiber so that the transmitted light of the fundamental wave light is maximized; Modifying the current temperature of the wavelength converting element, a step of sweeping the wavelength of the fundamental wave light within a predetermined wavelength range to determine a peak wavelength at which the level of the wavelength-converted light is maximized; Calculating a corrected temperature of the wavelength conversion element based on the operating wavelength of the wavelength conversion element, the peak wavelength, the current temperature and a temperature-dependent coefficient of a phase-matching wavelength; and resetting the wavelength converting element to the modified temperature. a modifying step, realigning the input fiber so that the level of the wavelength-converted light is maximized at the modified temperature; fixing the aligned input fiber to a metal housing of the optical module; A manufacturing method comprising:

2. Before the realigning step, determining whether an absolute value of a wavelength difference Δλ between the peak wavelength and the operating wavelength is less than or equal to a first threshold; repeating the correcting step under the condition that the wavelength difference Δλ exceeds the first threshold value; Furthermore, 2. The manufacturing method according to claim 1, further comprising the step of realigning the input fiber so that the level of the wavelength-converted light is maximized under the condition that the wavelength difference Δλ is equal to or less than the first threshold value.

3. A method for manufacturing an optical module including a wavelength conversion element and a temperature control element fixed to the wavelength conversion element via a metal plate, and connected to a fundamental wave input fiber, comprising: setting the wavelength conversion element to an initial temperature; aligning the output fiber so that the wavelength-converted light is maximized; Modifying the current temperature of the wavelength converting element, a step of sweeping the wavelength of the fundamental wave light within a predetermined wavelength range and determining a peak wavelength at which the level of the wavelength-converted light is maximized; Calculating a corrected temperature of the wavelength conversion element based on the operating wavelength of the wavelength conversion element, the peak wavelength, the current temperature and a temperature-dependent coefficient of a phase-matching wavelength; and resetting the wavelength converting element to the modified temperature. a modifying step, realigning the output fiber so that the level of the wavelength-converted light is maximized at the modified temperature; fixing the aligned output fiber to a metal housing of the optical module; A manufacturing method comprising:

4. Before the realigning step, determining whether an absolute value of a wavelength difference Δλ between the peak wavelength and the operating wavelength is less than or equal to a first threshold; repeating the correcting step under the condition that the wavelength difference Δλ exceeds the first threshold value; Furthermore, 4. The manufacturing method according to claim 3, further comprising the step of realigning the output fiber so that the level of the wavelength-converted light is maximized under the condition that the wavelength difference Δλ is equal to or less than the first threshold value.

5. After the realigning step, determining whether the level of the wavelength-converted light is greater than or equal to a second threshold; 4. The manufacturing method according to claim 1, further comprising the step of fixing the optical module to a metal housing under the condition that the level of the wavelength-converted light is equal to or greater than the second threshold value.

6. The modifying step includes: updating the temperature dependent coefficient based on the operating wavelength, the peak wavelength, the current temperature, and the corrected temperature. The method of claim 2 or 4, further comprising:

7. 4. The manufacturing method according to claim 1 or 3, wherein the initial temperature is either a previously obtained initial temperature corresponding to the operating wavelength of the wavelength conversion element or the corrected temperature obtained when connecting an input fiber to the optical module.

8. An apparatus for manufacturing an optical module including a wavelength conversion element and a temperature control element fixed to the wavelength conversion element via a metal plate, a light source that supplies fundamental wave light to the optical module; a first detector that detects wavelength-converted light from the optical module; a second detector that detects a fundamental wave transmitted light from the optical module; an aligner for the target fiber; a computer including at least a processor and a memory; Equipped with The processor: controlling data conversion of the electrical signals from the light source, the first detector, and the second detector, and the aligner; Reading element data including at least the operating wavelength, the initial temperature, and the temperature-dependent coefficient of the wavelength conversion element from the memory, the external storage device, or the network; and configured to update the initial temperature with the corrected temperature; A manufacturing apparatus for carrying out the method according to any one of claims 1 to 4.

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