Optical module

Abstract

To provide an optical module with an improved and novel structure that enables a reduced power load on a plurality of temperature regulators.SOLUTION: An optical module exemplarily comprises an optical component, a first heating element, a first temperature regulator for regulating temperature of the first heating element, a second heating element, a second temperature regulator having higher heat absorption capacity than that of the first temperature regulator and regulating temperature of the second heating element, and a controller for controlling operation of the first temperature regulator and the second temperature regulator. The first temperature regulator is thermally connected to the second heating element, and the second temperature regulator is thermally connected to the first heating element. The controller controls the first temperature regulator and the second temperature regulator in a manner that the second temperature regulator starts operating before the first temperature regulator when the first temperature regulator and the second temperature regulator are shifted from non-operation states to operation states so as to regulate the temperature of the first heating element.SELECTED DRAWING: Figure 1

Description

【Technical Field】 【0001】 The present invention relates to an optical module. 【Background Art】 【0002】 Conventionally, an optical module including a plurality of heating elements and a plurality of temperature control devices for adjusting the temperature of each heating element has been known (for example, Patent Document 1). The heating elements are active optical components such as laser elements and photodiodes. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2019-140306 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 In this type of optical module, when a plurality of temperature control devices that are feedback-controlled according to the detected temperature by a control unit operate simultaneously and in parallel, at least one of the plurality of temperature control devices temporarily enters an excessive heat absorption operating state, and accordingly, there is a risk that the power load supplied from the control unit temporarily increases. In particular, when there is a difference in the heat absorption capacity of a plurality of temperature control devices, the temperature control device with a lower heat absorption capacity may be in a more severe state. 【0005】 Therefore, one of the problems of the present invention is to obtain an optical module having an improved and novel configuration that can, for example, reduce the power load on a plurality of temperature control devices. 【Means for Solving the Problems】 【0006】 The optical module of the present invention comprises, for example, an optical component, a first heating element, a first temperature control device for adjusting the temperature of the first heating element, a second heating element, a second temperature control device for adjusting the temperature of the second heating element and having a higher heat absorption capacity than the first temperature control device, and a control unit for controlling the operation of the first temperature control device and the second temperature control device. The first temperature control device is thermally connected to the second heating element, and the second temperature control device is thermally connected to the first heating element. When the control unit controls the first temperature control device and the second temperature control device from a non-operating state to an operating state to adjust the temperature of the first heating element, it controls the first temperature control device and the second temperature control device so that the second temperature control device starts operating before the first temperature control device. 【0007】 In the optical module, when the control unit controls the first and second temperature control devices from a non-operating state to an operating state in order to adjust the temperature of the second heating element, it may control the first and second temperature control devices so that the second temperature control device starts operating before the first temperature control device. 【0008】 In the optical module, the time difference between the start of operation of the second temperature control device and the start of operation of the first temperature control device may be set to be longer as the distance between the first temperature control device and the second temperature control device decreases. 【0009】 In the optical module, the time difference may be inversely proportional to the square of the distance. 【0010】 In the optical module, the first temperature control device and the second temperature control device are thermoelectric cooling devices that operate using supplied power, and the control unit may set the rate at which it increases the power supplied to the second temperature control device when controlling the first temperature control device and the second temperature control device from a non-operating state to an operating state to be lower than the rate at which it increases the power supplied to the second temperature control device when the first temperature control device and the second temperature control device are operating. 【0011】 In the optical module, the first heating element is placed on the first end face in the first direction of the first temperature control device, and the second heating element is placed on the second end face in the first direction of the second temperature control device. The first and second temperature control devices extend in a second direction intersecting the first direction, and the first and second temperature control devices are spaced apart in a third direction intersecting the first and second directions. The first and second heating elements may be offset in the second direction. 【0012】 In the optical module, the first and second temperature control devices are formed with respect to the first heating element and a first region aligned in the third direction, the second heating element and a second region aligned in the third direction, and a third region located between the first and second regions and not aligned with either the first or second heating element in the third direction. The first distance in the third direction between the first and second temperature control devices in the first region, and the second distance in the third direction between the first and second temperature control devices in the second region, may be longer than the third distance in the third direction between the first and second temperature control devices in the third region. 【0013】 In the optical module, a recess or notch may be provided in the portion of the first edge of the first temperature control device facing the second temperature control device that faces the second heating element, and a recess or notch may be provided in the portion of the second edge of the second temperature control device facing the first temperature control device that faces the first heating element. 【0014】 In the optical module, the first heating element and the second heating element may be active optical components. [Effects of the Invention] 【0015】 According to the present invention, for example, an optical module with an improved and novel configuration can be obtained. [Brief explanation of the drawing] 【0016】 [Figure 1] Figure 1 is an illustrative and schematic plan view showing the configuration of the optical module of the first embodiment. [Figure 2] Figure 2 is a graph showing an exemplary and schematic change over time of the control current supplied from the control unit to one temperature control device in the optical module of the first embodiment, and shows the case when the two temperature control devices start operating simultaneously (dotted line), when one temperature control device starts operating a predetermined time after the other temperature control device starts operating (dashed line), and when one temperature control device starts operating a longer time after the other temperature control device starts operating than in the dashed line case (solid line). [Figure 3] Figure 3 is a graph showing an exemplary and schematic change over time of the control current supplied from the control unit to one temperature control device when two temperature control devices controlled by the control unit start operating simultaneously in the optical module of the first embodiment. The graph shows the case when the two temperature control devices are separated by a predetermined distance (dotted line), when the two temperature control devices are separated by a longer distance than the case of the dotted line (dashed line), and when the two temperature control devices are separated by a longer distance than the case of the dashed line (solid line). [Figure 4] Figure 4 is an exemplary control block diagram showing how the control current is determined from the temperature detection value in the control unit of the optical module of the first embodiment. [Figure 5] Figure 5 is a graph showing an exemplary and schematic change over time of the control current supplied from the control unit to a temperature control device in the optical module of the first embodiment, with graphs showing the case where the proportionality coefficient is high (dashed line) and the case where the proportionality coefficient is low (solid line). [Figure 6] Figure 6 is an illustrative and schematic plan view showing the configuration of the optical module of the second embodiment. [Figure 7] Figure 7 is an illustrative and schematic plan view showing the configuration of the optical module of the third embodiment. [Figure 8] Figure 8 is an illustrative and schematic plan view showing the configuration of the optical module of the fourth embodiment. [Modes for carrying out the invention] 【0017】 Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments shown below, as well as the actions and results (effects) brought about by such configurations, are examples. The present invention can also be realized by configurations other than those disclosed in the following embodiments. Further, according to the present invention, it is possible to obtain at least one of various effects (including derivative effects) obtained by the configuration. 【0018】 The plurality of embodiments shown below have similar configurations. Therefore, according to the configurations of each embodiment, similar actions and effects based on such similar configurations can be obtained. Further, in the following, the same reference numerals are given to those similar configurations, and duplicate explanations may be omitted. 【0019】 In this specification, ordinal numbers are given for convenience in distinguishing devices, parts, portions, directions, etc., and do not indicate priority or order, nor limit the number, etc. 【0020】 Also, in each figure, the X direction is represented by arrow X, the Y direction is represented by arrow Y, and the Z direction is represented by arrow Z. The X direction, Y direction, and Z direction intersect each other and are orthogonal to each other. 【0021】 [First Embodiment] FIG. 1 is a plan view of an optical module 100A (100) according to the first embodiment. As shown in FIG. 1, the optical module 100A (100) includes a first temperature control device 11 (11), a second temperature control device 12 (12), a first heating element 21, a second heating element 22, a control unit 30, and a sensor 40. 【0022】 The first temperature control device 11 and the second temperature control device 12 are, for example, known thermoelectric coolers (TECs). The thermoelectric cooler has a plurality of Peltier elements (not shown), and absorbs heat from the target object, the first heating element 21 or the second heating element 22, through the Peltier effect, in which the Peltier elements absorb heat in accordance with the supplied power. In each of the first temperature control device 11 and the second temperature control device 12, the plurality of Peltier elements are connected in series. The control unit 30 controls the first temperature control device 11 and the second temperature control device 12 to absorb heat by supplying power to each of them. When the control unit 30 starts supplying power, the first temperature control device 11 and the second temperature control device 12 start heat absorption operation, and when the control unit 30 stops supplying power, the first temperature control device 11 and the second temperature control device 12 stop heat absorption operation. In the following, the current supplied from the control unit 30 to the first temperature control device 11 will be referred to as control current I1, and the current supplied from the control unit 30 to the second temperature control device 12 will be referred to as control current I2. 【0023】 The first temperature control device 11 extends in the X direction with a substantially constant height in the Z direction and a substantially constant width in the Y direction. The Z-direction end face 11b of the first temperature control device 11 faces the Z direction and spreads out intersecting with the Z direction. The end face 11b may also be called the top surface or mounting surface. The Z direction is an example of a first direction, the X direction is an example of a second direction, and the Y direction is an example of a third direction. Furthermore, the end face 11b is an example of a first end face. 【0024】 The second temperature control device 12 extends in the X direction with a substantially constant height in the Z direction and a substantially constant width in the Y direction. The Z-direction end face 12b of the second temperature control device 12 faces the Z direction and spreads out intersecting the Z direction. The end face 12b may also be called the top surface or mounting surface. The end face 12b is an example of a second end face. 【0025】 Furthermore, in this embodiment, the edge 11a of the first temperature control device 11 in the opposite direction to the Y direction and the edge 12a of the second temperature control device 12 in the Y direction extend parallel to each other in the X direction. That is, the distance between edge 11a and edge 12a in the Y direction is approximately constant regardless of the position in the X direction. Edges 11a and 12a are the edges of the mounting substrate, respectively. Edge 11a is an example of a first edge, and edge 12a is an example of a second edge. 【0026】 The first heating element 21 is placed on the end face 11b, and the second heating element 22 is placed on the end face 12b. In this embodiment, the first heating element 21 is placed in the center of the end face 11b in the X direction, and the second heating element 22 is placed in the center of the end face 12b in the X direction. Therefore, in this embodiment, the first heating element 21 and the second heating element 22 are aligned in the Y direction. 【0027】 The first heating element 21 and the second heating element 22 are active optical components, such as a chip-on-submount in which a laser light-emitting element is mounted on a submount, a photodiode, or a photodiode array. The optical module 100 may also include optical components other than the first heating element 21 and the second heating element 22. In that case, the first heating element 21 and the second heating element 22 may be components other than optical components, such as electronic components. 【0028】 In this configuration, the temperature of the first heating element 21 is controlled by the first temperature control device 11, and the temperature of the second heating element 22 is controlled by the second temperature control device 12. That is, the first heating element 21 is thermally connected to the first temperature control device 11, and the second heating element 22 is thermally connected to the second temperature control device 12. However, in this embodiment, the first heating element 21 is also thermally connected to the second temperature control device 12, and the second heating element 22 is also thermally connected to the first temperature control device 11. 【0029】 Furthermore, in this embodiment, the heat absorption capacity of the second temperature control device 12 is set to be higher than that of the first temperature control device 11. Here, a higher heat absorption capacity means a larger maximum heat absorption amount per unit time. 【0030】 Sensor 40 is a temperature sensor such as a semiconductor temperature sensor or a thermocouple. Sensor 40 is provided on both the first heating element 21 and the second heating element 22. Note that sensor 40 only needs to be thermally connected to the first heating element 21 and the second heating element 22, and does not need to be directly provided on the first heating element 21 and the second heating element 22 as in the example in Figure 1. 【0031】 The control unit 30 includes, for example, a computer having a CPU, a main memory unit, an auxiliary memory unit, etc., and a drive circuit that supplies power according to the operation of the computer. In this case, the CPU operates according to the installed program, and the CPU controls the drive circuit, which changes the power supplied to the first temperature control device 11 and the second temperature control device 12, thereby adjusting the temperatures of the first heating element 21 and the second heating element 22. 【0032】 The control unit 30 provides feedback control to the first temperature control device 11 so that the first heating element 21 reaches a predetermined temperature, based on the detection value of the sensor 40 that detects the temperature of the first heating element 21. The control unit 30 provides feedback control to the second temperature control device 12 so that the second heating element 22 reaches a predetermined temperature, based on the detection value of the sensor 40 that detects the temperature of the second heating element 22. 【0033】 Figure 2 is a graph showing the change over time of the control current I1 supplied from the control unit 30 to the first temperature control unit 11. When both the first temperature control unit 11 and the second temperature control unit 12 start operating simultaneously while both are in a non-operating state, it was found that the control current I1 overshoots significantly from the target value It, as shown by the dashed line in Figure 2, and in some cases may exceed the upper limit Ith. This is thought to be due to the fact that the first temperature control unit 11 and the second temperature control unit 12 are located close together and are thermally connected to each other. 【0034】 The inventors then investigated and found that, as shown by the dashed line in Figure 2, delaying the operation of the first temperature control device 11 from the start of operation of the second temperature control device 12 (t=0) (the time difference being TD1) could reduce the overshoot of the control current I1. Furthermore, as shown by the solid line in Figure 2, they found that delaying the operation of the first temperature control device 11 from the start of operation of the second temperature control device 12 (t=0) even further (the time difference being TD2, which is longer than TD1) could further reduce the overshoot of the control current I1. 【0035】 Figure 3 is a graph showing the change over time of the control current I1 supplied from the control unit 30 to the first temperature control device 11 when both the first temperature control device 11 and the second temperature control device 12 start operating simultaneously. The dashed line indicates the case where the distance in the Y direction between the first temperature control device 11 and the second temperature control device 12 is relatively close, the broken line indicates the case where the distance in the Y direction between the first temperature control device 11 and the second temperature control device 12 is longer than that of the dashed line, and the solid line indicates the case where the distance in the Y direction between the first temperature control device 11 and the second temperature control device 12 is longer than that of the broken line. Thus, the inventors' investigation revealed that the overshoot increases as the first temperature control device 11 and the second temperature control device 12 are closer together, or in other words, decreases as the distance between the first temperature control device 11 and the second temperature control device 12 is greater. 【0036】 Further research by the inventors revealed that by setting the time difference TD1 and TD2 between the start of operation of the second temperature control device 12 and the start of operation of the first temperature control device 11 to be longer as the distance between the first temperature control device 11 and the second temperature control device 12 decreases, it is possible to quickly adjust the temperature while suppressing overshoot within a predetermined range. Furthermore, it was found that by setting this time difference to be inversely proportional to the square of the distance, an optimal time difference that can suppress overshoot within a predetermined range can be obtained depending on the distance between the first temperature control device 11 and the second temperature control device 12. 【0037】 In this embodiment, where the first temperature control device 11 and the second temperature control device 12 are located relatively close to each other, the first temperature control device 11 and the second heating element 22 are thermally connected, and the second temperature control device 12 and the first heating element 21 are thermally connected, the second temperature control device 12 can be used in addition to the first temperature control device 11 to adjust the temperature of the first heating element 21, and the first temperature control device 11 can be used in addition to the second temperature control device 12 to adjust the temperature of the second heating element 22. Therefore, temperature adjustment can be performed more quickly compared to when only the first temperature control device 11 is used to adjust the temperature of the first heating element 21, and when only the second temperature control device 12 is used to adjust the temperature of the second heating element 22. 【0038】 In this embodiment, when the control unit 30 controls the first temperature control device 11 and the second temperature control device 12 from a non-operating state to an operating state in order to adjust the temperature of the first heating element 21, it controls the first temperature control device 11 and the second temperature control device 12 so that the second temperature control device 12, which has a higher heat absorption capacity than the first temperature control device 11, starts operating before the first temperature control device 11. This makes it possible to adjust the temperature of the first heating element 21 more quickly while suppressing overshoot of the control currents I1 and I2. 【0039】 Furthermore, in this embodiment, even when the control unit 30 controls the first temperature control device 11 and the second temperature control device 12 from a non-operating state to an operating state in order to adjust the temperature of the second heating element 22, it is preferable to control the first temperature control device 11 and the second temperature control device 12 so that the second temperature control device 12 starts operating before the first temperature control device 11. In this case as well, it is possible to adjust the temperature of the first heating element 21 more quickly while suppressing overshoot of the control currents I1 and I2. 【0040】 Figure 4 is a control block diagram showing the logic by which the control unit 30 determines the control current I2 from the temperature detected by the sensor 40 T(t). In the example in Figure 4, the control unit 30 performs feedback control using PID control, which combines proportional control (P), integral control (I), and differential control (D). 【0041】 Figure 5 is a graph showing the change in the control current I2 over time when the proportionality constant Kp (coefficient) of the proportional control (P) in the PID is changed. In Figure 5, the dashed line shows the case when the proportionality constant Kp is large, and the solid line shows the case when the proportionality constant Kp is small. As is clear from Figure 5, by decreasing the proportionality constant Kp, the rate of increase of the control current I2, that is, the rate of increase of the power supplied to the second temperature control device 12, can be reduced. In addition, the overshoot O2 of the control current I2 when the proportionality constant Kp is small is smaller than the overshoot O1 of the control current I2 when the proportionality constant Kp is large. 【0042】 For example, when the control unit 30 changes the first temperature control device 11 and the second temperature control device 12 from a non-operating state to an operating state, as shown by the solid line in Figure 5, it can further suppress the overshoot of the control currents I1 and I2 by setting the proportionality constant Kp to a relatively small value. On the other hand, when the control unit 30 increases the power supplied to the second temperature control device 12 while the first temperature control device 11 and the second temperature control device 12 are operating, the increase in power is not so large, and overshoot itself is unlikely to occur. Therefore, it can adjust the temperature more quickly by setting the proportionality constant Kp to a relatively large value. 【0043】 As described above, according to this embodiment, for example, a novel and improved optical module 100A(100) can be obtained that can achieve faster temperature adjustment of the first heating element 21 and the second heating element 22 while suppressing overshoot of the control currents I1 and I2. 【0044】 [Second Embodiment] Figure 6 is a plan view of the optical module 100B(100) of the second embodiment. The optical module 100B of this embodiment also has the same configuration as the optical module 100A of the first embodiment. Furthermore, the control unit 30 performs the same control as in the first embodiment. Therefore, the same effects as in the first embodiment can be obtained with this embodiment as well. 【0045】 However, in this embodiment, as shown in Figure 6, the first heating element 21 and the second heating element 22 are not aligned in the Y direction, but are offset in the X direction. This arrangement makes it possible to suppress thermal interference between the first heating element 21 and the second heating element 22. 【0046】 Furthermore, due to the X-direction displacement of the first heating element 21 and the second heating element 22, the first temperature control device 11B(11) and the second temperature control device 12B(12) have a first region A1 aligned with the first heating element 21 in the Y direction, a second region A2 aligned with the second heating element 22 in the Y direction, and a third region A3 between the first region A1 and the second region A2. 【0047】 As is clear from Figure 6, in the first region A1 and the second region A2, the first temperature control device 11B and the second temperature control device 12B are further apart in the Y direction compared to the third region A3. In other words, the distance in the Y direction between the first temperature control device 11B and the second temperature control device 12B in the first region A1 (first distance), and the distance in the Y direction between the first temperature control device 11B and the second temperature control device 12B in the second region A2 (second distance) are longer than the distance in the Y direction between the first temperature control device 11B and the second temperature control device 12B in the third region A3 (third distance). 【0048】 As described above, when the first heating element 21 and the second temperature control device 12 are thermally connected, and the second heating element 22 and the first temperature control device 11 are thermally connected, the advantage is that the temperatures of the first heating element 21 and the second heating element 22 can be adjusted more quickly using both the first temperature control device 11 and the second temperature control device 12. However, when the first heating element 21 and the second temperature control device 12 are too close together, and when the second heating element 22 and the first temperature control device 11 are too close together, the overshoot of the control currents I1 and I2 becomes large. 【0049】 Therefore, in this embodiment, by changing the distance in the Y direction between the first temperature control device 11 and the second temperature control device 12 in the first region A1, the second region A2, and the third region A3, the first heating element 21 and the second temperature control device 12 are appropriately thermally connected, and the second heating element 22 and the first temperature control device 11 are appropriately thermally connected, thereby suppressing overshoot of the control currents I1 and I2. 【0050】 Specifically, in this embodiment, a notch 11a1 is provided in the portion of the edge 11a of the first temperature control device 11B(11) that faces the second temperature control device 12B(12), specifically in the portion that faces the second heating element 22. Similarly, a notch 12a1 is provided in the portion of the edge 12a of the second temperature control device 12B(12) that faces the first temperature control device 11B(11), specifically in the portion that faces the first heating element 21. The notches 11a1 and 12a1 are composed of edges 11a and 12a that are inclined with respect to the X direction. 【0051】 According to this embodiment, for example, a novel and improved optical module 100B(100) can be obtained that enables faster temperature adjustment of the first heating element 21 and the second heating element 22 while suppressing overshoot of the control currents I1 and I2, using a relatively simple configuration. 【0052】 [Third Embodiment] Figure 7 is a plan view of the optical module 100C(100) of the third embodiment. The optical module 100C of this embodiment also has the same configuration as the optical module 100B(100) of the second embodiment. Furthermore, the control unit 30 performs the same control as in the second embodiment, i.e., the first embodiment. Therefore, the same effects as in the second embodiment can be obtained with this embodiment as well. 【0053】 However, in this embodiment, as shown in Figure 7, a notch 11a2 is provided in the portion of the edge 11a of the first temperature control device 11C(11) that faces the second temperature control device 12C(12), specifically the portion that faces the second heating element 22. Also, a notch 12a2 is provided in the portion of the edge 12a of the second temperature control device 12C(12) that faces the first temperature control device 11C(11), specifically the portion that faces the first heating element 21. The notches 11a2 and 12a2 are formed as recesses that are indented in the Y direction or the opposite direction of the Y direction. 【0054】 This embodiment, like the second embodiment described above, provides a novel and improved optical module 100C(100) that enables faster temperature adjustment of the first heating element 21 and the second heating element 22 while suppressing overshoot of the control currents I1 and I2, using a relatively simple configuration. 【0055】 [Fourth Embodiment] Figure 8 is a plan view of the optical module 100D(100) of the fourth embodiment. The optical module 100D of this embodiment also has the same configuration as the optical module 100B(100) of the second embodiment. Furthermore, the control unit 30 performs the same control as in the second embodiment, i.e., the first embodiment. Therefore, the same effects as in the second embodiment can be obtained with this embodiment as well. 【0056】 However, in this embodiment, as shown in Figure 8, a notch 11a3 is provided in the portion of the edge 11a of the first temperature control device 11D(11) that faces the second temperature control device 12D(12), specifically in the portion that faces the second heating element 22. Similarly, a notch 12a3 is provided in the portion of the edge 12a of the second temperature control device 12D(12) that faces the first temperature control device 11D(11), specifically in the portion that faces the first heating element 21. Notches 11a3 and 12a3 are formed as rectangular recessed notches at the corners. 【0057】 This embodiment, like the second embodiment described above, provides a novel and improved optical module 100D(100) that enables faster temperature adjustment of the first heating element 21 and the second heating element 22 while suppressing overshoot of the control currents I1 and I2, using a relatively simple configuration. 【0058】 Although embodiments of the present invention have been illustrated above, these embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, each configuration, shape, and other specifications (structure, type, orientation, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate. 【0059】 For example, the shape of the notches and recesses can be varied. Furthermore, the position, shape, and size of the notches and recesses may differ between the first and second temperature control devices. [Explanation of symbols] 【0060】 11,11A~11D…First temperature controller 11a...edge (first edge) 11a1...notch 11a2... Notch (recess) 11a3...notch 11b...End face (first end face) 12,12A~12D…Second temperature controller 12a...Edge (second edge) 12a1...notch 12a2... Notch (recess) 12a3...notch 12b...End face (second end face) 21…First heating element (active optical component) 22…Second heating element (active optical component) 30…Control Unit 40...Sensor 100, 100A~100C… Optical Modules A1…first area A2…Second area A3…Third area I1, I2… Controlled currents It…Target value Ith... Upper limit O1, O2... Overshoot TD1, TD2…Time difference X…direction (second direction) Y…direction (third direction) Z…direction (first direction)

Claims

[Claim 1] Optical components, The first heating element and A first temperature control device for adjusting the temperature of the first heating element, The second heating element, A second temperature control device that adjusts the temperature of the second heating element and has a higher heat absorption capacity than the first temperature control device, A control unit that controls the operation of the first temperature control device and the second temperature control device, Equipped with, The first temperature control device is thermally connected to the second heating element, and the second temperature control device is thermally connected to the first heating element. The optical module controls the first and second temperature control devices so that the second temperature control device starts operating before the first temperature control device when the control unit controls the first and second temperature control devices from a non-operating state to an operating state in order to adjust the temperature of the first heating element. [Claim 2] The optical module according to claim 1, wherein when the control unit controls the first temperature control device and the second temperature control device from a non-operating state to an operating state in order to adjust the temperature of the second heating element, the control unit controls the first temperature control device and the second temperature control device so that the second temperature control device starts operating before the first temperature control device. [Claim 3] The optical module according to claim 1 or 2, wherein the time difference from the start of operation of the second temperature control device to the start of operation of the first temperature control device is set to become longer as the distance between the first temperature control device and the second temperature control device decreases. [Claim 4] The optical module according to claim 3, wherein the time difference is inversely proportional to the square of the distance. [Claim 5] The first temperature control device and the second temperature control device are thermoelectric cooling devices that operate using supplied power, The optical module according to claim 1 or 2, wherein the control unit controls the first and second temperature control devices from a non-operating state to an operating state, and the rate at which the power supplied to the second temperature control device increases is lower than the rate at which the power supplied to the second temperature control device increases when the first and second temperature control devices are operating. [Claim 6] The first heating element is placed on the first end face in the first direction of the first temperature control device, and the second heating element is placed on the second end face in the first direction of the second temperature control device. The first temperature control device and the second temperature control device extend in a second direction intersecting the first direction, The first temperature control device and the second temperature control device are arranged with a gap between them in a third direction that intersects the first and second directions. The optical module according to claim 1 or 2, wherein the first heating element and the second heating element are arranged offset in the second direction. [Claim 7] The first temperature control device and the second temperature control device are provided with a first region aligned with the first heating element in the third direction, a second region aligned with the second heating element in the third direction, and a third region located between the first and second regions and not aligned with either the first or second heating element in the third direction. The optical module according to claim 6, wherein the first distance in the third direction between the first temperature control device and the second temperature control device in the first region, and the second distance in the third direction between the first temperature control device and the second temperature control device in the second region, are longer than the third distance in the third direction between the first temperature control device and the second temperature control device in the third region. [Claim 8] A recess or notch is provided in the portion of the first edge of the first temperature control device facing the second temperature control device that faces the second heating element. The optical module according to claim 7, wherein a recess or notch is provided in the portion of the second edge of the second temperature control device facing the first temperature control device that faces the first heating element. [Claim 9] The optical module according to claim 1 or 2, wherein the first heating element and the second heating element are active optical components.