JPWO2005068951A1 - Photodetector, manufacturing method thereof, and optical module - Google Patents

Abstract

In a photodetector that detects an optical signal by a plurality of photodetectors for wavelength stabilization, the magnitude of current from each photodetector and the ratio thereof are within a desired range. The present invention includes a first small light receiver 110 that receives incident light, a first large light receiver 111, a first light detection unit 51 for detecting the light output of the incident light, and the incident light received. A second light detector for detecting the wavelength of the incident light, and a second light detector 52 for detecting the wavelength of the incident light, provided on the optical path of the light incident on the second light detector 52 and transmitting the incident light. The etalon 112 includes a plurality of Au wires respectively connected to the light receivers 110 and 111 of the first light detection unit 51 and the light receiver 113 of the second light detection unit 52. The plurality of Au wires are selectively connected or disconnected according to the light intensity of light incident on the first and second light detection units 51 and 52.

Description

  The present invention relates to a photodetector for measuring the wavelength and optical output of laser light emitted from, for example, a semiconductor laser or an optical fiber, a method for manufacturing the same, and an optical module.

  In optical communication using optical fibers, a high-density wavelength division multiplexing (DWDM) system has been put into practical use. In this method, signal lights emitted from a plurality of semiconductor lasers having different oscillation wavelengths are multiplexed, transmitted by being incident into one optical fiber, and demultiplexed into the respective wavelengths when receiving light at the transmission destination. It is.

  In recent years, in order to cope with the increase in the amount of information traffic, the amount of transmission information has been increased by further increasing the multiplexing density by narrowing the wavelength interval of multiplexed light. In this case, high wavelength stability is required for each semiconductor laser device in order to prevent interference between adjacent wavelength channels. In order to realize such high wavelength stability, a semiconductor laser module in which a wavelength monitor is connected to the semiconductor laser module or a wavelength monitor device is built in is used. Thus, high wavelength stability can be realized by inputting a signal from the wavelength monitor device to the external feedback circuit and controlling the wavelength with high accuracy.

  FIG. 1 shows an example of an external wavelength monitor device connected to a semiconductor laser device. As shown in FIG. 1, in a conventional external wavelength monitor, incident light from an optical fiber 401 is separated by a beam splitter 402, and one of the separated lights is a PD (photodiode). The other light enters the second light receiver 405 after passing through the wavelength filter 403.

  In general, the transmittance of the wavelength filter has wavelength dependency. For this reason, the monitor current IPD2 of the second light receiver 405 that receives the light that has passed through the wavelength filter 403 also depends on the wavelength. FIG. 2 shows an example of the wavelength dependence of the transmittance of the wavelength filter. In FIG. 2, the vertical axis represents the transmittance (%) of the wavelength filter, and the horizontal axis represents the wavelength (nm).

  The wavelength monitor device can monitor the wavelength by utilizing such characteristics. However, since the monitor current IPD2 also depends (proportional) on the intensity of received light, it is necessary to consider this effect. The monitor current IPD1 of the first light receiver 404 is proportional to the received light intensity and hardly depends on the wavelength. From this, the ratio (IPD2 / IPD1) of the monitor currents of the first light receiver 404 and the second light receiver 405 depends only on the wavelength.

  Therefore, the wavelength can be monitored by measuring the value of the monitor current (IPD2 / IPD1) ratio, and high wavelength stability can be realized by applying feedback so as to keep this value constant.

  On the other hand, in an LD (laser diode) module built-in type wavelength monitoring device, the laser rear light is often divided into two by a beam splitter and used for monitoring.

  FIG. 3 shows the structure of a wavelength monitoring device with a built-in LD module. As shown in FIG. 3, in the conventional wavelength monitoring device with a built-in LD module, the emitted light emitted from the LD 501 is collimated by the lens 502, and the parallel light is separated by the beam splitter 503. One light is incident on the first light receiver 505, and the other light is incident on the second light receiver 506 after passing through the wavelength filter 504.

  Even in the case of this built-in type, the wavelength can be monitored based on the value of the monitor current ratio (IPD2 / IPD1) as in the case of the external type described above, and wavelength stabilization with high accuracy is possible. Further, in the case of this built-in type, the value of the monitor current IPD1 is proportional to the light output forward from the LD 501, and thus is used as a light output monitor. That is, the two light receivers 505 and 506 can monitor and control the light output and the wavelength, respectively.

  As another wavelength monitoring device with a built-in LD module, JP-A-2001-257419 also discloses a structure in which a beam splitter is not used. As shown in FIG. 4, the wavelength monitor 604 is arranged so that only a part of the parallel light collimated by the lens 602 passes through the wavelength filter 604. In this wavelength monitoring device, light that does not pass through the wavelength filter 604 is received by the first light receiver 605, and light that has passed through the wavelength filter 604 is received by the second light receiver 606.

  This wavelength monitor device also has the same wavelength (and optical output) monitoring and control method as the wavelength monitor device having a structure in which light is separated by the beam splitter described above. Further, as a conventional wavelength monitoring device, there is a structure in which a part of the light emitted from the laser, that is, the light to be input to the optical fiber for transmission is extracted by a beam splitter and used for monitoring. However, the principle is the same in this structure.

  As described above, the wavelength is monitored using the values of the monitor currents IPD1 and IPD2, and high-precision wavelength stabilization is possible by applying feedback so as to keep the ratio of the monitor currents (IPD2 / IPD1) constant. It is. However, due to the configuration of the external feedback circuit, the value of the output current from the monitor is required to be within a predetermined required range.

  The monitor current value depends not only on the intensity of light from the semiconductor laser but also on the position of the monitor with respect to the optical axis direction of the emitted light. For this reason, in order to keep the monitor current value within the required range, high positional accuracy is required for the arrangement of members such as a lens, a beam splitter, and a light receiver.

  In addition to that, the ratio of monitor currents (IPD2 / IPD1) is often required to be within a predetermined range. In this case, even if the values of the monitor currents IPD1 and IPD2 fall within the required range, if one value is near the upper limit and the other value is near the lower limit, Since the value of the ratio (IPD2 / IPD1) may be out of the required range, the conditions become even more severe.

  In particular, a built-in monitor device is more difficult to satisfy such a requirement than an external monitor device. This is for the following reason. In the external monitor device, incident light is light from an optical fiber, and control of the relative position between the optical fiber and a collimator lens for parallelization is relatively easy. On the other hand, in the built-in monitor device, the control accuracy of the relative position between the semiconductor laser and the collimator lens is lower than that of the external type, and the radiation angle of the laser light for each LD chip varies. Controllability of light center position, light intensity distribution, and direction is relatively low.

  As shown in FIG. 4, in a structure in which a part of parallel light is transmitted through the wavelength filter 604 without using a beam splitter, the light incident on each of the light receivers 605 and 606 due to the angular deviation of the beam splitter is used. While there is an advantage that the intensity does not change, in such a structure, each of the light receivers 605 and 606 is formed on one PD chip or mounted on the same chip carrier. It is difficult to adjust the position of each light receiver 605,606. That is, there is a disadvantage that the values of the monitor currents IPD1 and IPD2 cannot be adjusted independently.

  In addition, when the first light receiver 605 is too close to the wavelength filter 604 side, a part of the filter transmitted light is incident on the first light receiver 605, and the first light receiver 605 also has wavelength dependency. Therefore, the relative position between the first light receiver 605 and the wavelength filter 604 is limited. That is, even if there is a point (position) where the ratio (IPD2 / IPD1) between the monitor currents IPD1 and IPD2 and the monitor current satisfies the standard value, it cannot be arranged in the vicinity of that point due to the relative position with respect to the wavelength filter 604. Things can happen.

  One way to satisfy the standards of monitor currents IPD1 and IPD2 is to adjust the mounting position of the photoreceiver while monitoring the current of the photoreceiver, so-called active mounting, or current when mounting the photoreceiver It is conceivable to perform so-called passive mounting without monitoring, monitor the current of the light receiver after mounting the light receiver, and perform re-mounting if the standard value is not met.

  In the above-described active mounting, it is necessary to apply a voltage from the electrode of the PD chip carrier and move the position of the light receiver in a state where a photocurrent flows, and a dedicated adjustment device is required. Furthermore, since the PD chip carrier is often fixed by solder and is adjusted at a high temperature, it is necessary to secure a structure in which the adjusting device can at least partially withstand the high temperature. An optical receiver mounting machine that satisfies these requirements is large and costly, and the time required for the optical receiver mounting process and the manufacturing cost increase.

  In the passive mounting, when the current value is out of the standard range, a process for remounting the light receiver and measuring the current value is required. If the standard does not meet even after this step, it is necessary to adjust this step repeatedly, resulting in a decrease in productivity and an increase in manufacturing cost.

  Therefore, it is desirable that the light receiver has a function of measuring the current value after performing the passive mounting described above and adjusting the current value without performing remounting when the current value is out of the standard. It is rare.

  Therefore, the present invention provides a photodetection device capable of keeping the magnitude of the current from each photoreceiver and the ratio of the current in each photoreceiver within a desired range without using a special photoreceiver mounting machine. An object of the present invention is to provide a manufacturing method and an optical module.

  In order to achieve the above-described object, a light detection device according to the present invention includes a first light detection unit that includes a plurality of light receivers that receive incident light and detects the light intensity of the incident light, and the incident light. A second photodetector for detecting the wavelength of incident light, having a single light receiver for receiving light, and a wavelength filter provided on an optical path of light incident on the second photodetector for transmitting incident light; And a plurality of connection wires electrically connected to the respective light receivers of the first light detection unit and the light receivers of the second light detection unit. The plurality of connection wirings are selectively connected or disconnected according to the light intensity of light incident on the first and second light detection units.

  According to the light detection device of the present invention configured as described above, a plurality of wirings electrically connected to a plurality of light receivers in the first light detection unit are connected to the first and second light beams. Depending on the light intensity of the light received by the detection unit, it is detected by each of the first and second light detection units by selectively connecting or disconnecting and changing the number of light receivers used simultaneously. The current (hereinafter referred to as monitor current) is controlled well.

  By the way, as an adjustment method for adjusting the monitor current, Japanese Patent Application Laid-Open No. 11-233814 has already disclosed a configuration using a plurality of light receivers. However, this configuration has a disadvantage in that the wavelength detection accuracy is lowered when used as a light receiver for wavelength monitoring. This is because the input light to the wavelength monitor is converted into parallel light by the lens, but is not completely parallel light, and therefore the angle varies slightly depending on the position. This is because the wavelength dependency of the transmittance of the wavelength filter changes depending on the incident angle of light. Therefore, when a plurality of light receivers are used for wavelength monitoring, the angles of light incident on the respective light receivers are slightly different when passing through the wavelength filter. For this reason, when the currents generated in the plurality of light receivers are combined into a monitor current, the wavelength dependency is reduced, that is, the ratio of the current change to the wavelength change is reduced. Therefore, it is not appropriate to use a plurality of light receivers as the light receiver for wavelength monitoring.

  On the other hand, since there is no such problem as a light receiver for optical output monitoring, the monitor current can be controlled by using a plurality of light receivers. Therefore, it is desirable that the wavelength monitor side uses a single light receiver and the light output monitor side uses a plurality of light receivers. In this case, the monitor current amount on the wavelength monitor side cannot be adjusted, but the monitor current ratio (IPD2 / IPD1) can be adjusted by adjusting the monitor current on the optical output side. It is possible to greatly reduce the positional accuracy required for the.

  Therefore, the photodetector of the present invention is configured to use a single light receiver for wavelength monitoring and to use a light detector composed of a plurality of light receivers only for light output monitoring.

  Moreover, it is preferable that the 1st photon detection part with which the photon detection apparatus of this invention is provided has a light-receiving area from which several light receivers differ, respectively, and the electric current amount which each light-receiver generates differs. As a result, the adjustment of the amount of current generated by the first light detection unit can be controlled at a level finer than the number of light receivers.

  As described above, a plurality of light receivers can be used for monitoring the optical output, but the monitor current ratio (IPD2 / IPD1) is controlled by adjusting only the monitor current IPD1. Become. Therefore, in order to finely adjust the ratio of the monitor current, it is necessary to adjust the optical output monitor current IPD1 in multiple stages. In order to control the monitor current amount in multiple stages, it is necessary to use a large number of light receivers. However, as the number of light receivers increases, it is necessary to connect or disconnect a large number of wires for adjustment, and the adjustment work becomes complicated, which increases the time and manufacturing cost for the process.

  Further, even when a plurality of light receivers are integrated and manufactured on the same PD chip, it is necessary to ensure a predetermined separation distance between the light receiving surfaces in the manufacturing process. Further, as the number of light receiving surfaces increases, the electrode area on the chip also increases. Since these portions do not contribute to the generation of the monitor current, the maximum monitor current in the same entire area decreases as the number of light receiving surfaces increases.

  Furthermore, as shown in FIG. 4, in the conventional wavelength monitor device, the first light receiver 605 and the second light receiver 606 used in the monitor system not using the beam splitter are integrated on one PD chip. Alternatively, in the light receiving system mounted on one chip carrier, since the area of the first light receiver 605 is limited in order to prevent interference of the filter transmitted light, it becomes difficult to increase the number of light receiving surfaces. Multistage control of current becomes difficult.

  To solve this problem and finely adjust the monitor current with a small number of light-receiving surfaces, it is effective to intentionally change the magnitude of the current generated on each light-receiving surface by varying the size of each light-receiving surface. It is. For example, in a structure in which the photodetector has two light receivers (light receiving surfaces), the light receiving area of each light receiver is set so that the ratio of currents generated on each light receiving surface is 1: 2. In this case, the current can be adjusted in three stages by using only one of the light receivers or by using both of the light receivers.

Furthermore, considering the case where the light receiving surface of the photodetector is divided into three parts, the current is adjusted in seven ways by setting the light receiving area so that the ratio of the current generated on each light receiving surface is 1: 2: 4. It becomes possible to do. In general, when the light receiving surface of the photodetector is divided into n parts and the current generated on each light receiving surface is set to be different from each other, the current can be adjusted up to 2 ⁿ −1. Become. As a result, the number of light receiving surfaces, that is, between the light receivers and the electrode area, that is, the entire area can be kept small, and multi-stage adjustment can be performed.

  An optical module according to the present invention includes the above-described photodetector of the present invention and a light source that emits laser light to the photodetector.

  Another optical module according to the present invention includes the above-described photodetection device of the present invention and an optical fiber that guides light to the photodetection device.

  In addition, the method for manufacturing a photodetecting device according to the present invention includes a first photodetecting unit having a plurality of light receivers for receiving incident light and detecting the light intensity of the incident light, and 1 for receiving the incident light. A second light detector having two light receivers for detecting the wavelength of the incident light, a wavelength filter provided on an optical path of the light incident on the second light detector, and transmitting the incident light; And a plurality of connection wires electrically connected to the light receivers of the second light detection unit, respectively, and each of the first and second light detection devices. Each of the first and second light detections can be performed by selectively connecting or disconnecting a plurality of connection wirings according to the light intensity of light incident on the light detection unit, thereby changing the number of light receivers used simultaneously. A wiring process for controlling the current detected by the unit.

  As described above, according to the present invention, the magnitude of the current from the first light detection unit for light output monitoring and the second light detection unit for wavelength monitoring and the ratio of currents by each light detection unit can be set as desired. Can be within the range. This eliminates the need for a re-mounting process of the photodetector for adjusting the current value and a mounting machine having a complicated structure for so-called active mounting, which greatly contributes to improvement of productivity and reduction of manufacturing cost. .

It is a top view which shows the structure of the conventional external type | mold wavelength monitor apparatus. It is a figure which shows an example of the wavelength dependence of the transmittance | permeability of a wavelength filter. It is a top view which shows typically the wavelength monitor apparatus of the conventional LD module built-in type. It is a top view which shows typically the structure of the other conventional wavelength monitor apparatus with a built-in LD module. 1 is a plan view showing a semiconductor laser module according to a first embodiment. It is a schematic diagram showing a chip carrier provided with a PD chip having two light receivers. It is sectional drawing which shows the semiconductor laser module which concerns on 2nd Embodiment. It is a schematic diagram showing a chip carrier provided with a PD chip having three light receivers. It is a perspective view which shows the relative position of the back output light from LD in 2nd Embodiment, an etalon, and a light receiver. It is a top view which shows typically the external type wavelength monitor apparatus which concerns on 3rd Embodiment. It is a schematic diagram which shows the connection state of the chip carrier provided with PD chip | tip which has two light receivers from which light reception area differs, and a case terminal.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  In the semiconductor laser module according to the present embodiment, a photodetector having two or more light receivers is used for optical output monitoring. Specifically, a configuration using a PD chip having two or more light receivers (photodiodes: PD) formed on a common semiconductor substrate, or two or more independent light receivers on one chip carrier. The configuration in which each is mounted and used is simple. Hereinafter, in the present embodiment, a configuration using a PD chip having two or more light receivers will be described.

(First embodiment)
The configuration of the semiconductor laser module according to the first embodiment of the present invention will be described with reference to FIGS. In this embodiment, as disclosed in, for example, Japanese Patent Application Laid-Open No. 9-219554, a wavelength stabilization mechanism using an etalon is provided and a structure in which transmitted light and non-transmitted light of an etalon are separated by a beam splitter. A configuration applied to a semiconductor laser module with a built-in wavelength monitor will be described as an example. Further, in the present embodiment, a case will be described in which the standard ranges of the light output monitor, the wavelength monitor, and the current values of each are 120 to 300 μA, and the ratio ratio between the two is 1/2 to 2.

  As shown in FIG. 5, the semiconductor laser module of the first embodiment includes a laser diode (LD) 102 that is a light source, and a collimator lens 106 into which laser light emitted from the LD 102 is incident along the optical path order. A beam splitter 107 that is a light separating means for separating the laser light that has passed through the collimator lens 106 and an etalon 112 that is a wavelength filter are provided. In addition, the semiconductor laser module includes two light receivers 110 and 111 that receive the laser light reflected by the beam splitter 107, a first light detection unit 51 for detecting the light output of the laser light, a beam It has a light receiver 113 that receives the laser light that has passed through the splitter 107, and includes a second light detection unit 52 that detects the wavelength of the laser light.

  The LD 102 is provided on a chip carrier 103 that is a support, and the chip carrier 103 is bonded to the support substrate 101.

  A method for manufacturing the above-described semiconductor laser module will be described.

  First, a chip carrier 103 provided with an LD 102, an optical isolator 104, a first lens 105, a temperature measurement thermistor (not shown) on a support substrate 101 made of a Cu—W alloy, solder, laser welding, etc. To fix each.

  Next, a collimator lens 106 that collimates the rear output from the LD 102 behind the LD 102, that is, on the opposite side of the external output light is disposed. A beam splitter 107 is mounted behind the collimator lens 106. The beam splitter 107 separates the light collimated by the collimator lens 106 in two directions. In the optical axis direction of the reflected light reflected by the beam splitter 107, as shown in FIG. 6, a PD chip 108, which is a semiconductor substrate having two light receivers 110 and 111 for detecting the reflected light, is a chip carrier. 109, and the chip carrier 109 is fixed.

In the present embodiment, the two light receivers 110 and 111 having different light receiving areas are used, and the light receiving area ratio of the two light receivers 110 and 111 is set to 1: 2. (Hereinafter, of the two light receivers 110 and 111, the light receiver 110 having the smaller area is referred to as the first small light receiver 110, and the larger light receiver 111 is referred to as the first large light receiver 111.)
An etalon 112, which is a wavelength filter, is disposed behind the beam splitter 107, that is, in the optical axis direction of the transmitted light, and behind the etalon 112, a wavelength monitor photodetector 113 for detecting the light passing through the etalon 112. The chip carrier 115 provided with is disposed. (Hereinafter, this light receiver 113 is referred to as a second light receiver 113.)
Next, a Peltier element (not shown) for adjusting the temperature of the LD 102 is fixed by soldering in the case 116, and then the LD 102, each of the light receivers 110, 111, 113, the etalon 112, and the like are arranged. The support substrate 101 is fixed on the Peltier element by soldering. Subsequently, the LD 102 and the case terminal are electrically connected by wire bonding using an Au wire as a connection wiring, and a current is supplied to the LD 102 so as to obtain a desired light output. The current generated in these light receivers 110, 111, and 113 is measured while also confirming the operation of 110, 111, and 113. Each electrode of each of the light receivers 110, 111, and 113 is electrically connected in advance to the electrodes formed on the chip carriers 109 and 115 by wire bonding using an Au wire as a connection wiring, and current measurement is performed. In this case, a needle-like probe is brought into contact with the electrodes on the chip carriers 109 and 115, a reverse bias is applied to each of the light receivers 110, 111, and 113 to receive light, thereby receiving the light receivers 110, 111, and 113. The photocurrent generated by 113 is measured.

  Subsequently, the electrodes on the chip carriers 109 and 115 connected to the electrodes of the light receivers 110, 111, and 113 and the case terminals are electrically connected by Au wire bonding. At this time, when the current obtained from the first small light receiver 110 is in the range of 40 to 100 μA during the PD current measurement, each of the first light receiver 110 and the first large light receiver 111 is used. Electrical connection to the same case terminal by wire bonding. Since the current value of the first large light receiver 111 is about twice the current value of the first small light receiver 110, the monitor current value is reduced by connecting the light receivers 110 and 111. This is about three times that of the light receiver 110. As a result, the monitor current value falls within the range of 120 to 300 μA.

  When the current obtained from the first small light receiver 110 is in the range of 60 to 150 μA, the current value of the first large light receiver 111 is approximately twice the current value of the first small light receiver 110. 120 to 300 μA. For this reason, only the first large light receiver 111 is electrically connected to the case terminal and the first small light receiver 110 is electrically disconnected, so that the monitor current value satisfies the standard value. .

  When the current obtained from the first small light receiver 110 is in the range of 150 to 300 μA, only the first small light receiver 110 is electrically connected to the case terminal, and the first large light receiver 111 is connected. By disconnecting electrically, the monitor current value falls within the standard range. Finally, the case 116 is sealed by, for example, seam welding of a lid (not shown), and the semiconductor lens module of this embodiment is completed through the connection of the second lens 117 and the optical fiber 118 and the like.

  In addition, when the electric current obtained from the 1st small light receiver 110 overlaps in each range mentioned above, the connection form in any case may be taken. As described above, since there are overlapping ranges, it is possible to tolerate manufacturing variations of the respective light receivers and the intensity distribution of incident light.

  In the present embodiment, two first small light receivers 110 and first large light receivers 111 having different light receiving areas are prepared for the rear output monitored for light output adjustment. Then, by measuring the PD current before wiring and selecting the number of light receivers connected to the case terminal according to the magnitude of the current, the current value of the first small light receiver 110 having a small light receiving area can be obtained. The monitor current value can be kept within the standard of 120 to 300 μA with respect to the light intensity range of 40 to 300 μA.

  On the other hand, considering the case where only one light receiver is used as in the prior art, when the light receiving area of the light receiver is the same as the light receiving area S of the first small light receiver 110, the current value is 120. It conforms to the standard only when it is ˜300 μA, and can be adapted when three light receivers are used, but it does not conform to the standard when it is 40 to 120 μA. When the light receiving area of the light receiver is increased, for example, when the light receiving area of the light receiver is three times that of the first small light receiver 110 (3 × S), that is, the same size as the sum of the three light receivers. When the current value is 120 to 300 μA, it conforms to the standard, but considering the area ratio, this corresponds to the light intensity when the current value per light receiver (area S) is 40 to 100 μA. . In the case of a light intensity at which the current per one light receiver (area S) is 100 to 300 μA, the light receiver having the area three times larger than this has a current value of 300 to 900 μA, which is incompatible with the standard.

  On the contrary, when the light receiving area of the light receiver is reduced, it can cope with the case where the light intensity is high, but it is easily understood that the standard is not compliant when the light intensity is low. The magnitude of the current generated in the light receiver is substantially proportional to the light reception intensity. In other words, from this, if there is only one light receiver regardless of the light receiving area, the ratio of the upper and lower limits of the received light intensity that can satisfy the standard is higher than the monitor current value standard. It is only 2.5 times the lower limit ratio. On the other hand, in the structure of the present embodiment, the ratio between the upper and lower limits of the received light intensity can be increased to 7.5 times.

  Conventionally, when the monitor current value is too large or too small than specified, it is necessary to remount the light receiver. However, this embodiment can be applied to a wide light intensity range by selecting a photoreceiver to be connected. For this reason, in this embodiment, it is not necessary to re-mount the light receiver, and the number of man-hours and thus the manufacturing cost can be reduced.

  In this embodiment, when the current value of the first small light receiver 110 is 60 to 100 μA, only the first large light receiver 111 or both of the light receivers 110 and 111 are connected. In the case of 120 to 150 μA, it is possible to conform to the standard by using only the first small light receiver 110 or only the first large light receiver 111. Since the light intensity is not completely uniform within the PD chip, even if the number of connected light receivers is doubled, that is, the light receiving area is doubled, the current value does not exactly double, but as described above This is not a problem because there is a margin in the current value range with respect to the change in the number of light receivers connected to.

  Considering the case where the wavelength monitor current value is 120 μA which is the lower limit of the standard, the optical output monitor needs to be within the range of 120 to 240 μA from the standard of the current ratio between the optical output monitor and the wavelength monitor. Even in this case, if each of the first small light receivers 110 and the first large light receivers 111 is used, and the monitor current generated in the first small light receiver 110 is in the range of 40 to 240 μA, the monitor The current can be adjusted to be within the specification.

  Conversely, when the wavelength monitor current value is 300 μA, which is the upper limit of the standard, the light output monitor needs to be 150 to 300 μA. However, even in this case, in the structure of the present embodiment, the standard can be satisfied if the monitor current generated in the first small light receiver 110 is 50 to 300 μA. Even in these cases, the ratio of the upper and lower limits of the received light intensity that can satisfy the monitor current standard is 2.5 times with one light receiver, while the structure of the present embodiment expands to 6 times. It becomes possible.

In this embodiment, two light receivers are used as the light output monitor, but three stages of adjustments are possible by using ones having different light receiving areas. Similarly, if light receivers having different light receiving areas are used, a maximum of 7 stages when there are three light receivers, a maximum of 15 stages when there are four light receivers, and generally 2 ⁿ -1 when there are n light receivers. The stage can be adjusted.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. 7, FIG. 8, and FIG. Here, as disclosed in Patent Document 1 described above, the etalon has a wavelength stabilization mechanism using an etalon, and the etalon is arranged so as to cover about half of the backward output light that has been collimated by the collimator lens. Furthermore, a case where a light receiving element is arranged behind the structure and applied to a structure where etalon passing light and non-passing light reach will be described as an example. Conventionally, as disclosed in the above publication, an element having two light receivers is used as a light receiving element, and the etalon passing light and non-passing light are detected by one light receiver. In the embodiment, a light receiving element having three light receivers formed on the same substrate is used, etalon non-passing light, that is, output monitor light is detected by two light receivers, and etalon passing light, that is, wavelength monitor light is received as one light. A case where detection is performed by a detector will be described. The standard range of the monitor current values of the etalon passing light and the non-passing light is set to 120 to 300 μA as in the first embodiment. In addition, regarding this embodiment, the same part as 1st Embodiment mentioned above uses the same name and code | symbol, and abbreviate | omits detailed description.

  As shown in FIGS. 7, 8, and 9, the semiconductor laser module of the present embodiment includes an LD 102 that is a light source, a collimator lens 106 to which laser light emitted from the LD 102 is incident, in the order of the optical path, And an etalon 112 which is a wavelength filter. The semiconductor laser module also receives two lasers 203 and 204 for receiving laser light that does not pass through the etalon 112 and detecting the light output of the laser light, and receives the laser light that has passed through the etalon 112 and receives the wavelength of the laser light. The light detection part 53 which has the light receiver 205 for detecting this is comprised.

  A method for manufacturing the above-described semiconductor laser module will be described.

  First, a chip carrier 103 provided with an LD 102, an optical isolator 104, a first lens 105, and a temperature measurement thermistor (not shown) are mounted on a support substrate 101 made of a Cu—W alloy by soldering, laser welding, or the like. Fix it. Next, a collimator lens 106 that collimates the rear output from the LD 102 behind the LD 102, that is, on the opposite side of the external output light is disposed.

Subsequently, as shown in FIG. 8, a chip carrier 202 on which a PD chip 201 having three light receivers 203, 204, 205 is placed is arranged behind the collimator lens 106. Since the etalon 112 is disposed between the collimator lens 106 and the PD chip 201 in a later process, the distance between the collimator lens 106 and the light receivers 203 and 204 is set larger than the thickness of the etalon 112. Further, as will be described later, the two light receivers 203 and 204 receive the etalon non-transmitted light, and the other light receiver 205 receives the etalon transmitted light. The light receivers 203 and 204 that receive the etalon non-transmitted light have different light receiving areas as in the configuration of the second embodiment, and the light receiving area ratio of the two light receivers 203 and 204 is 1: 2. Has been. (Hereinafter, of the two light receivers 203 and 204, the light receiver 203 having the smaller light receiving area is referred to as the first small light receiver 203, and the larger light receiver 204 is referred to as the first large light receiver 204). (The remaining light receiver 205 that receives the etalon transmitted light is referred to as a second light receiver 205.)
Next, as in the first embodiment, the LD 102 and the case terminal are electrically connected by Au wire bonding, and a current is supplied to the LD 102 so as to obtain a desired light output. The current generated in each of the light receivers 203, 204, and 205 is measured while also confirming the operation of 204 and 205. In this measurement, a needle-like probe is brought into contact with the electrode 206 on the PD chip carrier, and a reverse bias is applied to the light receivers 203, 204, 205 to measure the photocurrent generated by light reception.

  Subsequently, a Peltier element (not shown) for adjusting the temperature of the LD 102 is fixed in the case 116 by soldering, and then the support substrate 101 on which the LD 102, the light receivers 203, 204, 205, etc. are arranged is placed on the Peltier element. Fix it by soldering. Thereafter, the LD 102 and the electrode on the chip carrier connected to each electrode of each light receiver and the case terminal are electrically connected by Au wire bonding. At this time, the light receiver to be connected is selected according to the magnitude of the current value in the PD current measurement.

  Specifically, when the sum of the current flowing through the first small light receiver 203 and the current flowing through the first large light receiver 204 is 120 to 300 μA, each of the first small light receivers 203 and the first small light receivers 203 and Both positive electrodes (anodes) of the large light receiver 204 are electrically connected to the case terminals via Au wires. When the total current value is 180 to 450 μA, only the first large light receiver 204 is electrically connected to the case terminal. Considering the case where there is no large distribution of the light intensity incident on each of the two light receivers 203 and 204, the current flowing through the light receiver is substantially proportional to the light receiving area, so the first small light receiver 203 and the first large light receiver. The current flowing through the vessel 204 is approximately 1: 2.

  Therefore, when only the first large light receiver 204 is electrically connected, the current becomes approximately 2/3, that is, 120 to 300 μA, which satisfies the standard value. When the total current value is 360 to 900 μA, only the first small light receiver 203 is electrically connected, so that the current becomes approximately 1/3, that is, 120 to 300 μA, and conforms to the standard. When the measured value is 120 to 180 μA, even if the first small light receiver 203 and the first large light receiver 204 are connected together, only the first large light receiver 204 is connected. In the case of 300 to 450 μA, any one of the first small light receiver 203 and the first large light receiver 204 may be connected.

  In the present embodiment, the three light receivers of the first small light receiver 203, the first large light receiver 204, and the second light receiver 205 are formed on one PD chip as described above. The negative electrode (cathode) is common. As a matter of course, the common electrode and the anode of the second light receiver 205 are electrically connected to the case terminal via the Au wire in each case described above.

  Subsequent to the above process, as shown in FIG. 9, the etalon 112 is disposed behind the collimator lens 106 so as to cover about half of the rear output light collimated by the collimator lens 106. As a result, almost half of the light collimated by the collimator lens 106 passes through the etalon 112 and the other half becomes light that does not pass through the etalon 112. At this time, as described above, of the three light receivers 203, 204, and 205, the two first small light receivers 203 and the first large light receiver 204 are positioned at a portion where the etalon non-passing light reaches. The remaining second light receiver 205 adjusts the position of the etalon 112 so that the second light receiver 205 is positioned at a portion where the etalon passing light reaches (see FIG. 9).

  Finally, the case is sealed by seam welding a lid (not shown), and the connection of the second lens 117 and the optical fiber 118 and the like complete the semiconductor laser module of this embodiment.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. In the present embodiment, an example in which the light detection device according to the present invention is applied as an external wavelength monitor device will be described. In the present embodiment, similarly to the first embodiment, two photodetectors for light detection are arranged as an optical output monitor and a wavelength monitor, and the standard range of each monitor current value is 120 to 300 μA. In addition, the standard of the monitor current ratio of each light receiver is assumed to be 1/2 to 2.

  As shown in FIGS. 10 and 11, the wavelength monitoring device of the present embodiment includes a fiber collimator 302 and a beam splitter 303 that is a light separating unit that separates incident light from the fiber collimator 302 along the optical path order. An etalon 309, which is a wavelength filter, and a thermistor 304 for temperature measurement are provided. Further, this semiconductor laser module has two light receivers 307 and 308 for receiving the light reflected by the beam splitter 303, a first light detection unit 61 for detecting the light output of the laser light, and the beam splitter. It has a light receiver 310 that receives light transmitted through 303 and includes a second light detection unit 62 for detecting the wavelength of the light.

  A method for manufacturing the above-described semiconductor laser module will be described.

  In the case 301, a fiber collimator 302, a beam splitter 303, and a temperature measurement thermistor 304 in which an optical fiber and a collimator lens are integrated are fixed by soldering or laser welding. The parallel light emitted from the fiber collimator 302 is separated into two directions by the beam splitter 303. In order to detect the reflected light, a chip carrier 306 carrying a PD chip 305 having two light receivers 307 and 308 is fixed in the optical axis direction of the reflected light by the beam splitter 303 as shown in FIG. Yes. In the present embodiment, as in the first embodiment, the two light receivers 307 and 308 having different light receiving areas are used. Here, the light receiving area ratio of the two light receivers 307 and 308 is 1: 2. (Hereinafter, the light receiving device 307 having the smaller light receiving area is referred to as the first small light receiving device 307, and the larger light receiving device 308 is referred to as the first large light receiving device 308.) The rear side of the beam splitter 303, that is, the optical axis of the transmitted light. An etalon 309 is disposed in the direction, and a light receiver 310 (hereinafter referred to as a second light receiver 310) for detecting light passing through the etalon 309 is disposed behind the etalon 309.

  Subsequently, each element and the case terminal 311 are electrically connected by Au wire bonding. At this time, the anodes of the first small light receiver 307 and the first large light receiver 308 are respectively connected to the same case terminal 311, and the currents of the first light receiver 307 and the first large light receiver 308. Are taken out through one case terminal 311. Note that each of the first small light receivers 307 and the first large light receiver 308 is formed on one PD chip, and has a common cathode.

  Thereafter, a laser beam having a predetermined light intensity is input from the optical fiber collimator 302, and a current (monitor current) flowing between the case terminal and the received light is measured. During this measurement, a reverse bias is applied to each of the light receivers 307 and 308. This monitor current is the sum of the currents generated by the first small light receiver 307 and the first large light receiver 308. Since the light receiving area ratio of each of the light receivers 307 and 308 is 1: 2, The ratio of the currents flowing from the small light receiver 307 and the first large light receiver 308 is also approximately 1: 2.

  Here, when the measured value of the monitor current is 120 to 300 μA, the standard is satisfied as it is. When the measured value is 180 to 450 μA, by cutting the Au wire 312 which is a connection wiring for electrically connecting the anode of the first small light receiver 307 to the case terminal, the current is approximately 2/3, that is, It becomes 120 to 300 μA and satisfies the standard value.

  When the measured value is 360 to 900 μA, the current is reduced to approximately 1/3 by cutting the Au wire 313 which is a connection wiring for electrically connecting the first large light receiver 308 to the case terminal. That is, it becomes 120 to 300 μA and conforms to the standard. When the measured value is 120 to 180 μA, both the Au wires 312 and 313 may be left or only the Au wire 312 on the first small light receiver 307 side may be cut. In the case of 300 to 450 μA, either the Au wire 312 on the first small light receiver 307 side or the Au wire 313 on the first large light receiver 308 side may be cut. Finally, the case is sealed by seam welding a lid (not shown), and the wavelength monitoring device of this embodiment is completed.

  In the first and second embodiments, after mounting the light receiver, a current is once passed through the LD to emit light, the current of the light receiver is measured, and wire bonding is performed to the case terminal according to the magnitude of the monitor current at that time. The receiver is determined. However, in this embodiment, after all the light receivers and case terminals are electrically connected in advance by Au wire bonding, some Au wires are selectively cut according to the total monitor current value. Thus, adjustment of the monitor current is realized.

  In this method, since the Au wire is once connected and then cut as necessary, it can be said that there is a wasteful wire bonding step as compared with the first and second embodiments. Since the current is measured with the terminal being electrically connected, the current can be measured through the case terminal. Therefore, this method has an advantage that the measurement work is easy because there is no need to make a measurement by bringing a needle-shaped probe into contact with the chip carrier. Of course, as in the first and second embodiments, the necessary wire bonding may be performed after the monitor current of the light receiver is first measured.

  In addition, the manufacturing method of this invention is not limited to various embodiment mentioned above, A various deformation | transformation is possible in the range which does not deviate from the summary. For example, in this embodiment, the case where two light receivers are used for optical output monitoring has been described, but three or more light receivers may be applied. As the number of light receivers for one signal is increased, the light receiving current can be kept within the standard for a wider light intensity range.

  In the above-described embodiment, two or more light receivers are formed on one PD chip, and one electrode is shared by the substrate. Instead of this configuration, An independent PD chip may be used.

  In the first and second embodiments described above, an example in which the rear output of the semiconductor laser is detected as an optical detection method for optical output control or wavelength stabilization has been described. The present invention can also be applied to the case where a part is taken out and detected by a beam splitter or the like. The light source is applicable not only to a semiconductor laser but also to various optical device modules such as a semiconductor optical amplifier, a semiconductor optical modulator, and an optical integrated device combining them.

When a plurality of circular light receivers having different light receiving areas (light receiving diameters φ) are used, it is not always necessary that the light receiving diameters φ of all the light receiving devices are different from each other. For example, two φ = 30 μm, φ It is also possible to adopt a configuration in which three 50 μm are used, and a total of two types of light receivers are used.

Claims (9)

A first photodetector for detecting a light intensity of the incident light having a plurality of light receivers for receiving the incident light;
A second photodetector for detecting the wavelength of the incident light, having one light receiver for receiving the incident light;
A wavelength filter provided on an optical path of the incident light incident on the second light detection unit and transmitting the incident light;
A plurality of connection wires respectively connected to the light receivers of the first light detection unit and the light receivers of the second light detection unit;
The plurality of connection wirings are selectively connected or disconnected according to light intensity of light incident on the first and second light detection units.   The light detection device according to claim 1, further comprising: a light separation unit configured to separate incident light into the respective incident lights that are respectively incident on the first light detection unit and the second light detection unit.   2. The light detection device according to claim 1, wherein the plurality of light receivers have different light receiving areas, and the amount of current generated in each of the light receivers is different.   The light detection device according to claim 1, wherein the first and second light detection units are formed on the same semiconductor substrate.   The light detection apparatus according to claim 1, wherein the first and second light detection units are fixed on the same support. A light detection device according to any one of claims 1 to 5;
An optical module comprising: a light source that emits laser light to the light detection device. A light detection device according to any one of claims 1 to 5;
An optical module having an optical fiber for guiding light to the photodetector. A first light detector for detecting the light intensity of the incident light having a plurality of light receivers for receiving incident light, and a single light receiver for receiving the incident light for detecting the wavelength of the incident light A second light detection unit for performing, a wavelength filter provided on an optical path of the incident light incident on the second light detection unit and transmitting the incident light, and each of the first light detection units In manufacturing a photodetection device comprising a photoreceiver and a plurality of connection wires respectively connected to the photoreceiver of the second photodetection unit,
By selectively connecting or disconnecting the plurality of connection wirings according to the light intensity of light incident on each of the first and second light detection units, the number of the light receivers used simultaneously can be changed. A method for manufacturing a photodetection device, comprising a wiring process for controlling a current detected by each of the first and second photodetection units. 9. The photodetecting device according to claim 8, wherein in the wiring step, the connection wiring is selectively disconnected after the connection wirings of all the light receivers of the first and second light detection units are connected in advance. Manufacturing method.

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