JP2008294262A - Optical element module and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element module capable of stabilizing the operation temperature of an optical element without being affected by circumferential temperature change, and also rapidly stabilizing the operation temperature of the optical element even when the operation temperature of the optical element is changed. <P>SOLUTION: The optical element module includes: a semiconductor laser 103 for outputting light; a lens 106 for collecting light; an optical fiber 108 to be optically coupled with the semiconductor laser 103 via the lens 106; a case body 101 for storing and fixing the semiconductor laser 103, the lens 106, and the optical fiber 107; a stem 102; and a cap 105. The appearing parts of the case body 101, the stem 102, and the cap 105 are covered with a positive temperature coefficient heater 201 which is formed in a sheet shape and is fixed at prescribed temperature. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical element module on which a semiconductor optical element typified by a semiconductor laser is mounted, and more particularly to an optical element module suitable for use in an optical communication system and an optical network, and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, in an optical communication optical element module (hereinafter simply referred to as “optical element module”) that is mounted with a semiconductor optical element typified by a semiconductor laser and is used in an optical communication system and an optical network, for example, −40 What can operate | move in a wide temperature range, such as (degreeC-85 degreeC), has come to be calculated | required. An optical element mounted on such an optical element module is required to have a characteristic satisfying a desired specification in a wide temperature range without providing a temperature adjusting means for cost reduction.

  With the spread of the Internet and broadband, optical communication systems are required to have high speed and large capacity, and communication devices tend to become overcrowded. Accordingly, optical elements for optical communication used in communication apparatuses are being used in dense and harsh temperature conditions, reducing the power consumption, miniaturization, and high temperature environment of the optical elements themselves. There is a need for stabilization of the operation below. For example, as described in Non-Patent Document 1, the temperature range that ensures the characteristics required of the optical element is further expanding.

  Against this background, in recent years, in order to stabilize the operation of the semiconductor laser mounted on the optical element module, the temperature of the semiconductor laser is controlled using an overheating element that is less expensive than the Peltier element, and the operating temperature Proposals have been made to stabilize the operation of the semiconductor laser by narrowing the range. In particular, in the case of an image storage laser, since the sensitivity of the photosensitive member varies depending on the oscillation wavelength, there has been a proposal for stabilizing the oscillation wavelength by controlling the temperature of the semiconductor element using the overheating element as described above.

  For example, in Patent Document 1, even when a plurality of optical elements are mounted on the same substrate, mounting is performed by mounting a heating element for each mounted optical element so that the back surface of the substrate has a constant temperature. There has been proposed a hybrid optical integrated substrate in which the temperature can be controlled for each optical element.

JP 2000-91692 A T. Takeshita et al., “Highly Reliable (<1000 FITs at 95 ° C) 1.5 μm DFB Laser with High-Mesa SIBH Structure for CWDM Systems”, OThN2.pdf, 2006

  However, in the conventional optical element module described above, the temperature of the optical element changes due to the influence of the ambient temperature change, and the operation of the optical element may become unstable.

  For this reason, the present invention realizes an optical element module that can stabilize the operating temperature of the optical element without being affected by changes in ambient temperature, and the operating temperature of the optical element has changed. An object of the present invention is to realize an optical element module capable of quickly detecting a temperature change and performing various controls to stabilize the characteristics of the optical element. Furthermore, in order to avoid an increase in the cost of the optical element module by stabilizing the operating temperature of the optical element, it is possible to stabilize the operating temperature of the optical element with a simple configuration by simply attaching the accessory parts. An object of the present invention is to realize an inexpensive and compact optical element module.

  An optical element module according to a first aspect of the present invention for solving the above-described problems is optically coupled to the optical element via the optical element that inputs or outputs light, a lens that collects the light, and the lens. And an optical element module having a package for housing and fixing the optical element, the lens, and the optical fiber. The outer peripheral portion of the package is formed into a sheet shape and is a positive temperature that is constant at a predetermined temperature. It is characterized by being covered with a temperature coefficient heater.

  The positive temperature coefficient heater is heated by its own heat when a voltage is applied, and has a self-control function in which the resistance value increases exponentially as the temperature rises and becomes constant at a predetermined temperature. No external control functions such as Peltier elements or heat wire heaters are required.

  An optical element module according to a second invention is the optical element module according to the first invention, wherein the temperature of the optical element is derived based on a resistance value of the positive temperature coefficient heater, and the optical element is calculated based on the derived temperature of the optical element. And a control means for controlling the operation.

  The optical element module according to a third aspect of the present invention is the optical element module according to the second aspect, wherein the optical element is a semiconductor laser, and the control means outputs the optical output of the semiconductor laser based on the measured resistance value of the positive temperature coefficient heater. It is characterized by controlling.

  According to a fourth aspect of the present invention, there is provided the optical element module according to the second aspect, wherein the optical element is an avalanche photodiode, and the control means is configured to detect the avalanche photodiode based on the measured resistance value of the positive temperature coefficient heater. The multiplication factor is controlled.

  An optical element module according to a fifth invention is the optical element module according to the second invention, wherein the optical element is an optical modulator integrated laser, and the control means is configured to control the optical modulator based on a resistance value of the positive temperature coefficient heater. The voltage applied to the optical modulator of the integrated laser is controlled.

  An optical element module according to a sixth invention is characterized in that, in the third or fifth invention, the optical element is a buried optical element having a semi-insulating buried layer doped with ruthenium.

  An optical element module according to a seventh invention is the optical element module according to any one of the first to sixth inventions, wherein the control of the characteristic of the optical element is detected based on the resistance value of the positive temperature coefficient heater. It is characterized by comparing the temperature with the temperature characteristics of the optical element measured in advance.

  An optical element module according to an eighth invention is characterized in that, in any one of the first to seventh inventions, a heat insulating sheet is further provided on an outer peripheral portion of the positive temperature coefficient heater.

  According to a ninth aspect of the present invention, there is provided an optical element module manufacturing method comprising: an optical element that inputs or outputs light; a lens that collects the light; an optical fiber that is optically coupled to the optical element via the lens; A method of manufacturing an optical element module having a package for housing and fixing the optical element, the lens and the optical fiber, and a positive temperature coefficient heater covering an outer peripheral surface of the package, wherein the optical element, The method includes a step of covering the outside portion of the package with a sheet-like positive temperature coefficient heater after housing and fixing the lens and the optical fiber.

  According to a tenth aspect of the present invention, there is provided an optical element module manufacturing method according to the ninth aspect, the step of fixing the semiconductor optical element to the stem, the step of sealing the semiconductor optical element with a cap, and at least the stem and the cap A step of covering the exposed portion with the sheet-like positive temperature coefficient heater.

  An optical element module characteristic stabilization device according to an eleventh aspect of the invention is an optical element that inputs or outputs light, a lens that collects the light, and an optical fiber that is optically coupled to the optical element via the lens, And an optical element module having a positive temperature coefficient heater that covers an outer peripheral surface of the optical element, a package that houses and fixes the lens and the optical fiber, an optical element power source that drives the optical element, A heater voltage source for applying a voltage to the positive temperature coefficient heater, a resistance meter for applying a voltage from the heater voltage source and measuring a resistance value of the positive temperature coefficient heater, and the positive temperature measured by the resistance meter The optical element power supply includes a control device that adjusts a voltage or a current applied to the optical element based on a resistance value of a coefficient heater.

  According to a twelfth aspect of the present invention, there is provided an optical element module temperature characteristic control method comprising: an optical element that inputs or outputs light; a lens that collects the light; and an optical fiber that is optically coupled to the optical element via the lens. And a package that houses and fixes the optical element, the lens, and the optical fiber, and a positive temperature coefficient heater that is formed in a sheet shape and is provided on the outer periphery of the package and is constant at a predetermined temperature. A method for controlling temperature characteristics of an element module, wherein the resistance value of the positive temperature coefficient heater is measured, the temperature of the optical element is derived based on the measured resistance value, and the temperature of the derived optical element is measured in advance. A temperature characteristic control method for an optical element module, wherein the operating current of the optical element is adjusted by comparing with the temperature characteristic of the optical element.

  According to a thirteenth aspect of the invention, in the twelfth aspect of the invention, the heater voltage source for applying a voltage to the positive temperature coefficient heater has a temperature of the positive temperature coefficient heater from a predetermined value. When the temperature is small, a constant voltage is applied to the positive temperature coefficient heater, and when the temperature of the positive temperature coefficient heater is equal to or higher than a predetermined value, a voltage is applied to the positive temperature coefficient heater at regular time intervals. And

  According to the above-described optical element module according to the present invention, the configuration using the positive temperature coefficient heater to control the temperature of the semiconductor optical element makes it easier than the conventional temperature control using the Peltier element. And an inexpensive optical element module can be realized. Specifically, the positive temperature coefficient heater has a self-control function in which a resistance value increases exponentially as the temperature rises and becomes constant at a predetermined temperature while heating by its own heat when a voltage is applied. Since an external control function such as a conventional Peltier element or a heat ray heater is not required, a simple and inexpensive optical element module can be realized.

  In addition, since the characteristics of the optical element can be controlled based on the resistance value of the positive temperature coefficient heater, the temperature of the optical element can be determined from the resistance value of the positive temperature coefficient heater even when the operating temperature of the optical element changes. Changes can be detected quickly and various controls can be performed.

  For example, when the optical element module is a semiconductor laser module, the temperature of the semiconductor laser can be derived from the resistance value of the positive temperature coefficient heater, and the optical output can be feedforward controlled based on the derived temperature. The light monitoring light receiving element can be omitted. When the optical element module is an avalanche photodiode module, the temperature of the avalanche photodiode can be derived from the resistance value of the positive temperature coefficient heater, and the multiplication factor can be controlled based on the derived temperature. If the optical element module is an optical modulator integrated laser module, the temperature of the optical modulator integrated laser is derived from the resistance value of the positive temperature coefficient heater, and the optical modulator integrated based on the derived temperature. It is possible to control the voltage applied to the optical modulator of the laser.

  Furthermore, if the optical element to be mounted is an embedded optical element having a semi-insulating embedded layer doped with ruthenium, an inexpensive optical element module capable of high-speed transmission can be realized.

  In addition, according to the method for manufacturing an optical element module according to the present invention, the above-described function can be obtained by adding a process of covering the outside portion of the package with a sheet-like positive temperature coefficient heater to the conventionally used method for manufacturing an optical element module. A low-priced and compact optical element module having the above can be manufactured.

  In the following examples, embodiments of the present invention will be described in detail.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an external view showing a part of a semiconductor laser module according to the present embodiment, FIG. 2 is a sectional view of the semiconductor laser module main body according to the present embodiment, and FIG. FIG. 4 is a block diagram showing a control device for the positive temperature coefficient heater of this embodiment, and FIG. 5 is an explanatory diagram showing an example of a voltage applied to the positive temperature coefficient heater in this embodiment. FIG. 6A is a graph showing the relationship between the resistance value of the positive temperature coefficient heater and the temperature of the semiconductor laser in this embodiment, and FIG. 6B shows the relationship between the temperature of the semiconductor laser and the emission wavelength in this embodiment. FIG. 6C is a graph showing the relationship between the operating current of the semiconductor laser and the emission wavelength in this example.

  The optical element module shown in FIG. 1 is a 1.3 μm band distributed feedback semiconductor laser module (hereinafter simply referred to as “semiconductor laser module”) used in an optical transmission system for 10 Gbps Ethernet (registered trademark). A positive temperature coefficient heater 201 is provided as laser temperature control means.

  Referring to FIGS. 1 to 3 in detail, in this embodiment, the module main body 100 has a plate-like stem 102 disposed on one end face 101a side of a casing 101 formed in a substantially cylindrical shape. A 1.3 μm band distributed feedback semiconductor laser (hereinafter simply referred to as “semiconductor laser”) 103, which is a transmitting element for transmitting an optical signal, is mounted as an optical element on a mounting surface 102a located on the housing 101 side of Yes. The semiconductor laser 103 is electrically connected to a plurality of pins 104 provided through the stem 102.

  A cap 105 that covers the semiconductor laser 103 is further fixed to the mounting surface 102 a of the stem 102, and the periphery of the semiconductor laser 103 is sealed by the cap 105. The cap 105 is fixed to the mounting surface 102a, and is attached to the one end surface 101a side of the housing 101. A lens 106 that collects light is disposed on a portion of the cap 105 facing the semiconductor laser 103. It is supported.

  A ferrule collar 109 that holds an optical fiber 108 via a ferrule 107 is attached to the other end surface 101 b side of the housing 101. An optical isolator 110 is fixed to the end face of the optical fiber 108 located on the housing 101 side.

  Thereby, the optical fiber 108 held by the ferrule collar 109 is optically connected to the semiconductor laser 103 via the lens 106 and the optical isolator 110. With the structure shown in FIGS. 1 to 3, the module main body 100 is inexpensive to manufacture.

  The cap 105, the ferrule 107, and the ferrule collar 109 are metal processed parts, and it is preferable to use a material (SUS304, SF20T, etc.) suitable for YAG (Yttrium Aluminum Garnet) laser welding.

  As shown in FIG. 3, the positive temperature coefficient heater 201 is attached so as to cover a portion extending from the outer peripheral surface of the stem 102 of the module main body 100 to a part of the housing 101. The positive temperature coefficient heater 201 is provided with a lead wire 202 for connecting a power source. Here, the positive temperature coefficient heater 201 is formed in a sheet shape using a flexible material such as silicon resin. For this reason, even when the module main body is uneven, it is possible to closely contact the module main body without any gap, and the heating efficiency can be improved. In this embodiment, the positive temperature coefficient heater 201 has a width of 4 mm, a length of 35 mm, a thickness of about 1 mm, and a length that can be wound almost twice on the stem 102 having a diameter of 5.6 mm.

  Further, a portion having a length of about 18 mm corresponding to the second winding of the positive temperature coefficient heater 201 (a portion on the right side of the broken line portion in FIG. 3) is wound around the outer peripheral portion, in other words, the positive temperature coefficient heater 201. The heat insulating sheet 203 is provided on the outer peripheral surface portion in such a state that the positive temperature coefficient heater 201 is covered with the heat insulating sheet 203 when the positive temperature coefficient heater 201 is wound around the module body. The positive temperature coefficient heater 201 can be attached even when the semiconductor laser module is mounted in the transceiver. In addition, the positive temperature coefficient heater 201 and the heat insulation sheet 203 shown in FIG.

  A temperature control method for the semiconductor laser module according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 4, a semiconductor laser power source 121 for driving the semiconductor laser 103 is connected to the semiconductor laser 103 mounted on the module main body 100 in this embodiment. The positive temperature coefficient heater 201 includes a resistance meter 122 for measuring a resistance value in the positive temperature coefficient heater 201 and a heater voltage source 123 for applying a voltage to the positive temperature coefficient heater 201 and the resistance meter 122. It is connected. The semiconductor laser power supply 121 and the ohmmeter 122 are connected to a control device 124 as control means.

  The control device 124 derives the temperature of the semiconductor laser 103 based on the resistance value of the positive temperature coefficient heater 201 measured by the resistance meter 122, and the semiconductor laser power supply 121 applies the semiconductor laser 103 to the semiconductor laser 103 based on the derived temperature. The oscillation wavelength of the semiconductor laser 103 is controlled by adjusting the current (or voltage). In the present embodiment, an ohmmeter 122 is provided as shown in FIG. 4 and the temperature of the semiconductor laser 103 is derived based on the resistance value detected by this, but an ammeter is used instead of the ohmmeter 122. The temperature of the semiconductor laser 103 may be derived based on the detected and detected current value.

  The effect by a present Example is demonstrated. When the semiconductor laser 103 is operated, the temperature of the semiconductor laser 103 itself increases, and accordingly, the temperature of the semiconductor laser module increases. Also in the positive temperature coefficient heater 201, when the temperature rises due to application of a voltage, the resistance increases and the amount of current flowing through the positive temperature coefficient heater 201 decreases.

  If the resistance value of the positive temperature coefficient heater 201 increases, the temperature of the semiconductor laser 103 can be determined by measuring the amount of increase in the resistance value (in the case where an ammeter is provided instead of the resistance meter 122, the amount of decrease in the heater current). Can be detected. In this embodiment, for example, the control device in advance uses the relationship between the resistance value of the positive temperature coefficient heater 201 and the temperature of the semiconductor laser 103 as shown in FIG. 6A as a reference value (hereinafter referred to as a first reference value). It is stored in 124. The measured resistance value is input to the control device 124, and the temperature of the semiconductor laser 103 is derived by comparing the measured resistance value with the first reference value. In this embodiment, as shown in FIG. 6A, when the resistance value increases from R1 to R2, it can be derived that the temperature of the semiconductor laser 103 has increased from T1 to T2.

  For example, as shown in FIG. 6B, in the semiconductor laser 103, the oscillation wavelength increases as the temperature rises. In FIG. 6B, it can be seen that when the temperature of the semiconductor laser 103 increases from T1 to T2, the oscillation wavelength of the semiconductor laser 103 increases from λ1 to λ2.

  Further, for example, as shown in FIG. 6C, the oscillation wavelength of the semiconductor laser 103 varies depending on the operating current amount of the semiconductor laser 103. Therefore, the relationship between the temperature of the semiconductor laser 103 and the oscillation wavelength is measured, and the operation for outputting a predetermined oscillation wavelength from the temperature of the semiconductor laser 103 detected based on the current amount of the positive temperature coefficient heater 201 based on this relationship. It is assumed that the current is derived, and the relationship between the derived temperature, oscillation wavelength, and operating current is stored in the control device 124 in advance as a reference value (hereinafter referred to as a second reference value).

  In the present embodiment, the temperature of the semiconductor laser 103 is derived based on the measured resistance value of the positive temperature coefficient heater 201 input to the control device 124, and this derived temperature and the control device 124 are referred to the second reference. The operating current required for the semiconductor laser 103 is determined from the relationship between the temperature, oscillation wavelength and operating current stored as values.

  Then, the operating current value derived based on the resistance value in the positive temperature coefficient heater 201 measured by the resistance meter 122 is set as the operating current of the semiconductor laser 103, in other words, the semiconductor laser power supply 121 is set by the control device 124 by the semiconductor laser 103. By adjusting the current applied to the semiconductor laser 103, the oscillation wavelength of the semiconductor laser 103 can be controlled to be a predetermined oscillation wavelength. As shown in FIG. 6C, for example, when the temperature of the semiconductor laser 103 is T2, the operating current of the semiconductor laser 103 is reduced from I2 to I1, thereby changing the oscillation wavelength of the semiconductor laser 103 from λ2 to λ1. Can do.

  Therefore, even if the temperature of the semiconductor laser 103 rises from T1 to T2, the oscillation current of the semiconductor laser 103 can be maintained at λ1 by reducing the operating current of the semiconductor laser 103 from I2 to I1. As described above, the oscillation wavelength of the semiconductor laser 103 tends to increase as the temperature rises. On the other hand, the operating current of the semiconductor laser 103 is adjusted by using the control device 124, thereby changing the temperature of the semiconductor laser 103. The fluctuation of the oscillation wavelength can be suppressed and the operation of the semiconductor laser can be stabilized.

  As shown in FIG. 5, in the present embodiment, the heater voltage source 123 applies a constant voltage to the positive temperature coefficient heater 201 when the temperature of the positive temperature coefficient heater 201 is equal to or lower than a set value. When the temperature of the positive temperature coefficient heater 201 is equal to or higher than the set value, in principle, the voltage applied to the positive temperature coefficient heater 201 is set to zero for power saving. However, if the applied voltage is zero while the temperature of the positive temperature coefficient heater 201 is equal to or lower than the set value, the resistance value cannot be measured by the ohmmeter 122, and the temperature transition of the semiconductor laser 103 cannot be measured. . Therefore, when the temperature of the positive temperature coefficient heater 201 is equal to or higher than the set value, a pulse voltage is applied at regular time intervals in order to monitor the temperature of the positive temperature coefficient heater 201.

  In this way, if the applied voltage is pulsed when the temperature of the positive temperature coefficient heater 201 is equal to or higher than the set value, the temperature of the positive temperature coefficient heater 201 and the semiconductor laser module can be increased because the voltage application time is short. Therefore, the temperature of the semiconductor laser 103 can be monitored. When the temperature of the positive temperature coefficient heater 201 becomes equal to or lower than the set value, a constant voltage is applied to the positive temperature coefficient heater 201 again.

  Note that the time interval for applying the pulse voltage need not be constant. Further, the voltage applied to the positive temperature coefficient heater 201 may not be constant, and the temperature can be controlled more efficiently by changing the voltage according to the measured temperature.

  Hereinafter, a second embodiment of the present invention will be described with reference to FIG. FIG. 7 is a graph showing the relationship between the oscillation wavelength of the semiconductor laser module according to the present embodiment and the operating temperature, and is an example when the saturation temperature of the positive temperature coefficient heater is set to 60 ° C. This example is an example in which the saturation temperature of the positive temperature coefficient heater 201 is set in advance in the semiconductor laser module of Example 1 shown in FIGS. 1 to 6 and described below. The same members are described with the same reference numerals, and the description overlapping with the first embodiment is omitted.

  In an actual WDM (wavelength division multiplexing) communication system, optical signals having a plurality of wavelengths are used for communication. Therefore, stability for each wavelength signal is important, and problems occur when the wavelength varies by 10 nm. It is necessary to suppress to a certain extent. Conventionally, however, the wavelength fluctuates by about 10 nm when the temperature fluctuates from −10 ° C. to 85 ° C. When the semiconductor laser is actually operated at room temperature (about 20 ° C.), the semiconductor laser itself generates heat and the temperature of the semiconductor laser continues to rise, and rises to 85 ° C. or higher in a sealed state such as a package. Due to this temperature rise, the fluctuation of the wavelength becomes 10 nm or more, which makes it difficult to apply to a WDM communication system.

  In this example, in the semiconductor laser module of Example 1 described above, the saturation temperature of the positive temperature coefficient heater 201 was set to 60 ° C. in advance. That is, a voltage is applied to the positive temperature coefficient heater 201 so that the saturation temperature is 60 ° C. The positive temperature coefficient heater 201 generates heat and increases in temperature when a current flows. Along with this, the current flowing through the positive temperature coefficient heater 201 decreases. When the temperature of the positive temperature coefficient heater 201 reaches 60 ° C., the current amount becomes constant and the heat generation amount becomes constant. The temperature of 201 is kept constant at 60 ° C.

  Under this circumstance, when the temperature variation of the laser characteristics is controlled using the positive temperature coefficient heater 201 as in the first embodiment, the oscillation wavelength is constant up to 60 ° C. even if the semiconductor laser 103 itself generates heat, and about 80 ° C. The fluctuation of the oscillation wavelength of the semiconductor laser 103 can be suppressed to about 2 nm with the temperature rise up to.

  Specifically, as shown in FIG. 7, in the case of the configuration including the positive temperature coefficient heater according to the present embodiment, the oscillation wavelength is 1314 nm to -10 ° C. to 85 ° C. in the operating temperature range as shown by the solid line in the drawing. It can be seen that fluctuations of 1316 nm and about 2 nm are suppressed. On the other hand, in the case of the conventional configuration in which no positive temperature coefficient heater is provided, the oscillation wavelength fluctuates by about 10 nm from 1306 nm to 1316 nm in the operating temperature range of −10 ° C. to 85 ° C. as indicated by the broken line in the figure.

  As the temperature of the positive temperature coefficient heater 201 is set to a higher temperature, the range in which the temperature variation of the oscillation wavelength of the semiconductor laser 103 can be suppressed can be expanded, but the optical output of the semiconductor laser 103 decreases. On the other hand, if the temperature is set to a relatively low temperature, a decrease in the optical output of the semiconductor laser 103 can be suppressed, but the range in which the temperature variation of the oscillation wavelength of the semiconductor laser 103 can be suppressed is reduced. Therefore, it is preferable that the set temperature of the positive temperature coefficient heater 201 is determined by the characteristics of the semiconductor laser 103 and the allowable range under the element application conditions. For example, if the semiconductor laser is applied to a communication system as in this embodiment, it can be set in the range of 50 ° C. to 100 ° C. and is effective in the range of 60 ° C. to 85 ° C.

  As described above, in the optical element module according to the first embodiment, by setting the saturation temperature of the positive temperature coefficient heater 201 to an appropriate value, the temperature fluctuation of the oscillation wavelength of the semiconductor laser 103 is suppressed to a range applicable to the WDM communication system. can do.

  The third embodiment of the present invention will be described below with reference to FIG. FIG. 8 is a graph showing the operating temperature dependence of the optical output and operating current of the semiconductor laser module according to this example. In this embodiment, in the semiconductor laser module of the first embodiment described above, the control device 124 detects the temperature from the resistance value of the positive temperature coefficient heater 201, and feedforward controls the temperature fluctuation of the optical output based on the detected temperature. In the following description, the same members as those shown in FIGS. 1 to 6 are described with the same reference numerals, and the description overlapping with that of the first embodiment is omitted.

  When the operating current of the semiconductor laser is kept constant at 60 mA in the conventional semiconductor laser module, the optical output of the semiconductor laser varies depending on the operating temperature as shown by the broken line in FIG. For this reason, in a conventional semiconductor laser module, a light output monitor light receiving element is mounted in the immediate vicinity of the semiconductor laser, and the light output is stabilized by controlling the current value to be constant. However, a tracking error may occur due to other factors of temperature variation such as coupling efficiency.

  In contrast, the semiconductor laser module of the present embodiment, in which the controller 124 detects the temperature from the resistance value of the positive temperature coefficient heater 201 and performs feedforward control, the semiconductor laser 103 optical output value as shown by the solid line in FIG. It can be seen that is stable.

  The semiconductor laser module according to the present embodiment can be controlled in consideration of all temperature fluctuation factors, so that a more stable light output can be obtained.

  The fourth embodiment of the present invention will be described below with reference to FIG. FIG. 9 is a partial cross-sectional view showing the optical element module according to the present embodiment. Members having the same configurations as those shown in FIGS. Omitted.

  The optical element module according to the present embodiment is an avalanche photodiode module used in a 10 Gbps optical transmission system, and has a configuration in which a positive temperature coefficient heater 201 is provided in the module body 300.

  As shown in FIG. 9, the avalanche photodiode module according to the present embodiment is configured by providing a module body 300 with a positive temperature coefficient heater 201. In the module main body 300 of the present embodiment, a plate-like stem 302 is disposed on one end surface 301a side of a substantially cylindrical casing 301, and the mounting surface 302a of the stem 302 positioned on the casing 301 side. In addition, an avalanche photodiode (APD) 303 which is a light receiving element for receiving an optical signal is mounted as an optical element. The avalanche photodiode 303 is electrically connected to a plurality of pins 304 provided through the stem 302.

  A cap 305 is fixed to the mounting surface 302 a of the stem 302 so as to cover the avalanche photodiode 303, and the cap 305 is attached to one end surface 301 a side of the housing 301. A lens 306 that collects light is supported on a portion of the cap 305 facing the avalanche photodiode 303. The cap 305 has a structure for sealing the periphery of the avalanche photodiode 303 by being fixed to the mounting surface 302a of the stem 302.

  Further, a ferrule collar 309 that holds the optical fiber 308 via a ferrule 307 is attached to the other end surface 301 b side of the housing 301.

  Thus, the optical fiber 308 held by the ferrule collar 309 is optically connected to the avalanche photodiode 303 via the lens 306. The module body has the structure shown in FIG.

  The cap 305, the ferrule 307, and the ferrule collar 309 are metal processed parts, and it is preferable to use a material (SUS304, SF20T, etc.) suitable for YAG (Yttrium Aluminum Garnet) laser welding.

  A portion of the module main body 301 extending from a part of the casing 301 to the outer peripheral surface of the stem 302 is attached with a positive temperature coefficient heater 201 partially covered with a heat insulating sheet 203, thereby completing the avalanche photodiode module of this embodiment. . The positive temperature coefficient heater 201 is provided with a lead wire (not shown) for connecting a power source.

  According to the avalanche photodiode module according to the present embodiment, even if the temperature of the module fluctuates due to the positive temperature coefficient heater 201, the fluctuation of the operating temperature of the avalanche photodiode 303 can be suppressed. Magnification control is almost unnecessary. Even if the operating temperature of the avalanche photodiode 303 changes, the same configuration as that shown in FIG. 4 is provided as the control means, and the temperature of the avalanche photodiode 303 is determined from the resistance value of the positive temperature coefficient heater 201. And gain control can be performed.

  In the conventional avalanche photodiode module, the temperature is detected by a thermistor installed outside the module, and gain control is performed. However, there is a distance on the order of several centimeters between the module and the thermistor, and there is a possibility that a delay or error in detection of temperature fluctuations occurs.

  In contrast, according to the avalanche photodiode module according to the present embodiment, the positive temperature coefficient heater 201 is in thermal contact with the stem that is in direct thermal contact with the avalanche photodiode 303 to detect the temperature of the avalanche photodiode 303. Therefore, it is possible to realize an avalanche photodiode module that can perform multiplication control with higher accuracy and quick response.

  The fifth embodiment of the present invention will be described below with reference to FIG. FIG. 10 is a partial cross-sectional view showing the structure of the optical element module according to the present embodiment. Members having the same configurations as those shown in FIGS. Is omitted as appropriate.

  The optical element module according to the present embodiment is an embedded optical modulator integrated (EA-DFB) laser module having a semi-insulating embedded layer doped with ruthenium used in a 10 Gbps optical transmission system.

  As shown in FIG. 10, the embedded optical modulator integrated laser module according to this embodiment is configured by providing a positive temperature coefficient heater 201 in the module main body 400. More specifically, in the module main body of the present embodiment, a plate-like stem 402 is disposed on one end surface 401a side of a substantially cylindrical casing 401, and the stem 402 is positioned on the casing 401 side. On the mounting surface 402a, an embedded optical modulator integrated laser 403, which is a light emitting element that transmits an optical signal, is mounted as an optical element. The embedded optical modulator integrated laser 403 is electrically connected to a plurality of pins 404 provided through the stem 402.

  A cap 405 is fixed to the mounting surface 402 a of the stem 402 so as to cover the embedded optical modulator integrated laser 403, and the cap 405 is attached to one end surface 401 a side of the housing 401. A lens 406 for condensing light is supported on a portion of the cap 405 facing the embedded optical modulator integrated laser 403. The cap 405 is structured to seal the periphery of the embedded optical modulator integrated laser 403 by being fixed to the mounting surface 402 a of the stem 402.

  A ferrule collar 409 that holds an optical fiber 408 is attached to the other end surface 401 b side of the housing 401 via a ferrule 407. An optical isolator 410 is fixed to the end surface of the optical fiber 408 located on the housing 401 side.

  Accordingly, the optical fiber 408 held by the ferrule collar 409 is optically connected to the embedded optical modulator integrated laser 403 via the lens 406 and the optical isolator 410. The module main body has the structure shown in FIG.

  The cap 405, the ferrule 407, and the ferrule collar 409 are metal processed parts, and it is preferable to use a material (SUS304, SF20T, etc.) suitable for YAG (Yttrium Aluminum Garnet) laser welding.

  A positive temperature coefficient heater 201 partially covered with a heat insulating sheet 203 is attached to a part extending from a part of the casing 401 of the module main body to the outer peripheral surface of the stem 402, so that the embedded optical modulator of this embodiment is integrated. The laser module is completed. The positive temperature coefficient heater 201 is provided with a lead wire (not shown) for connecting a power source.

  According to the embedded optical modulator integrated laser module according to the present embodiment, the operating temperature of the embedded optical modulator integrated laser 401 can be stabilized by the positive temperature coefficient heater 201. Further, even if the operating temperature changes, it is possible to provide the same configuration as the configuration shown in FIG. 4 as the control means, derive the temperature from the resistance value of the positive temperature coefficient heater 201, and perform feedforward control. .

  In conventional embedded optical modulator integrated laser modules, a light receiving element for optical output monitoring is mounted in the immediate vicinity of the embedded optical modulator integrated laser, and the optical output is stabilized by controlling the current value to be constant. Because of this structure, tracking errors may occur due to other factors of temperature fluctuations such as coupling efficiency.

  On the other hand, according to the embedded optical modulator integrated laser module according to the present embodiment, since it is possible to control in consideration of all temperature fluctuation factors, the embedded type that obtains a more stable light output. It is possible to realize an optical modulator integrated laser module.

  Furthermore, the embedded optical modulator integrated laser module according to the present embodiment can suppress the fluctuation of the operating temperature of the embedded optical modulator integrated laser 401 even when the operating temperature of the module fluctuates. Voltage control is almost unnecessary. Furthermore, even if the temperature of the embedded optical modulator integrated laser 401 changes, the temperature of the embedded optical modulator integrated laser 401 is derived from the resistance value of the positive temperature coefficient heater 201, and the modulator The applied voltage can be controlled.

  In a conventional embedded type optical modulator integrated laser module, the temperature is detected by a thermistor installed inside the module to control the voltage applied to the modulator. However, it was necessary to install a dedicated pin for the thermistor on the stem, and it was necessary to change the conventionally used stem.

  On the other hand, in this embodiment, since the temperature can be detected by the positive temperature coefficient heater 201 having a lead wire independently, the conventional stem can be used without any change, so that a simple and inexpensive embedded optical modulator can be used. An integrated laser module can be realized. Furthermore, an inexpensive optical element module capable of high-speed transmission could be realized by using an optical element module that is an embedded optical element having a semi-insulating embedded layer doped with ruthenium as the optical element to be mounted. .

  The present invention relates to an optical element module equipped with a semiconductor optical element typified by a semiconductor laser, and is particularly suitable for application to an optical element module used in an optical communication system and an optical network.

It is an external view which fractures | ruptures and shows a part of semiconductor laser module which concerns on Example 1 of this invention. 1 is a cross-sectional structure diagram of a semiconductor laser module body according to Embodiment 1 of the present invention. It is explanatory drawing which shows a part of manufacturing method of the semiconductor module which concerns on Example 1 of this invention. It is a block diagram which shows the control apparatus of the positive temperature coefficient heater of Example 1 of this invention. It is explanatory drawing which shows the example of the voltage applied to the positive temperature coefficient heater in Example 1 of this invention. FIG. 6A is a graph showing the relationship between the resistance value of the positive temperature coefficient heater and the temperature of the semiconductor laser in Example 1 of the present invention, and FIG. 6B is the temperature of the semiconductor laser in Example 1 of the present invention. FIG. 6C is a graph showing the relationship between the emission wavelength and FIG. 6C is a graph showing the relationship between the operating current of the semiconductor laser and the emission wavelength in Example 1 of the present invention. It is a graph which shows the relationship between the oscillation wavelength of the semiconductor laser module by Example 2 of this invention, and operating temperature. It is a graph which shows the optical output of the semiconductor laser module by Example 3 of this invention, and the operating temperature dependence of an operating current. It is a fragmentary sectional view which shows the structure of the optical element module which concerns on Example 4 of this invention. It is a fragmentary sectional view which shows the structure of the optical element module which concerns on Example 5 of this invention.

Explanation of symbols

101, 301, 401 Housing 102, 302, 402 Stem 103 1.3 μm band distributed feedback semiconductor laser 104, 304, 404 Pin 105, 305, 405 Cap 106, 306, 406 Lens 107, 307, 407 Ferrule 108, 308 , 408 Optical fiber 109, 309, 409 Ferrule color 110, 410 Isolator 121 Semiconductor laser power supply 122 Resistance meter 123 Heater voltage source 124 Controller 201 Positive temperature coefficient heater 202 Pin 203 Thermal insulation sheet 303 Avalanche photodiode 403 Embedded light modulation Integrated laser

Claims (13)

An optical element for inputting or outputting light;
A lens that collects the light;
An optical fiber optically coupled to the optical element through the lens;
In an optical element module having the optical element, the lens, and a package for housing and fixing the optical fiber,
An optical element module, wherein the outer periphery of the package is covered with a positive temperature coefficient heater that is formed in a sheet shape and is constant at a predetermined temperature.   2. The apparatus according to claim 1, further comprising a control unit that derives a temperature of the optical element based on a resistance value of the positive temperature coefficient heater and controls an operation of the optical element based on the derived temperature of the optical element. The optical element module according to 1.   3. The optical element module according to claim 2, wherein the optical element is a semiconductor laser, and the control means controls the optical output of the semiconductor laser based on the measured resistance value of the positive temperature coefficient heater.   3. The optical element according to claim 2, wherein the optical element is an avalanche photodiode, and the control means controls the multiplication factor of the avalanche photodiode based on the measured resistance value of the positive temperature coefficient heater. module.   The optical element is an optical modulator integrated laser, and the control means controls a voltage applied to the optical modulator of the optical modulator integrated laser based on a resistance value of the positive temperature coefficient heater. The optical element module according to claim 2.   6. The optical element module according to claim 3, wherein the optical element is an embedded optical element having a semi-insulating embedded layer doped with ruthenium.   Control of the characteristics of the optical element is performed by comparing the temperature of the optical element detected based on the resistance value of the positive temperature coefficient heater with the temperature characteristic of the optical element measured in advance. The optical element module of any one of Claim 1 thru | or 6.   The optical element module according to any one of claims 1 to 7, further comprising a heat insulating sheet provided on an outer peripheral portion of the positive temperature coefficient heater. An optical element for inputting or outputting light;
A lens that collects the light;
An optical fiber optically coupled to the optical element through the lens;
A package for housing and fixing the optical element, the lens and the optical fiber;
A method of manufacturing an optical element module having a positive temperature coefficient heater covering an outer peripheral surface of the package,
A method for manufacturing an optical element module, comprising: housing and fixing the optical element, the lens, and the optical fiber in the package; and covering the outside portion of the package with a sheet-like positive temperature coefficient heater.   A step of fixing the semiconductor optical device to the stem; a step of sealing the semiconductor optical device with a cap; and a step of covering at least the exposed portion of the stem and the cap with the sheet-like positive temperature coefficient heater. A method for manufacturing an optical element module according to claim 9. An optical element that inputs or outputs light, a lens that condenses the light, an optical fiber that is optically coupled to the optical element via the lens, and the optical element, the lens, and the optical fiber that are housed and fixed And an optical element module having a positive temperature coefficient heater covering the outer peripheral surface of the package;
An optical element power source for driving the optical element;
A heater voltage source for applying a voltage to the positive temperature coefficient heater;
A resistance meter that applies a voltage from the heater voltage source and measures the resistance value of the positive temperature coefficient heater;
And a control device that adjusts a voltage or current applied to the optical element by the power supply for the optical element based on a resistance value of the positive temperature coefficient heater measured by the resistance meter. Stabilizer. An optical element that inputs or outputs light; a lens that collects the light; an optical fiber that is optically coupled to the optical element via the lens; and the optical element, the lens, and the optical fiber that are housed and fixed And a temperature characteristic of an optical element module having a positive temperature coefficient heater that is formed in a sheet shape and is provided on an outer peripheral portion of the package and is constant at a predetermined temperature,
The resistance value of the positive temperature coefficient heater is measured, the temperature of the optical element is derived based on the measured resistance value, and the temperature of the derived optical element is compared with the temperature characteristics of the optical element measured in advance. A method for controlling temperature characteristics of an optical element module, characterized by adjusting an operating current of the optical element. The heater voltage source that applies a voltage to the positive temperature coefficient heater applies a constant voltage to the positive temperature coefficient heater when the temperature of the positive temperature coefficient heater is lower than a predetermined value, while the positive temperature coefficient heater 13. The method of controlling temperature characteristics of an optical element module according to claim 12, wherein a voltage is applied to the positive temperature coefficient heater at regular time intervals when the temperature of the optical element module is equal to or higher than a predetermined value.

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