JP2005234267A - Semiconductor optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a semiconductor optical module which reduces power consumption without deteriorating high frequency characteristics. <P>SOLUTION: The semiconductor optical module has a hermetically sealed package, an electronic cooler mounted inside the package, an electrical field imbibe type modulator mounted on the electronic cooler, a shelf part separated from the electronic cooler and mounted inside the package, a terminator resistor mounted on the shelf part and connected to the electrical field imbibe type modulator, an input terminal to input a signal to the electrical field imbibe type modulator, a capacitor connected between the input terminal and the electrical field imbibe type modulator, an inductor connected in parallel to the electrical field imbibe type modulator and the terminal resistor and a terminal to adjust an electric potential on the anode side of the electrical field imbibe type modulator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes an electronic cooler (TEC) provided in a hermetically sealed package and an electro-absorption (EA) modulator provided on the electronic cooler. The present invention relates to a semiconductor optical module.

  In a semiconductor optical module used for optical communication, it is important to obtain a stable optical output waveform with little waveform distortion following an input high-frequency electric signal. For this purpose, it is necessary to maintain the operating temperature of the semiconductor optical module below a certain level to improve the high frequency characteristics.

  Therefore, a semiconductor optical module in which an electronic cooler is provided in a hermetically sealed package and an optical element is provided on the electronic cooler has been proposed (for example, see Patent Document 1). Thereby, the heat generated from the optical element can be discharged outside the package through the electronic cooler.

JP-A-1-192188

  However, in the conventional semiconductor optical module, the termination resistor, which is a heating element, is arranged on the electronic cooler together with the optical element. For this reason, the electronic cooler must also exhaust heat generated from the terminal resistor, which increases the power consumption of the electronic cooler, resulting in an increase in the power consumption of the semiconductor optical module.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a semiconductor optical module capable of reducing power consumption without deteriorating high-frequency characteristics.

  A semiconductor optical module according to the present invention includes a hermetically sealed package, an electronic cooler provided in the package, an electroabsorption modulator provided on the electronic cooler, and an electronic cooler in the package. Is a shelf provided separately, a termination resistor provided on the shelf and connected to the electroabsorption modulator, an input terminal for inputting a signal to the electroabsorption modulator, and the input terminal and the electroabsorption A capacitor connected between the type modulators, an inductor connected in parallel with the electroabsorption modulator and the terminating resistor, and a terminal for adjusting the potential on the anode side of the electroabsorption modulator. Other features of the present invention will become apparent below.

  According to the present invention, power consumption can be reduced without deteriorating high-frequency characteristics.

Embodiment 1 FIG.
FIG. 1A is a top view showing a semiconductor optical module according to Embodiment 1 of the present invention, and FIG. 1B is a sectional view thereof. As shown in this figure, an electronic cooler 12 and a shelf 13 are provided in a hermetically sealed package 11. However, the shelf 13 is provided separately from the electronic cooler 12.

  An electroabsorption modulator 14, a thermistor 15 that detects the temperature on the electrocooler 12, and a monitor photodiode 16 that detects the intensity of output light from the electroabsorption modulator 14 are provided on the electrocooler 12. It has been.

  A termination resistor 17 is provided on the shelf 13. One end of this termination resistor 17 is connected to the electroabsorption modulator 14 by a gold wire 18, and the other end is connected to a GND 19.

  Further, an input terminal 20 for inputting a modulation signal to the electroabsorption modulator 14 is provided. A capacitor 21 is connected between the input terminal 20 and the electroabsorption modulator 14. Further, in order to connect the capacitor 21 and the electroabsorption modulator 14, a transmission line substrate 22 is provided so as to bridge the shelf 13 and the electronic cooler 12. The characteristic impedance of the transmission line substrate 22 and the characteristic impedance of the termination resistor 17 are substantially equal, and impedance matching is achieved.

  An inductor 23 is connected in parallel with the electroabsorption modulator 14 and the termination resistor 17. The inductor 23 has one end connected to the capacitor 21 and the other end connected to the GND 19. A terminal 24 is provided to adjust the potential on the anode side of the electroabsorption modulator 14. A lens 24 is provided for coupling light from the electroabsorption modulator 14 to an optical fiber (not shown).

  The operation of the semiconductor optical module having the above configuration will be described. First, a high frequency modulation signal is input from the input terminal 20, this modulation signal is transmitted to the electroabsorption modulator 14 via the transmission line substrate 22, and terminated from the electroabsorption modulator 14 via the gold wire 18. The signal is transmitted to the resistor 17 and terminated by the termination resistor 17. The electroabsorption modulator 14 modulates the light emitted from the semiconductor laser (not shown) according to the input modulation signal. At this time, since the electroabsorption modulator 14 is maintained at a constant temperature by the electronic cooler 12, high frequency characteristics can be improved.

  Next, the operation of the semiconductor optical module according to the first embodiment will be described in more detail with reference to the circuit diagram shown in FIG. First, when a modulation signal of V [Vpp] is input from the input terminal 20, the offset voltage of the modulation signal becomes 0 [V] by the capacitor 21 on the transmission line. Then, by setting the potential of the terminal 24 to + V / 2 [V] and the potential of the cathode side of the electroabsorption modulator 14 to + V / 2 [V], the electroabsorption modulator 14 has 0 to −V. A voltage of [V] is applied, and the electroabsorption modulator 14 can be driven under the same conditions as usual. In this way, by adjusting the potential of the terminal 24, the voltage offset value applied to the electroabsorption modulator 14 can be freely adjusted.

Then, since the absorption current generated in the electroabsorption modulator 14 flows to the GND 19 through the inductor 23, an AC voltage of −V / 2 to V / 2 [V] is applied to the termination resistor 17. Power consumption can be reduced.

  Further, as described above, the termination resistor 17 that is a heating element is provided on the shelf 13 provided separately from the electronic cooler 12, so that the heat of about 0.1 W generated by the termination resistor 17 is generated. Heat can be exhausted directly to the package 11 without going through the electronic cooler 12. Thereby, the necessary heat absorption amount of the electronic cooler 12 is only the heat generation of the electroabsorption modulator 14 itself, the heat amount flowing in from the transmission line substrate 22, and the heat amount flowing in via the gold wire 18. . Therefore, the required heat absorption amount of the electronic cooler 12 is reduced, and the power consumption in the electronic cooler 12 can be reduced.

Embodiment 2. FIG.
FIG. 3A is a top view showing a semiconductor optical module according to Embodiment 2 of the present invention, and FIG. 3B is a cross-sectional view thereof. Constituent elements similar to those in FIG.

  In the semiconductor module according to the second embodiment, the first transmission line connecting the input terminal 20 and the electroabsorption modulator 14 is configured by the transmission line substrate 31. The transmission line substrate 31 is provided so as to bridge the shelf 13 and the electronic cooler 12.

  Further, the second transmission line connecting the electroabsorption modulator 14 and the termination resistor 17 is constituted by the transmission line substrate 32. The transmission line substrate 32 is provided on the electronic cooler 12 so as to exist from the electroabsorption modulator 14 to the end of the electronic cooler 12. The transmission line substrate 32 and the termination resistor 17 are connected by a gold wire 33. The characteristic impedance of the transmission line substrates 32 and 33 and the characteristic impedance of the termination resistor 17 are substantially equal, and impedance matching is obtained.

  As described above, the provision of the transmission line substrate 32 can shorten the wire length of the gold wire 33 that causes the high frequency characteristics to deteriorate, and can improve the high frequency characteristics. Here, since the electroabsorption modulator 14 is used with a reverse bias, it exhibits a very high impedance under operating conditions. Therefore, even if the electroabsorption modulator 14 is disposed between the transmission line substrate 32 and the transmission line substrate 33, the propagation of the modulation signal in the transmission line is not disturbed and the high frequency characteristics are not deteriorated.

  Further, similarly to the first embodiment, since the electroabsorption modulator 14 is maintained at a constant temperature by the electronic cooler 12, high frequency characteristics can be improved. Then, the termination resistor 17 as a heating element is provided on the shelf 13 provided separately from the electronic cooler 12, so that heat generated by the termination resistor 17 can be directly packaged without using the electronic cooler 12. 11, the required heat absorption amount of the electronic cooler 12 is reduced, and the power consumption in the electronic cooler 12 can be reduced.

Embodiment 3 FIG.
FIG. 4A is a top view showing a semiconductor optical module according to Embodiment 3 of the present invention, and FIG. 4B is a cross-sectional view thereof. Constituent elements similar to those in FIG.

  In the semiconductor module according to the third embodiment, the transmission line substrate 41 constitutes the second transmission line connecting the electroabsorption modulator 14 and the termination resistor 17. The transmission line substrate 41 is provided so as to bridge from the upper surface of the electronic cooler 12 to the upper surface of the shelf 13. The transmission line substrate 41 and the termination resistor 17 are connected by a gold wire 42. Further, the characteristic impedance of the transmission line substrates 32 and 41 and the characteristic impedance of the termination resistor 17 are substantially equal, and impedance matching is obtained.

  As described above, since the transmission line substrate 41 that bridges the electronic cooler 12 and the shelf 13 can be provided, the wire length of the gold wire 42 that causes the high frequency characteristics to deteriorate can be shortened. Compared with Embodiment 2, the high frequency characteristics are further improved.

  In addition, if the transmission line substrates 32 and 41 that bridge the electronic cooler 12 and the shelf 13 are made of a material having a low thermal conductivity, the amount of heat flowing into the electronic cooler 12 through the transmission line substrates 32 and 41 can be suppressed. Therefore, the power consumption in the electronic cooler 12 can be reduced.

Embodiment 4 FIG.
FIG. 5A is a top view showing a semiconductor optical module according to Embodiment 4 of the present invention, and FIG. 5B is a cross-sectional view thereof. Constituent elements similar to those in FIG.

  In the semiconductor module according to the fourth embodiment, the second transmission line connecting the electroabsorption modulator 14 and the termination resistor 17 is constituted by the transmission line substrate 51. The transmission line substrate 51 is provided so as to bridge from the upper surface of the electronic cooler 12 to the upper surface of the shelf portion 13. The termination resistor 17 is integrated with the transmission line substrate 51.

  As described above, since the termination resistor 17 and the transmission line substrate 51 are integrated, it is not necessary to use a gold wire for both connections, so that the high frequency characteristics are further improved as compared with the third embodiment.

Embodiment 5 FIG.
FIG. 6A is a top view showing a semiconductor optical module according to Embodiment 5 of the present invention, and FIG. 6B is a cross-sectional view thereof. Constituent elements similar to those in FIG.

  In the semiconductor module according to the fifth embodiment, the first transmission line connecting the input terminal 20 and the electroabsorption modulator 14 and the second transmission line connecting the electroabsorption modulator 14 and the termination resistor 17. Is composed of one transmission line substrate 61. The transmission line substrate 61 is provided so as to bridge from the upper surface of the electronic cooler 12 to the upper surface of the shelf portion 13. The termination resistor 17 is integrated with the transmission line substrate 61.

  As described above, since the first transmission line and the second transmission line are configured with one transmission line substrate 61, the number of components to be used can be reduced, so that a module can be manufactured at low cost. it can.

Embodiment 6 FIG.
FIG. 7A is a top view showing a semiconductor optical module according to Embodiment 6 of the present invention, and FIG. 7B is a cross-sectional view thereof. Constituent elements similar to those in FIG.

  In the semiconductor module according to the sixth embodiment, a power supply wiring 71 for supplying power to the electroabsorption modulator 14, the thermistor 15, the monitor photodiode 16, and the like on the electronic cooler 12 is integrated with the transmission line substrate 61. It has become.

  As described above, by integrating the power supply wiring 71 with the transmission line substrate 61, the number of components to be used can be further reduced as compared with the fifth embodiment, and therefore, a module can be manufactured at a lower cost. Can do.

Embodiment 7 FIG.
In the semiconductor module according to the seventh embodiment, the transmission line substrate 61 shown in FIG. 7 is configured by a flexible substrate. Since the flexible substrate is very thin compared to a normal ceramic substrate, the thermal resistance is large. Thereby, the amount of heat flowing into the electronic cooler 12 through the transmission line substrate 61 can be suppressed, and the power consumption in the electronic cooler 12 can be reduced.

Embodiment 8 FIG.
FIG. 8A is a top view showing a semiconductor optical module according to Embodiment 8 of the present invention, and FIG. 8B is a cross-sectional view thereof. Constituent elements similar to those in FIG.

  In the semiconductor module according to the eighth embodiment, the upper surface of the electronic cooler 12 and the upper surface of the shelf 13 are different in height, and there is a step between them. Thereby, since the distance which the transmission line board | substrate 61 bridges becomes long, compared with the case where there is no level | step difference, the thermal resistance of the transmission line board | substrate 61 can be enlarged. Therefore, the amount of heat flowing into the electronic cooler 12 through the transmission line substrate 61 can be suppressed, and the power consumption in the electronic cooler 12 can be reduced.

  Further, if the transmission line substrate 61 is formed of a flexible substrate, the flexible substrate can be bent unlike a normal ceramic substrate, so that the step can be absorbed and bridged.

It is the top view and sectional drawing which show the semiconductor optical module which concerns on Embodiment 1 of this invention. 1 is a circuit diagram of a semiconductor optical module according to Embodiment 1 of the present invention. It is the top view and sectional drawing which show the semiconductor optical module which concerns on Embodiment 2 of this invention. It is the upper side figure and sectional drawing which show the semiconductor optical module which concerns on Embodiment 3 of this invention. It is the top view and sectional drawing which show the semiconductor optical module which concerns on Embodiment 4 of this invention. It is the upper side figure and sectional drawing which show the semiconductor optical module which concerns on Embodiment 5 of this invention. It is the top view and sectional drawing which show the semiconductor optical module which concerns on Embodiment 6 of this invention. It is the top view and sectional drawing which show the semiconductor optical module which concerns on Embodiment 7 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Package 12 Electronic cooler 13 Shelf part 14 Electroabsorption modulator 17 Termination resistor 18, 33, 42 Gold wire 20 Input terminal 21 Capacitor 23 Inductor 24 Terminals 22, 31, 32, 33, 41, 51, 61 Transmission line substrate 71 Power supply wiring

Claims (9)

A hermetically sealed package;
An electronic cooler provided in the package;
An electroabsorption modulator provided on the electronic cooler;
A shelf provided separately from the electronic cooler in the package;
A termination resistor provided on the shelf and connected to the electroabsorption modulator;
An input terminal for inputting a signal to the electroabsorption modulator;
A capacitor connected between the input terminal and the electroabsorption modulator;
An inductor connected in parallel to the electroabsorption modulator and the termination resistor;
A semiconductor optical module comprising a terminal for adjusting a potential on the anode side of the electroabsorption modulator. A hermetically sealed package;
An electronic cooler provided in the package;
An electroabsorption modulator provided on the electronic cooler;
A shelf provided separately from the electronic cooler in the package;
A termination resistor provided on the shelf and connected to the electroabsorption modulator;
An input terminal for inputting a modulation signal to the electroabsorption modulator;
A first transmission line connecting the input terminal and the electroabsorption modulator;
A semiconductor optical module comprising a second transmission line connecting the electroabsorption modulator and the termination resistor. A wire connecting the second transmission line and the termination resistor;
The semiconductor optical module according to claim 2, wherein the second transmission line exists from the electroabsorption modulator to an end of the electronic cooler. A wire connecting the second transmission line and the termination resistor;
3. The semiconductor optical module according to claim 2, wherein the second transmission line includes a substrate that bridges from the upper surface of the electronic cooler to the upper surface of the shelf. The second transmission line is composed of a substrate that bridges from the upper surface of the electronic cooler to the upper surface of the shelf,
The semiconductor optical module according to claim 2, wherein the termination resistor is integrated with the substrate.   The semiconductor optical module according to claim 2, wherein the first transmission line and the second transmission line are formed of a single substrate.   The semiconductor optical module according to claim 6, further comprising power supply wiring integrated with the substrate for supplying electric power to the electronic cooler.   The semiconductor optical module according to claim 4, wherein the substrate is a flexible substrate.   9. The semiconductor optical module according to claim 4, wherein there is a step between the upper surface of the electronic cooler and the upper surface of the shelf.

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