JP4526767B2 - Optical semiconductor device and optical transmission device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical semiconductor device and an optical transmission device, and more particularly to an optical semiconductor device and an optical transmission device that include an optical semiconductor element that outputs an optical signal modulated based on an electrical signal.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a semiconductor laser driving circuit that drives a semiconductor laser to emit an optical signal is provided, and an impedance matching element and a fall time adjusting resistor element are provided between the semiconductor laser driving circuit and the semiconductor laser. There is an optical semiconductor device that supplies an optical modulation signal (see, for example, Patent Document 1). The fall time adjusting resistor element is arranged in parallel with the semiconductor laser, and corrects an impedance mismatch between the semiconductor laser and the semiconductor laser driving circuit due to an impedance error of the semiconductor laser and the impedance matching element. Further, the fall time adjusting resistor element adjusts the fall time of the optical signal.
[0003]
Conventionally, there is known an optical semiconductor device in which an external resistor including a finite parasitic inductance component is connected in parallel to a serial connection body composed of a semiconductor laser and a damping resistor (see, for example, Patent Document 2). . In this document, a technique is disclosed in which the amount of inductance in the entire parallel connection element such as a semiconductor laser, a damping resistor, and an external resistor is reduced as compared with the case where the resistor is not connected when viewed from the drive circuit side, An optical output waveform in which ringing is suppressed is obtained without increasing the fall time on the optical transmission waveform.
[0004]
Furthermore, as a conventional technique, a differential amplifier circuit, an impedance matching element, a drive amplitude adjustment current source, and a power source are provided, and a waveform shaping circuit is connected between a signal input terminal to the differential amplifier circuit and the differential amplifier. There is an optical semiconductor device (see, for example, Patent Document 3). In the optical semiconductor device described in this document, the drive waveform of the light modulation element is adjusted, and an optimum and high-speed light output waveform is obtained. Further, in the adjustment of the drive waveform, the cross point of the optical output waveform is set to an optimum state.
[0005]
Conventionally, when a semiconductor laser drive circuit having a relatively long rise time or fall time is intended to improve its rise characteristic or fall characteristic, the semiconductor laser drive circuit should have peaking characteristics. It is known that slight ringing occurs by adjusting to (for example, see Non-Patent Document 1).
[0006]
[Patent Document 1]
JP-A-5-327617 (page 4-8, FIG. 1)
[Patent Document 2]
JP 7-46194 A (page 3-4, FIG. 1)
[Patent Document 3]
JP-A-11-223802 (first and third pages, FIG. 3)
[Non-Patent Document 1]
A Versatile Si-Bipolar Driver Circuit with High Output Voltage Swing for External and Direct Laser Modulation in 10 Gb / s Optical-Fiber Links IEEE JOURNAL OF SOLID-STATE CIRCUITS, Vol. 29, No. 9 (pages 1014-1017, Fig. 3)
[0007]
[Problems to be solved by the invention]
However, in the conventional optical semiconductor device as described above, in order to improve an optical signal having a long fall time, an impedance matching element or a damping resistor is provided between the semiconductor laser and the semiconductor laser driving circuit, and in parallel therewith. A resistive element was connected. However, since a high-frequency signal leaks to the ground plane through the parallel-connected resistance elements, there is a problem that a large power loss is involved.
[0008]
Further, in the conventional optical semiconductor device, in order to eliminate the deviation of the cross point of the optical output waveform, the position of the cross point is adjusted by the waveform shaping circuit, and the apparent optical output waveform is within the range of the deviation of the cross point. The fall time was shortened. However, when the fall gradient (falling speed) of the optical output waveform is reduced and the eye opening of the optical output waveform is distorted into an asymmetric shape, the fall time is made faster. Adjustment, that is, adjustment that makes the falling gradient larger, cannot be made, and the time that can be shortened is naturally limited.
[0009]
In addition, the technique for adjusting the semiconductor laser driving circuit to have peaking characteristics in order to improve the falling characteristic of the semiconductor laser driving circuit having a relatively long falling time has been described above. In the past, it was handled as something that should be eliminated or reduced (see Patent Document 2 and Non-Patent Document 1), and this peaking characteristic is to be actively utilized. There was no way of thinking.
[0010]
However, even if the optical waveform undulates due to the ringing characteristics of the semiconductor laser driving circuit, it is sufficient that the eye opening of the electrical waveform after being photoelectrically converted by the receiver and passing through the electrical filter is improved.
[0011]
The present invention has been made in view of the above, and an object of the present invention is to provide an optical semiconductor device and an optical transmission device that can improve the fall time of the optical output waveform output from the optical semiconductor element.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, the optical semiconductor device according to the present invention includes an optical semiconductor element and a drive circuit that outputs a drive current to the optical semiconductor element, and the drive circuit Outputs a signal current that is a superposition of a square-wave drive current and an AC signal current generated by ringing that includes a sine wave component at a frequency that is three or more times the maximum repetition frequency of the drive current. as well as, the alternating signal current to decay with time, and applying with the rise of the driving current of the square wave.
[0013]
According to the invention, the drive circuit provided in the optical semiconductor device to output a drive current to the optical semiconductor element includes a drive current of a square wave, or maximum repetition 3 times the frequency to the frequency of the drive current by outputting the alternating signal current containing more sinusoidal components of the frequency, a signal current obtained by superimposing a drive signal, to improve the falling characteristics of the electrical signal after equalized by the filter.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an optical semiconductor device and an optical semiconductor device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.
[0015]
FIG. 1 is a circuit configuration diagram illustrating an example of an optical semiconductor device according to the first embodiment. In the figure, a laser diode driving circuit (hereinafter referred to as an LD driving circuit) 1 includes an input buffer 11 having a differential input configuration and a pair of differentials having a differential configuration for outputting a negative phase signal and a positive phase signal. The transistors 12 and 13 are the loads of the collectors of the transistors 14 and 13 that operate at a constant current and the differential transistors 12 and 13, respectively, and are provided with resistors 15 and 16 for impedance matching, respectively.
[0016]
The input buffer 11 shapes the waveform of the input negative phase signal and the positive phase signal, and generates the adjusted negative phase signal and the positive phase signal that are input to the bases of the differential transistors 12 and 13.
[0017]
A pair of differential transistors 12 and 13 and a transistor 14 forming a differential configuration constitute a differential amplifier. The collector side of each of differential transistors 12 and 13 is connected to one side of resistors 15 and 16. The other side of the resistors 15 and 16 is connected to the ground terminal. The emitters of the differential transistors 12 and 13 are connected to a transistor 14 that operates at a constant current.
[0018]
The base of the differential transistor 12 is connected to the negative phase signal output terminal of the input buffer 11, and the base of the differential transistor 13 is connected to the positive phase signal output terminal of the input buffer 11. Both the emitter side of the transistor 14 and the voltage input terminal of the input buffer 11 are connected to a negative power source (Vee).
[0019]
The collector-side output terminals of the differential transistors 12 and 13 are a pair of laser diodes (hereinafter referred to as LDs) 20 via a distributed constant circuit 18 constituted by a microstrip line or a grounded coplanar line, and matching resistors 19a and 19b. The electrodes (anode and cathode) are respectively connected.
[0020]
The differential transistors 12 and 13 may be field effect transistors (FETs). In this case, both the anode and the cathode of the LD 20 are connected to the drain side of the field effect transistor.
[0021]
The LD module 2 side is connected to an LD 20 having a high frequency impedance of about 5Ω via a distributed constant circuit 18 and matching resistors 19a and 19b for impedance matching of about 20Ω. The anode side of the LD 20 is joined to a conductor line electrically connected to the matching resistor 19b by solder or the like, and the cathode side of the LD 20 is connected to a conductor line electrically connected to the matching resistor 19a via a wire bond 29. Is done.
[0022]
The distributed constant circuit 18 connects the output terminals of the differential type differential transistors 13 and 12 of the LD drive circuit 1 and the matching resistors 19a and 19b by differential lines or wire bonds. Composed. The differential line forms a distributed constant line by arranging two conductor lines (first and second conductor lines) close to each other. A conductor line constituting the differential line constitutes a microstrip line with a strip conductor formed on the surface of the dielectric substrate and a ground conductor formed on the back surface of the dielectric substrate. Alternatively, as another conductor line, the strip conductor may be another microwave transmission line such as a coplanar line, a grounded coplanar line, or a triplate line. The differential line increases the electrical coupling between the two lines by performing signal transmission such that one of the input signals to the two conductor lines is a positive phase signal and the other is a reverse phase signal. Leakage loss can be reduced. For this reason, the differential line is also called a coupled line.
[0023]
Here, for example, one end (normal phase signal output terminal or negative phase signal output terminal) of the output terminal of the LD drive circuit 1 is connected to the cathode of the LD 20 and the anode of the LD 20 is grounded to the ground. Think about the case. In this case, since the large current that has driven the LD returns to the LD drive circuit via the ground, the ground potential varies. For this reason, when the optical circuit of the optical receiving system is installed close to the electronic circuit (for example, a preamplifier, a transimpedance amplifier, etc.) that detects a weak current may be adversely affected.
[0024]
On the other hand, in this embodiment, since the LD is pushed and pulled using the differential line, a large current flows through the differential line, and the fluctuation of the ground potential is reduced, which affects the peripheral circuit. There is an advantage that is hard to come out.
[0025]
The differential line is a differential microstrip line (microstrip differential line) in which the above-described two signal transmission conductor lines (first and second conductor lines) are arranged close to each other, or differential. It is constituted by a type of grounded coplanar line (grounded coplanar differential line), a differential pin (or lead) in which two conductor pins are arranged close to each other.
[0026]
A first bias circuit 28a is composed of a solenoid 21a (first inductance element) having a high impedance to a high frequency and a resistor 22a connected in parallel to the solenoid 21a and reducing the Q value to prevent resonance. A second bias circuit 28b is composed of a solenoid 21b (second inductance element) having a high impedance to high frequency and a resistor 22b connected in parallel to the solenoid 21b and reducing the Q value to prevent resonance. The solenoids 21a and 21b pass a bias current (DC), and a modulation signal (an electric signal of several hundred kHz to several tens GHz) output from the LD drive circuit 1 is supplied to the first and second bias circuits 28a, An air-core coil is used to suppress leakage from 28b, that is, to block high-frequency signals.
[0027]
The solenoid 21a of the first bias circuit 28a and the solenoid 21b of the second bias circuit 28b are both electrically connected to the anode and cathode of the LD 20 through wire bonds 23a and 23b, respectively. It is connected to the conductor line. As a result, the bias circuit 28 a is connected to the conductor line electrically connected to the matching resistor 19 a via the wire bond 23 a and connected to the cathode of the LD 20 via the wire bond 29. The bias circuit 28b is connected to a conductor line electrically connected to the matching resistor 19b through the wire bond 23b, and is connected to a soldered conductor line (pad) of the anode of the LD 20.
[0028]
The anode side of the LD 20 is connected to a ground terminal through a parallel circuit of a wire bond 23b and a second bias circuit 28b. The cathode side of the LD 20 is connected to the transistor 24 through a parallel circuit of a wire bond 23a and a second bias circuit 28a. The transistor 24 has an emitter side connected to a negative voltage source (Vee) and performs a constant current operation. This negative power source is the same voltage as the negative power source (Vee) to which the transistor 14 of the LD drive circuit 1 is connected, but may be a different voltage. Note that the bias circuits 28a and 28b work together with the wire bonds 23a and 23b and the like as an ungrounded open terminal in terms of high frequency.
[0029]
According to the driving configuration of the LD 20, a direct current bias current is supplied to the anode and the cathode of the LD 20 via the pair of first and second bias circuits 28a and 28b, and a pair of differential type differential transistors 12, 13, a high-frequency modulation current is differentially input to the anode and cathode of the LD 20.
[0030]
That is, when the differential transistor 12 of the LD driving circuit 1 is turned from ON to OFF (the differential transistor 13 is turned from OFF to ON), a modulation current flows through the LD 20, and the laser light output from the LD 20 is turned from OFF to ON. Further, when the differential transistor 13 is turned from ON to OFF (the differential transistor 12 is turned from OFF to ON), the modulation current flowing through the LD 20 is reduced, and the laser light output from the LD 20 is turned from ON to OFF.
[0031]
Therefore, the modulated electric signal output from the differential transistors 12 and 13 of the LD driving circuit 1 which are differentially configured is transmitted to the LD 20 through the distributed constant circuit 18 and the like, and the modulated electric signal is converted into an optical modulation signal in the LD 20. Converted. The light modulation signal generated from the LD 20 is condensed on the optical fiber 26 by the condenser lens 25 and is output through the optical fiber 26.
[0032]
Here, FIG. 2 is a diagram illustrating an example of an eye pattern of an electric signal waveform output from a general LD driving circuit driven with a negative voltage. Since this LD drive circuit is driven with a negative voltage, the rising portion of the electrical signal pulse corresponding to the rising portion of the optical signal pulse is the downward portion, and conversely, corresponds to the falling portion of the optical signal pulse. The falling portion of the electric signal pulse to be performed is a portion directed upward. Assuming that the fall time is Tf and the rise time is Tr, Tf is approximately 40% longer than Tr as shown in FIG.
[0033]
FIG. 3A is an explanatory diagram schematically showing the rising and falling characteristics of the pair of differential transistors 12 and 13 of the LD driving circuit 1, and FIG. 3B is a diagram illustrating the pair of differential transistors 12 and 13. It is explanatory drawing which shows the principle by which the rise and fall characteristics of 13 are averaged.
[0034]
Assuming that the characteristics of the pair of differential transistors 12 and 13 are the same, as shown in FIG. 2, there is a relationship of Tr <Tf between the fall time Tf and the rise time Tr. Is a waveform as shown in FIG.
[0035]
On the other hand, as shown in FIG. 1, the positive phase signal and the negative phase signal pass through the distributed constant circuit 18, one of which is connected to the cathode of the LD 20 via the matching resistor 19a, and the other is the matching resistor 19b. To the anode of the LD 20. With these connections, when the differential transistor 12 rises, the differential transistor 13 falls simultaneously, and when the differential transistor 12 falls, the differential transistor 13 rises simultaneously. , 13 is driven by push-pull.
[0036]
Therefore, since the circuit of the optical semiconductor device of the present invention shown in FIG. 1 performs such a push-pull operation, the distributed constant circuit 18 becomes a differential line, and the current is pushed into and pulled out from the LD 20. When viewed from the LD 20, the operation is performed with an average time ((Tr + Tf) / 2) of the rise time (Tr) of the differential transistor 12 and the fall time (Tf) of the differential transistor 13. . As a result, as shown in FIG. 3B, the rise time and the fall time are averaged, and a rising / falling characteristic having a symmetrical shape is obtained.
[0037]
FIG. 4 is a diagram in which the optical waveform and the electric waveform after equalization are overwritten by changing the ringing frequency. The waveform shown in the figure is an injection current in which the rate equation of an InGaAsP laser diode element, which is an optical semiconductor, is a square wave of NRZ (Non Return to Zero) and 2 ⁷ −1 PRBS (Pseudo-Random Binary Sequence). A light waveform ("no filter" shown in the center of the figure) that is output when a sine wave amplitude (sine wave-like electric waveform) of each frequency is superimposed on the waveform (electric waveform of a square wave digital output), This optical output waveform is simulated with an electrical waveform ("with filter" shown on the right side of the figure) after equalizing with a (fourth order) Bessel filter.
[0038]
As is clear from the simulation results, the maximum repetition frequency of the square wave signal is 5 GHz, whereas the ringing frequency is approximately three times 15 GHz or higher, and the electrical signal after equalization by the filter It can be seen that a higher quality optical output waveform with a large eye opening is obtained.
[0039]
Here, the signal current having a sinusoidal electric waveform attenuates the sinusoidal amplitude with time, and the signal current has a significant duration for at least 1.5 cycles. It is characterized by.
[0040]
For example, when the waveform line in the eye opening of the optical output waveform overlaps several times and the waveform quality deteriorates, the bit error increases at the transmission destination (optical receiver side) of the optical output signal. The conventional optical semiconductor device has a limit in such a waveform improvement effect.
[0041]
However, in this embodiment, by superposing a sinusoidal electric waveform approximately three times the maximum repetition frequency of the electric waveform on the electric waveform of the square wave digital output of the LD driving circuit, the eye opening having a larger eye opening is superposed. A high-quality optical output waveform is obtained.
[0042]
FIG. 5A is a diagram showing an optical waveform which is an experimental example of the present invention, and FIG. 5B is a diagram showing an electric waveform after filter equivalence which is an experimental example of the present invention. FIG. 6 is a diagram showing an electrical waveform after filter equivalence when the present invention is not used.
[0043]
The waveform shown in FIG. 5A is an optical waveform output from an optical semiconductor device (or optical transmission device) that actually applies this principle. At first glance, as shown in this figure, the eye opening becomes smaller and the optical signal appears to have deteriorated. However, a good eye pattern can be obtained by looking at the waveform shown in FIG. 5B, which shows the electrical waveform after equalization by the Bessel filter provided in the optical receiver not shown. I understand that. Further, it can be seen that a sufficient improvement effect is obtained as compared with FIG. 6 which is an example of an electric output waveform when this principle is not used. In addition, although the case where the Bessel filter was used was shown here, other low-pass filters other than this may be used.
[0044]
The maximum repetition frequency is 5 GHz when the transmission rate is 10 Gbit / sec in the NRZ system, and 10 GHz when the transmission rate is 10 Gbit / sec in the RZ (Return to Zero) system, and the frequency varies depending on the signal pattern. .
[0045]
The optical signal transmitted from the optical transmitter is transmitted via an optical fiber and then received by an optical receiver provided with a Bessel filter. When the transmission distance of the optical fiber is transmitted over a long distance exceeding 100 km, the waveform deteriorates due to the influence of the dispersion characteristic of the optical wavelength. For this reason, the wavelength of the optical signal output from the optical semiconductor device of this embodiment (the output wavelength of the LD 20) is preferably in the 1.3 μm band where the influence of chromatic dispersion characteristics hardly occurs. However, an LD 20 that outputs an optical signal in another wavelength band such as a 1.5 μm band may be used as long as it is within the range not affected by the wavelength dispersion characteristics.
[0046]
According to this embodiment, the electrical waveform of the square wave digital output of the LD drive circuit is superimposed with a sinusoidal electrical waveform that is approximately three times the maximum repetition frequency of the electrical waveform. At the start of the fall, the light intensity is relatively high. For this reason, even if the fall times are the same, the gradient of the light output change becomes large, and as a result, a good eye opening can be obtained.
[0047]
As described above, according to the optical semiconductor device of this embodiment, the drive circuit provided in the optical semiconductor device for outputting the drive current to the optical semiconductor element includes the square-wave drive current and the drive current. Since a signal current obtained by superimposing a sinusoidal signal current having a frequency approximately three times the maximum repetition frequency or higher is output as the drive signal, the electric signal after equalization by the filter As a result, the optical output waveform having a large eye opening and a higher quality can be obtained.
[0048]
Also, according to the optical semiconductor device of this embodiment, the sine wave amplitude attenuates with time in the square wave drive current output from the drive circuit, and this sine wave amplitude is at least a square wave drive current. By superimposing signal currents that are significantly maintained during a period of approximately 1.5 times the maximum repetition period, the effect of improving the falling characteristics of the electrical signal can be effectively achieved. Here, “significant” means that a sinusoidal signal superimposed on the square-wave drive current is output to the extent that an effect of improving the falling characteristics of the electric signal is produced.
[0049]
In addition, according to the optical transmission device of this embodiment, a photoelectric conversion element (not shown) that receives and photoelectrically converts an optical signal output from the optical semiconductor device, and a low band connected to the subsequent stage of the photoelectric conversion element By providing an optical receiving device (not shown) having a pass filter and the above-described optical semiconductor device, an optical output waveform having a large eye opening and a higher quality can be obtained.
[0050]
【The invention's effect】
As described above, according to the optical semiconductor device of the present invention, the driving circuit provided in the optical semiconductor device for outputting the driving current to the optical semiconductor element includes the square-wave driving current and the maximum of the driving current. Since a signal current obtained by superimposing a sinusoidal signal current having a frequency approximately three times the repetition frequency or higher is output as the drive signal, the electric signal after equalization by the filter is output. The falling characteristic is improved, and an optical output waveform having a larger eye opening and a higher quality can be obtained.
[0051]
Moreover, if the optical semiconductor device according to the present invention is used, an optical transmission device useful for optical signal transmission can be provided.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram illustrating an example of an optical semiconductor device according to a first embodiment;
FIG. 2 is a diagram showing an example of an eye pattern of an electric signal waveform output from a general LD driving circuit driven with a negative voltage.
3A is an explanatory diagram schematically showing rise and fall characteristics of a pair of differential transistors of an LD drive circuit, and FIG. 3B is a rise and fall characteristic of a pair of differential transistors. It is explanatory drawing which shows the principle by which is averaged.
FIG. 4 is a diagram in which an optical waveform and an electric waveform after equalization are overwritten by changing the ringing frequency.
5A is a diagram showing an optical waveform which is an experimental example of the present invention, and FIG. 5B is a diagram showing an electric waveform after filter equivalence which is an experimental example of the present invention.
FIG. 6 is a diagram showing an electric waveform after filter equivalence when the present invention is not used.
[Explanation of symbols]
1 LD driving circuit, 2 LD module, 11 input buffer, 12, 13 differential transistor, 14, 24 transistor, 15, 22a, 22b resistance, 18 distributed constant circuit, 19a, 19b matching resistance, 20 LD, 21a, 21b solenoid , 23a, 23b, 29 Wire bond, 25 Condensing lens, 26 optical fiber, 28a, 28b Bias circuit, Tf fall time, Tr rise time.

Claims (7)

An optical semiconductor device that transmits an optical signal to an optical receiver having a photoelectric conversion element and a low-pass filter connected to a subsequent stage of the photoelectric conversion element,
An optical semiconductor element that outputs an optical signal ;
A driving circuit that outputs a driving current to the optical semiconductor element;
The drive circuit is a signal obtained by superimposing a square-wave drive current and an AC signal current caused by ringing including a sine wave component having a frequency three times or higher than the maximum repetition frequency of the drive current. The AC signal current that outputs current and decays with time is applied with the rise of the square-wave drive current,
The amplitude of the AC signal current is maintained significantly at least for a period of 1.5 times the maximum repetition period of the square-wave drive current . An optical semiconductor device that transmits an optical signal to an optical receiver having a photoelectric conversion element and a low-pass filter connected to a subsequent stage of the photoelectric conversion element,
An optical semiconductor element that outputs an optical signal ;
A driving circuit that outputs a driving current to the optical semiconductor element;
The drive circuit is a signal obtained by superimposing a square-wave drive current and an AC signal current caused by ringing including a sine wave component having a frequency three times or higher than the maximum repetition frequency of the drive current. The AC signal current that outputs current and decays with time is applied with the rising and falling of the driving current of the square wave ,
The amplitude of the AC signal current is maintained significantly at least for a period of 1.5 times the maximum repetition period of the square-wave drive current . 3. The optical semiconductor device according to claim 1, wherein an output optical signal of the optical semiconductor element is a 10 Gbps NRZ (Non Return to Zero) signal, and the maximum repetition frequency is 5 GHz. 3. The optical semiconductor device according to claim 1, wherein an output optical signal of the optical semiconductor element is a 10 Gbps RZ (Return to Zero) signal, and the maximum repetition frequency is 10 GHz. An optical semiconductor device that transmits an optical signal to an optical receiver having a photoelectric conversion element and a low-pass filter connected to a subsequent stage of the photoelectric conversion element,
An optical semiconductor element that outputs an optical signal ;
A driving circuit that outputs a driving current to the optical semiconductor element;
The drive circuit is a signal obtained by superimposing a square-wave drive current and an AC signal current caused by ringing including a sine wave component having a frequency three times or higher than the maximum repetition frequency of the drive current. The AC signal current that outputs current and decays with time is applied with the rise of the square-wave drive current,
The drive circuit is composed of a differential amplifier, and has a pair of output terminals for outputting a pair of positive phase signals and a negative phase signal,
A first conductor line having one end connected to one of the pair of output terminals of the drive circuit and the other end connected to one of the pair of electrodes of the optical semiconductor element;
One end is connected to the other of the pair of output terminals of the drive circuit, the other end is connected to the other of the pair of electrodes of the optical semiconductor element, and the pair of differential lines together with the first conductor line A second conductor line comprising:
A first inductance element connected to a connection portion between the first conductor line and one electrode of the optical semiconductor element, and through which a bias current flows;
A second inductance element connected to a connection portion of the second conductor line and the other electrode of the optical semiconductor element and through which a bias current flows;
The optical semiconductor device you comprising the. The optical semiconductor device, an optical semiconductor device according to any one of claims 1-5, characterized in that output optical signals of wavelengths of 1.3μm band. An optical semiconductor device according to any one of claims 1 to 6 ,
A light receiving device having a photoelectric conversion element that receives and photoelectrically converts an optical signal output from the optical semiconductor device, and a low-pass filter connected to a subsequent stage of the photoelectric conversion element;
An optical transmission device comprising:

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