JP2020021797A - Optical reception sub assembly and optical module - Google Patents

Abstract

To uniform a characteristic in each channel.SOLUTION: An optical reception sub assembly comprises: a plurality of light reception elements 10 which are monolithically integrated in accordance with a plurality of channels; a carrier 20 having a plurality of circuits 22 corresponding to the plurality of channels; a plurality of amplification elements 34 which are monolithically integrated in accordance with the plurality of channels; and a first wire Wconnecting a first wire 26 and a first pad 36 in each of the plurality of channels and a second wire Wconnecting a second wire 28 and a second pad 38. The plurality of channels contain a pair of channels adjacent so as to be different in total wire length L of the first wire Wand the second wire W. The pair of channels are different in resistance value held by each of the plurality of circuits 22 between a second electrode 18 and the second wire W, and the resistance value is higher in the total wire length L longer in the pair of channels.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an optical receiving subassembly and an optical module.

  In recent years, the integration of optical transmission modules having a transmission speed of about 25 Gbps has been advanced, and a plurality of light emitting elements and a plurality of light receiving elements have been mounted in one optical transmission module (Patent Documents 1 and 2). ). As the size of packages has been reduced, the pitch between channels of an array of devices (optical elements, electric amplifiers) having a plurality of channels has been narrowed due to the miniaturization and high density of components contained in the packages.

JP 2012-138601 A JP 2014-192510 A JP-A-2017-135194

  The pitch between channels may vary from device to device. For example, in the optical receiving subassembly, the pitch between channels of the input pad of the electric amplifier is different from the pitch between channels of the light receiving element (for example, Photo Diode). In that case, the length of the wire electrically connecting the light receiving element and the electric amplifier differs for each channel. When the wire that is the transmission path of the electric signal becomes longer, the inductance L increases in proportion to the wire length, and the transmission characteristics (high-frequency characteristics) are degraded by the LC resonance circuit configured with the internal capacitance C of the light receiving element. That is, the characteristics are different for each channel.

  Patent Literature 3 considers a skew difference as a channel characteristic difference. In order to fill the skew difference, the structure and pattern of the submount are different for each channel. However, increasing the size of the submount or using a submount having a step structure is disadvantageous in terms of cost.

  An object of the present invention is to make the characteristics uniform for each channel.

  (1) An optical receiving subassembly according to the present invention has a first electrode and a second electrode to which a bias is applied corresponding to a plurality of channels, and converts an input optical signal into an electric signal. A plurality of monolithically integrated light receiving elements and a first electrically connected to the first electrode and the second electrode corresponding to the plurality of channels, respectively, such that the electric signal is output from the first electrode. A plurality of circuits each having a wiring and a second wiring, a carrier on which the plurality of light receiving elements are mounted, and a first pad and a second pad corresponding to the plurality of channels, respectively, A plurality of monolithically integrated amplifying elements, a first wire connecting the first wiring and the first pad in each of the plurality of channels, so as to amplify each signal; A second wire connecting the second wiring and the second pad, wherein the plurality of channels includes a pair of adjacent channels that differ in the total wire length of the first wire and the second wire. Wherein the pair of channels differ in a resistance value that each of the plurality of circuits has between the second electrode and the second wire, and wherein the total wire length of the pair of channels is longer, It is characterized by a higher resistance value.

  According to the present invention, the characteristics for each channel are adjusted and uniformed by the difference in the resistance value even if there is a factor that becomes non-uniform due to the difference in the total wire length of the first wire and the second wire. .

  (2) The optical receiving subassembly according to (1), wherein the plurality of amplifying elements are arranged in a line, and the plurality of circuits are arranged in a line along a line of the plurality of amplifying elements. The pitch of the plurality of circuits may be different from the pitch of the plurality of amplifying elements.

  (3) The optical receiving subassembly according to (2), wherein the plurality of light receiving elements are arranged in a line along a line of the plurality of circuits, and a pitch of the plurality of light receiving elements is equal to the plurality of light receiving elements. The pitch may be different from the pitch of the amplifying element.

  (4) The optical receiving subassembly according to (3), wherein the pitch of the plurality of circuits is equal to the pitch of the plurality of light receiving elements.

  (5) The optical receiving subassembly according to any one of (2) to (4), wherein the total wire length is the shortest in the channels at both ends in the arrangement direction of the plurality of light receiving elements. It may be characterized by being long.

  (6) The optical receiving subassembly according to (5), wherein the total wire length is the shortest in at least one of the channels located at the center in the arrangement direction of the plurality of light receiving elements. Good.

  (7) The optical receiving subassembly according to any one of (2) to (4), wherein the total wire length of the channel at one end in the arrangement direction of the plurality of light receiving elements is less than or equal to the total length. The total length of the wire may be the longest in the shortest channel at the other end in the arrangement direction of the plurality of light receiving elements.

  (8) The optical receiving subassembly according to (7), wherein the total wire length is longer as the total wire length is closer to the channel having the longest length.

  (9) The optical receiving subassembly according to any one of (1) to (8), wherein each of the plurality of circuits is at least the channel whose total wire length is not the shortest, The semiconductor device may further include a resistor connected in series to the second wiring, wherein the longer the total wire length of the pair of channels, the higher the resistance value of the resistor.

  (10) The optical receiving subassembly according to (9), wherein each of the plurality of circuits includes the resistor.

  (11) The optical receiving subassembly according to (9) or (10), wherein the second wire includes a pair of second wires, and the second wiring includes a pair of the second wires. It may be characterized by having a pair of ends to be bonded.

  (12) In the optical receiving subassembly according to (11), the pair of second wires have different lengths, and the resistor is connected to a longer one of the pair of second wires and the second wire. Only the electrode may be connected in series to the second wiring.

  (13) The optical receiver subassembly according to any one of (9) to (12), wherein the resistor overlaps a chip component in which the plurality of light receiving elements are monolithically integrated. Is also good.

  (14) An optical module according to the present invention includes an optical receiving subassembly according to any one of (1) to (13), and an optical transmitting subassembly that outputs an optical signal converted from an input electric signal. And an assembly.

FIG. 2 is an exploded perspective view of the optical module according to the first embodiment to which the present invention has been applied. FIG. 2 is a plan view showing the internal structure of the optical receiving subassembly according to the first embodiment to which the present invention has been applied. FIG. 3 is a plan view illustrating main components constituting the optical receiving subassembly illustrated in FIG. 2. FIG. 3 is a diagram illustrating an equivalent circuit of the optical receiving subassembly illustrated in FIG. 2. FIG. 9 is an exploded view of an optical receiving subassembly according to a modification of the first embodiment. FIG. 9 is a diagram illustrating a result of a first simulation. It is a figure showing the result of the 2nd simulation. FIG. 9 is a diagram illustrating a relationship between a resistance value _Rd , a 3 dB band, and a deviation. FIG. 9 is a diagram illustrating the relationship between the ratio of the total wire length of the wires and the resistance value R _d1 for each resistance value R _d2 when the transmission characteristics of the channel are made uniform. It is a figure showing an optical receiving subassembly concerning a 2nd embodiment.

  Hereinafter, embodiments of the present invention will be described specifically and in detail with reference to the drawings. In all the drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and a repeated description thereof will be omitted. In addition, the drawings shown below are for the purpose of describing the embodiments of the embodiments, and the size of the drawings does not always correspond to the scale described in the present embodiments.

[First Embodiment]
FIG. 1 is an exploded perspective view of an optical module according to a first embodiment to which the present invention is applied. The optical module 100 includes an optical transmission sub-assembly (TOSA) for converting an electric signal into an optical signal and an optical receiving sub-assembly (ROSA: Receiver) for converting an optical signal into an electric signal. Optical Sub-Assembly). On the transmission side, an electric signal sent from a host board (not shown) is converted into an optical signal via the optical interface 102 via the optical transmission subassembly 106, and transmitted from the optical interface 104. The receiving side receives the optical signal and outputs an electric signal to a host-side board (not shown).

  FIG. 2 is a plan view showing the internal structure of the optical receiving subassembly according to the first embodiment to which the present invention has been applied. The optical signal enters the light receiving subassembly 108, is collected by a lens (not shown), and enters the light receiving element 10.

The light receiving sub-assembly has a plurality of light receiving elements 10 (for example, a photodiode (PD)). The light receiving element 10 is a back-illuminated light receiving element having a light receiving section 12 (absorption layer) on a surface (bottom surface) opposite to a surface (top surface) on which an optical signal is incident. The plurality of light receiving elements 10 are monolithically integrated on a chip component 14 (PD array or the like). A plurality of light-receiving element 10, respectively, corresponding to the plurality of channels CH ₁ to CH _4.

FIG. 3 is a plan view showing main components constituting the optical receiving sub-assembly shown in FIG. The plurality of light receiving elements 10 are arranged in a line. Pitch P ₁ of the plurality of light receiving elements 10 is, for example, 500 um. The light receiving element 10 has a first electrode 16 and a second electrode 18 to which a bias is applied. The first electrode 16 and the second electrode 18 are on the bottom surface of the chip component 14. The light receiving element 10 converts an optical signal input from the light receiving unit 12 into an electric signal, and outputs an electric signal from the first electrode 16.

  The light receiving element 10 is an InP-based semiconductor element having a PN junction, and the side connected to the p-type semiconductor may be called an anode, and the side connected to the n-type semiconductor may be called a cathode. That is, the first electrode 16 and the second electrode 18 can also be referred to as an anode and a cathode, respectively. In other words, the p-type semiconductor side may be called a signal electrode, and the n-type semiconductor side may be called a bias electrode. Note that the names of the anode and the cathode are for convenience and may be called in reverse. That is, the names of the anode and the cathode here indicate that the light receiving element 10 has two electrodes (the first electrode 16 and the second electrode 18) having different polarities (different potential differences).

The optical receiving subassembly has a carrier 20 on which a plurality of light receiving elements 10 are mounted. The carrier 20 is one substrate that integrally supports the plurality of light receiving elements 10 (chip components 14). Carrier 20 is provided with a plurality of circuits 22 respectively corresponding to the plurality of channels CH ₁ to CH ₄ (or a plurality of light receiving elements 10). The plurality of circuits 22 are arranged in a row along the array of the plurality of light receiving elements 10. Pitch P ₁ of the plurality of circuit 22 is equal to the pitch P ₁ of the plurality of light receiving elements 10.

  The circuit 22 is electrically connected to the light receiving element 10. Solder 24 is used for electrical connection. The solder 24 is a solder ball in the bonding process of the chip component 14. Note that the connection is not limited to the solder 24 as long as the circuit 22 and the light receiving element 10 can be electrically connected.

  The first electrode 16 and the second electrode 18 of the light receiving element 10 face the circuit 22. The circuit 22 has a first wiring 26 electrically connected to the first electrode 16. The circuit 22 has a second wiring 28 electrically connected to the second electrode 18. The second wiring 28 has a pair of ends and has, for example, a U-shape. The first wiring 26 is arranged between a pair of ends of the second wiring 28. The first wiring 26 and the second wiring 28 are formed of a metal having a low resistance value (for example, Au, aluminum, platinum, silver, or the like).

Each of the plurality of circuits 22 has a resistor 30. In a pair of channels next to each other (e.g., the first channel CH ₁ and the second channel CH _2), different in the resistance value of the resistor 30 included in the circuit 22. The resistor 30 is a film made of a material having a high resistance value, such as a compound of Ni and Cr, a compound of Ta and N, Ti, and Mo. The resistor 30 is connected to the second wiring 28 in series. More specifically, a resistor 30 is provided between one end of the second wiring 28 and an intermediate part (a part where the second electrode 18 is joined or the solder 24 is provided), and the other end of the second wiring 28 is provided. There is no resistor 30 between the part and the middle part. At least a part or all of the resistor 30 overlaps the chip component 14 in which the plurality of light receiving elements 10 are monolithically integrated.

The optical receiving subassembly includes an amplifier 32 such as a preamplifier, a limiting amplifier, an auto gain controller, or a transimpedance amplifier. The amplifier 32 is arranged next to the carrier 20, and the interval between them is, for example, 70 um. In the amplifier 32, a plurality of amplifying elements 34 (for example, operational amplifiers) are monolithically integrated. A plurality of amplifying elements 34 are arranged along the arrangement direction of the plurality of circuits 22 (the plurality of light receiving elements 10). The plurality of amplifying elements 34 are arranged in a line. The pitch P ₂ of the amplifying element 34 is, for example, 250 μm, which is different from the pitch P ₁ (500 μm) of the plurality of light receiving elements 10 (the plurality of circuits 22). The center of the plurality of amplifying elements 34 in the arrangement direction coincides with the center of the plurality of circuits 22 in the arrangement direction.

A plurality of amplifying elements 34, corresponding to the plurality of channels CH ₁ to CH _4, for amplifying an electrical signal, respectively. The amplification element 34 has a first pad 36. An electric signal from the light receiving element 10 is input to the first pad 36. The amplification element 34 has a second pad 38. On the second pad 38, a bias voltage to be supplied to the light receiving element 10 appears. The first pad 36 and the second pad 38 are provided directly on the amplifier 32.

  Amplifier 32 has a power supply pad 40 for supplying power to amplification element 34. The power supply pad 40 is connected to an external power supply line by wires 42 and 44. One electrode of a flat plate capacitor 46 is connected between the wires 42 and 44. The amplifier 32 has another power supply pad 48 for applying a bias to the light receiving element 10. The power supply pad 48 is connected to an external power supply line by wires 50 and 52. One electrode of the flat plate capacitor 54 is connected between the wires 50 and 52.

  The light receiving sub-assembly has a wiring board 56. The wiring board 56 has a plurality of signal patterns 58. The pair of signal patterns 58 constitute a differential transmission line. The pair of signal patterns 58 are sandwiched between a pair of GND patterns 60. The GND pattern 60 is connected to a GND plane 64 on the back surface through a through hole 62. The output pad 66 of the amplifier 32 is connected to the signal pattern 58 by a wire 68 so as to output an amplified electric signal. The GND pad 70 of the amplifier 32 is connected to the GND pattern 60 by a wire 72.

Optical receiver subassembly at each of a plurality of channels CH ₁ to CH _4, it has a first wire W ₁ for connecting the first wiring 26 and the first pad 36. Optical receiver subassembly at each of a plurality of channels CH ₁ to CH _4, it has a second wire W ₂ for connecting the second wiring 28 and the second pad 38. In each channel, the first wire W ₁ and a second wire W ₂ has a total wire length L.

The pair of channels next to each other, differ in the first total wire length L of the wire W ₁ and a second wire W _2. In the first channel CH ₁ or the fourth channel CH ₄ at both ends in the arrangement direction of the plurality of light receiving elements 10, the longest total wire length L. In the second channel CH ₂ or the third channel CH ₃ in the center in the arrangement direction of the plurality of light receiving elements 10, the shortest total wire length L. The ratio of the total wire length L approximates the ratio of the inductance. The difference in the total wire length L causes different transmission characteristics for each channel.

Second wire W ₂ includes a pair of second wire W _2. The second wiring 28 has a pair of end second wire W ₂ of the pair are bonded, respectively. Second wire W ₂ of the pair, as shown in Figure 2, the different lengths. Resistor 30 included in the circuit 22, only between the longer and the second electrode 18 of the pair of second wire W _2, are connected in series to the second wiring 28.

According to the present embodiment, in a pair of adjacent channels, the resistance value of the resistor 30 is higher when the total wire length L is longer (for example, the first channel CH ₁ ). Thereby, even if the transmission characteristics for each channel become non-uniform due to the difference in the total wire length L of the first wire W ₁ and the second wire W ₂ , the transmission characteristics are adjusted by the difference in the resistance value of the resistor 30 and become uniform. Can be

FIG. 4 is a diagram showing an equivalent circuit of the optical receiving subassembly shown in FIG. The light receiving element 10 is a current source that pushes out a photocurrent I _pd (ω) proportional to the received light, and can be considered as an element having an internal capacitance C _pd and an internal resistance R _pd . Amplifying element 34 has an input impedance is approximated to the input resistor R _in.

In the present embodiment, a positive voltage is applied to the second electrode 18 (reverse bias state). A voltage V _pd for applying a bias is supplied from the amplifier 32 to the light receiving element 10. Many semiconductor light receiving elements 10 are used by applying a bias voltage in the same direction as in the present embodiment, but the positive and negative directions of the voltage are not particularly limited, and are appropriately selected depending on the light receiving elements 10 used.

Application of the bias to the light receiving element 10 from the power source 74 that is external, made from the second wire W ₂ via the second wiring 28. In many cases, a filter or the like is attached to the bias line in the amplifier 32, and the routing method and the like differ depending on each manufacturer of the amplifier 32.

When an optical signal is input to the light receiving element 10, an electric signal proportional to the received light is generated. Electrical signal is input to the amplifying element 34 through the first first pad 36 via a wire W _1.

Relationship of the light receiving element 10 through the photocurrent I _pd (omega) and the voltage is input to the amplifier element 34 V _in (ω) is expressed by the following equation.

Incidentally, R _d is the resistance value of the resistor 30, L is a first total wire length of the wire W ₁ and a second wire W ₂ L. To obtain the same frequency characteristics in all channels, in proportion to the difference in L, it may be changed value of R _d.

であり、Ｌ₁＝Ｌ_1-1＋Ｌ_1-2＋Ｌ_1-3である。 For example, if it is the first channel,

And L ₁ = L _1-1 + L _1-2 + L _1-3 .

であり、Ｌ₂＝Ｌ_2-1＋Ｌ_2-2＋Ｌ_2-3である。 For the second channel,

And L ₂ = L _2-1 + L _2-2 + L _2-3 .

In order to obtain the same frequency characteristics in the first and second channels,
R _in + R _pd + R _d1 + jωL ₁ = R _in + R _pd + R _d2 + jωL ₂
Should be satisfied.

Based on the difference between the total wire lengths L ₁ and L ₂ , the resistance value R _d1 can be obtained from the resistance value R _d2 by the following equation.

[Modification of First Embodiment]
FIG. 5 is an exploded view of an optical receiving subassembly according to a modification of the first embodiment. In this example, in the channel with the shortest total wire length L, circuit 122 has no resistor. That is, the second channel CH ₂ or the third channel CH ₃ has a resistance of 0Ω between the second electrode 118 and the second wire W ₂ . Note that, here, the resistance of the second wiring 128 itself is sufficiently small to be considered. Each of the plurality of circuits 122 has a resistor 130 connected in series to the second wiring 128 except for the channel having the shortest total wire length L. Thus, the longer the total wire length L of the adjacent pair of channels (first channel CH ₁ and the second channel CH ₂ or the third channel CH ₃ and the fourth channel CH ₄₎ is more, the resistance value of the circuit 122 Is higher. The resistance of the circuit 122 between the second electrode 118 and the second wire W ₂ is increased by the presence of the resistor 130.

In this example, the first inductance of the wire W ₁ is the 679 pH, the second inductance of the wire W ₂ is 506 pH. The ratio of the total wire length of the total wire length L and the second wire W ₂ of the first wire W ₁ L is approximate to the ratio of the inductance, in _{L 1 / L 2 = 679 pH} / 506 pH = 1.34 is there.

の式から、（30＋20＋Ｒ_d1）／（30＋20＋Ｒ_d2）＝679／506であるため、Ｒ_d1＝17.1 Ωが求められる。 _Assuming that R _{pd of the} light receiving element 110 is 20 Ω, the input resistance of the amplifying element 34 is R _in = 30 Ω, and the resistance R _d2 = 0 Ω, as described above,

Since (30 + 20 + R _d1 ) / (30 + 20 + R _d2 ) = 679/506, R _d1 = 17.1 Ω is obtained from the following equation.

FIG. 6 is a diagram illustrating a result of the first simulation. The horizontal axis is frequency, and the vertical axis is S21 indicating transmitted power characteristics. In FIG. 6, when the circuit has no resistor in both the first channel and the second channel (R _d1 = 0 Ω, R _d2 = 0 Ω), the peak intensity of the first channel is lower than that of the second channel by 1.3. dB large. This is because the total wire length of the first wire and the second wire is longer in the first channel than in the second channel.

In contrast, modification of the first embodiment as shown in (FIG. 5), by the first channel CH ₁ is provided a resistor _{130 (R d1 = 17.1 Ω)} , the first channel CH ₁ and the the peak intensity of 2-channel CH ₂ can be suppressed to equal 1.1 dB. The 3 dB band (the frequency at which S21 becomes 3 dB) is 27.3 GHz (25 GHz or higher), and a sufficient band is secured for the 25 Gbps transmission module.

FIG. 7 is a diagram showing the result of the second simulation. In this simulation, as shown in the first embodiment (FIGS. 2 and 3), the resistor 30 to the circuit 22 in the first channel CH ₁ of (R _d1 = 25 Ω) is provided, the circuit on the second channel CH ₂ 22 is provided with a resistor 30 (R _d2 = 10Ω). As a result, 3 dB bandwidth is at 25 GHz or more, the peak intensity of the first channel CH ₁ and the second channel CH ₂ may be kept uniform to 0.5 dB.

FIG. 8 is a diagram illustrating a relationship between the resistance value _Rd , the 3 dB band, and the deviation. Deviation indicates how much it deviates from 0 dB in the frequency domain within the transmission band. Here, it indicates the maximum value (peak intensity) of the amount deviating in the positive direction from 0 to 25 GHz. I have. In order to secure sufficient transmission characteristics in a 25 Gbps transmission module, it is required that the 3 dB band is 25 GHz or more and the deviation is 1.5 dB or less. The simulation results show that if R _d1 is 10 to 30 Ω, the transmission characteristics are good. By arranging the resistors, the deviation between CHs can be made uniform (approximately). When the value of the resistor is increased, the band tends to be reduced by 3 dB. However, in order to make the transmission characteristics between channels uniform, it is more effective to make the deviation equal to each other. Transmission characteristics can be made uniform.

FIG. 9 is a diagram showing the relationship between the ratio of the total wire length L of the wires and the resistance value R _d1 for each resistance value R _d2 when the transmission characteristics of the channel are made uniform. Within the range of the resistance value R _d is 10 to 30 Omega, it is described above that good transmission characteristics can be obtained. Therefore, it is desired that the resistance value R _{d1 be} in the range of 10 to 30Ω.

Modification of the first embodiment as shown in (FIG. 5), examples of the resistance R _d2 = 0 Ω of the second channel CH ₂ of the circuit 122. If the ratio of the first total wire length of the wire W ₁ and a second wire W ₂ L is 1.2 to 1.6, in order to equalize the transmission characteristics of the first channel CH ₁ and the second channel CH ₂ is 10 a resistor 130 having a resistance value R _d1 in the range of to 30 Omega may be provided to the first circuit 122 of the channel CH _1.

As shown in the first embodiment (FIGS. 2 and 3), if also provided a resistor 30 to the second channel CH ₂ of circuit 22, when the resistance value R _d2 is increased, a uniform transmission characteristics obtained The range of the ratio of the total wire length L when it is applied is narrowed. When the resistance value R _d2 = 10Ω, the ratio of the total wire length L needs to be in the range of 1.0 to 1.3.

[Second embodiment]
FIG. 10 is a diagram illustrating an optical receiving subassembly according to the second embodiment. In the present embodiment, the chip component 214 is arranged such that the light receiving element 210 at one end in the arrangement direction and the amplification element 234 (first channel CH ₁ ) at one end in the arrangement direction are adjacent to each other in a direction orthogonal to the arrangement direction. And the amplifier 232 are lined up.

In the first channel CH ₁ in the array direction at one end of the plurality of light receiving elements 210, the shortest total wire length L. In the fourth channel CH ₄ at the other end in the arrangement direction of the plurality of light receiving elements 210, the longest total wire length L. Total wire length L is longer the closer the total wire length L is the longest fourth channel CH _4.

Also in the present embodiment, the correlation shown in FIG. 9 is established. However, in the present embodiment, the resistor 30 of resistance R _d2 is in the first channel CH _1, resistor 30 of resistance R _d1 is in the second channel CH _2. Relationship between the first channel CH ₁ and the second channel CH ₂ may also correspond to a second channel CH ₂ and the third channel CH _3, also corresponds with the third channel CH ₃ and the fourth channel CH _4.

  The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the configuration described in the embodiment can be replaced with a configuration having substantially the same configuration, a configuration having the same operation and effect, or a configuration capable of achieving the same object.

Reference Signs List 10 light receiving element, 12 light receiving section, 14 chip component, 16 first electrode, 18 second electrode, 20 carrier, 22 circuit, 24 solder, 26 first wiring, 28 second wiring, 30 resistor, 32 amplifier, 34 amplification Element, 36 first pad, 38 second pad, 40 power pad, 42 wire, 44 wire, 46 plate capacitor, 48 power pad, 50 wire, 52 wire, 54 plate capacitor, 56 wiring board, 58 signal pattern, 60 GND Pattern, 62 through hole, 64 GND plane, 66 output pad, 68 wire, 70 GND pad, 72 wire, 74 power supply, 100 optical module, 102 electrical interface, 104 optical interface, 106 optical transmission subassembly, 108 optical reception Subassembly, 110 Light receiving element, 11 The second electrode, 122 circuit, 128 second wiring 130 resistor, 210 light receiving elements, 214 chip component 232 amplifier, 234 amplifying elements, C _pd internal volume, CH ₁ first channels, CH ₂ second channels, CH ₃ Third channel, CH ₄ fourth channel, I _pd (ω) _photocurrent , P ₁ pitch, P ₂ pitch, R _d1 resistance, R _d2 resistance, R _in input resistance, R _pd internal resistance, V _pd voltage, V _in (ω) voltage, W ₁ first wire, W ₂ second wire.

Claims (14)

Each of the plurality of channels has a first electrode and a second electrode to which a bias is applied, converts an input optical signal into an electric signal, and outputs the electric signal from the first electrode. And a plurality of monolithically integrated light receiving elements,
A plurality of circuits each having a first wiring and a second wiring electrically connected to the first electrode and the second electrode, respectively, corresponding to the plurality of channels, and a carrier on which the plurality of light receiving elements are mounted; ,
A plurality of monolithically integrated amplifying elements, each of which has a first pad and a second pad corresponding to the plurality of channels, and amplifies the electric signal,
A first wire connecting the first wiring and the first pad and a second wire connecting the second wiring and the second pad in each of the plurality of channels;
Has,
The plurality of channels include a pair of adjacent channels that differ in a total wire length of the first wire and the second wire,
The pair of channels differ in a resistance value each of the plurality of circuits has between the second electrode and the second wire,
The optical receiving sub-assembly, wherein the resistance value is higher when the total wire length of the pair of channels is longer. The optical receiving subassembly according to claim 1, wherein:
The plurality of amplifying elements are arranged in a line,
The plurality of circuits are arranged in a line along a line of the plurality of amplifying elements,
The optical receiving subassembly according to claim 1, wherein a pitch of the plurality of circuits is different from a pitch of the plurality of amplifying elements. The optical receiving subassembly according to claim 2, wherein:
The plurality of light receiving elements are arranged in a line along a line of the plurality of circuits,
The pitch of the plurality of light receiving elements is different from the pitch of the plurality of amplifying elements. The optical receiving subassembly according to claim 3, wherein:
The optical receiving subassembly according to claim 1, wherein the pitch of the plurality of circuits is equal to the pitch of the plurality of light receiving elements. An optical receiving sub-assembly according to any one of claims 2 to 4, wherein:
The optical receiving sub-assembly, wherein the total wire length is the longest in the channels at both ends in the arrangement direction of the plurality of light receiving elements. The optical receiving subassembly according to claim 5, wherein:
The optical receiving sub-assembly, wherein the total wire length is the shortest in at least one of the channels at the center in the arrangement direction of the plurality of light receiving elements. An optical receiving sub-assembly according to any one of claims 2 to 4, wherein:
In the channel at one end in the arrangement direction of the plurality of light receiving elements, the total wire length is the shortest,
The optical receiving subassembly, wherein the total wire length is the longest in the channel at the other end in the arrangement direction of the plurality of light receiving elements. The optical receiving subassembly according to claim 7, wherein:
The optical receiving sub-assembly, wherein the total wire length is longer as the total wire length is closer to the channel having the longest. An optical receiving sub-assembly according to claim 1, wherein:
Each of the plurality of circuits has a resistor connected in series to the second wiring at least in the channel where the total wire length is not the shortest,
The optical receiving sub-assembly, wherein the longer the total wire length of the pair of channels, the higher the resistance of the resistor. The optical receiving subassembly according to claim 9, wherein:
An optical receiving subassembly, wherein each of the plurality of circuits includes the resistor. An optical receiving sub-assembly according to claim 9 or claim 10, wherein
The second wire includes a pair of second wires,
The optical receiving sub-assembly according to claim 2, wherein the second wiring has a pair of ends to which the pair of second wires are respectively bonded. The optical receiving subassembly according to claim 11, wherein:
The pair of second wires have different lengths,
The optical receiving subassembly, wherein the resistor is connected in series to the second wiring only between a longer one of the pair of second wires and the second electrode. An optical receiving sub-assembly according to any one of claims 9 to 12, wherein:
The optical receiving subassembly, wherein the resistor overlaps a chip component in which the plurality of light receiving elements are monolithically integrated. An optical receiving subassembly according to any one of claims 1 to 13, and
An optical transmission subassembly that outputs an optical signal converted from the input electric signal,
An optical module comprising:

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