JP7132671B2 - Optical receiver subassembly and optical module - Google Patents

Description

The present invention relates to optical receiver subassemblies and optical modules.

In recent years, the integration of optical transmission modules having a transmission speed of about 25 Gbps has 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). ). The miniaturization of packages has progressed, and the miniaturization and high density of components housed in the packages have reduced the pitch between channels of arrayed devices (optical elements, electrical amplifiers) having a plurality of channels.

Japanese Unexamined Patent Application Publication No. 2012-138601 JP 2014-192510 A JP 2017-135194 A

The channel-to-channel pitch may vary from device to device. For example, in the optical receiver subassembly, the channel-to-channel pitch of the input pads of the electrical amplifier is different from the channel-to-channel pitch of the light-receiving elements (for example, Photo Diodes). In that case, the length of the wire electrically connecting between the light receiving element and the electric amplifier is different for each channel. As the wire, which is the transmission path of the electrical signal, becomes longer, the inductance L increases in proportion to the wire length, and the transmission characteristics (high frequency characteristics) deteriorate due to the LC resonance circuit formed together with the internal capacitance C of the light receiving element. In other words, the characteristics differ for each channel.

As a channel characteristic difference, Patent Document 3 addresses the skew difference, and in order to compensate for the skew difference, the structure and pattern of the submount are made different for each channel. However, increasing the size of the submount or using a submount with a stepped structure is disadvantageous in terms of cost.

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

(1) The optical receiver subassembly according to the present invention has first and second electrodes to which a bias is applied corresponding to a plurality of channels, and converts an input optical signal into an electrical signal. a plurality of light-receiving elements monolithically integrated so as to respectively output the electrical signals from the first electrodes; 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 amplifier elements monolithically integrated so as to each amplify a signal; a second wire connecting pads, wherein the plurality of channels includes a pair of adjacent channels that differ in total wire length of the first wire and the second wire, the pair of channels comprising: Each of the plurality of circuits has a different resistance value between the second electrode and the second wire, and the resistance value is higher in the channel having the longer total wire length among the pair of channels. and

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

(2) In the optical receiver subassembly described in (1), the plurality of amplifying elements are arranged in a row, the plurality of circuits are arranged in a row along the row of the plurality of amplifying elements, and the The pitch of the plurality of circuits may be characterized by being different from the pitch of the plurality of amplifying elements.

(3) In the optical receiving subassembly described in (2), the plurality of light receiving elements are arranged in a line along the arrangement of the plurality of circuits, and the pitch of the plurality of light receiving elements is the same as the plurality of light receiving elements. It may be characterized by being different from the pitch of the amplifying elements.

(4) The optical receiver subassembly described in (3) may be characterized in that the pitch of the plurality of circuits is equal to the pitch of the plurality of light receiving elements.

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

(6) In the optical receiver subassembly described in (5), the total wire length is the shortest in at least one of the channels located in the center in the arrangement direction of the plurality of light receiving elements. good.

(7) In the optical receiver subassembly according to any one of (2) to (4), the total wire length is The shortest channel may be characterized in that the total wire length is the longest in the channel located at the other end in the arrangement direction of the plurality of light receiving elements.

(8) The optical receiver subassembly described in (7), wherein the total wire length is longer the closer to the channel where the total wire length is the longest.

(9) The optical receiver subassembly according to any one of (1) to (8), wherein each of the plurality of circuits is at least the channel in which the total wire length is not the shortest, A resistor connected in series with the second wiring may be provided, and the resistance value of the resistor may be higher in the channel having the longer total wire length among the pair of channels.

(10) The optical receiver subassembly of (9), wherein any of the plurality of circuits may include the resistor.

(11) The optical receiver subassembly according to (9) or (10), wherein the second wires include a pair of second wires, and the second traces are respectively connected to the pair of second wires. It may be characterized by having a pair of ends that are bonded together.

(12) In the optical receiver subassembly described in (11), the pair of second wires are different in length, and the resistor is connected to the longer one of the pair of second wires and the second wire. It may be characterized by being connected in series with the second wiring only between the electrodes.

(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. good too.

(14) An optical module according to the present invention comprises an optical receiver subassembly according to any one of (1) to (13), and an optical transmitter subassembly that outputs an optical signal converted from an input electrical signal. and an assembly.

1 is an exploded perspective view of an optical module according to a first embodiment to which the present invention is applied; FIG. 1 is a plan view showing the internal structure of an optical receiver subassembly according to a first embodiment to which the present invention is applied; FIG. FIG. 3 is a plan view showing the main components that make up the optical receiver subassembly shown in FIG. 2; 3 is a diagram showing an equivalent circuit of the optical receiver subassembly shown in FIG. 2; FIG. FIG. 5 is an exploded view of an optical receiver subassembly according to a modification of the first embodiment; It is a figure which shows the result of a 1st simulation. It is a figure which shows the result of a 2nd simulation. FIG. 4 is a diagram showing the relationship between resistance value R _d and 3 dB band and deviation; FIG. 10 is a diagram showing the relationship between the ratio of the total wire length of wires and the resistance value _Rd1 when the transmission characteristics of the channels are made uniform for each resistance value _Rd2 ; FIG. 11 shows an optical receiver subassembly according to a second embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described specifically and in detail based on the drawings. In addition, in all the drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted. It should be noted that the drawings shown below are only for explaining examples of the embodiments, and the sizes of the drawings and the reduced scales described in this example do not necessarily match.

[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 transmitter sub-assembly 106 (TOSA) for converting electrical signals into optical signals, and an optical receiver sub-assembly 108 (ROSA) for converting optical signals into electrical signals. Optical Sub-Assembly) and On the transmission side, an electrical signal sent from a host substrate (not shown) is converted into an optical signal through an electrical interface 102 and an optical transmission subassembly 106, which is then transmitted from an optical interface 104. FIG. The receiving side receives the optical signal and outputs an electrical signal to a host-side board (not shown).

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

The optical receiver subassembly has a plurality of light receiving elements 10 (for example, photodiodes (PD)). The light-receiving element 10 is a back-illuminated light-receiving element having a light-receiving portion 12 (absorption layer) on a surface (bottom surface) opposite to a surface (top surface) on which an optical signal is incident. A plurality of light receiving elements 10 are monolithically integrated on a chip component 14 (PD array or the like). A plurality of light receiving elements 10 correspond to a plurality of channels CH ₁ to CH ₄ respectively.

FIG. 3 is a plan view showing main parts constituting the optical receiver subassembly shown in FIG. A plurality of light receiving elements 10 are arranged in a line. A pitch P ₁ of the plurality of light receiving elements 10 is, for example, 500 μm. The light receiving element 10 has a first electrode 16 and a second electrode 18 to which a bias is applied. A first electrode 16 and a 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 section 12 into an electrical signal and outputs the electrical 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 a p-type semiconductor may be called an anode, and the side connected to an n-type semiconductor may be called a cathode. That is, the first electrode 16 and the second electrode 18 can also be called an anode and a cathode, respectively. Alternatively, the p-type semiconductor side may be called a signal electrode, and the n-type semiconductor side may be called a bias electrode. The terms anode and cathode are used for convenience and may be used interchangeably. That is, the designations anode and cathode herein indicate that the light receiving element 10 has two electrodes (first electrode 16 and second electrode 18) of different polarities (different potential differences).

The optical receiver subassembly has a carrier 20 on which a plurality of photodetectors 10 are mounted. The carrier 20 is one substrate that integrally supports the plurality of light receiving elements 10 (chip components 14). The carrier 20 comprises a plurality of circuits 22 respectively corresponding to the plurality of channels CH ₁ -CH ₄ (or the plurality of light receiving elements 10). The multiple circuits 22 are arranged in a line along the alignment of the multiple light receiving elements 10 . The pitch P ₁ of the multiple circuits 22 is equal to the pitch P ₁ of the multiple light receiving elements 10 .

Circuit 22 is electrically connected to light receiving element 10 . Solder 24 is used for electrical connection. The solder 24 is a solder ball in the chip component 14 bonding process. Any connection means other than the solder 24 may be selected as long as the circuit 22 and the light receiving element 10 can be electrically connected.

A first electrode 16 and a second electrode 18 of the light receiving element 10 face the circuit 22 . The circuit 22 has a first wire 26 electrically connected to the first electrode 16 . The circuit 22 has a second wire 28 electrically connected to the second electrode 18 . The second wiring 28 has a pair of ends and is, for example, U-shaped. 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 made of a metal with a low resistance value (for example, Au, aluminum, platinum, silver, etc.).

Each of the plurality of circuits 22 has a resistor 30 . A pair of adjacent channels (for example, the first channel CH ₁ and the second channel CH ₂ ) have different resistance values of the resistors 30 of 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. A resistor 30 is connected in series with the second wiring 28 . Specifically, there is a resistor 30 between one end of the second wiring 28 and an intermediate portion (the joint with the second electrode 18 or the portion where the solder 24 is provided), and the other end of the second wiring 28 There is no resistor 30 between the section and the middle section. At least 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 receiver subassembly includes an amplifier 32, such as a preamplifier, limiting amplifier, autogain controller or transimpedance amplifier. The amplifier 32 is placed next to the carrier 20 and the distance between them is eg 70 um. The amplifier 32 monolithically integrates a plurality of amplifying elements 34 (for example, operational amplifiers). A plurality of amplifying elements 34 are arranged along the direction in which the plurality of circuits 22 (the plurality of light receiving elements 10) are arranged. A plurality of amplifying elements 34 are arranged in a line. The pitch P2 of the amplifying elements 34 is, for example, ₂₅₀ um, which is different from the pitch P1 (500 um) of the plurality of light receiving elements ₁₀ (plurality of circuits 22). The center of the arrangement direction of the plurality of amplifying elements 34 and the center of the arrangement direction of the plurality of circuits 22 are aligned.

A plurality of amplifying elements 34 respectively amplify electrical signals corresponding to a plurality of channels CH ₁ to CH ₄ . Amplifying element 34 has a first pad 36 . An electrical signal from the light receiving element 10 is input to the first pad 36 . Amplifying element 34 has a second pad 38 . A bias voltage to be supplied to the light receiving element 10 appears at the second pad 38 . A first pad 36 and a second pad 38 are directly attached to the amplifier 32 .

Amplifier 32 has a power pad 40 for powering amplifying element 34 . Power pads 40 are connected to external power rails by wires 42 and 44 . One electrode of a plate capacitor 46 is connected between wires 42 and 44 . Amplifier 32 has another power supply pad 48 for biasing photodetector 10 . Power pads 48 are connected to external power rails by wires 50 and 52 . One electrode of a plate capacitor 54 is connected between wires 50 and 52 .

The optical receiver subassembly has a wiring board 56 . The wiring board 56 has a plurality of signal patterns 58 . A pair of signal patterns 58 constitute a differential transmission line. A pair of signal patterns 58 are sandwiched between a pair of GND patterns 60 . A GND pattern 60 is connected to a GND plane 64 on the back side through a through hole 62 . An output pad 66 of amplifier 32 is connected by wire 68 to signal trace 58 to output an amplified electrical signal. GND pad 70 of amplifier 32 is connected to GND pattern 60 by wire 72 .

The optical receiver subassembly has a first wire W ₁ connecting the first wiring 26 and the first pad 36 for each of the plurality of channels CH ₁ -CH ₄ . The optical receiver subassembly has a second wire W ₂ connecting the second wiring 28 and the second pad 38 for each of the plurality of channels CH ₁ -CH ₄ . In each channel, the _first wire W1 and the _second wire W2 have a total wire length L.

Adjacent pairs of channels differ in the total wire length L of the _first wire W1 and the _second wire W2. The total wire length L is the longest in the first channel CH ₁ or the fourth channel CH ₄ located at both ends in the arrangement direction of the plurality of light receiving elements 10 . The total wire length L is the shortest in the second channel CH ₂ or the third channel CH ₃ located in the center in the arrangement direction of the plurality of light receiving elements 10 . The ratio of total wire lengths L approximates the ratio of inductances. A difference in the total wire length L causes a difference in transmission characteristics for each channel.

The _second wire W2 includes a pair of _second wires W2. The second wiring 28 has a pair of ends to which the pair of _second wires W2 are respectively bonded. As shown in FIG. ₂ , the pair of second wires W2 have different lengths. A resistor 30 included in the circuit 22 is connected in series with the second wiring 28 only between the longer of the pair of second wires W ₂ and the second electrode 18 .

According to this embodiment, in a pair of adjacent channels, the resistance value of the resistor 30 is higher in the channel having the longer total wire length L (for example, the first channel CH ₁ ). As a result, even if the transmission characteristics of each channel become uneven due to the difference in the total wire length L of the _first wire W1 and the _second wire W2, they can be made uniform by adjusting the difference in the resistance value of the resistor 30. can be

FIG. 4 is a diagram showing an equivalent circuit of the optical receiver 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 with an internal capacitance C _pd and an internal resistance R _pd . Amplifying element 34 has an input impedance that approximates the input resistance R _in .

In this 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 an amplifier 32 to the light receiving element 10 . Although many semiconductor light receiving elements 10 are used with a bias voltage applied in the same direction as in the present embodiment, the positive and negative directions of the voltage are not particularly limited and are appropriately selected depending on the light receiving element 10 to be used.

A bias is applied to the light receiving element 10 from the external power source 74 via the second wire W ₂ from the second wiring 28 . A filter or the like is often attached to the bias line within the amplifier 32, and the routing method and the like differ depending on the manufacturer of the amplifier 32. FIG.

When an optical signal is input to the light receiving element 10, an electrical signal proportional to the received light is generated. An electrical signal is input to the amplifying element 34 through the first pad 36 via the _first wire W1.

The relationship between the photocurrent I _pd (ω) flowing through the light receiving element 10 and the voltage V _in (ω) input to the amplifying element 34 is expressed by the following equation.

_Rd is the resistance value of the resistor 30, and L is the total wire length L of the _first wire W1 and the _second wire W2. In order to obtain equal frequency characteristics in all channels, the value of _Rd should be changed in proportion to the difference in L.

であり、Ｌ₁＝Ｌ_1-1＋Ｌ_1-2＋Ｌ_1-3である。 For example, for 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 equivalent frequency characteristics in the first channel and the second channel,
R _in +R _pd +R _d1 +jωL ₁ =R _in +R _pd +R _d2 +jωL ₂
should be established.

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 formula.

[Modification of First Embodiment]
FIG. 5 is an exploded view of an optical receiver 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 _CH2 or the third channel _CH3 has a resistance value of 0Ω between the second electrode 118 and the _second wire W2. Note that the resistance of the second wiring 128 itself is sufficiently small and is not considered here. Each of the plurality of circuits 122 has a resistor 130 connected in series with a second wire 128, except for the channel with the shortest total wire length L. As _a result _, the resistance _value of the circuit ₁₂₂ is set to is higher. The resistance that the circuit 122 has between the second electrode 118 and the second wire W ₂ is increased by the presence of the resistor 130 .

In this example, the inductance of the _first wire W1 is 679 pH and the inductance of the _second wire W2 is 506 pH. The ratio of the total wire length L of the _first wire W1 to the total wire length L of the _second wire W2 approximates the ratio of the inductances, L1 _/ L2 ₌ 679 pH/506 pH=1.34. be.

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 R _in of the amplifying element 34 is 30 Ω, and the resistance R _d2 is 0 Ω, as described above,

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

FIG. 6 is a diagram showing the results of the first simulation. The horizontal axis is frequency, and the vertical axis is S21 indicating the transmitted power characteristic. In FIG. 6, when the circuit has no resistors in either the first or second channel (R _d1 =0 Ω, R _d2 =0 Ω), the peak intensity is 1.3 Ω in the first channel than in the second channel. dB large. This is because the total wire length of the first and second wires is longer in the first channel than in the second channel.

In contrast, as shown in the modification of the first embodiment (FIG. 5), by providing a resistor 130 (R _d1 =17.1 Ω) in the first channel CH ₁ , the first channel CH ₁ and the first channel CH 1 The peak intensity of ₂ -channel CH2 can be suppressed to the same 1.1 dB. The 3 dB band (frequency at which S21 is 3 dB) is 27.3 GHz (25 GHz or higher), ensuring a sufficient band for the 25 Gbps transmission module.

FIG. 7 is a diagram showing the results of the second simulation. In this simulation, as shown in the first embodiment (FIGS. 2 and 3), in the first channel CH ₁ the circuit 22 is provided with a resistor 30 (R _d1 =25 Ω) and in the second channel CH ₂ the circuit 22 is provided with a resistor 30 (R _d2 =10 Ω). As a result, the 3 dB band is 25 GHz or more, and the peak intensity in the _first channel CH1 and the second channel _CH2 can be uniformly suppressed to 0.5 dB.

FIG. 8 is a diagram showing the relationship between the resistance value _Rd and the 3 dB band and deviation. Deviation indicates the amount of deviation from 0 dB in the frequency domain within the transmission band. Here, it indicates the maximum value (peak intensity) of deviation in the positive direction in the range of 0 to 25 GHz. there is 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. As a result of simulation, it can be seen that the transmission characteristics are good when R _d1 is 10 to 30 Ω. By arranging the resistors, the deviation between CHs can be made uniform (to the same degree). When the value of the resistor is increased, the band tends to become smaller by 3 dB. transmission characteristics can be made uniform.

FIG. 9 is a diagram showing the relationship between the ratio of the total wire length L of wires and the resistance value _Rd1 for each resistance value _Rd2 when the transmission characteristics of the channels are made uniform. As described above, good transmission characteristics can be obtained if the resistance value _Rd is in the range of 10 to 30 Ω. Therefore, it is desired that the resistance value R _d1 is within the range of 10 to 30 Ω.

As shown in the modified example of the first embodiment (FIG. 5), an example of the resistance value R _d2 =0Ω of the circuit 122 of the second channel CH ₂ will be given. If the ratio of the total wire length L of the _first wire W1 and the _second wire W2 is _1.2 to 1.6, ₁₀ A resistor 130 having a resistance value R _d1 in the range of ˜30 Ω may be provided in the circuit 122 of the first channel CH ₁ .

As shown in the first embodiment (FIGS. 2 and 3), when the resistor 30 is also provided in the circuit 22 of the _second channel CH2, uniform transmission characteristics can be obtained as the resistance value _Rd2 increases. The range of ratios of total wire lengths L when When the resistance value R _d2 =10 Ω, the ratio of total wire length L should be in the range of 1.0 to 1.3.

[Second embodiment]
FIG. 10 is a diagram showing an optical receiver subassembly according to the second embodiment. In this embodiment, the chip component 214 is arranged so 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 the direction perpendicular to the arrangement direction. and an amplifier 232 are arranged side by side.

The total wire length L is the shortest in the first channel CH ₁ located at one end in the arrangement direction of the plurality of light receiving elements 210 . The total wire length L is the longest in the fourth channel CH ₄ located at the other end in the arrangement direction of the plurality of light receiving elements 210 . The total wire length L is longer the closer to the _fourth channel CH4 where the total wire length L is the longest.

Also in this embodiment, the correlation shown in FIG. 9 is established. However, in this embodiment, the resistor 30 with the resistance value R _d2 is in the first channel CH ₁ and the resistor 30 with the resistance value R _d1 is in the second channel CH ₂ . The relationship between the _first channel CH1 and the second channel _CH2 applies to the second channel _CH2 and the third channel _CH3 as well as the third channel _CH3 and the _fourth channel CH4.

The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the configurations described in the embodiments can be replaced with configurations that are substantially the same, configurations that produce the same effects, or configurations that can achieve the same purpose.

10 Light receiving element 12 Light receiving part 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 supply pad 42 wire 44 wire 46 plate capacitor 48 power supply 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, 118 second electrode, 122 circuit, 128 second wiring, 130 resistor, 210 light receiving element, 214 chip part, 232 amplifier, 234 amplifying element, C _pd internal capacitance, CH ₁ first channel, CH ₂ second channel, CH ₃ third channel, CH ₄ fourth channel, I _pd (ω) photocurrent, P ₁ pitch, P ₂ pitch, R _d1 resistance value, R _d2 resistance value, R _in input resistance, R _pd internal resistance, V _pd voltage, V _in (ω) voltage, W ₁ first wire, W ₂ second wire.

Claims (13)

Each has a first electrode and a second electrode to which a bias is applied corresponding to a plurality of channels, converts an input optical signal into an electric signal, and outputs the electric signal from the first electrode. a plurality of monolithically integrated light receiving elements,
A carrier comprising a plurality of circuits each having a first wiring and a second wiring electrically connected to the first electrode and the second electrode corresponding to the plurality of channels , respectively, and on which the plurality of light receiving elements are mounted. When,
a plurality of amplifying elements each having a first pad and a second pad corresponding to the plurality of channels and monolithically integrated so as to amplify the electrical signals;
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 includes a pair of adjacent channels that differ in total wire length of the first wire and the second wire;
the pair of channels are different in resistance value that each of the plurality of circuits has between the second electrode and the second wire;
the longer the total wire length of the pair of channels, the higher the resistance;
the second wire includes a pair of second wires,
The pair of second wires have different lengths,
An optical receiving subassembly , wherein a resistor is connected in series with the second wiring only between the longer one of the pair of second wires and the second electrode . An optical receiver subassembly according to claim 1, comprising:
The plurality of amplifying elements are arranged in a row,
The plurality of circuits are arranged in a line along the arrangement of the plurality of amplifying elements,
The optical receiver subassembly, wherein the pitch of the plurality of circuits is different from the pitch of the plurality of amplifying elements. An optical receiver subassembly according to claim 2, comprising:
The plurality of light receiving elements are arranged in a row along the arrangement of the plurality of circuits,
The optical receiving subassembly, wherein the pitch of the plurality of light receiving elements is different from the pitch of the plurality of amplifying elements. An optical receiver subassembly according to claim 3, comprising:
The optical receiving subassembly, wherein the pitch of the plurality of circuits is equal to the pitch of the plurality of light receiving elements. An optical receiver subassembly according to any one of claims 2 to 4,
The optical receiving subassembly, wherein the total wire length is the longest in the channels located at both ends in the array direction of the plurality of light receiving elements. An optical receiver subassembly according to claim 5, comprising:
An optical receiving subassembly, wherein the total wire length is the shortest in at least one of the channels located in the center in the array direction of the plurality of light receiving elements. An optical receiver subassembly according to any one of claims 2 to 4,
In the channel located at one end in the arrangement direction of the plurality of light receiving elements, the total wire length is the shortest,
An optical receiving subassembly, wherein the total wire length is the longest in the channel located at the other end in the array direction of the plurality of light receiving elements. An optical receiver subassembly according to claim 7, comprising:
The optical receiver subassembly, wherein the total wire length is longer the closer to the channel where the total wire length is the longest. An optical receiver subassembly according to any one of claims 1 to 8 ,
An optical receiver subassembly, wherein each of said plurality of circuits includes said resistor. An optical receiver subassembly according to any one of claims 1 to 9 ,
The optical receiver subassembly, wherein the second wiring has a pair of ends to which the pair of second wires are respectively bonded. Each has a first electrode and a second electrode to which a bias is applied corresponding to a plurality of channels, converts an input optical signal into an electric signal, and outputs the electric signal from the first electrode. a plurality of monolithically integrated light receiving elements,
A carrier comprising a plurality of circuits each having a first wiring and a second wiring electrically connected to the first electrode and the second electrode corresponding to the plurality of channels , respectively, and on which the plurality of light receiving elements are mounted. When,
a plurality of amplifying elements each having a first pad and a second pad corresponding to the plurality of channels and monolithically integrated so as to amplify the electrical signals;
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 includes a pair of adjacent channels that differ in total wire length of the first wire and the second wire;
the pair of channels are different in resistance value that each of the plurality of circuits has between the second electrode and the second wire;
the longer the total wire length of the pair of channels, the higher the resistance;
a resistor connected in series with the second wire in the channel where the total wire length is not the shortest;
An optical receiver subassembly , wherein the channel having the shortest total wire length has no resistor connected in series with the second wire . An optical receiver subassembly according to any one of claims 1 to 11 ,
An optical receiving subassembly, wherein the resistor overlaps a chip component in which the plurality of light receiving elements are monolithically integrated. an optical receiver subassembly according to any one of claims 1 to 12 ;
an optical transmission subassembly that outputs an optical signal converted from an input electrical signal;
An optical module characterized by comprising:

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