Optical device and method for determining correction parameters of the optical device

Abstract

To provide a new and improved optical device and a new and improved determination method of a correction parameter of an optical device.SOLUTION: A switching device 100 (an optical device) comprises: a circuit board having an insulator and a plurality of pieces of signal wiring 12; a semiconductor integrated circuit (a switch ASIC30) provided in the circuit board; and a plurality of optical transceivers 20 that are provided in the circuit board, and transmit electric signals between the optical transceivers 20 and the semiconductor integrated circuit via an individual signal wiring 12. The semiconductor integrated circuit and correction portions 34 and 24 of each optical transceiver correct an eye pattern of a signal transmission in each signal wiring 12, and can change a level of a correction in accordance with a value of a correction parameter. The eye pattern acquired in each signal wiring 12 can set an initial value of the correction parameter in a searching processing for searching the value of the correction parameter that becomes a state for satisfying a predetermined condition as a value different in each signal wiring 12.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to an optical device and a method for determining correction parameters of the optical device.

Background Art

[0002] Conventionally, as an optical device used in a network switch device, an optical device equipped with a small optical transceiver is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the optical device disclosed in Patent Document 1, a switch ASIC (application specific integrated circuit) as a signal processing IC (integrated circuit) and a plurality of optical transceivers are mounted on the surface of a circuit board. Between the switch ASIC and each optical transceiver, an electrical signal is transmitted via signal wiring provided on the circuit board.

[0005] The electrical signal transmitted between the switch ASIC and each optical transceiver deteriorates when passing through the signal wiring. As a result, there is a risk that the bit error rate increases.

[0006] The quality of the bit error rate can be determined by the size of the opening of an eye pattern obtained by overlapping the waveform of the change over time of the signal level (voltage). The smaller the opening of the eye pattern, the higher the bit error rate.

[0007] When the coding error rate does not meet the desired conditions, correction processing of the electrical signal, such as enlarging the eye pattern aperture, is known as a measure to reduce the coding error rate. Examples of such correction processing include emphasis, gain correction, and peaking.

[0008] Each of these correction processes, such as emphasis, gain correction, and peaking, produces a different effect.

[0009] Furthermore, in optical devices with multiple signal lines, the degree of electrical signal degradation may differ for each signal line.

[0010] Therefore, in optical devices having multiple signal lines, it is preferable to select a suitable correction process for each signal line and to perform a process (hereinafter simply referred to as a search process) to search for the value of a parameter that determines the degree of the correction process (hereinafter simply referred to as a correction parameter).

[0011] However, as the number of signal wires increases, the search process becomes more time-consuming.

[0012] Therefore, one of the objectives of the present invention is to obtain a novel and improved optical device, and a method for determining the correction parameters of an optical device, that can shorten the time required for searching for the values ​​of correction parameters when performing a correction process to widen the aperture of the eye pattern in response to an electrical signal. [Means for solving the problem]

[0013] The optical device of the present invention comprises, for example, a circuit board having an insulator and a plurality of signal wirings, a semiconductor integrated circuit provided on the circuit board, a plurality of optical transceivers provided on the circuit board for transmitting electrical signals to the semiconductor integrated circuit via separate signal wirings, and a correction unit for correcting the signal transmission eye pattern in each of the signal wirings, wherein the degree of correction can be changed according to a correction parameter, and the initial value of the correction parameter in a search process that searches for a correction parameter that satisfies a predetermined condition by changing the correction parameter so that the discrepancy between the eye pattern acquired for each of the signal wirings and the eye pattern that satisfies a predetermined condition is reduced, can be set to a different value for each of the signal wirings.

[0014] In the optical device, the initial value may be determined in the search process for each of the signal lines based on the correction parameter obtained by the search process for the other signal lines.

[0015] In the optical device, the plurality of signal lines are grouped into a plurality of groups, and in the search process for each of the signal lines, the initial value may be determined based on the correction parameter obtained by the search process for other signal lines belonging to the same group.

[0016] In the optical device, the plurality of signal lines are grouped into a plurality of groups, and in the search process for each of the signal lines, the initial value may be set for each group.

[0017] In the optical device, the plurality of groups may be configured according to the length of the signal wiring.

[0018] In the optical device, the circuit board has a plurality of signal lines that pass through different layers in the thickness direction of the circuit board, and each of the groups may include a signal line that has a section passing through the same layer.

[0019] In the optical device, the plurality of groups may be set according to the mounting positions on the circuit board of the optical transceiver that transmits electrical signals to and from the semiconductor integrated circuit via the signal wiring.

[0020] In the optical device, the plurality of groups may be set according to the correction parameters set for the plurality of signal wirings of other individuals of the optical device having the same structure.

[0021] The optical device may include a search processing unit that executes a search process for searching for the correction parameter that satisfies a predetermined condition by changing the correction parameter so that the deviation between the eye pattern acquired for each of the signal wirings and the eye pattern that satisfies the predetermined condition is reduced.

[0022] The optical device may include a plurality of search processing units that can execute search processes for different signal wirings in parallel as a search processing unit that executes a search process for searching for the correction parameter that satisfies a predetermined condition by changing the correction parameter so that the deviation between the eye pattern acquired for each of the signal wirings and the eye pattern that satisfies the predetermined condition is reduced.

[0023] The optical device may include a plurality of search processing units that can execute search processes for searching for different correction parameters as a search processing unit that executes a search process for searching for the correction parameter that satisfies a predetermined condition by changing the correction parameter so that the deviation between the eye pattern acquired for each of the signal wirings and the eye pattern that satisfies the predetermined condition is reduced.

[0024] The optical device may include, as the search processing unit, a first search processing unit provided in the semiconductor integrated circuit.

[0025] The optical device may include, as the search processing unit, a second search processing unit provided in each of the optical transceivers.

[0026] The optical device may include, as the correction unit, a first enhancement process for enlarging an aperture before a reference time of an eye pattern, a second enhancement process for enlarging the aperture after the reference time of the eye pattern, and a first correction unit that performs at least one of the enhancement processes, which is a third enhancement process for enlarging the aperture when signals are continuous regardless of whether it is before or after the reference time.

[0027] The optical device may include, as the correction unit, a second correction unit that is at least one of a gain correction unit and a peaking process unit.

[0028] In the optical device, the optical transceiver may include a light emitting unit that outputs an optical signal in response to an electrical signal from the semiconductor integrated circuit, a light receiving unit that receives the optical signal and outputs an electrical signal to the semiconductor integrated circuit corresponding to the optical signal, and a transmission path that transmits the optical signal from the light emitting unit to the light receiving unit.

[0029] The optical device includes an acquisition unit that acquires the eye pattern for each of the signal wirings, an output signal based on an acquisition result by the acquisition unit, and an input signal from a search processing unit that executes a search process for searching for a correction parameter that satisfies a predetermined condition by changing the correction parameter so that a deviation between the eye pattern acquired for each of the signal wirings based on the output signal and provided in a device different from the optical device and the eye pattern that satisfies the predetermined condition is reduced, and a signal transmission unit that transmits the input signal between the optical device and the device.

[0030] The present invention provides a method for setting correction parameters for an optical device, for example, in an optical device comprising: a circuit board having an insulator and a plurality of signal wirings; a semiconductor integrated circuit provided on the circuit board; a plurality of optical transceivers provided on the circuit board for transmitting electrical signals to the semiconductor integrated circuit via separate signal wirings; and a correction unit for correcting the signal transmission eye pattern in each of the signal wirings, wherein the correction unit can change the degree of correction according to a correction parameter. The method for setting the correction parameter allows the initial value of the correction parameter in a search process that searches for a correction parameter that satisfies a predetermined condition by changing the correction parameter so that the discrepancy between the eye pattern acquired for each of the signal wirings and the eye pattern that satisfies a predetermined condition decreases, to be set as a different value for each of the signal wirings. [Effects of the Invention]

[0031] According to the present invention, a novel and improved optical device and a method for determining the correction parameters of the optical device can be obtained. [Brief explanation of the drawing]

[0032] [Figure 1] Figure 1 is an illustrative and schematic plan view of an optical communication device equipped with a switch device as an optical device in the first embodiment. [Figure 2] Figure 2 is an illustrative and schematic plan view of the switch device according to the first embodiment. [Figure 3] Figure 3 is an illustrative and schematic plan view of a part of the switch device of the first embodiment. [Figure 4] Figure 4 is a partial exemplary and schematic cross-sectional view including the signal wiring of the switch device of the first embodiment. [Figure 5] Figure 5 is a different, more illustrative and schematic cross-sectional view from Figure 4, showing the signal wiring of the switch device of the first embodiment. [Figure 6] Figure 6 is an illustrative diagram illustrating the eye pattern correction process performed by the switch device of the first embodiment. [Figure 7] Figure 7 is an illustrative block diagram of a switch device according to the first embodiment. [Figure 8] Figure 8 is an exemplary flowchart showing the procedure of the search process by the switch device of the first embodiment. [Figure 9] Figure 9 is an illustrative block diagram of a switch device according to the second embodiment. [Figure 10] Figure 10 is an illustrative block diagram of a switch device according to the third embodiment. [Figure 11] Figure 11 is an illustrative schematic diagram of a correction parameter determination system including a switch device according to the fourth embodiment. [Modes for carrying out the invention]

[0033] Illustrative embodiments of the present invention are disclosed below. The configurations of the embodiments shown below, as well as the actions and results (effects) brought about by such configurations, are examples only. The present invention can also be realized by configurations other than those disclosed in the following embodiments. Furthermore, according to the present invention, it is possible to obtain at least one of the various effects (including derived effects) that can be obtained by the configuration.

[0034] The multiple embodiments shown below have similar configurations. Therefore, the configuration of each embodiment yields similar functions and effects based on the same configuration. In addition, the same reference numerals are used for these similar configurations below, and redundant explanations may be omitted.

[0035] In this specification, ordinal numbers are assigned for convenience to distinguish directions, parts, sections, specifications, partial structures, etc., and do not indicate priority or order.

[0036] In each figure, the X direction is represented by arrow X, the Y direction by arrow Y, and the Z direction by arrow Z. The X, Y, and Z directions intersect and are also orthogonal to each other. The Z direction may also be referred to as the layering direction or thickness direction.

[0037] Furthermore, each diagram is a schematic representation for explanatory purposes, and the scale and proportions of each diagram may not necessarily match those of the actual object.

[0038] [First Embodiment] Figure 1 is a plan view of the optical communication device 200 according to the first embodiment. As shown in Figure 1, the optical communication device 200 includes a motherboard 201, an IC 202, and a plurality of switch devices 100. In addition to these, the optical communication device 200 may also include a power supply module, a cooling fan, etc. (not shown).

[0039] Motherboard 201 has a substantially constant thickness in the Z direction and extends in a direction that intersects with the Z direction. Motherboard 201 has two surfaces, surface 201a and surface 201b. Surface 201a faces the Z direction and intersects with the Z direction. Surface 201b faces the opposite direction from surface 201a and intersects with the Z direction.

[0040] Multiple switch devices 100 are mounted on surface 201a, and IC 202 is mounted on surface 201b. Alternatively, IC 202 may be mounted on surface 201a.

[0041] IC202 controls the operation of multiple switch devices 100 and transmits electrical signals between these switch devices 100. IC202 is an example of a signal processing circuit.

[0042] The conductor (not shown) of the motherboard 201 and the conductor (not shown) of the switch device 100 are electrically connected via the conductor (not shown) inside the connector.

[0043] Figure 2 is a plan view of the switch device 100. As shown in Figure 2, the switch device 100 comprises a circuit board 10, a plurality of optical transceivers 20, and a switch ASIC 30 (ASIC: application specific integrated circuit). The optical transceivers 20 and the switch ASIC 30 may also be referred to as electronic components. The switch device 100 has a board assembly configuration comprising the circuit board 10 and the electronic components. The switch device 100 may also be referred to as an optical device.

[0044] The circuit board 10 has a square (quadrilateral) shape. The circuit board 10 has a plate-like shape, extending both perpendicularly and intersecting the Z direction. The circuit board 10 has a surface 10a facing the Z direction and a surface 10b opposite to surface 10a, facing the opposite direction of the Z direction. Surfaces 10a and 10b extend both perpendicularly and intersecting the Z direction. The circuit board 10 may also be called, for example, a printed wiring board. Surface 10a is an example of a first surface, and the Z direction is an example of a first direction.

[0045] As shown in Figure 2, multiple optical transceivers 20 are arranged along each of the four sides 10c of the circuit board 10. Optical fibers (not shown) extend from each optical transceiver 20. The optical fibers may extend substantially along the Z-direction from the optical transceiver 20, or substantially along a direction intersecting the Z-direction.

[0046] Furthermore, in this embodiment, the optical transceiver 20 is mounted on the surface 10a of the circuit board 10. The optical transceiver 20 is attached to, for example, a socket (not shown) in a direction intersecting the Z direction, but is not limited to this.

[0047] The switch ASIC 30 is flip-chip mounted on surface 10a at a location away from each of the edges 10c of the circuit board 10 (in this embodiment, for example, approximately in the center of the circuit board 10). The switch ASIC 30 controls the operation of each optical transceiver 20 and transmits electrical signals between the multiple optical transceivers 20. The switch ASIC 30 is an example of a semiconductor integrated circuit and may also be referred to as a signal processing IC.

[0048] Figure 3 is a plan view of a part of the switch device 100, which is an enlarged view of a portion of Figure 2. As shown in Figure 3, the conductors in the switch ASIC 30 and the conductors in each optical transceiver 20 are electrically connected via separate signal wiring 12. The switch ASIC 30 and the optical transceivers 20 transmit electrical signals to each other via the signal wiring 12. In Figure 3, only one set of signal wiring 12 is shown corresponding to each optical transceiver 20, but in reality, multiple sets of signal wiring 12 are often provided corresponding to each optical transceiver 20.

[0049] The signal wiring 12 is provided within the circuit board 10, or on surface 10a or surface 10b of the circuit board 10. The signal wiring 12 is made of a conductive metallic material, such as a copper-based material. Furthermore, the signal wiring 12 is a differential signal wiring.

[0050] Here, as shown in Figure 3, the length of the signal wiring 12 differs depending on the position of the optical transceiver 20. Specifically, the length of the signal wiring 12 is longer the closer the corresponding optical transceiver 20 is to the corner 10d of the circuit board 10 (see Figure 2), and shorter the further the corresponding optical transceiver 20 is from the corner 10d of the circuit board 10. In this example, the multiple signal wirings 12 in Figure 3 are assumed to extend in a direction intersecting the Z direction at the same position in the Z direction of the circuit board 10. In this embodiment, the multiple signal wirings 12 are grouped according to their length. In the example in Figure 3, the signal wirings 12 that are relatively long are classified into group G1, and the signal wirings 12 that are relatively short are classified into group G2. Also, as is clear from Figure 3, the length of the signal wiring 12 differs depending on the position (mounting position) of the optical transceiver 20. For this reason, the multiple signal wirings 12 can also be grouped according to the position of the optical transceiver 20. Specifically, the signal lines 12 are grouped according to the distance from the corner 10d of the circuit board 10 to the corresponding optical transceiver 20, i.e., the optical transceiver 20 that transmits electrical signals to the switch ASIC 30 via the signal line 12. In the example in Figure 3, the signal lines 12 corresponding to optical transceivers 20 that are relatively close to the corner 10d are classified into group G1, and the signal lines 12 corresponding to optical transceivers 20 that are relatively long to the corner 10d are classified into group G2. Alternatively, the length of the signal lines 12 can be said to be grouped according to the distance between the corresponding optical transceiver 20 and the centroid Cg (see Figure 2) of the switch ASIC 30. In the example in Figure 3, the signal lines 12 corresponding to optical transceivers 20 that are relatively long to the centroid Cg are classified into group G1, and the signal lines 12 corresponding to optical transceivers 20 that are relatively short to the corner 10d are classified into group G2. Note that the example in Figure 3 is just one example, and the method of dividing the signal wiring 12 is not limited to the example in Figure 3. The effects of grouping the signal wiring 12 will be described in detail later.

[0051] Figures 4 and 5 are cross-sectional views of separate parts of the switch device 100, including a portion of the signal wiring 12. As shown in Figures 4 and 5, the circuit board 10 has a plurality of insulating layers 11a1 to 11a4 stacked in the Z direction as an insulator 11. The insulating layers 11a1 to 11a4 each extend in a direction intersecting the Z direction. The signal wiring 12 each has two electrodes 12a1 and 12a2 that are separated in a direction intersecting the Z direction, and between these electrodes 12a1 and 12a2 there are vias 12b1 and 12b2 and an extension 12c. The vias 12b1 and 12b2 each extend in the opposite direction to the Z direction from the electrodes 12a1 and 12a2. The extension 12c extends in a direction intersecting the Z direction with a substantially constant width at the boundary between adjacent insulating layers 11a1 to 11a4 between vias 12b1 and 12b2. The extension 12c can extend between multiple layers, i.e., in any of the multiple layers. The signal wiring 12 goes from electrode 12a1 to electrode 12a2 via via 12b1, extension 12c, and via 12b2.

[0052] As is clear from comparing Figures 4 and 5, the extension 12c extends at different levels in the Z direction. In other words, the circuit board 10 has multiple signal lines 12 that pass through different levels in the Z direction. In this case, the signal lines 12 are each divided into different groups G3 and G4. Furthermore, among the multiple signal lines 12, those signal lines 12 that have extensions 12c (sections) passing through the same level are divided into the same group. Also, the Z-direction lengths of vias 12b1 and 12b2 of the signal line 12 shown in Figure 4 are longer than the Z-direction lengths of vias 12b1 and 12b2 of the signal line 12 shown in Figure 5. Therefore, the grouping of signal lines 12 in Figures 4 and 5 can be said to be an example of grouping according to the length of the signal lines 12.

[0053] [Eye pattern correction and search process] In the switch device 100, a correction process is performed to improve the eye pattern of the electrical signals transmitted through each signal wiring 12. Figure 6 is an explanatory diagram showing an example of the eye pattern correction process. In Figure 6, the upper panel shows the eye pattern before correction, and the lower panel shows the eye pattern after correction. In both the upper and lower panels, the horizontal axis represents time, and the vertical axis represents voltage, which indicates the signal level. As described above, the eye pattern is a graph in which waveforms of the time-dependent change in signal level (voltage) are superimposed. In this embodiment, the correction process is performed on at least one of the transmitting and receiving sides so that the upper edge Eu of the aperture O of the eye pattern is greater than or equal to the reference C, and the lower edge El of the aperture O is less than or equal to the reference C.

[0054] The correction processing performed by the switch ASIC30 during transmission includes, for example, enhancement processes such as the well-known pre-emphasis, post-emphasis, and de-emphasis. Pre-emphasis is an enhancement process that expands the aperture O before the reference time t0 of the eye pattern and is an example of a first-order enhancement process. Post-emphasis is an enhancement process that expands the aperture O after the reference time t0 of the eye pattern and is an example of a second-order enhancement process. De-emphasis is an enhancement process that expands the aperture O when the signal is continuous, regardless of whether it is before or after the reference time t0 and is an example of a third-order enhancement process.

[0055] Furthermore, correction processing during transmission by the optical transceiver 20 includes, for example, well-known gain correction and peaking processing. Gain correction is a process that changes the vertical width of the aperture O by changing the vertical width of the eye pattern voltage, while peaking processing is a process that improves the rise time and rise time of the aperture O by changing the gain in the high-frequency region.

[0056] In this embodiment, each signal wiring 12 transmits, for example, a pseudo random bit sequence (PRBS) as an electrical signal (test signal) multiple times (e.g., 10,000 times or more) between the switch ASIC 30 and the optical transceiver 20. The test signal is a signal with a signal level (voltage) corresponding to a bit of 0 or 1. Then, for the multiple received signals (which correspond to the eye pattern), the aperture O and the reference C are compared to determine whether correction processing is necessary, to decide which correction processing to execute, and to determine (set) the values ​​of the parameters of the correction processing (hereinafter referred to as correction parameters). Hereinafter, the transmission of electrical signals multiple times in the signal wiring 12, and the series of processes such as comparing the transmitted electrical signals with the aperture O and the reference C, determining whether correction processing is necessary, deciding which correction processing to execute, and determining the values ​​of the correction parameters will be referred to as a trial. The correction parameters for each correction process are, for example, the gain used when amplifying or attenuating the signal in a predetermined time interval within the signal period (e.g., pre-stage, middle stage, post-stage, etc.), and various coefficients. In this embodiment, the values ​​of the correction parameters for a correction process that yields an eye pattern satisfying a predetermined condition are searched for by repeatedly changing the values ​​of the correction parameters until a predetermined condition is met, that is, until the upper edge Eu of the eye pattern opening O is greater than or equal to the reference C, and the lower edge El of the opening O is less than or equal to the reference C. This process is called the search process.

[0057] The groups of signal wiring 12 described above correspond to the correction process executed in the first trial and the initial values ​​of said correction process. That is, the first trial for signal wiring 12 belonging to the same group is performed with the same pre-set correction process and the same initial values. Through the inventors' diligent research, it has been found that the information indicating the correction process for each signal wiring 12 and the values ​​of the correction parameters are similar according to the specifications of the signal wiring 12. Furthermore, in order to improve the convergence of the trials, it is difficult to significantly change the values ​​of the correction parameters in each trial. Therefore, by grouping the signal wiring 12 according to predetermined specifications as described above, and by making the correction process executed in the first trial and the initial values ​​of the correction parameters in said correction process common, the number of trials for each signal wiring 12 can be reduced, and the time required for the search process can be shortened.

[0058] Figure 7 is a block diagram of the switch device 100A(100) of this embodiment. Although only one optical transceiver 20 is shown in Figure 7, the other optical transceivers 20 have the same configuration as the optical transceiver 20 in Figure 7.

[0059] As shown in Figure 7, the switch ASIC 30 includes a search processing unit 31, a signal generation unit 32, a correction unit 34, a correction information storage unit 35, an eye pattern acquisition unit 36, and a processing information storage unit 37.

[0060] The search processing unit 31 performs the determination of correction processing and the search processing for the values ​​of correction parameters. That is, the search processing unit 31 controls each part to perform the determination of correction processing and the search processing according to a predetermined procedure, and also performs comparison of the aperture O of the acquired eye pattern with the reference C, judgment of whether each correction processing is necessary, determination of the correction processing to be executed, determination of the values ​​of the correction parameters, etc. The search processing unit 31 is an arithmetic processing circuit. The search processing unit 31 is an example of the first search processing unit. The search processing unit 31 may also be called the correction processing determination unit.

[0061] The correction information storage unit 35 is a non-volatile, rewritable storage unit that stores information indicating the correction process to be executed (hereinafter also referred to as correction process information) and the values ​​of correction parameters for each signal wiring 12. The information indicating the correction process and the values ​​of correction parameters are rewritten by the search processing unit 31, etc.

[0062] The signal generation unit 32 is controlled by the search processing unit 31 and generates electrical signals that are transmitted multiple times in each signal wiring 12.

[0063] The correction unit 34 is a circuit that executes the correction process stored in the correction information storage unit 35 using the values ​​of the correction parameters stored in the correction information storage unit 35. The correction unit 34 can change the degree of correction according to the values ​​of the correction parameters. In the transmission of electrical signals from the switch ASIC 30 to the optical transceiver 20 in the signal wiring 12, the correction unit 34 performs at least one of pre-emphasis, post-emphasis, and de-emphasis. Furthermore, the correction unit 34 executes the correction process if correction parameters are set in the correction information storage unit 35, and does not execute the correction process if no correction parameters are set in the correction information storage unit 35, or if correction parameters that do not substantially correct are set. Note that the correction unit 34 and the correction information storage unit 35 are provided for each signal wiring 12. The correction unit 34 is an example of a first correction unit.

[0064] The eye pattern acquisition unit 36 ​​acquires the eye pattern of the electrical signal transmitted multiple times in the signal wiring 12 based on the electrical signal from the light receiving unit 23.

[0065] The processing information storage unit 37 is a non-volatile storage unit that stores information used in the search processing in the search processing unit 31, as well as information as a result of calculation processing in the search processing unit 31. The information stored in the processing information storage unit 37 can be updated as needed.

[0066] Furthermore, the optical transceiver 20 includes a light-emitting unit 22, a light-receiving unit 23, a correction unit 24, and a correction information storage unit 25.

[0067] The light-emitting unit 22 outputs an optical signal corresponding to the electrical signal input via the correction unit 24. The light-emitting unit 22 is, for example, a laser diode.

[0068] The light-receiving unit 23 outputs an electrical signal corresponding to the input optical signal. The light-receiving unit 23 includes, for example, a photodiode or a transimpedance amplifier.

[0069] In normal operation, which is not a search process, the light-emitting unit 22 outputs an optical signal to an output optical fiber, and the light-receiving unit 23 receives an optical signal from an input optical fiber. On the other hand, in the search process, an optical signal transmission path 28 is provided between the light-emitting unit 22 and the light-receiving unit 23. The transmission path 28 is, for example, an optical fiber or a waveguide structure. As a result, the switch device 100 can receive the electrical signal (test signal) transmitted in the signal wiring 12 as an electrical signal that has been photoelectrically converted by the light-receiving unit 23. The eye pattern acquisition unit 36 ​​acquires an eye pattern for the electrical signal output from the light-receiving unit 23 in response to the test signal. Thus, in this embodiment, by providing a transmission path 28, the configuration of the switch device 100 can be effectively utilized to acquire an eye pattern with a relatively simple configuration.

[0070] The correction unit 24 is a circuit that executes the correction process stored in the correction information storage unit 25 using the values ​​of the correction parameters stored in the correction information storage unit 25. The correction unit 24 can change the degree of correction according to the values ​​of the correction parameters. In the transmission of electrical signals from the switch ASIC 30 to the optical transceiver 20 in the signal wiring 12, the correction unit 24 performs at least one of gain correction and peaking processing. The correction unit 24 is an example of a second correction unit.

[0071] The correction information storage unit 25 is a non-volatile, rewritable storage unit that stores information indicating the correction process to be executed and the values ​​of the correction parameters for each signal wiring 12. The information indicating the correction process and the values ​​of the correction parameters are rewritten by the search processing unit 31, etc.

[0072] Figure 8 is a flowchart illustrating an example of the procedure for the search process for the signal wiring 12. First, the search processing unit 31 controls each unit to perform a trial (S11). That is, in S11, the signal generation unit 32 outputs test signals multiple times. The correction units 34 and 24 refer to the corresponding correction information storage units 35 and 25, respectively, and if a correction process corresponding to the signal wiring 12 to be searched is set, they execute the correction process for each test signal. The light-emitting unit 22 outputs an optical signal corresponding to the test signal (electrical signal) received via the correction unit 24. The optical signal output by the light-emitting unit 22 is transmitted to the light-receiving unit 23 via the transmission path 28. The light-receiving unit 23 outputs an electrical signal corresponding to the optical signal received from the light-emitting unit 22. The eye pattern acquisition unit 36 ​​acquires the eye patterns of the multiple electrical signals output by the light-receiving unit 23, that is, the eye patterns of the test signals transmitted multiple times through the signal wiring 12. The value of the correction parameter that is already set during the first trial is the initial value of the correction parameter.

[0073] Next, the search processing unit 31 determines whether the eye pattern acquired by the eye pattern acquisition unit 36 ​​meets the criteria (S12).

[0074] In S12, if the eye pattern does not meet the criteria (N in S12), the search processing unit 31 compares the edges Eu,El of the aperture O shown in Figure 6 with the criterion C, and, according to a predetermined algorithm, determines and stores the correction process to be performed in the next trial and the values ​​of the correction parameters in the correction process, depending on the overlap state between the edges Eu,El and the criterion C (S13). Specifically, in S13, for example, if the aperture O is narrower than the criterion C only before the reference time t0, the search processing unit 31 decides to perform pre-emphasis or de-emphasis as a correction process in the next trial, and determines the values ​​of the correction parameters that determine the degree of pre-emphasis and de-emphasis according to the degree of narrowing. Alternatively, for example, if the aperture O is narrower than the criterion C only after the reference time t0, the search processing unit 31 decides to perform post-emphasis in the next trial, and determines the values ​​of the correction parameters that determine the degree of post-emphasis according to the degree of narrowing. Alternatively, the search processing unit 31, for example, if the aperture O is narrower than the reference C both before and after the reference time t0, decides to perform at least one of gain correction and peaking processing in the next trial, and determines the value of a correction parameter that determines the degree of gain correction or peaking processing according to the degree of the narrowness. The processing information storage unit 37 stores, for example, maps, tables, functions, etc., as information showing the correlation between the value of a parameter that shows the overlap state between the aperture O and the reference C and the value of each correction parameter for each correction parameter, and the search processing unit 31 determines the value of the parameter based on the information showing the correlation. Furthermore, in S13, the search processing unit 31 stores the information showing the determined correction processing and the value of the correction parameter in the correction information storage units 35, 25 in association with the signal wiring 12 and the correction units 34, 24. Specifically, the search processing unit 31 writes information indicating the correction process to be performed by the correction unit 34 in accordance with the signal wiring 12, and the values ​​of the correction parameters to the correction information storage unit 35, and writes information indicating the correction process to be performed by the correction unit 24 in accordance with the signal wiring 12, and the values ​​of the correction parameters to the correction information storage unit 25.The information regarding the correction process and the method (algorithm) for determining the values ​​of the correction parameters described herein are merely examples and can be modified in various ways. Furthermore, the values ​​of the correction parameters already set in the first trial represent the initial values ​​of those correction parameters.

[0075] In S12, if the eye pattern meets the criteria (Y in S12), the information indicating the correction process and the values ​​of the correction parameters stored in the correction information storage units 35 and 25 at that time become valid as the information indicating the correction process and the values ​​of the correction parameters corresponding to the signal wiring 12 in the transmission of electrical signals via the signal wiring 12 during normal operation, not during searching, between the switch ASIC 30 and the optical transceiver 20. The search processing unit 31 also determines whether there is another signal wiring 12 in the same group of signal wiring 12 as the signal wiring 12 in question that has not yet undergone search processing (S14).

[0076] In S14, if there are other signal lines 12 in the same group that have not yet been searched (Y in S14), the search processing unit 31 stores the information indicating the correction process and the values ​​of the correction parameters for all other signal lines 12 in the same group that have not yet been searched, as information indicating the correction process and the values ​​of the correction parameters (S15). Specifically, in S15, the search processing unit 31 writes the information indicating the correction process to be executed by the correction unit 34 in association with the other signal lines 12 and the values ​​of the correction parameters to the correction information storage unit 35. Also in S15, the search processing unit 31 writes the information indicating the correction process to be executed by the correction unit 24 in association with the other signal lines 12 and the values ​​of the correction parameters to the correction information storage unit 25 of the optical transceiver 20 that transmits electrical signals through the other signal lines 12. The parameter values ​​written in this case become the initial values ​​for the search process of the other signal lines 12. As described above, in many cases, the eye pattern satisfies the predetermined conditions when the same correction process is performed on multiple signal lines 12 with similar specifications using the same correction parameter values. Therefore, by performing S15, the time required for the search process on other signal lines 12 in the same group that have not yet been searched becomes shorter, and consequently, the time required for the search process on all signal lines 12 of the switch device 100 becomes shorter. Note that in S15, the initial value of the correction parameter corresponding to another signal line 12 does not need to be the value of the correction parameter of the signal line 12 whose eye pattern satisfies the criteria in S12, i.e., the value of the correction parameter obtained by the search process itself. It is sufficient if it is a value based on the value of the correction parameter obtained by the search process, such as a value corrected by the same rule as the value of the correction parameter obtained by the search process (for example, a value multiplied by 0.8).

[0077] In S14, if there are no other signal lines 12 remaining in the same group that have not yet been searched (N in S14), the search processing unit 31 determines whether there is another group of signal lines 12 that have not yet been searched (S16). If there is no other group of signal lines 12 that have not yet been searched (N in S16), the process ends.

[0078] After S15, the search processing unit 31 determines the next signal wiring 12 to be searched from within the same group as the signal wiring 12 whose eye pattern met the criteria in S12 (S17), and proceeds to the search process for the next determined signal wiring 12 (S11). Also, in S16, if there is another group for which the search process has not yet been performed (Y in S16), the search processing unit 31 determines the next signal wiring 12 to be searched from within that other group (S17), and proceeds to the search process for the next determined signal wiring 12 (S11).

[0079] With the configuration described above, the switch device 100 (optical device) of this embodiment allows the initial value of the correction parameter in the search process to be set to a different value for each signal line 12. If the initial value of the correction parameter were set to a common value for all signal lines 12, the search process to find a suitable correction parameter value might take a long time depending on the signal line 12. In this respect, according to this embodiment, since the initial value of the correction parameter in the search process can be set to a different value for each signal line 12, the time required for the search process can be shortened.

[0080] Furthermore, in this embodiment, the initial value is set for each group of signal wiring 12, or based on the correction parameter value of other signal wiring 12, which has the advantage of shortening the time required for the search process.

[0081] Furthermore, the initial value may be set according to the value of a correction parameter set in the same location signal wiring 12 of another unit of the switch device 100 having the same structure. In this case, the initial value may be the same as the value of the correction parameter of the same location signal wiring 12 of the other unit, or it may be a value based on the value of the correction parameter of the same location signal wiring 12 of the other unit, such as a value corrected according to the same rule (for example, a value multiplied by 0.8).

[0082] [Second Embodiment] Figure 9 is a block diagram of the switch device 100B(100) of the second embodiment. Although only one optical transceiver 20 is shown in Figure 9, the other optical transceivers 20 have the same configuration as the optical transceiver 20 in Figure 9.

[0083] As shown in Figure 9, in this embodiment, in addition to the light-emitting unit 22, light-receiving unit 23, correction unit 24, correction information storage unit 25, and transmission path 28 similar to those in the first embodiment, the optical transceiver 20 also has a search processing unit 21, an eye pattern acquisition unit 26, and a processing information storage unit 27.

[0084] The search processing unit 21 performs the determination of the correction process and the search for the values ​​of the correction parameters for the corrections performed by the correction unit 24, such as gain correction and peaking. On the other hand, the search processing unit 31 performs the determination of the correction process and the search for the values ​​of the correction parameters for the corrections performed by the correction unit 34, such as pre-emphasis, post-emphasis, de-emphasis, etc. In other words, the search processing unit 21 and the search processing unit 31 can each perform steps S11 to S13 in Figure 8 for different correction parameters. The search processing unit 21 is an arithmetic processing circuit. The search processing unit 21 is an example of a second search processing unit.

[0085] The eye pattern acquisition unit 26 acquires the eye pattern of the electrical signal transmitted multiple times in the signal wiring 12 based on the electrical signal from the light receiving unit 23.

[0086] The processing information storage unit 27 is a non-volatile storage unit that stores information used in the search processing in the search processing unit 21, as well as information as a result of calculation processing in the search processing unit 21. The information stored in the processing information storage unit 27 can be updated as needed.

[0087] Although only one signal generation unit 32 is shown in Figure 9, the switch ASIC 30 is equipped with multiple signal generation units 32 that can operate in parallel. Each signal generation unit 32 can receive a signal from the search processing unit 31 or the search processing unit 21 and output a test signal in parallel.

[0088] In this embodiment, the search processing unit 31 and the search processing unit 21 can perform processes to search for different correction parameter values. Specifically, for example, after the search processing unit 31 of the switch ASIC 30 performs the process of determining the correction process in the correction unit 34 and searching for the correction parameter value (determination of the correction parameter value) for the signal wiring 12, the search processing unit 21 of the optical transceiver 20 can perform the process of determining the correction process in the correction unit 24 and searching for the correction parameter value for the same signal wiring 12. In this case, furthermore, while the search processing unit 21 of the optical transceiver 20 is performing the process of determining the correction process in the correction unit 24 and searching for the correction parameter value, the search processing unit 31 of the switch ASIC 30 can perform the process of determining the correction process in the correction unit 34 and searching for the correction parameter value for another signal wiring 12.

[0089] Thus, the switch device 100B of this embodiment includes multiple search processing units 31, 21 capable of performing search processing to find values ​​for different correction parameters. This makes it possible to shorten the time required for the search processing compared to a case where a single search processing unit performs the search processing for all correction parameter values.

[0090] Furthermore, the switch device 100B of this embodiment includes multiple search processing units 31, 21 that can perform search processing in parallel, which makes it possible to shorten the time required for search processing compared to the case where a single search processing unit (for example, search processing unit 31) performs the search processing for all correction parameter values.

[0091] Furthermore, the search processing units 21 of multiple optical transceivers 20 may perform the search process in parallel. In this case, the time required for the search process can be further reduced. In this case, the search processing units 21 of multiple optical transceivers 20 that transmit electrical signals via signal wiring 12 belonging to the same group may, but are not limited to, perform the search process in parallel.

[0092] [Third Embodiment] Figure 10 is a block diagram of the switch device 100C(100) of the third embodiment. Although only one optical transceiver 20 is shown in Figure 10, the other optical transceivers 20 have the same configuration as the optical transceiver 20 in Figure 10.

[0093] In this embodiment, the eye pattern acquisition unit 26 is provided on the optical transceiver 20, and information indicating the eye pattern, such as data indicating the aperture O of the eye pattern, is transmitted from the eye pattern acquisition unit 26 of the optical transceiver 20 to the search processing unit 31 of the switch ASIC 30. The search processing unit 31 can perform a search process based on the information indicating the eye pattern acquired from the eye pattern acquisition unit 26. According to this embodiment, for example, the advantage of simplifying the device configuration can be obtained.

[0094] [Fourth Embodiment] Figure 11 is a schematic configuration diagram of a correction parameter determination system 1000 including a switch device 100D(100) of the fourth embodiment. As shown in Figure 11, in this embodiment, the determination of the correction process and the search and determination of the correction parameters are performed by a processing unit 300 that is electrically connected to the switch device 100D(100) via a connector cable 400. In this case, the switch device 100D has an eye pattern acquisition unit 36 ​​provided in the switch ASIC 30 or an eye pattern acquisition unit 26 provided in the optical transceiver 20, as shown in Figure 9. Furthermore, a search processing unit that determines the correction process in the correction unit 34 of the switch ASIC 30 (see Figure 9, etc.) and performs the search process, and a search processing unit 301 that determines the correction process in the correction unit 24 of the optical transceiver 20 (see Figure 9, etc.) and performs the search process are provided in the processing unit 300. The search processing unit 301 of the processing unit 300 instructs the signal generation unit 32 (see Figure 9, etc.) to output a test signal via the connector cable 400, acquires information indicating the eye pattern via the connector cable 400, performs a search process, and determines the value of the correction parameter. The search processing unit 301 writes the determined value of the correction parameter to the correction information storage units 35,25 (see Figure 9, etc.) via the connector cable 400. Thus, the search processing unit 301 may be provided outside the switch device 100. The connector cable 400 may also be called a signal transmission unit.

[0095] Although embodiments of the present invention have been illustrated above, these embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, each configuration, shape, and other specifications (structure, type, orientation, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate. [Explanation of Symbols]

[0096] 10... Circuit board 10a...side 10b...side 10c…side 10d…Corner 11…Insulator 11a1~11a4...Insulating layer 12…Signal wiring 12a1,12a2...electrode 12b1, 12b2… Via 12c…Nobube 20… Optical transceiver 21... Search Processing Unit 22...Light-emitting part 23...Light receiving section 24... Correction section 25... Correction Information Storage Unit 26... Eye pattern acquisition section 27... Processing information storage unit 28…Transmission path 30…Switch ASIC 31…Search Processing Unit 32... Signal generation unit 34...Correction section 35... Correction Information Storage Unit 36... Eye pattern acquisition unit 37… Processing Information Storage Unit 100, 100A~100D... Switching device (optical device) 200… Optical communication equipment 201...Motherboard 201a, 201b...plane 202…IC 300… Processing equipment 301... Search Processing Unit 400…Cable with connector 1000... Correction parameter determination system C…Standard Cg…center of gravity El, Eu... Edge G1~G4...Group O…Opening t0…Reference time X…direction Y... Direction Z…direction

Claims

1. A circuit board having an insulator and multiple signal lines, A semiconductor integrated circuit provided on the circuit board, A plurality of optical transceivers provided on the circuit board and transmitting electrical signals to the semiconductor integrated circuit via separate signal wiring, A correction unit for correcting the signal transmission eye pattern in each of the aforementioned signal wirings, the correction unit being capable of changing the degree of correction according to a correction parameter, Equipped with, In the search process for finding a correction parameter that satisfies a predetermined condition by changing the correction parameter so that the discrepancy between the eye pattern acquired for each of the signal lines and the eye pattern that satisfies a predetermined condition is reduced, the initial value of the correction parameter can be set to a different value for each of the signal lines. An optical device in which, in the search process for each of the signal lines, the initial value is determined based on the correction parameter obtained by the search process for the other signal lines.

2. The aforementioned multiple signal lines are grouped into multiple groups, The optical device according to claim 1, wherein in the search process for each of the signal lines, the initial value is determined based on the correction parameter obtained by the search process for other signal lines belonging to the same group.

3. A circuit board having an insulator and a plurality of signal lines, A semiconductor integrated circuit provided on the circuit board, A plurality of optical transceivers provided on the circuit board and transmitting electrical signals to the semiconductor integrated circuit via separate signal wiring, A correction unit for correcting the signal transmission eye pattern in each of the aforementioned signal wirings, the correction unit being capable of changing the degree of correction according to a correction parameter, Equipped with, In the search process for finding a correction parameter that satisfies a predetermined condition by changing the correction parameter so that the discrepancy between the eye pattern acquired for each of the signal lines and the eye pattern that satisfies a predetermined condition is reduced, the initial value of the correction parameter can be set to a different value for each of the signal lines. The aforementioned multiple signal lines are grouped into multiple groups, In the search process for each of the signal lines, the initial value is set for each group of optical devices.

4. The optical device according to claim 2 or 3, wherein the plurality of groups are set according to the length of the signal wiring.

5. The circuit board has a plurality of signal lines that pass through different layers in the thickness direction of the circuit board as signal lines. The optical device according to claim 2 or 3, wherein each of the groups includes the signal wiring having a section passing through the same hierarchy.

6. The optical device according to claim 2 or 3, wherein the plurality of groups are set according to the mounting positions on the circuit board of the optical transceiver that transmits electrical signals to the semiconductor integrated circuit via the signal wiring.

7. The optical device according to claim 2 or 3, wherein the initial value of the correction parameter is set according to the correction parameter set in the plurality of signal wiring of other individuals of the optical device having the same structure.

8. The optical device according to claim 1, further comprising a search processing unit that performs a search process to search for a correction parameter that satisfies a predetermined condition by changing the correction parameter so that the discrepancy between the eye pattern acquired for each of the signal wirings and the eye pattern that satisfies a predetermined condition is reduced.

9. The optical device according to claim 1, comprising a plurality of search processing units capable of performing search processing for different signal wirings in parallel, wherein the search processing unit performs a search process to search for correction parameters that satisfy predetermined conditions by changing the correction parameters so that the discrepancy between the eye pattern acquired for each of the signal wirings and the eye pattern that satisfies predetermined conditions is reduced.

10. The optical device according to any one of claims 1, 3, and 9, wherein the optical device is further comprising a plurality of search processing units capable of performing a search process to search for a different correction parameter, each of which is a search processing unit that performs a search process to search for a correction parameter that satisfies a predetermined condition by changing the correction parameter so that the discrepancy between the eye pattern acquired for each of the signal wirings and the eye pattern that satisfies a predetermined condition is reduced.

11. The optical device according to claim 8, wherein the search processing unit comprises a first search processing unit provided in the semiconductor integrated circuit.

12. The optical device according to claim 8 or 11, further comprising a second search processing unit provided in each of the optical transceivers as the search processing unit.

13. The optical device according to any one of claims 1, 3, and 8, further comprising a first correction unit that performs at least one enhancement process from a first enhancement process that expands the aperture before a reference time of the eye pattern, a second enhancement process that expands the aperture after a reference time of the eye pattern, and a third enhancement process that expands the aperture when the signal is continuous regardless of whether it is before or after the reference time.

14. The optical device according to any one of claims 1, 3, and 8, further comprising a second correction unit which is at least one of a gain correction unit and a peaking processing unit as the correction unit.

15. A circuit board having an insulator and a plurality of signal lines, A semiconductor integrated circuit provided on the circuit board, A plurality of optical transceivers provided on the circuit board and transmitting electrical signals to the semiconductor integrated circuit via separate signal wiring, A correction unit for correcting the signal transmission eye pattern in each of the aforementioned signal wirings, the correction unit being capable of changing the degree of correction according to a correction parameter, Equipped with, In the search process for finding a correction parameter that satisfies a predetermined condition by changing the correction parameter so that the discrepancy between the eye pattern acquired for each of the signal lines and the eye pattern that satisfies a predetermined condition is reduced, the initial value of the correction parameter can be set to a different value for each of the signal lines. The optical transceiver is an optical device comprising: a light-emitting unit that outputs an optical signal in response to an electrical signal from the semiconductor integrated circuit; a light-receiving unit that receives the optical signal and outputs an electrical signal to the semiconductor integrated circuit in response to the optical signal; and a transmission path that transmits the optical signal from the light-emitting unit to the light-receiving unit.

16. The optical device according to claim 15, further comprising a search processing unit that performs a search process to search for a correction parameter that satisfies a predetermined condition by changing the correction parameter so that the discrepancy between the eye pattern acquired for each of the signal wirings and the eye pattern that satisfies a predetermined condition is reduced.

17. An acquisition unit that acquires the eye pattern for each of the aforementioned signal lines, A signal transmission unit transmits between the optical device and the device an output signal based on the acquisition results of the acquisition unit, and an input signal from a search processing unit that performs a search process to search for correction parameters that satisfy predetermined conditions by changing the correction parameters so as to reduce the discrepancy between the eye pattern acquired for each of the signal wirings based on the output signal provided in a device different from the optical device and the eye pattern that satisfies predetermined conditions. An optical device according to any one of claims 1, 3, and 15, comprising the above.

18. A method for setting the correction parameter in an optical device according to any one of claims 1, 3, and 15, A method for setting correction parameters for an optical device, wherein the initial value of the correction parameter in a search process for finding a correction parameter that satisfies predetermined conditions is set to a different value for each of the signal lines, by changing the correction parameter so that the discrepancy between the eye pattern acquired for each of the signal lines and the eye pattern that satisfies predetermined conditions is reduced.

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