JP2007318220A - Optoelectric converter, light-receiving circuit and light-receiving module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and inexpensive optoelectric converter capable of actualizing an operation of separating an electric signal superimposed on an optical signal and having different frequency band and amplifying the separated signals, and to provide a light-receiving circuit. <P>SOLUTION: The optoelectric converter is provided with: a photodiode 1 to which an optical signal superimposed with electric signals of different bands; and a parallel resonation circuit 2 configured of at least one or more capacitors C, and an inductor L or a transmission line, and resonating with at least one or more frequencies of the electric signal. One end of the parallel resonant circuit 2 is grounded in AC at a capacitor 6<SB>1</SB>, and the other end is connected to a cathode terminal of the photodiode 1, and electric signals having different frequency bands are extracted from the two terminals, i. e. an anode terminal and the cathode terminal. Further, an AM band amplifier 5<SB>1</SB>for amplifying a signal having a frequency approximate to the resonant frequency is connected to the cathode terminal connected to the parallel resonant circuit 2, and an FM band amplifier 5<SB>2</SB>for amplifying a signal having a frequency different from the resonant frequency or a digital signal amplifier is connected to the anode terminal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical / electrical converter, an optical receiver circuit, and an optical receiver module, and more particularly, to an optical receiver that optically transmits a frequency-multiplexed signal or an optical receiver that hybrid-transmits a signal of a different modulation scheme by frequency multiplexing. The present invention relates to a photoelectric converter, a light receiving circuit, and a light receiving module.

  As an optical video distribution system, an AM-FDM signal typified by terrestrial broadcasting and an FM-FDM signal typified by satellite broadcasting are frequency-multiplexed at an electrical stage, and both frequency-multiplexed signals are superimposed on an optical signal, At the same time, an AM / FM-FDM hybrid optical image distribution system that optically transmits to a user's home via an optical fiber has been studied (see Patent Document 1). In addition, compared to the FDM system, an FM batch conversion system that can expand the dynamic range and improve the reflected light resistance of optical connectors, etc. is adopted, and other unused frequency regions outside the FM band are used. A method of superimposing signals has also been studied (see Non-Patent Document 1).

  In recent years, in an optical video distribution system, it is strongly demanded to increase transmission channels using such a hybrid transmission technique. Here, an important point is to make the apparatus as low-cost and compact as possible. From this point of view, for example, it is not a configuration including individual optical reception circuits for AM signal reception and FM signal reception based on WDM technology or the like, but includes only one photodiode as one optical reception module. Realization of an optical receiver circuit configuration is strongly desired.

The configuration of the conventional optical receiver circuit shown in FIG. 13 is disclosed in Patent Document 1. In this configuration, an electrical signal from one photodiode 1 provided in the optical receiving circuit is separated into, for example, an AM signal and an FM signal by the low-pass filter 21 and the high-pass filter 22, respectively, and is optimal for each signal band. The AM band amplifier 23 and the FM band amplifier 24 are amplified. Therefore, since the signals are separated before being input to the AM band amplifier 23 and the FM band amplifier 24, the AM-FM signal between the AM and FM signals due to the nonlinearity of the amplifier is compared with the configuration in which the photodiode 1 and the amplifier are directly connected. There is an advantage that the intermodulation distortion and the harmonic distortion of signals in different bands can be greatly reduced.
Japanese Patent No. 3317450 Shibata et al. "Subcarrier multiplexing transmission using FM batch conversion technology and digital baseband signal superposition method" IEICE Transactions B vol. J85-B, no. 1-8. January 2002

  However, in the configuration of the optical receiving circuit shown in FIG. 13, each of the low-pass filter 21 and the high-pass filter 22 requires a plurality of inductors and capacitors as shown in the drawing, which is advantageous for downsizing and cost reduction. When a simple monolithic integrated circuit is used, the area occupied by these filters increases and the chip size increases, and the reception sensitivity decreases due to the loss that occurs when the signal passes through the filter. There is a point. Further, the increase in the chip size has a problem that the cost of the optical receiver module configured using the optical receiver circuit is increased.

  Also, for example, when receiving FM collective signals or digital signals, a flat group delay characteristic is required in the signal frequency band. To flatten the group delay characteristic, a multistage filter is required. As a result, there has been a problem that the circuit scale is increased, resulting in an increase in cost and loss (decrease in reception sensitivity).

  The present invention has been made in view of such a problem, and enables an operation of separating and amplifying electric signals having different frequency bands superimposed on an optical signal with a configuration in which a photodiode and an amplifier are directly connected, and An object of the present invention is to provide a high-performance, small, and low-cost photoelectric converter, optical receiver circuit, and optical receiver module by greatly reducing the number of filter parts.

  The present invention comprises the following technical means in order to solve the above-mentioned problems.

  A first technical means is an optoelectric converter comprising a photodiode to which an optical signal in which an electric signal of a different frequency band is superimposed is input, and a parallel resonance circuit that resonates with at least one frequency of the electric signal. The parallel resonant circuit has one end grounded in an alternating manner, the other end connected to the anode or cathode of the photodiode, and takes out electrical signals from the anode and cathode of the photodiode, respectively. To do.

  According to a second technical means, in the photoelectric converter according to the first technical means, the optical signal input to the photodiode is in parallel with the first signal near the resonant frequency of the parallel resonant circuit. Signals in two types of frequency bands are superimposed on a second signal having a frequency lower than or higher than the resonance frequency of the circuit.

  According to a third technical means, in the photoelectric converter according to the second technical means, the first signal is at least one AM signal, and the second signal is an FM signal or a digital signal. It is a signal.

  According to a fourth technical means, in the photoelectric converter according to any one of the first to third technical means, the parallel resonant circuit includes at least one capacitor and at least one inductor or transmission line. It is characterized by being.

  According to a fifth technical means, in the photoelectric converter according to the fourth technical means, a part or all of the inductor includes a wire.

  According to a sixth technical means, in the photoelectric converter according to any one of the first to fifth technical means, the photodiode and a part or all of the parallel resonant circuit are integrated on the same semiconductor substrate. It is characterized by being.

  According to a seventh technical means, in the photoelectric converter according to any one of the first to fifth technical means, a part or all of the parallel resonant circuit and a part or all of the bias circuit of the photodiode Are integrated on the same substrate.

  An eighth technical means is an optical receiver circuit comprising the photoelectric converter according to any one of the first to seventh technical means, a first amplifier, and a second amplifier. The input terminal of the amplifier is connected to the one of the anode or cathode of the photodiode to which the parallel resonant circuit is connected, and the input terminal of the second amplifier is the anode or cathode of the photodiode, The parallel resonant circuit is connected to the unconnected side.

  A ninth technical means is the optical receiver circuit according to the eighth technical means, wherein the first amplifier amplifies a signal in the vicinity of a resonance frequency of the parallel resonant circuit, and the second amplifier A signal having a frequency lower than or higher than the resonance frequency of the parallel resonance circuit is amplified.

  According to a tenth technical means, in the optical receiver circuit according to the eighth or ninth technical means, the first amplifier is composed of an AGC amplifier or a first preamplifier and an AGC amplifier. The second amplifier includes a second preamplifier and a limit amplifier.

  The eleventh technical means is the optical receiver circuit according to the eighth or ninth technical means, wherein the first amplifier is a first AGC amplifier, or a first preamplifier and a first AGC amplifier. The second amplifier is composed of a second preamplifier and a second AGC amplifier.

  A twelfth technical means is characterized in that, in the optical receiver circuit according to the eleventh technical means, the power detection circuits of both the first AGC amplifier and the second AGC amplifier are common. .

  A thirteenth technical means is the optical receiver circuit according to any one of the eighth to twelfth technical means, wherein the first amplifier and a part or all of the parallel resonant circuit are on the same semiconductor substrate. It is characterized by being accumulated.

  A fourteenth technical means is the optical receiver circuit according to any one of the eighth to thirteenth technical means, wherein the first amplifier and the second amplifier are integrated on the same semiconductor substrate. Features.

  A fifteenth technical means is the optical receiver circuit according to any one of the eighth to fourteenth technical means, wherein an anode terminal and a cathode terminal of the photodiode form a photodiode chip. Alternatively, the photodiodes are arranged on opposite sides of a semiconductor substrate on which the photodiodes are integrated.

  Sixteenth technical means is the optical receiver circuit according to any one of the eighth to fourteenth technical means, wherein the anode terminal and the cathode terminal of the photodiode form a photodiode chip. Alternatively, the semiconductor substrate is arranged on adjacent sides of the semiconductor substrate on which the photodiode is integrated.

  Seventeenth technical means is the optical receiver circuit according to any one of the eighth to fourteenth technical means, wherein an anode terminal and a cathode terminal of the photodiode form a photodiode chip. Alternatively, the photodiodes are arranged on the same side of the semiconductor substrate on which the photodiodes are integrated.

  An eighteenth technical means is the optical receiver module comprising the optical receiver circuit according to any one of the seventh to seventeenth technical means, wherein the first amplifier of the anode terminal or the cathode terminal of the photodiode is used. The terminal connected to the input terminal and the input terminal of the first amplifier are arranged at positions facing each other and close to each other, and the terminal connected to the input terminal of the second amplifier among the anode terminal or the cathode terminal of the photodiode And the input terminal of the second amplifier are arranged at positions that face each other and are close to each other.

  In the photoelectric converter, the optical receiver circuit, and the optical receiver module according to the present invention, a parallel resonant circuit having one end AC-grounded is connected to the anode terminal or the cathode terminal of the photodiode, and the anode terminal and the cathode terminal are different from each other. An amplifier for amplifying a photodiode and two electrical signals output from the photodiode without providing a filter for separating the signals into different frequency bands by adopting a configuration for taking out two electrical signals in the frequency band It is possible to realize a configuration that can be directly connected to an (amplifier), and to significantly reduce the number of parts of the filter. Thus, high performance, miniaturization, and cost reduction of the photoelectric converter, optical receiver circuit, and optical receiver module can be realized.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Exemplary embodiments of a photoelectric converter, an optical receiver circuit, and an optical receiver module according to the present invention will be described below in detail with reference to the drawings.

(First embodiment)
First, an example of the configuration of the photoelectric converter according to the present invention will be described as a first embodiment.

  FIG. 1 is a circuit diagram showing the photoelectric converter according to the first embodiment of the present invention.

  The photoelectric converter 100 shown in FIG. 1 includes a photodiode 1, a bias resistor 3, and a parallel resonance circuit 2. The parallel resonant circuit 2 is configured by a parallel connection of a capacitor C and an inductor L, one end of which is AC-grounded and the other end is connected to the cathode terminal of the photodiode 1. Note that a reverse bias voltage can be applied to the photodiode 1 via a bias resistor 3.

  Here, in addition to the cathode terminal of the photodiode 1, an electric signal is taken out from the anode terminal, so that a signal (first signal) in the vicinity of the resonance frequency of the parallel resonance circuit 2 is output from the cathode terminal of the photodiode 1. Further, it is possible to selectively output a signal (second signal) having a frequency lower than or higher than the resonance frequency of the parallel resonance circuit 2 from the anode terminal. That is, the photoelectric converter 100 of FIG. 1 includes a parallel resonant circuit 2 that resonates with at least one frequency of electrical signals in different frequency bands superimposed on an optical signal input to the photodiode 1. Therefore, it is possible to take out electrical signals in separate frequency bands from the two terminals of the anode terminal and the cathode terminal of the photodiode 1.

  This is because the parallel resonant circuit 2 that is short-circuited at one end is open at the other end, and therefore, for example, at the cathode terminal of the photodiode 1 to which the other end is connected, the resonant frequency of the parallel resonant circuit 2 is selectively selected. Since the signal amplitude in the vicinity increases and this energy component decreases at the anode terminal, a signal having a frequency lower than or higher than the resonance frequency of the parallel resonance circuit 2 is selectively selected from the anode terminal of the photodiode 1. It is because it can output to.

  3 and 4 are simulations of this situation. That is, FIG. 3 is a graph showing a simulation result of amplitude characteristics of the photoelectric converter 100 according to the first embodiment of the present invention, and FIG. 4 is a photoelectric conversion according to the first embodiment of the present invention. 10 is a graph showing a simulation result of group delay characteristics of the device 100. In the simulations of FIGS. 3 and 4, the resonance frequency of the parallel resonance circuit 2 is 2fo. Looking at the frequency characteristics of the amplitude shown in FIG. 3, the output from the cathode terminal of the photodiode 1 is output with a selectively large amplitude only in the vicinity of 2fo, and the output from the anode terminal of the photodiode 1. It can be seen that the amplitude characteristics are flat from DC to (3/2) fo. On the other hand, when looking at the group delay characteristic of FIG. 4, the output from the cathode terminal of the photodiode 1 has a substantially flat characteristic up to about fo.

  Therefore, under such conditions, signals in two types of frequency bands, a narrow band signal (first signal) of 2fo band and a wideband signal (second signal) of DC to foGHz or DC to foGbit / s, are obtained. When being input to the photodiode 1 as a superimposed optical signal, it is possible to output signals in respective frequency bands almost independently from the cathode terminal side and the anode terminal side. Thus, with the configuration shown in FIG. 1, the required number of inductors is reduced from four to one and the required number of capacitors is reduced from four to one as compared with the conventional example shown in FIG. Can be reduced. Furthermore, since it becomes possible to directly connect the photodiode 1 and the amplifier without going through a low-pass filter or a high-pass filter, for example, the output on the cathode terminal side of the photodiode 1 to which the parallel resonant circuit 2 is connected is AM. A configuration in which the output on the anode terminal side of the photodiode 1 that is directly connected to the band (narrowband) amplifier and not connected to the parallel resonance circuit 2 is directly connected to the FM band (wideband) amplifier or the digital signal (wideband) amplifier is enabled. As a result, the degree of separation between the first signal and the second signal can be further improved by the effect of the parallel resonance circuit 2 and the synergistic effect of the frequency characteristics of the respective amplifiers.

  FIG. 2 is a circuit diagram showing the photoelectric converter according to the modification of the first embodiment of the present invention. The photoelectric converter 100A of FIG. 2 uses a parallel resonant circuit 2A configured by a parallel connection of a capacitor C and an inductive transmission line Lt instead of the parallel resonant circuit 2 of the photoelectric converter 100 of FIG. ing. That is, the parallel resonant circuit 2A is configured using an inductive transmission line Lt instead of the inductor L in the parallel resonant circuit 2 illustrated in FIG. In the photoelectric converter 100A of FIG. 2, one end of the parallel resonance circuit 2A is grounded in an alternating manner, and the other end is connected to the anode terminal of the photodiode 1. A reverse bias voltage can be applied through the resistor 3.

  Therefore, also in the photoelectric converter 100A, the signal near the resonance frequency of the parallel resonance circuit 2A is not connected to the anode terminal of the photodiode 1 to which the parallel resonance circuit 2A is connected, and the parallel resonance circuit 2A is not connected. From the cathode terminal of the photodiode 1, a signal having a frequency lower than or higher than the resonance frequency of the parallel resonance circuit 2A can be selectively output. That is, the photoelectric converter 100A of FIG. 2 can take out electrical signals in separate frequency bands from the two terminals of the anode terminal and the cathode terminal of the photodiode 1, similarly to the photoelectric converter 100 of FIG. It has become.

  Note that the number of capacitors C and inductors L forming the parallel resonant circuit 2 in the configuration of the photoelectric converter 100 in FIG. 1 is not limited to one, but at least one capacitor and at least one inductor. Further, the capacitor C and the inductive transmission line Lt forming the parallel resonant circuit 2A in the configuration of the photoelectric converter 100A in FIG. 2 are not limited to one each. It may be configured by at least one capacitor and at least one transmission line.

  Of the two types of electric signals superimposed on the optical signal input to the photodiode 1, the first signal having a frequency near the resonance frequency of the parallel resonance circuit 2 is at least one AM signal. On the other hand, the second signal having a frequency lower than or higher than the resonance frequency of the parallel resonance circuit 2 may be an FM signal or a digital signal. . Further, instead of directly connecting a bias circuit (bias resistor 3, power supply connection terminal, etc.) for applying a reverse bias voltage to the photodiode 1 to the terminal of the photodiode 1, the photodiode is connected via the parallel resonant circuits 2 and 2A. In this case, the terminals of the parallel resonant circuits 2 and 2A connected to the bias circuit are grounded in an AC manner by a capacitor having a sufficiently large capacitance value, for example. Configured.

  Furthermore, the parallel resonant circuit 2 of the photoelectric converter 100 of FIG. 1 may be replaced with the parallel resonant circuit 2A of FIG. 2, or conversely, the parallel resonant circuit 2A of the photoelectric converter 100A of FIG. The parallel resonant circuit 2 shown in FIG. Further, the photodiode 1 in the photoelectric converters 100 and 100A of FIGS. 1 and 2 and a part or all of the parallel resonant circuits 2 and 2A may be integrated on the same semiconductor substrate.

(Second Embodiment)
In the present embodiment, an example relating to the configuration of the optical receiver circuit according to the present invention will be described. In other words, the optical receiver circuit exemplified in the present embodiment is configured using the photoelectric converter as described in the first embodiment and the first and second amplifiers (amplifiers). The optical signal input to the photodiode 1 is a resonance between the first signal (for example, at least one AM signal) having a frequency near the resonance frequency of the parallel resonance circuits 2 and 2A and the resonance of the parallel resonance circuit 2. An anode terminal of the photodiode 1 in which an electric signal of two kinds of frequency bands is superimposed on a second signal (for example, an FM signal or a digital signal) having a frequency lower than the frequency or higher than the resonance frequency. Or, among the cathode terminals, a first amplifier having an input terminal connected to a terminal to which the parallel resonant circuits 2 and 2A are connected amplifies the first signal, while the parallel resonant circuit 2 Second amplifier A is input to the photodiode 1 of the terminal that is not connected is connected, and shows an example configured to amplify the second signal.

  Here, in the following description, like the photoelectric converter 100 described in FIG. 1 of the first embodiment, the parallel resonant circuit 2 in FIG. 1 or the parallel resonant circuit 2A in FIG. The case where it is connected to the cathode terminal will be described.

  However, like the photoelectric converter 100A described in FIG. 2 of the first embodiment, the parallel resonant circuits 2 and 2A may be connected to the anode terminal of the photodiode 1, or the parallel resonant circuit may be connected. The capacitors C and inductors L or inductive transmission lines Lt forming the circuits 2 and 2A are not limited to one each, but at least one capacitor and at least one inductor or at least one transmission. You may make it comprise with a track.

  FIG. 5 is a circuit diagram showing an optical receiver circuit according to the second embodiment of the present invention.

The optical receiver circuit 200 shown in FIG. 5 has a configuration in which an amplifier (amplifier) 5 is connected to the photoelectric converter 100 of the first embodiment illustrated in FIG. Here, the cathode terminal of the photodiode 1 parallel resonance circuit 2 is connected to the input terminal of the AM band amplifier 5 _1, while the anode terminal of the photodiode 1 parallel resonance circuit 2 is not connected, FM It is connected to input terminals of the band amplifier 5 _2. Unlike the case of FIG. 1, the bias circuit (such as the bias resistor 3) that applies a reverse bias voltage to the cathode terminal of the photodiode 1 is connected via the parallel resonance circuit 2. Here, preferably, the capacitance value of the capacitor ₆₁ is located at a sufficiently large value as in the two kinds of signal frequency band superimposed on the optical signal input to the photodiode 1 is shorted to the AC to ground potential in addition, the capacitance value of the capacitor 6 _2, in the frequency band of the AM signal included in the optical signal input to the photodiode 1 is set to a value such that impedance is sufficiently small.

By applying such a capacitor 6 _1, 6 _2, it becomes possible to apply a reverse bias voltage to the photodiode 1, it is possible to the AM band amplifier 5 _first input interface capacitive coupling. Here, AM band amplifier 5 ₁ is a characteristic of amplifying only the signal of the AM band, FM band amplifier 5 ₂ if characteristic for amplifying only a signal FM band, together with the effect of the parallel resonance circuit 2, different It is possible to greatly reduce the influence between the bands.

Moreover, the AM band amplifier 5 ₁ and FM band amplifier 5 ₂ can be configured as an amplifier chip 5 which is integrated on the same semiconductor substrate. Furthermore, the photodiode 1, the parallel resonance circuit 2, and the capacitors 6 ₁ and 6 ₂ can be configured as a photodiode chip 4 integrated on the same semiconductor substrate.

By using integrated circuits such as the photodiode chip 4 and the amplifier chip 5, it becomes easy to reduce the number of components and to remove parasitic components due to mounting, and to improve characteristics, reduce size, and reduce costs. Can do. Incidentally, the capacitor 6 _2, the photodiode chip 4 without, or may be in a form that is provided to the amplifier chip 5 side. The capacitor _61, without built in photodiode chip 4, may be configured to externally. Further, as illustrated below, not all of the parallel resonant circuit 2 but a part thereof may be integrated on the same semiconductor substrate as the photodiode 1.

FIG. 6 is a circuit diagram showing an optical receiver circuit according to a first modification of the second embodiment of the present invention. The optical receiver circuit 200A of FIG. 6 is configured by a parallel resonant circuit 2A in which the inductor L in the parallel resonant circuit 2 of the optical receiver circuit 200 illustrated as the second embodiment in FIG. 5 is replaced with an inductive transmission line Lt. point you are, further, differs in that a the transmission line Lt and the capacitor ₆₁ to the outside of the photodiode chip 4A. The capacitor 6 ₂ also, the photodiode chip 4A without has a form with the amplifier chip 5A side.

  By adopting a configuration such as the optical receiver circuit 200A of FIG. 6, the yield of the photodiode chip 4A can be improved and the cost can be reduced, and by providing the transmission line Lt outside the photodiode chip 4A, the photodiode can be obtained. Even when the capacitance value of the capacitor C for the parallel resonant circuit 2A in the chip 4A deviates from the design value due to manufacturing variation, the line length and impedance of the transmission line Lt can be easily adjusted. The resonant frequency of the parallel resonant circuit 2A can be set according to the set value.

Further, the optical receiver circuit 200A of FIG. 6, the AM band amplifier ₅ 1, FM band amplifier _{5 2} in the optical receiver circuit 200 of FIG. 5, constituted by two amplifiers respectively, connected two-stage, AM band preamplifier _{5 1A} And AM band AGC amplifier _51B , FM band preamplifier _52A and FM band AGC amplifier _52B . As a result, it becomes possible to share the power detecting circuit 5 ₃ used for both the rear stage of the AGC amplifier 5 _1B, 5 _2B, makes it easy to configure an integrated circuit as an amplifier chip 5A, the characteristic Can be improved. Note that the AM band amplifier _{5 1,} AM band preamplifier _{5 1A} and AM band AGC amplifier _{5 1B,} or may be constituted only by the AM band AGC amplifier _{5 1B,} the FM band amplifier _{5 2,} the FM band AGC amplifier _52B may be replaced with a limit amplifier, and an FM band preamplifier _52A and a limit amplifier may be used.

FIG. 7 is a circuit diagram showing an optical receiver circuit according to a second modification of the second embodiment of the present invention. Optical receiving circuit 200B of FIG. 7 is transferred to the parallel resonant circuit 2 and the capacitor 6 ₂ of the photodiode chip 4 of the optical receiver circuit 200 illustrated as a second embodiment in FIG. 5 to the AM band amplifier 5 ₁ side , together with the photodiode chip 4B which integrates only the photodiode 1 as a separate semiconductor chip, further, to separate the AM band amplifier 5 ₁ and FM band amplifier 5 _{and second} amplifier chip 5 on a separate IC chip, and AM band amplifier chip 5B that integrate AM band amplifier 5 ₁ with parallel resonance circuit 2 and the capacitor 6 ₂ except that constitutes and integrated FM band amplifier 5 ₂ as an FM band amplifier chip 5C.

By adopting a configuration such as the optical receiver circuit 200B of FIG. 7, general-purpose components can be applied to the photodiode chip 4B, so that the cost can be reduced and the amplifier has a separate chip configuration. by, it becomes easy to reduce crosstalk between the AM band amplifier 5 ₁ and FM band amplifier 5 _2. The amplifiers integrated in each of the AM band amplifier chip 5B and the FM band amplifier chip 5C are two amplifiers (AM band preamplifier _51A and AM band AGC amplifier _51B , FM) as shown in FIG. it may be composed of strip preamplifier _{5 2A} and FM band AGC amplifier _{5 2B} or limit amplifier), also, as in the AM band amplifier chip 5B, the same semiconductor and an AM band amplifier _{5 1} a parallel resonant circuit 2 Also when integrating on the substrate, not all of the amplifier and the parallel resonant circuit, but a part of each circuit unit may be integrated.

FIG. 8 is a circuit diagram showing an optical receiver circuit according to a third modification of the second embodiment of the present invention. The optical receiver circuit 200C of FIG. 8 removes the capacitor C of the parallel resonant circuit 2A in the photodiode chip 4A of the optical receiver circuit 200A illustrated as the first modification of the second embodiment in FIG. while only the photodiode 1 and the photodiode chip 4B which integrates the parallel resonant circuit 2A formed of a transmission line Lt of the inductive and capacitor C, the resonance together with the bias circuit consisting of resistor 3 and the capacitor 6 ₁ Tokyo circuit chip 7 Are different from each other in that they are integrated on the same substrate (for example, a ceramic substrate) and configured outside the photodiode chip 4B.

  By adopting a configuration such as the optical receiving circuit 200C of FIG. 8, the resonant circuit chip 7 composed of only passive circuits can be formed of a ceramic substrate that is cheaper than a semiconductor substrate. In combination with the application of the chip 4B, further cost reduction can be achieved. Note that the resonant circuit chip 7 is not all of the parallel resonant circuit 2 and the bias circuit as shown in FIG. 8, for example, as described above, the transmission line Lt constituting the parallel resonant circuit 2 is externally attached and connected in parallel. A part of the resonance circuit 2 and the bias circuit may be integrated.

(Third embodiment)
In the present embodiment, an example of the configuration of the optical receiver module according to the present invention will be described. The optical receiver module has an optical receiver circuit and an upper surface that are open as described in the second embodiment. It is configured using TO (Top Open) package. Here, in the present embodiment, the arrangement positions of the two terminals of the anode terminal and the cathode terminal of the photodiode 1 forming the photoelectric converter in the optical receiver circuit, and the AM band amplifier connected to each terminal or Among the two terminals of the anode terminal and the cathode terminal, in order to arrange the arrangement position of any one of the two amplifiers of the FM band amplifier as close as possible in the element mounting portion on the TO package The terminal connected to the input terminal of the AM band amplifier, for example, and the input terminal of the AM band amplifier are arranged in a position facing each other and close to each other, and the other terminal, for example, the input terminal of the FM band amplifier. The case where the terminal to connect and the input terminal of this FM band amplifier are arrange | positioned in the position which opposes mutually and adjoined is shown.

FIG. 9 is a top view showing the top surface of the optical receiver module according to the third embodiment of the present invention. The optical receiving module 300 shown in FIG. 9 has three openings 10 ₁ , 10 ₂ , and 10 ₁₀ formed in a device mounting portion that is raised on a plateau of a conductive substrate 9 on a TO (Top Open) package 8. In each of the openings 10 ₁ , 10 ₂ , 10 ₁₀ , lead pins 11 ₁ , 11 ₂ , 11 ₁₀ are fixed and insulated from the conductive substrate 9.

The element mounting portion of the TO package 8, the photodiode chip 4, the amplifier chip 5, the chip capacitors ₆₁ and chip resistor 3 is mounted. Here, the amplifier chip 5, as shown in FIG. 5, the AM band amplifier 5 ₁ and FM band amplifier 5 ₂ are integrated. Here, as shown in FIG. 9, the AM band amplifier 5 _first output terminal and the output terminal of the FM band amplifier 5 ₂ are arranged divided into opposite sides of the amplifier chip 5, AM band amplifier 5 ₁ output terminal, the lead pin 11 ₁ fixed to the opening 10 ₁ which is disposed in the vicinity, also, the output terminal of the FM band amplifier 5 _2, the lead pin 11 ₂ fixed to the opening 10 ₂ arranged near each It is connected and can be connected to an external circuit.

One end of the chip resistor 3 is connected to the cathode terminal of the photodiode chip 4 through the one end of the chip capacitor ₆₁ disposed in the vicinity of (K), the other end, the apertures 10 _10, which is arranged in the vicinity It is connected to a fixed lead pins 11 ₁₀ and is connectable with the bias power supply. One end of the chip capacitor _61, as described above, are connected to the cathode terminal of the photodiode chip 4 (K) with one end of the chip resistor 3 and the other end is connected to the conductive substrate 9 Grounded.

Incidentally, the photodiode chip 4 shown in FIG. 9, unlike the case shown in FIG. 5, the parallel resonance circuit 2 and the capacitor 6 ₂ are integrated, the capacitor 6 ₁ shows a case in which the external Yes. Further, the anode terminal of the photodiode 1 in the photodiode chip 4 (A), and the cathode terminal via the capacitor 6 ₂ (K), are collected in the same side of the photodiode chip 4, whereas, the photodiode chip The two input terminals of the amplifier chip 5 to which the output terminals 4 are connected are also collected on the same side, arranged in positions close to each other and connected to each other, and connected to each other, thereby affecting the influence of the wire inductance. Thus, it is possible to greatly reduce, and it is possible to obtain good characteristics even for wideband / high-frequency signals.

  FIG. 10 is a top view showing the top surface of the optical receiver module according to the first modification of the third embodiment of the present invention. An optical receiver module 300A shown in FIG. 10 shows a form in which, for example, an optical receiver circuit 200C illustrated as a third modification of the second embodiment in FIG. 8 is mounted on the module. An optical receiver module 300A shown in FIG. 10 is formed of a ceramic substrate that is cheaper than a semiconductor substrate, as described in the second embodiment, as a chip mounted on the element mounting portion of the conductive substrate 9A on the TO package 8. And a configuration using a general-purpose photodiode chip 4B to which general-purpose components can be applied. Yes.

  FIG. 11 is a top view showing the top surface of the optical receiver module according to the second modification of the third embodiment of the present invention. An optical receiving module 300B shown in FIG. 11 shows a form in which, for example, an optical receiving circuit 200B illustrated as a second modification of the second embodiment in FIG. 7 is mounted on the module. Here, as a chip to be mounted on the element mounting portion of the conductive substrate 9B on the TO package 8, the cathode terminal (K) and the anode terminal (A) of the photodiode chip 4B are placed on opposite sides of the photodiode chip 4B. By disposing them separately, it becomes possible to connect to the respective input terminals of the AM band amplifier chip 5B and the FM band amplifier chip 5C at the shortest distance from each other, greatly affecting the influence of the wire inductance. Through this reduction, it is possible to obtain good characteristics for wideband / high frequency signals.

  Compared with the optical receiving modules 300 and 300A shown in FIGS. 9 and 10, one amplifier chip (that is, the amplifier chips 5 and 5A) is replaced with two AM band amplifier chips 5B and 5C. Due to the effect divided into two, the size of the TO package 8 can be reduced, and the cost of the package can be reduced.

  Further, by arranging the two amplifier chips of the AM band amplifier chip 5B and the FM band amplifier chip 5C with the photodiode chip 4B interposed therebetween, mutual crosstalk can be greatly reduced.

In FIG. 11, the FM band amplifier chips 5B, and a differential output terminal connected to the lead pins 11 ₃ fixed to the output terminal and the opening ₁₀₃ to be connected to the lead pin 11 ₂ fixed to the opening 10 ₂ Although an example of a differential output configuration is shown, a single-ended output may be used. Further, as described in the second embodiment, each of the two amplifier chips of the AM band amplifier chip 5B and the FM band amplifier chip 5C in FIG. 11 includes two amplifiers (AM band preamplifier 5) connected in two stages. _1A and AM band AGC amplifier _51B , FM band preamplifier _52A and FM band AGC amplifier _52B or limit amplifier).

  FIG. 12 is a top view showing the top surface of the optical receiver module according to the third modification of the third embodiment of the present invention. An optical receiver module 300C shown in FIG. 12 is an optical receiver exemplified as a third modification of the second embodiment in FIG. 8, for example, as a chip mounted on the element mounting portion of the conductive substrate 9C on the TO package 8. Like the circuit 200C, it has a configuration including the resonance circuit chip 7 and can be applied to a general-purpose photodiode chip 4B.

Further, as in the case of the optical receiving module 300B shown in FIG. 11, compared with the optical receiving modules 300 and 300A shown in FIG. 9 and FIG. The size can be reduced, and the package can be reduced in cost. Of the two divided amplifier chips, the FM band amplifier chip is the same FM band amplifier chip 5C as in FIG. 11, but the AM band amplifier chip is replaced with the AM band amplifier of FIG. The AM band amplifier chip 5D is composed of only an AM band amplifier from which the parallel resonant circuit 2 is removed from the chip 5B. Similarly to the case of FIG. 11, each of the two amplifier chips of the AM band amplifier chip 5D and the FM band amplifier chip 5C in FIG. 12 has two amplifiers (AM band preamplifier _51A and AM band AGC) connected in two stages. (Amplifier _51B , FM band preamplifier _52A and FM band AGC amplifier _52B or limit amplifier).

  Further, by arranging the two amplifier chips of the AM band amplifier chip 5D and the FM band amplifier chip 5C with the photodiode chip 4B interposed therebetween, it is possible to greatly reduce the mutual crosstalk.

  12 shows an example in which the FM band amplifier chip 5C has a differential output configuration as in the case of the optical reception module 300B in FIG. 11, it may be a single-ended output.

  Further, in the optical receiving modules 300B and 300C shown in FIGS. 11 and 12, the anode terminal (A) and the cathode terminal (K) of the photodiode chip 4B are bent at adjacent sides (90 degrees). In addition, the input terminals of the AM band amplifier chips 5B and 5D and the FM band amplifier chip 5C are positioned close to the sides of the cathode terminal (K) and the anode terminal (A). The arrangement may be arranged. In this case, there is an advantage that bias supply (not shown) to each amplifier can be easily shared.

(Other embodiments)
The parallel resonant circuit in the photoelectric converter disclosed in the present invention is not limited to the form of the parallel resonant circuits 2 and 2A illustrated in FIG. 1 and FIG. 2, but a combination of a plurality of capacitors / inductors / transmission lines. You may comprise. Further, a wire may be included as a means for realizing part or all of the inductor.

  Furthermore, the optical receiver circuit disclosed in the present invention is not limited to the optical receiver circuits 200, 200A, 200B, and 200C exemplified in the embodiment, and all the components of the optical receiver circuit are semiconductors. You may comprise with OEIC (Opto-Electronic IC) integrated on the board | substrate.

  The optical receiver module disclosed in the present invention is not limited to the optical receiver modules 300, 300A, 300B, and 300C exemplified in the embodiments. For example, the optical receiver module constituting the optical receiver module is not limited thereto. The converter may have a circuit configuration as illustrated in FIGS. 1 and 2 or may have a chip configuration as illustrated in any of FIGS.

For the two amplifiers in the optical receiver circuit disclosed in the present invention, signals in the vicinity of the resonant frequency of the parallel resonant circuits 2 and 2A are generated according to the electrical signal superimposed on the optical signal input to the photodiode 1. AM band amplifier 5 ₁ to be amplified, may be constituted so as to amplify at least one or more of the AM signal, while the high frequency signals than low or resonant frequency than the resonant frequency of the parallel resonant circuit 2 The amplifier to be amplified can be configured to amplify a digital signal as well as the FM signal.

1 is a circuit diagram showing an optoelectric converter according to a first embodiment of the present invention. It is a circuit diagram which shows the photoelectric converter concerning the modification of the 1st Embodiment of this invention. It is a graph which shows the simulation result of the amplitude characteristic of the photoelectric converter of the 1st Embodiment of this invention. It is a graph which shows the simulation result of the group delay characteristic of the photoelectric converter of the 1st Embodiment of this invention. It is a circuit diagram which shows the optical receiver circuit concerning the 2nd Embodiment of this invention. It is a circuit diagram which shows the optical receiver circuit concerning the 1st modification of the 2nd Embodiment of this invention. It is a circuit diagram which shows the optical receiver circuit concerning the 2nd modification of the 2nd Embodiment of this invention. It is a circuit diagram which shows the optical receiver circuit concerning the 3rd modification of the 2nd Embodiment of this invention. It is a top view which shows the upper surface of the optical receiver module concerning the 3rd Embodiment of this invention. It is a figure which shows the optical receiver module of the 1st modification of the 3rd Embodiment of this invention. It is a figure which shows the optical receiver module of the 2nd modification of the 3rd Embodiment of this invention. It is a figure which shows the optical receiver module of the 3rd modification of the 3rd Embodiment of this invention. It is a circuit diagram which shows the structure of the conventional optical receiver.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photodiode, 2 and 2A ... Parallel resonance circuit, 3 ... Resistance (chip resistance, bias resistance), 4, 4A, 4B ... Photodiode chip, 5, 5A ... Amplifier chip, 5B ... AM band amplifier chip, 5C ... FM band amplifier chip, 5D ... AM band amplifier chip, 5 ₁ ... AM band amplifier, 5 _1A ... AM band preamplifier, 5 _1B ... AM band AGC amplifier, 5 ₂ ... FM band amplifier, _{52 A} ... FM band preamplifier, 5 _2B ... FM band AGC amplifier, 5 ₃ ... Power detection circuit, 6 ₁ , 6 ₂ ... Capacitor (chip capacitor), 7 ... Resonant circuit chip, 8 ... TO package, 9, 9A, 9B, 9C ... Conductive substrate, 10 ₁ , 10 ₂ , 10 ₃ , 10 ₁₀ ... opening, 11 ₁ , 11 ₂ , 11 ₃ , 11 ₁₀ ... lead pin, 21 ... low-pass filter, 22 ... high-pass filter Luther, 23 ... AM band amplifier, 24 ... FM band amplifier, 100, 100A ... Photoelectric converter, 200, 200A, 200B, 200C ... Optical receiver circuit, 300, 300A, 300B, 300C ... Optical receiver module.

Claims (18)

  In a photoelectric converter including a photodiode to which an optical signal in which an electrical signal of a different frequency band is superimposed is input, and a parallel resonant circuit that resonates with at least one frequency of the electrical signal, the parallel resonant circuit includes: An optoelectric converter characterized in that one end is grounded in an alternating manner and the other end is connected to an anode or a cathode of the photodiode, and electrical signals are respectively taken out from the anode and the cathode of the photodiode.   2. The photoelectric converter according to claim 1, wherein an optical signal input to the photodiode is lower than or equal to a resonance frequency of the first signal near the resonance frequency of the parallel resonance circuit and the resonance frequency of the parallel resonance circuit. A photoelectric converter characterized in that signals of two types of frequency bands are superimposed on a second signal having a higher frequency.   3. The photoelectric converter according to claim 2, wherein the first signal is at least one AM signal, and the second signal is an FM signal or a digital signal. converter.   4. The photoelectric converter according to claim 1, wherein the parallel resonant circuit includes at least one capacitor and at least one inductor or transmission line. 5. Electrical converter.   5. The photoelectric converter according to claim 4, wherein a part or all of the inductor includes a wire.   6. The photoelectric converter according to claim 1, wherein the photodiode and a part or all of the parallel resonant circuit are integrated on the same semiconductor substrate. .   6. The photoelectric converter according to claim 1, wherein a part or all of the parallel resonant circuit and a part or all of the bias circuit of the photodiode are integrated on the same substrate. Characteristic photoelectric converter.   8. An optical receiver circuit comprising: the photoelectric converter according to claim 1; a first amplifier; and a second amplifier. An input terminal of the first amplifier is connected to the photodiode. The anode or cathode is connected to the one connected to the parallel resonant circuit, and the input terminal of the second amplifier is connected to the one of the anode or cathode of the photodiode not connected to the parallel resonant circuit. An optical receiving circuit characterized by being connected.   9. The optical receiver circuit according to claim 8, wherein the first amplifier amplifies a signal in the vicinity of a resonance frequency of the parallel resonance circuit, and the second amplifier is lower than a resonance frequency of the parallel resonance circuit or An optical receiver circuit that amplifies a signal having a frequency higher than a resonance frequency.   10. The optical receiver circuit according to claim 8, wherein the first amplifier includes an AGC amplifier or a first preamplifier and an AGC amplifier, and the second amplifier includes a second amplifier. An optical receiving circuit comprising a preamplifier and a limit amplifier.   The optical receiver circuit according to claim 8 or 9, wherein the first amplifier includes a first AGC amplifier, or a first preamplifier and a first AGC amplifier, and the second amplifier includes: An optical receiving circuit comprising a second preamplifier and a second AGC amplifier.   12. The optical receiver circuit according to claim 11, wherein power detection circuits of both the first AGC amplifier and the second AGC amplifier are common.   13. The optical receiver circuit according to claim 8, wherein the first amplifier and a part or all of the parallel resonant circuit are integrated on the same semiconductor substrate. .   14. The optical receiver circuit according to claim 8, wherein the first amplifier and the second amplifier are integrated on the same semiconductor substrate.   15. The optical receiver circuit according to claim 8, wherein an anode terminal and a cathode terminal of the photodiode are formed of a photodiode chip forming the photodiode or a semiconductor substrate on which the photodiode is integrated. The optical receiving circuit is arranged on opposite sides.   15. The optical receiver circuit according to claim 8, wherein an anode terminal and a cathode terminal of the photodiode are formed of a photodiode chip forming the photodiode or a semiconductor substrate on which the photodiode is integrated. An optical receiving circuit, which is disposed on adjacent sides.   15. The optical receiver circuit according to claim 8, wherein an anode terminal and a cathode terminal of the photodiode are formed of a photodiode chip forming the photodiode or a semiconductor substrate on which the photodiode is integrated. The optical receiving circuit is arranged on the same side.   18. An optical receiver module comprising the optical receiver circuit according to claim 8, wherein a terminal connected to an input terminal of the first amplifier among an anode terminal or a cathode terminal of the photodiode and the first amplifier An input terminal of the amplifier is disposed at a position facing and close to each other, and a terminal connected to the input terminal of the second amplifier among the anode terminal or the cathode terminal of the photodiode and the input terminal of the second amplifier An optical receiver module, wherein the optical receiver modules are arranged at positions close to each other.

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