Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/02—Structural details or components not essential to laser action
  • H01S5/026—Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers

Definitions

• This disclosure relates to a CAN-type optical module and an optical transceiver.
• Patent Document 1 discloses a CAN-type optical module.
• This optical module has a semiconductor optical element.
• the semiconductor optical element monolithically integrates a semiconductor laser, an optical modulator, and an optical amplifier.
• a DC bias is also applied to the matching resistor connected to the optical modulator. This can result in increased power consumption due to heat generation in the matching resistor.
• a capacitor is connected between the matching resistor and GND to reduce power consumption. This can make the optical modulator more susceptible to charging, generating a surge and potentially causing the optical modulator to malfunction.
• the purpose of this disclosure is to provide a CAN-type optical module and optical transceiver that can reduce failures in the optical modulator section.
• the CAN-type optical module comprises a stem having a main surface and a surface opposite to the main surface, a lead pin penetrating the stem from the main surface to the surface opposite to the main surface, a support portion provided on the main surface of the stem, a first submount supported by the support portion and provided so that its mounting surface is perpendicular to the main surface of the stem, a semiconductor optical integrated element provided on the mounting surface of the first submount and having a semiconductor laser portion and an optical modulator portion, and a second submount provided on the main surface of the stem, all of which are arranged in series with each other.
• a matching resistor and a capacitor for the optical modulator section connected to the first submount, a series circuit connected in parallel with the optical modulator section, and a protective resistor connected in parallel with the series circuit; a first signal line and a first GND pattern are formed on the second submount; a second signal line connecting the optical modulator section and the first signal line and a second GND pattern are formed on the first submount; and the protective resistor is connected between the first signal line and the first GND pattern or between the second signal line and the second GND pattern.
• the optical transceiver disclosed herein comprises a CAN-type optical module, a flexible printed circuit board connecting the CAN-type optical module and a transceiver board, and a protective resistor.
• the CAN-type optical module comprises: a stem having a main surface and a surface opposite to the main surface; lead pins penetrating the stem from the main surface to the surface opposite to the main surface; a support portion provided on the main surface of the stem; a first submount supported by the support portion and provided so that its mounting surface is perpendicular to the main surface of the stem; a semiconductor optical integrated device provided on the mounting surface of the first submount and having a semiconductor laser portion and an optical modulator portion; and a series circuit connected in parallel to the optical modulator portion, the series circuit including a matching resistor and a capacitor for the optical modulator portion connected in series to each other; the protective resistor is connected in parallel to the series circuit and is provided on the flexible printed circuit board or the transceiver board.
• FIG. 1 is a perspective view of a CAN-type optical module according to a first embodiment
• 1A and 1B are diagrams illustrating a configuration of a semiconductor optical integrated device according to a first embodiment.
• FIG. 10 is a perspective view of the CAN-type optical module according to the first embodiment, viewed from another angle.
• 3 is a diagram illustrating a circuit formed by an optical modulator section, a matching resistor, a capacitor, and a protective resistor according to the first embodiment.
• FIG. FIG. 10 is a diagram illustrating a protective resistor according to a second embodiment.
• 10A and 10B are diagrams illustrating the reflection characteristics of a CAN-type optical module according to a second embodiment.
• FIG. 11 is a perspective view of an optical transceiver according to a third embodiment.
• FIGS. 10A and 10B are diagrams illustrating a protective resistor according to a third embodiment.
• 10A and 10B are diagrams illustrating the reflection characteristics of an optical transceiver according to a third embodiment.
• 10A and 10B are diagrams illustrating a protective resistor according to a fourth embodiment.
• 10A and 10B are diagrams illustrating a protective resistor according to a fifth embodiment.
• FIG. 13 is a perspective view of an optical transceiver according to a sixth embodiment.
• 13A and 13B are diagrams illustrating a protective resistor according to a sixth embodiment.
• FIG. 13 is a perspective view of a CAN-type optical module according to a seventh embodiment.
• FIG. 13 is a perspective view of a CAN-type optical module according to an eighth embodiment.
• 13A and 13B are diagrams illustrating the transmission characteristics of a CAN-type optical module according to an eighth embodiment.
• FIG. 1 is a perspective view of a CAN-type optical module 100 according to a first embodiment.
• the CAN-type optical module 100 includes a stem 1 having a main surface 1a and a surface opposite to the main surface 1a.
• the stem 1 is, for example, circular in plan view.
• the diameter of the stem is, for example, 5.6 mm.
• the stem 1 is made of metal.
• the stem 1 is formed by plating the surface of a material with high thermal conductivity, such as Cu, with Au or the like.
• Lead pins 2a to 2f penetrate the stem 1 from the main surface 1a to the surface opposite the main surface 1a.
• Glass 3 is generally used to secure the lead pins 2a to 2f to the stem 1. If there is an impedance mismatch, multiple reflections of the signal will degrade the frequency response characteristics, making high-speed modulation difficult. For this reason, the glass 3 is made of a material with a low dielectric constant.
• a support portion is provided on the main surface 1a of the stem 1.
• the support portion includes, for example, a temperature control module 10 mounted on the main surface 1a of the stem 1, and a first support block 20 mounted on the temperature control module 10 on the side opposite the main surface 1a of the stem 1.
• the first support block 20 is also called a carrier.
• the first support block 20 supports the first submount 30.
• thermoelectric elements made of a material such as BiTe are sandwiched between a lower substrate and an upper substrate made of a material such as AlN.
• the lower substrate of the temperature control module 10 has a protrusion that protrudes further than the upper substrate in a direction parallel to the main surface 1a of the stem 1.
• An electrode pattern for supplying power to the thermoelectric elements is provided on this protrusion.
• the electrode pattern is electrically connected to lead pins 2d, 2e.
• the temperature control module 10 may be omitted.
• a first support block 20 is mounted on the top surface of the temperature control module 10.
• the bottom surface of the first support block 20 and the top surface of the temperature control module 10 are joined using solder or the like.
• the first support block 20 is made of metal.
• the first support block 20 is formed by applying Au plating or the like to the surface of a material with high thermal conductivity, such as Cu.
• the stem 1 and the support part may be separate components, or may be a single component.
• the first submount 30 is supported by a support and is arranged so that its mounting surface is perpendicular to the main surface 1a of the stem 1. Specifically, the first submount 30 is mounted on the side of the first support block 20.
• the first submount 30 is, for example, a dielectric substrate.
• the first submount 30 is made of a ceramic material such as AlN, and has electrical insulation and heat transfer functions. A metal pattern is formed on the mounting surface of the first submount 30.
• FIG. 2 is a diagram illustrating the configuration of a semiconductor optical integrated device 50 according to the first embodiment.
• a semiconductor laser section 50a, an optical modulator section 50b, and an optical amplifier section 50c are provided on the mounting surface of the first submount 30.
• the semiconductor laser section 50a, the optical modulator section 50b, and the optical amplifier section 50c are integrated into the semiconductor optical integrated device 50, but the optical modulator section 50b and the optical amplifier section 50c may be provided separately.
• the optical amplifier section 50c may be omitted.
• the semiconductor optical integrated device 50 is mounted at an angle relative to the direction perpendicular to the main surface 1a of the stem 1.
• the semiconductor laser section 50a, optical modulator section 50b, and optical amplifier section 50c are electrically insulated from one another by a semi-insulating substrate such as Fe-doped InP, allowing current to flow independently. This improves current controllability.
• the semiconductor laser section 50a, optical modulator section 50b, and optical amplifier section 50c share a common GND.
• the oscillation wavelength of the semiconductor optical integrated device 50 fluctuates with changes in temperature. For this reason, it is necessary to maintain the temperature of the semiconductor optical integrated device 50 as constant as possible. If the temperature of the semiconductor optical integrated device 50 rises, the temperature control module 10 cools it, while if the temperature of the semiconductor optical integrated device 50 drops, the temperature control module 10 generates heat. This makes it possible to maintain a constant temperature of the semiconductor optical integrated device 50. Furthermore, heat generated by the semiconductor optical integrated device 50 is absorbed by the temperature control module 10 and dissipated via the stem 1 to the back side of the stem 1.
• a thermistor 55 is provided on the second portion 22 of the first support block 20.
• the lead pin 2a is electrically connected to the thermistor 55.
• the thermistor 55 indirectly measures the temperature of the semiconductor optical integrated device 50 and provides feedback to the temperature control module 10.
• the temperature control module 10 controls the temperature of the semiconductor optical integrated device 50 based on the temperature measured by the thermistor 55.
• Capacitors C0, C1, and C2 are mounted in an aligned order on the side of the first support block 20 on which the first submount 30 is mounted. Capacitors C0, C1, and C2 may be mounted on the support section or on the temperature control module 10. Capacitor C0 is a capacitor for the semiconductor laser section, and electrically connects the anode of the semiconductor laser section 50a to the lead pin 2b. Capacitor C1 is a capacitor for the optical modulator section. A series circuit of capacitor C1 and matching resistor R1 is connected in parallel to the optical modulator section 50b. Capacitor C2 is a capacitor for the optical amplifier section, and electrically connects the anode of the optical amplifier section 50c to the lead pin 2c.
• Capacitors C0 and C2 can cut power supply noise. Capacitor C1 can also be used to cut the DC component flowing through matching resistor R1, enabling an AC coupling method. Also, as shown in Figure 1, by placing capacitor C1 near the optical modulator section 50b, the wire between capacitor C1 and optical modulator section 50b can be shortened. This helps prevent deterioration of high-frequency characteristics.
• a second support block 79 and a second submount 80 are provided on the main surface 1a of the stem 1.
• the second submount 80 is mounted on the side of the second support block 79.
• the second submount 80 is, for example, a dielectric substrate.
• the second submount 80 is formed from a ceramic material such as AlN.
• a signal line 80a and a GND pattern 80b are formed on the second submount 80.
• the first submount 30 is formed with a signal line 30a that connects the optical modulator section 50b and the signal line 80a via a wire, and a GND pattern 30b.
• the GND pattern 30b is connected to the GND pattern 80b via a wire.
• the lead pin 2f is connected to the signal line 80a of the second submount 80. In other words, the lead pin 2f is electrically connected to the optical modulator section 50b via the signal line 80a and the signal line 30a.
• the lead pin 2f is an RF power supply lead pin.
• Figure 3 is a perspective view of the CAN-type optical module 100 according to embodiment 1, viewed from a different angle.
• the first support block 20 has, for example, a first portion 21 and a second portion 22.
• the first portion 21 supports the first submount 30.
• the second portion 22 is provided on the temperature control module 10 and protrudes from the first portion 21 on the side opposite the first submount 30.
• the height of the cap's inner wall must be increased to prevent interference between the wire loop and the cap.
• the upper surface of the second support block 79 and the second portion 22 are connected by wire W0. Because the second portion 22 is lower than the first portion 21, there is no need to consider the wire loop height. Therefore, it is possible to strengthen the GND potential of the first support block 20 and improve high-frequency characteristics while reducing the height of the CAN-type optical module 100.
• the first support block 20 has the role of transferring heat generated by the semiconductor optical integrated device 50 to the temperature control module 10, and the thermal resistance of the first support block 20 must be reduced as much as possible. If the height of the second portion 22 is too low, the thermal resistance will increase, which may result in an increase in the power consumption of the temperature control module 10. For this reason, it is desirable to make the second portion 22 tall enough so that the height of the wire W0 does not exceed the height of the first portion 21.
• FIG. 4 is a diagram illustrating the circuit formed by the optical modulator section 50b, matching resistor R1, capacitor C1, and protective resistor R2 according to embodiment 1.
• the optical modulator section 50b is depicted as a diode D1.
• a series circuit including the matching resistor R1 and capacitor C1 connected in series is connected in parallel to the optical modulator section 50b.
• a protective resistor R2 is connected in parallel to this series circuit.
• the resistance value of the matching resistor R1 is, for example, 50 ⁇ or 40 ⁇ .
• the capacitance of the capacitor C1 is, for example, 1 to 10 nF.
• the resistance value of the protective resistor R2 is, for example, 1000 ⁇ . These resistance values and capacitances are not limited to the above values. It is preferable that the resistance value of the matching resistor R1 is less than the resistance value of the protective resistor R2.
• the protective resistor R2 is connected between the signal line 30a and the GND pattern 30b of the first submount 30. This results in a circuit like that shown in Figure 4.
• the protective resistor R2 is, for example, a thin-film resistor formed on or attached to the first submount 30.
• the protective resistor R2 connected between the anode of the optical modulator section 50b and GND can prevent charging of the optical modulator section 50b. Furthermore, even if a surge is input, current flows through the protective resistor R2. This prevents failure of the optical modulator section 50b.
• FIG. 5 is a diagram illustrating a protective resistor R2 according to the second embodiment.
• the position of the protective resistor R2 differs from that of the CAN-type optical module 100 according to the first embodiment.
• the other structures are the same as those of the first embodiment.
• the protective resistor R2 according to the present embodiment is connected between the signal line 80a and the GND pattern 80b of the second submount 80. This results in a circuit as shown in FIG. 4.
• the protective resistor R2 is, for example, a thin-film resistor formed on or attached to the second submount 80.
• Figure 6 is a diagram illustrating the reflection characteristic S11 of the CAN-type optical module 200 of embodiment 2. Looking at the area indicated by the arrow in the figure, it can be seen that in embodiment 2, the electromagnetic field resonance that occurred in embodiment 1 does not occur, and the reflection characteristic has been improved. In other words, better high-frequency characteristics can be obtained by placing the protective resistor R2 on the second submount 80 rather than on the first submount 30.
• the GND pattern 30b of the first submount 30 is hollowed out to form the protective resistor R2. This may have caused the GND potential to become unstable, causing a slight change in impedance in the GSG line of the first submount 30 and deteriorating characteristics.
• the line of the second submount 80 is a microstrip line, and there is no need to hollow out the GND pattern to form the protective resistor R2 as in embodiment 1. This is thought to have suppressed impedance changes and resulted in good high-frequency characteristics.
• the second submount 80 may also be a coplanar line.
• the protective resistor R2 does not necessarily have to be connected between the signal line 80a and the upper GND pattern 80b. It may also be connected between the signal line 80a and the lower GND pattern.
• Embodiment 3. 7 is a perspective view of an optical transceiver 1000 according to a third embodiment.
• the optical transceiver 1000 includes a CAN-type optical module 101 and a flexible printed circuit board 70 that connects the CAN-type optical module 101 to a transceiver board (described later).
• the CAN-type optical module 101 can have the same structure as the CAN-type optical modules 100 and 200, except for the placement of the protective resistor R2.
• a lens cap 91 is provided on the stem 1. Note that the lens cap 91 is omitted from Figure 1.
• the flexible printed circuit board 70 is attached to the side of the stem 1 opposite the main surface 1a.
• Figure 8 is a diagram illustrating the protective resistor R2 according to the third embodiment.
• Figure 8 is a diagram showing the flexible printed circuit board 70 as viewed from the back side.
• the protective resistor R2 is provided on the flexible printed circuit board 70.
• Lead pins 2a to 2f protrude from the back side of the flexible printed circuit board 70.
• lead pin 2f is an RF power supply lead pin electrically connected to the optical modulator section 50b.
• the protective resistor R2 connects the signal line 70a and GND pattern 70b of the flexible printed circuit board 70. This results in a circuit like the one shown in Figure 4.
• the protective resistor R2 is, for example, a thin-film resistor formed on the flexible printed circuit board 70.
• Figure 9 is a diagram illustrating the reflection characteristic S11 of the optical transceiver 1000 of embodiment 3. Looking at the area indicated by the arrow in the figure, it can be seen that the reflection characteristic of embodiment 3 is improved compared to embodiment 1.
• the line of the flexible printed circuit board 70 is also a microstrip line, so there is no need to cut out the GND pattern to form the protective resistor R2. This is thought to have suppressed impedance changes and resulted in good high-frequency characteristics.
• FIG. 10 is a diagram illustrating a protective resistor R2 according to the fourth embodiment.
• the type of protective resistor R2 in the optical transceiver 2000 of the present embodiment differs from that in the optical transceiver 1000 of the third embodiment.
• the protective resistor R2 in the present embodiment is a chip resistor. Other configurations are similar to those in the third embodiment.
• it may be difficult to form a thin-film resistor.
• increasing the precision of the resistance value of the thin-film resistor by laser trimming may increase manufacturing costs.
• the manufacturer can provide the protective resistor R2 by purchasing and joining a chip resistor. This simplifies the manufacturing process and reduces costs.
• Embodiment 5 is a diagram illustrating a protective resistor R2 according to the fifth embodiment.
• the type of protective resistor R2 is different from that of the CAN-type optical module 200 of the second embodiment.
• the protective resistor R2 of this embodiment is a chip resistor.
• Other configurations are the same as those of the second embodiment.
• the manufacturing process can be simplified and costs can be reduced in this embodiment as well.
• the protective resistor R2 of the first embodiment may be replaced with a chip resistor.
• Embodiment 6. 12 is a perspective view of an optical transceiver 3000 according to a sixth embodiment.
• the arrangement of the protective resistor R2 differs from that of the third embodiment.
• the remaining configuration is the same as that of the third embodiment.
• a receptacle 102 for securing an optical fiber is attached to a CAN-type optical module 101.
• a transceiver board 60 which mounts integrated circuits for driving the CAN-type optical module 101 and the optical receiver module 106, is connected to the CAN-type optical module 101 and the optical receiver module 106 via a flexible printed circuit board 70.
• the CAN-type optical module 101, the optical receiver module 106, the flexible printed circuit board 70, the receptacle 102, and the transceiver board 60 are housed in a case 105.
• a heat dissipation block 103 between the CAN-type optical module 101 and the case 105. It is desirable that the heat dissipation block 103 have a semicircular structure that allows the CAN-type optical module 101 to be fixed along the entire length of its side. Furthermore, a heat dissipation block 104 may be attached to the CAN-type optical module 101. Like the heat dissipation block 103, the heat dissipation block 104 has a semicircular structure that allows the CAN-type optical module 101 to be fixed along the entire length of its side. Furthermore, the heat dissipation block 104 has a fin-shaped side on the side opposite the CAN-type optical module 101.
• FIG. 13 is a diagram illustrating a protective resistor R2 according to embodiment 6.
• FIG. 13 is an enlarged view of area A1 in FIG. 12.
• the protective resistor R2 of this embodiment is provided on a transceiver board 60.
• the transceiver board 60 is provided with multiple electrodes 61, each connected to a signal line 70a and a GND pattern 70b of a flexible printed circuit board 70.
• the protective resistor R2 connects the multiple electrodes 61. This results in a circuit as shown in FIG. 4.
• the protective resistor R2 is, for example, a thin-film resistor formed on the transceiver board 60.
• the protective resistor R2 may also be a chip resistor.
• Embodiment 7. 14 is a perspective view of a CAN-type optical module 400 according to the seventh embodiment.
• the CAN-type optical module 400 includes a wire W1 that connects a GND pattern 10a formed on the surface of the temperature control module 10 on which the first support block 20 is provided, to the stem 1.
• the top surface of the temperature control module 10 is electrically connected to the GND patterns of the first support block 20 and the first submount 30, and is at GND potential.
• Embodiment 8. 15 is a perspective view of a CAN-type optical module 500 according to the eighth embodiment.
• This embodiment differs from the seventh embodiment in the shape of the first support block 520 and the position of the wire for strengthening the GND.
• the other configurations are the same as those of the seventh embodiment.
• the first support block 520 has a first portion 521 that supports the first submount 30, and a second portion 522 that is provided on the temperature control module 10 and protrudes from the first portion 521 toward the first submount 30.
• the first support block 520 can also be said to be inverted T-shaped.
• the CAN-type optical module 500 includes a wire W2 that connects the second portion 522 of the first support block 520 to the stem 1.
• the CAN-type optical module 500 also includes a wire W3 that connects the second portion 522 of the first support block 520 to the GND pattern 80c of the second submount 80.
• the GND on the top surface of the temperature control module 10 can be strengthened, further improving the high-frequency characteristics. Note that only one or both of the wires W2 and W3 may be provided.
• Figure 16 is a diagram illustrating the transmission characteristic S21 of the CAN-type optical module 500 according to embodiment 8.
• the solid line indicates the case where wires W2 and W3 are present, and the dashed line indicates the case where wires W2 and W3 are not present. Looking at the areas indicated by the arrows in the figure, it can be seen that providing wires W2 and W3 can suppress resonance in the transmission characteristic.
• protective resistor R2 is provided in the position shown in embodiment 2, but wires W1, W2, and W3 may be provided in any of the embodiments.
• wire W0 described in embodiment 1 may be combined with at least one of wires W1, W2, and W3 and applied to each embodiment.
• first support block 520 may be provided on temperature control module 10 and have third portion 523 that protrudes from first portion 521 on the side opposite first submount 30, and the top surface of second support block 79 and third portion 523 may be connected by wire W0.

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• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Optics & Photonics (AREA)
• Semiconductor Lasers (AREA)

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Citations (5)

• 2024
  • 2024-01-26 JP JP2024523827A patent/JP7513228B1/ja active Active
  • 2024-01-26 WO PCT/JP2024/002410 patent/WO2025158647A1/ja active Pending
  • 2024-12-18 TW TW113149325A patent/TW202531667A/zh unknown

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