JP2715672B2 - Optical semiconductor photodetector with built-in preamplifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor photodetector and, more particularly, to a high band optical semiconductor photodetector having a built-in preamplifier.

[0002]

2. Description of the Related Art In recent years, higher bit rates have been demanded in trunk line optical communication, and transmission / reception elements capable of high speed have been developed. In modularizing these elements, the performance of the photodetector module is greatly affected by the connection method between the photodetector and the amplifier.

In a conventional light receiving element module, there are a light receiving element alone mounted in a case and fiber-coupled, and a preamplifier mounted in a case as represented by a PIN / FET module. In this module structure with a built-in preamplifier, the light receiving element mounting substrate and the preamplifier mounting substrate are separate, and the light receiving element is mounted on an element mounting substrate on which an electrode pattern for electrical connection is formed, The preamplifier element is mounted on a substrate on which an electrode pattern for mounting another element is formed.These element mounting substrates are placed in a case, and the light receiving element mounting carrier has the light receiving surface of the light receiving element facing the fiber end face. For this purpose, a preamplifier mounting substrate is mounted on the bottom surface in the case or on another substrate surface with solder or the like. The light receiving element is electrically connected to the preamplifier by a metal wire via each electrode pattern.

[0004]

In the above-described conventional preamplifier light receiving element device, the light receiving element surface and the preamplifier mounting surface are mounted in the vertical direction, so that the light receiving element and the preamplifier light receiving element are mounted in a vertical direction. The electrical connection with the amplifier cannot be directly connected, but is connected via a connection wire and via an electrode pattern.The problem is that the connection distance is long, the inductance of the electrical connection is large, and there is a restriction in the high frequency band. there were. For example, when a connection wire having a thickness of about 50 μmφ which is usually used between the light receiving element and the preamplifier is used, the connection distance becomes 5 mm or more in the case of the conventional structure,
The inductance of the wire itself is 5 nH or more. Therefore, the band is limited to about 2 to 3 GHz.

Further, the hermetic sealing of the element in the conventional structure is a method in which the fiber pigtail portion is hermetically sealed with solder or the like by a method of taking the whole case. Therefore, there is also a problem that a hermetic sealing test is performed after the module is assembled, and a leak test cannot be performed because the fiber coating is made of resin.

[0006]

An optical semiconductor photodetector device with a built-in preamplifier according to the present invention has an electrode pattern for mounting an electric element and has at least four lead terminals for external connection from the bottom surface of the mount. A light receiving element, a preamplification IC for amplifying an output electric signal of the light receiving element, and a capacitor are mounted on the same carrier, and a transparent glass plate is attached to the upper surface in the light incident direction. The light receiving element, the preamplifier IC, and the capacitor are mounted in a case using an integrated element storage carrier in which the element is hermetically sealed.

[0007]

Next, the present invention will be described with reference to the drawings. 1 (a) and 1 (b) are a top view (a) and a side sectional view (b) of an optical semiconductor photodetector device with a built-in preamplifier according to an embodiment of the present invention, and FIGS. FIG. 3 is a front view and a bottom view of the element storage carrier which is a main part of the present invention.

The element storage carrier 1 has a concave shape on the fiber end face side, and a pattern for mounting the element is formed in the concave portion of the fiber, and is connected to the lead terminal 10 on the bottom surface. Further, a mount plate 12 having a thickness of several mm is, for example, AuCu soldered on the bottom portion so that the lead terminals 10 on the bottom portion do not short-circuit when the element storage carrier 1 is fixed. The preamplifier IC 14, the light receiving element 15, the capacitors 16, 1 are mounted on the element mounting surface of the element storage carrier 1.
7 is fixed with, for example, AuSn solder, and after electrical connection is made with each of the bonding wires 19, the glass cap 11 metallized in a nitrogen atmosphere is hermetically sealed with, for example, AR-coated sapphire glass on the sealing surface 18 with AuSn solder. Stop. BT-sorted element storage carrier 1 in the state of element storage carrier 1 on which elements are mounted as described above.
Is fixed to the mounting substrate 5 on the surface of the mounting plate 12 by PbSn solder. The optical coupling between the fiber and the light receiving element is performed by fitting a fiber ferrule 4 to a lens holder 3 to which, for example, a Selfox lens (trademark) is fixed in advance with a rod lens, and fixing the ferrule 4 by soldering or YAG welding.
The mount substrate 5 to which the element storage carrier is fixed and the lens holder 3 to which the fiber ferrule 4 is fixed are fixed by YAG welding via a slide ring 6. At this time, the optical axis is adjusted in the XYZ axis direction so that the output current is maximized while light is incident from the end of the fiber and the output current of the light receiving element is monitored.

The optical system assembled as described above via the mount board 5 is soldered to the bottom of the case 7 having the external lead terminals 10 with solder having a lower melting point than the solder used when the element storage carrier is fixed, for example, InSn solder. After fixing, the lead terminals 13 of the element storage carrier and the case lead terminals 10 are connected by soldering or YAG welding.
And the cap 8 is sealed with a seam welder or the like to complete the light receiving device.

In this embodiment, a ternary AP is used for the light receiving element.
D, using Si-IC as preamplifier IC, 2.4
In Gb / S, the minimum receiving sensitivity is -32 dBm (BER is 10
^-11 ), an optical semiconductor photodetector device with a built-in preamplifier obtained at a wavelength of 1.3 μm was obtained.

3 and 4 show a second embodiment of the present invention. FIG. 3 is a bottom view of an element storage carrier, and FIG.
FIG. 3 is an assembly diagram in which is fixed to a mount substrate 5. Since the mounting plate 19 affixed to the bottom surface of the element storage carrier has a shape protruding outside the bottom surface of the element storage carrier, when fixing the mounting substrate 5 to the mounting substrate 5, the first embodiment is first performed.
Temporarily fix with solder etc. in the same manner as
It can be permanently fixed by laser welding. Therefore, in this embodiment, there is an advantage that the reliability of the fixing portion is improved by performing YAG laser welding for fixing the element storage carrier, and the melting point of the solder to be used thereafter can be increased.

[0012]

As described above, according to the present invention, the light receiving element and the preamplifier are mounted on the same surface,
The length of the connecting wire connecting the output of the light receiving element and the input of the preamplifier is shortened, and the inductance which becomes a problem in a high frequency range is reduced, so that the band can be widened. In addition, by hermetically sealing with an element storage carrier on which a bare chip is mounted, there is an effect that handling at the time of assembling in a module is easy and a device having excellent reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a mounting diagram of an optical semiconductor photodetector device with a built-in preamplifier of the present invention.

FIG. 2 is an element mounting view of the element storage carrier shown in FIG.

FIG. 3 is a diagram showing an example of an element storage carrier.

FIG. 4 is a fixed mounting diagram of the element storage carrier and the mounting board shown in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Element storage carrier 2 Lens 3 Lens holder 4 Fiber ferrule 5 Mounting board 6 Slide ring 7 Case 8 Cap 9 Solder 10 External lead terminal 11 Glass cap 12 Mounting plate 13 Lead terminal 14 Preamplifier IC 15 Light receiving element 16, 17 Capacitor 18 Sealing surface 19 Bonding wire 21, 22, 23, 24, 25 YAG weld

Claims (2)

(57) [Claims] And 1. A light receiving element mounted on the carrier, and the immobilized binding lenses in the lens holder, and a light input optical fiber having a ferrule, an optical semiconductor incorporated in a box-type case having an external connection lead terminals in the light receiving element unit, before Kimoto child storage carrier, a light incident side fiber-
In driver side recessed shape, the electrode pattern is formed on the recess deep an element mounting surface, or One lead terminal external connection
But has at least 4 or more from the bottom part is an element housed carrier mounting surface, of the device housing carrier
An IC for preamplification for amplifying an output electrical signal of said light receiving element and the light receiving element on the element mounting surface, and a capacitor is <br/> mounted on the same surface, transparent to the light incident direction side of the element housing carrier Attaching a glass plate to the light receiving element, preamplifier IC,
The capacitor is hermetically sealed in the element storage carrier, and
A preamplifier , wherein the element storage carrier is stored in the box-shaped case, and an external connection lead terminal of the storage carrier is fixedly connected to an external connection lead terminal of the box-shaped case. Built-in optical semiconductor light receiving device. 2. A light receiving element mounted on a carrier and a lens.
With a coupling lens fixed to the holder and a ferrule
Optical input optical fiber has external connection lead terminals.
Optical semiconductor light-receiving device built in a box-shaped case
The element storage carrier has an optical fiber on the light incident side.
The recessed side of the device has a concave shape.
A pole pattern is formed and the external connection lead terminal
However, there is a small amount from the bottom
At least four or more, and the bottom part has a bottom contour
A metal plate with a shape protruding outward from the
A light receiving element and the light receiving element are mounted on the element mounting surface of the element storage carrier.
A preamplifier IC for amplifying the output electric signal of the
Sensor is mounted on the same surface,
Paste a transparent glass plate on the light incident direction side and
Element, pre-amplification IC, and capacitor
A) and hermetically sealed in the box.
Stored in the storage case, and
Fixed to the external connection lead terminal of the box-shaped case.
.Optical semiconductor integrated with a preamplifier, characterized by being connected
Body light receiving device.