JPH11283269A - Semiconductor-integrated light receiving and emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components and the thickness of a light receiving and emiting device by forming light emitting and light receiving elements on the first surface and on the inclined surface of an integrated circuit substrate on which the first surface and a second surface that is lower than the first surface are connected by the inclined surface, making the emitted light beams from the light emitting element incident on an optical medium through a prescribed optical path and providing a spectroscopic means which makes the reflected light beams from the medium incident on the light receiving element. SOLUTION: A step is formed on a silicon substrate (PDIC). A light receiving element 5 is provided on a PDIC inclined surface 7 between a PDIC first surface 8 and a PDIC second surface 9. A semiconductor light emitting element 2 is formed on the surface 8. An optical block, which is transparent and has a parallel planar shape, is formed on the optical axis of the laser light beam emitting direction of the element 2. A grating 3 is formed on one of the surfaces of the block and a hologram 6 is formed on the other surface. Thus, parallel laser light beams are emitted from the element 2 to the PDIC 1 without loosing the cross section of the beams, and a beam splatter is not required.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor integrated light emitting / receiving device applied to an optical pickup device for reading an optical medium such as an optical disk by irradiating light.
In particular, the present invention relates to a semiconductor integrated light emitting and receiving device that irradiates a laser beam onto an optical disk surface and reads data by changing the intensity of a reflected laser beam.

[0002]

2. Description of the Related Art An example of a conventional semiconductor integrated light emitting / receiving device will be described below with reference to FIG. PDIC (Photo Diode) which is a substrate obtained by cutting a single crystal of silicon
The light receiving element 5 is formed above the IC 1. PDI
A PIN diode 13 formed by cutting out a single crystal of silicon similarly to the PDIC 1 is provided above the C1. In order to control the power of the laser by monitoring the intensity of the emitted laser light at a position where the laser light can be incident by reflecting a part of the emitted laser light using the upper surface of the PIN diode 13 or the beam splitter 14. APC (Automatic
A light receiving element 4 for Power Control is incorporated.

FIG. 7 shows a substrate (PDIC) in the emission direction of the laser diode 2 using a beam splitter 14.
1 shows an example in which a light receiving element 4 for laser power control is provided on the light receiving element 1. The laser diode 2, which is a semiconductor light emitting device, is formed above the PIN diode 13;
The N diode 13 is an LOP (Laser on Pho)
Also referred to as "to Diode". Laser diode 2
Is installed so as to emit laser light in parallel to the PDIC 1.

On the PDIC 1, a beam splitter 14 is formed on the optical axis of the laser light emitted from the laser diode 2. The beam splitter 14 has a reflective film 15 on the upper surface, and has therein a beam splitter surface 16 that reflects one optical axis at an arbitrary angle at an arbitrary angle. The beam splitter surface 16 is arranged so as to be inclined by 45 ° with respect to the optical axis of the emitted laser light. The reflection film 15 on the upper surface of the beam splitter 14 may be parallel to the optical axis of the laser light, but in FIG. 7, the reflection film 15 having a predetermined angle with respect to the optical axis of the laser light is provided. Case shown. PDIC at any position under reflective film 15
1, the light receiving element 5 is formed.

A grating 3 and a hologram 6 for splitting one light beam into an arbitrary number of light beams are provided on the extension of the beam splitter 14 along the optical axis.
The grating 3 and the hologram 6 have stripes (grooves) of a certain shape formed on the surface of the transparent plate, and the stripes split the laser beam into an arbitrary number at a certain angle.

In the lateral emission type semiconductor integrated light emitting and receiving device having the above structure, the laser light emitted from the laser diode 2 enters the beam splitter 14. The incident laser light is partially reflected on the beam splitter surface 16, and the incident light that coincides with the optical axis of the emitted laser light travels in the direction of the PDIC 1 at an angle of 90 ° with respect to the laser light emission direction. This directly reflected light is received by the front APC light receiving element 4.
And is used as monitor light of the emitted laser.

The laser beam transmitted through the beam splitter surface 16 is transmitted through the beam splitter 14 and then split by the grating 3 and the hologram 6 into several laser beams having a certain angle. Of the split laser light, the laser light traveling in the direction coincident with the optical axis of the emitted laser light is reflected by the reflecting mirror 10 at 90 ° toward the optical disk. The reflected laser light is transmitted through the objective lens 1
The light is condensed on the optical disk 12 by 1. The reflected light of the laser light from the optical disk 12 includes a signal component recorded on the optical disk 12.

That is, when the pits formed on the optical disk 12 are irradiated with the laser light, the reflected light is attenuated by the phase difference from the incident light to a low level, and the portions other than the pits are irradiated with the laser light. At that time, most of the incident light is reflected to a high level. The signal components recorded on the optical disk 12 can be read by converting the intensity of the reflected light into a voltage by the light receiving element.

The laser light imaged on the optical disk 12 is reflected on the optical disk, and the reflected laser light (return laser light) passes through the objective lens 11 again and is reflected by the reflecting mirror 10.
Bend at The bent laser light is divided by the hologram 6 into zero-order light and diffracted light. Further, the returning laser light enters the beam splitter 14 and is reflected at a constant rate on the beam splitter surface 16. The return laser light traveling in the direction coinciding with the optical axis of the emitted laser light,
The light is reflected in the direction of 90 ° with respect to the beam splitter surface 16 and is incident on the reflection film 15 having an arbitrary angle on the upper surface of the beam splitter 14.

The laser light reflected on the reflection film 15 is detected by the light receiving element 5 formed on the PDIC 1. The light receiving element 5 detects a beam spot diameter of the laser beam, a change in position, and the like, and reads data recorded on the optical disc 12. By appropriately adjusting the angle of diffraction by the hologram 6, three beams of 0th-order light and ± 1st-order diffracted light are simultaneously detected separately, and an information signal (RF), a focus error signal (FE), and a tracking error signal (TE) are detected. Can be detected.

The RF signal is output by an RF amplifier to a signal processing circuit of a reproducing system. The focus error signal is obtained by, for example, the Foucault method, and is used for driving a focus actuator for moving the objective lens in the optical axis direction. The tracking error signal is obtained by, for example, a three-beam method, and is used for driving a tracking actuator for moving the objective lens in the radial direction of the optical disc.

[0012]

However, since the laser beam emitted from the laser diode has the property of spreading to some extent, in the above-mentioned conventional lateral emission type semiconductor integrated light emitting / receiving device, a light emitting element is directly provided on the PDIC. When the laser beam is installed, a part (peripheral portion) of the laser beam hits the PDIC and becomes a beam cross section which is lost, so that the entire spot of the laser beam cannot be incident on the light receiving element 5. Therefore, the laser diode 2 needs to be installed on a PIN diode (LOP).

Further, since the direction of incidence and emission of the laser and the surface of the light receiving element are at 90 °, a beam splitter 14 for bending the laser light and entering the light receiving element is required. As described above, the above-described conventional lateral emission type semiconductor integrated light receiving and emitting device requires an LOP and a beam splitter, which is disadvantageous in reducing the cost, weight, and size of the device by reducing the number of components. .

The present invention has been made in view of the above-mentioned problems. Therefore, the present invention does not require a beam splitter and a PIN diode, and has fewer components compared to a conventional semiconductor integrated light emitting and receiving device. It is an object of the present invention to provide a semiconductor integrated light emitting and receiving device that is thinner in the laser emission direction.

[0015]

To achieve the above object, a semiconductor integrated light emitting and receiving device according to the present invention has a first surface and a second surface at a position lower than the first surface. An integrated circuit board connected between the first surface and the second surface by an inclined surface, a light emitting element formed on the first surface, a light receiving element formed on the inclined surface, and the light emitting element And a spectroscopic means for causing light emitted from the optical medium to enter an optical medium via a predetermined optical path, and causing reflected light from the optical medium to enter the light receiving element.

In the semiconductor integrated light emitting and receiving device according to the present invention, preferably, the light splitting means splits the light emitted from the light emitting element into an arbitrary number of light beams at a predetermined angle; A hologram for causing reflected light from a medium to enter the light receiving element by diffraction.

In the semiconductor integrated light receiving and emitting device according to the present invention, more preferably, the diffraction grating and the hologram are arranged on opposing surfaces of a polyhedron formed of a material that transmits light. It is formed on the second surface of the integrated circuit substrate.

In the semiconductor integrated light emitting and receiving device according to the present invention, preferably, the spectroscopic means has an optical element for condensing light emitted from the light emitting element and making the light incident on an optical medium. . In the semiconductor integrated light emitting and receiving device according to the present invention, more preferably, the optical element is an objective lens whose position can be adjusted.

Preferably, in the semiconductor integrated light emitting and receiving device according to the present invention, the spectroscopic means has a reflection mirror that specularly reflects light emitted from the light emitting element and makes the light incident on an optical medium. It is characterized by. Also, in the semiconductor integrated light emitting and receiving device of the present invention, preferably, the light emitting element is a laser diode formed on a silicon substrate.

As described above, the light emitted from the light emitting element is emitted in the horizontal direction from the light emitting element formed at the end of the upper surface (corresponding to 8 in FIG. 1) of the integrated circuit substrate. It is possible to prevent a part of the emitted light from hitting the integrated circuit substrate, thereby preventing the beam cross section from being lost. Therefore, a laser diode is installed above a PIN diode (LOP) which is a light receiving element for laser power control.
As compared with a conventional lateral emission type semiconductor integrated light receiving and emitting device, a package which is significantly thinner can be manufactured.

Further, in the semiconductor integrated light emitting and receiving device of the present invention, by forming the light receiving element on the step surface between the upper and lower stages as described above, the incoming and outgoing directions of light and the light receiving element surface are in the same direction. And makes an acute angle arrangement. This allows
Unlike a conventional lateral emission type semiconductor integrated light emitting and receiving device in which the direction of incidence and emission of laser light and the light receiving element surface form 90 °, a beam splitter for causing return light to enter the light receiving element becomes unnecessary. Therefore, cost reduction, weight reduction, and downsizing of the device can be achieved by reducing the number of parts, and the number of assembly steps is also reduced.

Further, in the semiconductor integrated light receiving and emitting device of the present invention, similarly to the conventional semiconductor integrated light emitting and receiving device, by appropriately adjusting the diffraction angle of the hologram, the 0th-order light can be adjusted.
Although it is possible to simultaneously detect three beams of the first-order diffracted light simultaneously and separately to detect an information signal (RF), a focus error signal (FE), and a tracking error signal (TE), the semiconductor integrated light receiving and emitting of the present invention is performed. In the device, by using an integrated circuit substrate having a step, the light receiving element, the optical element, and the like can be integrated by a relatively simple process, and the size of the device can be reduced.

In order to achieve the above object, a semiconductor integrated light emitting and receiving device according to the present invention has a first surface and a second surface lower than the first surface. Between the second surfaces, an integrated circuit board connected by an inclined surface, a light emitting element formed on the first surface, a light receiving element formed on the inclined surface, and light emitted from the light emitting device the light,
Spectral means for entering the optical recording medium via a predetermined optical path and causing reflected light from the optical recording medium to enter the light receiving element, and information on the optical recording medium based on a change in light intensity incident on the light receiving element. And signal detection means for reading out the data.

In the semiconductor integrated light emitting and receiving device according to the present invention, preferably, the spectroscopic means splits the light emitted from the light emitting element into an arbitrary number of light beams at a predetermined angle; A hologram for causing reflected light from a recording medium to enter the light receiving element by diffraction.

In the semiconductor integrated light emitting and receiving device according to the present invention, more preferably, the diffraction grating and the hologram are arranged on opposing surfaces of a polyhedron formed of a material that transmits light. It is formed on the second surface of the integrated circuit substrate.

In the semiconductor integrated light emitting and receiving device according to the present invention, preferably, the spectroscopic means has an optical element for condensing light emitted from the light emitting element and causing the light to enter an optical recording medium. I do. In the semiconductor integrated light emitting and receiving device according to the present invention, more preferably, the optical element is an objective lens whose position can be adjusted.

In the semiconductor integrated light emitting and receiving device according to the present invention, preferably, the spectroscopic means has a reflecting mirror that specularly reflects (mirror reflects) light emitted from the light emitting element and makes the light incident on an optical recording medium. It is characterized by the following. Also, in the semiconductor integrated light emitting and receiving device of the present invention, preferably, the light emitting element is a laser diode formed on a silicon substrate.

As a result, the laser light is emitted in the horizontal direction from the laser diode formed at the end of the upper surface (corresponding to 8 in FIG. 1) of the silicon substrate, so that part of the laser light impinges on the PDIC. In addition, the laser beam cross section can be prevented from being lost. Therefore, the PIN diode (L
It is possible to manufacture a significantly thinner package as compared with a conventional lateral emission type semiconductor integrated light emitting and receiving device in which a laser diode is installed on the upper part of OP).

Further, in the semiconductor integrated light emitting / receiving device of the present invention, a step is provided on the integrated circuit substrate made of a silicon substrate, and the upper first surface and the lower second surface are connected by an inclined surface, and the step is formed. A light receiving element is formed on a surface (inclined surface, corresponding to 7 in FIG. 1). The step surface (inclined surface) can be formed by etching, and it is not particularly necessary to perform anisotropic etching and it is not necessary to use an optical surface such as a mirror surface, so that processing can be performed simply and inexpensively. As a result, the light emitting element is directly installed on the silicon substrate, so that a thin package can be obtained as compared with a conventional semiconductor integrated light emitting and receiving device.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the semiconductor integrated light emitting and receiving device of the present invention will be described below with reference to the drawings. An example in which a laser diode is used as a semiconductor light emitting device will be described.

FIG. 1 is a schematic perspective view of a lateral emission type semiconductor integrated light receiving and emitting device of this embodiment. Integrated circuit board PDIC
A step is formed in 1, and a light receiving element 5 is provided on a step surface 7 between an upper substrate surface 8 and a lower substrate surface 9. A laser diode 2 serving as a light emitting element is formed on the upper surface 8 of the PDIC 1, and a laser beam L is emitted from the laser diode 2 in parallel with the PDIC 1 as shown in FIG.

On the optical axis of the laser diode 2 in the laser beam emission direction, a transparent parallel plate-shaped optical block made of glass or plastic is formed. A grating 3 is formed on one surface of the optical block, and a hologram 6 is formed on the other surface, usually by sticking. The emitted laser light passes through the grating 3,
The laser beam is divided into three laser beams having a predetermined angle. These three laser beams are reflected by the reflection mirror 10 and enter the objective lens 11, and are condensed on the optical disk 12 by the objective lens 11.

Each laser beam reflected on the optical disk 12 is reflected by the reflection mirror 10 at 90 ° and bent toward the semiconductor integrated light emitting / receiving device. Laser light is hologram 6
And is further divided into three by this, and the step surface 7
Is bent in the direction of the light receiving element 5 formed at an arbitrary position, and enters the light receiving element 5. Of these six laser beams in total, two laser beams on both sides are incident on the light receiving element 5 formed on the step surface 7 of the PDIC substrate 1 as shown in FIG.

In this case, by increasing the diffraction angle of the hologram 6, it is possible to sufficiently separate each of the two laser beams into the light receiving element 5 and make them incident as spots S1 to S5. In each of the spots S1 to S5, a signal is detected. In order to increase the angle of diffraction by the hologram 6, the pitch of the grooves formed on the hologram 6 is reduced to be equal to or less than the wavelength of the incident light. As a material of the hologram element, a high-refractive-index substrate into which various metallic materials are mixed to increase the refractive index is used, and the grooves are formed by a method such as reactive ion etching.

The light receiving element 5 detects a spot diameter of the laser beam, a change in position, and the like, and outputs a focus error signal (F).
E), a tracking error signal (TE) and an information signal (RF) recorded on the optical disk are read. Extraction of these signals can be performed by known methods.

The detection of a focus error caused by the vertical shake (shift in the optical axis direction) between the optical disk and the objective lens can be performed by a method called Foucault method. As shown in FIG. 3, outputs from respective segments of a 5-division photodiode (PD) in a 5-division light receiving element are denoted by S1, S2, S3, S4, and S5. From signals S2 and S3 obtained at D2 and D3 at the center,
The focus error signal (FE) is obtained by the calculation of FE = S2-S3.

The detection of the focus error signal will be described in detail. As shown in FIG. 4, the reflected light modulated by the pits on the signal disk passes through the objective lens,
Further, the light is diffracted by the hologram and converted
Guided to a split photodiode. The hologram is composed of two regions having different grating periods, and the reflected light of the main beam enters one of the regions and is collected on the dividing line of the photodetectors D2 and D3. Part D
4 are collected. When the focus is not just focused, the beam focused on the light receiving element is shown in FIG.
As shown in (c), the light is focused in a semicircular shape. The focus of the left and right laser beams is just
As shown in (a), the light is condensed uniformly on the left and right. Also,
The reflected lights of the sub-beams are condensed on the photodetectors D1 and D5, respectively.

These condensed beams change as shown in FIGS. 5B and 5C in accordance with the condensed state of the beam on the disk. Therefore, a focus error signal can be obtained by detecting a relative change between S2 and S5. The focus error signal is output from the RF amplifier to the focus actuator as a focus servo signal. The movement of the objective lens in the optical axis direction, that is, the position adjustment is performed by driving the focus actuator.

The detection of a tracking error signal caused by a relative displacement between a target pit on the optical disc and the objective lens in the radial direction can be performed by a well-known three-beam method. As shown in FIG. 3, signals obtained at both ends of the light receiving element divided into five, that is, S1, S
5, a tracking error signal (TE) is obtained by the calculation of TE = S1-S5.

The detection of the tracking error signal will be described in detail. FIG. 6A to FIG. 6C show that three beam spots Sb1, Sb2, and Sb3 divided by the grating described with reference to FIG. Indicates a state in which

The three beams irradiated and reflected on the optical disk return as six beams as described above. Of these, the three beams directed to the optical disk are split into two beams, respectively. Detection is performed using the beams (spots S1 and S5 in FIG. 3) on both sides that have been returned.

That is, in the on-track state shown in FIG. 6A, the spots S1 and S5 in FIG. 3 have the same brightness, for example, and no tracking error signal is detected. On the other hand, in the off-track state shown in FIG. 6B or FIG. 6C, for example, the brightness of spots S1 and S6 in FIG. 3 is large or small, and the brightness of S3 and S4 is small or small. As a result, the tracking error signal is output from the RF amplifier to the tracking actuator as a tracking servo signal. By driving the tracking actuator, movement of the objective lens in the radial direction, that is, position adjustment is performed.

The information signal RF can be detected by the sum of the signals of the spots S2, S3 and S4 in FIG. That is, RF is obtained by the calculation of RF = S2 + S3 + S5. The RF signal is output to a signal processing circuit of a reproduction system by an RF amplifier.

The lateral emission type semiconductor integrated light emitting and receiving device of the present invention is not limited to the above embodiment. For example, in a transmission hologram used in the apparatus of the present invention, an anti-reflection film may be formed on the hologram in order to reduce reflection loss of laser light generated on a critical surface between air and the hologram surface. In addition, various changes can be made without departing from the gist of the present invention.

[0045]

According to the semiconductor integrated light emitting and receiving device of the present invention, by providing a step in the PDIC, the laser beam can be emitted from the laser diode in parallel to the PDIC without losing the cross section of the laser beam. It becomes possible.
Further, by providing the light receiving element on the step surface (inclined surface) of the PDIC, the light receiving element surface almost coincides with the optical axis direction of the laser, and a beam splitter becomes unnecessary. Therefore, since the number of parts is reduced, the manufacturing process is simplified, and the device can be made thinner, smaller, and lighter.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a lateral emission type semiconductor integrated light emitting / receiving device of the present invention.

FIG. 2 is a configuration diagram of an optical pickup device using the lateral emission type semiconductor integrated light receiving and emitting device of the present invention.

FIG. 3 is a configuration diagram illustrating an example of a light receiving element of the present invention and an example of a signal obtained in the light receiving element.

FIG. 4 is a diagram showing a method for detecting a focus error signal in the semiconductor integrated light emitting and receiving device of the present invention.

FIG. 5 is a diagram illustrating a state of a laser spot incident on a light receiving element of the semiconductor integrated light emitting and receiving device of the present invention. (A) shows a case where the position of the optical disk is proper, (b) shows a case where the position of the optical disk is too far, and (c) shows a case where the position of the optical disk is too close.

FIG. 6 is a diagram illustrating a focus state of laser light focused on an optical disk in the semiconductor integrated light emitting and receiving device of the present invention. (A) shows the case where the focus is in the on-track state on the optical disc, (b) shows the case where the focus is in the off-track state on the optical disc, and (c) shows the case where the focus is in the off-track state on the optical disc.

FIG. 7 shows a configuration diagram of an optical pickup device using a conventional lateral emission type semiconductor integrated light receiving and emitting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Silicon substrate (PDIC), 2 ... Semiconductor light emitting element (laser diode), 3 ... Grating, 4 ... Light receiving element for laser power control, 5 ... Light receiving element, 6 ...
Hologram, 7: PDIC inclined surface (step surface), 8: PD
IC first surface (upper surface), 9 PDIC second surface (lower surface), 10 reflection mirror, 11 objective lens, 12 optical disk, 13 PIN diode, 14 beam splitter, 15 reflection film, 16 … Beam splitter surface.

Claims (14)

[Claims] A first surface and a second surface located lower than the first surface;
An integrated circuit board connected between the first surface and the second surface by an inclined surface; a light emitting device formed on the first surface; and a light emitting device formed on the inclined surface. Semiconductor integrated light receiving and emitting device, comprising: a light receiving element that emits light emitted from the light emitting element through a predetermined optical path into an optical medium, and light reflected from the optical medium incident on the light receiving element. apparatus. 2. The light separating device according to claim 1, wherein the light splitting unit splits the light emitted from the light emitting element into an arbitrary number of light beams at a predetermined angle, and diffracts the light reflected from the optical medium by diffraction. 2. The semiconductor integrated light emitting and receiving device according to claim 1, further comprising: a hologram that is incident on the light receiving device. 3. The diffraction grating and the hologram are disposed on opposing surfaces of a polyhedron formed of a material that transmits light, and the diffraction grating is formed on a second surface of the integrated circuit substrate. The integrated semiconductor light receiving and emitting device according to claim 2. 4. The semiconductor integrated light emitting / receiving device according to claim 3, wherein said light splitting means has an optical element for condensing light emitted from said light emitting element and causing the light to enter an optical medium. 5. The semiconductor integrated light emitting and receiving device according to claim 4, wherein said optical element is an objective lens whose position can be adjusted. 6. The semiconductor integrated light emitting / receiving device according to claim 3, wherein said spectral means has a reflecting mirror for specularly reflecting (mirror reflecting) light emitted from said light emitting element and causing the light to enter an optical medium. 7. The semiconductor integrated light emitting and receiving device according to claim 3, wherein said light emitting element is a laser diode formed on a silicon substrate. 8. A first surface, and a second surface located at a position lower than the first surface.
An integrated circuit board connected between the first surface and the second surface by an inclined surface; a light emitting device formed on the first surface; and a light emitting device formed on the inclined surface. Light receiving element, the light emitted from the light emitting element, incident on an optical recording medium via a predetermined optical path, reflected light from the optical recording medium,
A semiconductor integrated light emitting / receiving device, comprising: a light splitting unit that makes the light incident on the light receiving element; and a signal detecting unit that reads information from the optical recording medium based on a change in intensity of light that enters the light receiving element. 9. A diffraction grating for splitting light emitted from the light emitting element into an arbitrary number of light fluxes at a predetermined angle, and receiving the reflected light from the optical recording medium by diffraction. 9. The semiconductor integrated light emitting and receiving device according to claim 8, further comprising a hologram to be incident on the element. 10. The diffraction grating and the hologram are arranged on opposing surfaces of a polyhedron formed of a light transmitting material, and the diffraction grating is formed on a second surface of the integrated circuit substrate. The semiconductor integrated light emitting and receiving device according to claim 9. 11. The semiconductor integrated light emitting / receiving device according to claim 10, wherein said light splitting means has an optical element for condensing light emitted from said light emitting element and causing the light to enter an optical recording medium. 12. A semiconductor integrated light emitting and receiving device according to claim 11, wherein said optical element is an objective lens whose position can be adjusted. 13. The semiconductor integrated light emitting / receiving device according to claim 10, wherein said spectral means has a reflecting mirror for specularly reflecting (mirror reflecting) light emitted from said light emitting element and causing the light to enter an optical recording medium. 14. A semiconductor integrated light emitting and receiving device according to claim 10, wherein said light emitting element is a laser diode formed on a silicon substrate.