JPH0552702A - Light detecting apparatus - Google Patents

Abstract

PURPOSE:To measure spectrum characteristics and optical-output characteristics by moving an optical fiber based on each photovoltaic force of a plurality of light receiving regions of a photoelectric converting part, and making an emitting light axis agree with the optical fiber. CONSTITUTION:Laser beam emitted from a semiconductor laser diode 1 is condensed through a lens 3. The light is detected with four photodetectors 6 (6a-6d). The light is monitored with photovoltaic forces 7 (78-7d). At this time, the photodetectors 6 are scanned in the directions (x) and (y) so that the four photovoltaic forces 7 become equal. The axis of the fiber 4 agrees with the axis of the laser 2b. The direction (z) is also scanned, and the fiber 4 is aligned with a focal point 5, where the input of the laser beam 26 into the fiber 4 becomes the maximum value. As a result, the optical fiber can be made to agree with the optical axis of the emitted light quickly and positively. Furthermore, the measurements of the optical output characteristics of the laser beam and the spectrum characteristics can be performed at the same time by adding the photovoltaic forces 7 obtained from the photodetectors 6 during the scanning of the photodetector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photodetector used for inspecting or detecting the position of a light emitting element, and more particularly to a photodetector having a structure for guiding emitted light to an optical fiber.

[0002]

2. Description of the Related Art FIG. 3 is a schematic diagram showing a light input method of a conventional photodetector using an optical fiber.
Reference numeral 1 is a semiconductor laser diode (hereinafter abbreviated as LD), 2 is a laser beam emitted from the LD 1 to the outside, 2a is a laser beam before being condensed, and 2b is a laser beam condensed by a lens 3. Reference numeral 5 is a focus of the condensed laser light 2, reference numeral 4 is an optical fiber for taking in the laser light 2b condensed by the lens 3, and a photodetector (not shown) is arranged in the subsequent stage. Further, x, y, and z are directions in which the optical fiber 4 is scanned so that the input of the laser beam 2b taken into the optical fiber 4 is maximized.

Next, the operation will be described. The laser light 2 a emitted from the LD 1 is condensed by the lens 3.
The optical fiber 4 is scanned in the x, y, z directions so that the focused laser beam 2b can be input to the optical fiber 4 to the maximum extent, and the laser beam 2 is aligned with the focal point 5. Then, the light input to the optical fiber 4 is detected in its light amount and the like by a photodetector (not shown).

[0004]

The conventional photo-detecting device is constructed as described above, and the light input to the optical fiber adjusts the position of the optical fiber to the focal position of the focused laser light. There was a problem that it took a lot of time.

The present invention has been made in order to solve the above problems, and the optical axis of the incident light can be aligned with the optical fiber in a short time, and not only the spectral characteristics but also the optical output characteristics can be measured. It is an object of the present invention to obtain a light detection device that can also perform the above.

[0006]

A photodetector according to the present invention comprises a photoelectric conversion section having a plurality of light receiving regions, and an optical fiber fixed through the photoelectric conversion section.

[0007]

In the present invention, the optical fiber is moved on the basis of each photovoltaic force of the plurality of light receiving regions of the photoelectric conversion section,
Since the positioning is performed so that the light input to the optical fiber is maximized, it is possible to quickly find the optical axis of the light emitted from the light source and perform the optical axis alignment.

Further, when the optical axes are aligned, the light output characteristic can be detected from the photoelectromotive force generated in each light receiving region of the photoelectric conversion section.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A photodetector according to an embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same reference numerals as those in FIG. 3 denote the same or corresponding parts, and 6 is a four-division photodetector, which is composed of four-division photodetection units 6a, 6b, 6c, 6d. The photoelectromotive force 7a, 7b, 7c, 7d which is O / E converted in the section is obtained. In addition, the above-mentioned four divided light detection units 6a, 6b, 6
An optical fiber 4 is arranged at the center of c and 6d.

Next, the operation will be described. The laser light 2 a emitted from the LD 1 is condensed by the lens 3. The focused laser beam 2b is supplied to the four photo detectors 6a of the photo detector 6,
6b, 6c and 6d are detected and monitored by the photoelectromotive force 7a, 7b, 7c and 7d obtained from each photodetector. At this time, so that 7a = 7b = 7c = 7d,
The photodetector 6 is scanned in the x and y directions to align the optical axes of the optical fiber 4 and the laser beam 2b, and is further scanned in the z direction so that the laser beam 2b is input to the optical fiber 4 at the focal point 5. Align to fit.

In this way, the spectrum of the laser beam 2 taken from the optical fiber 4 after alignment is measured by a photodetector (not shown) connected to the other end of the optical fiber 4. Further, during the alignment, the total light output is measured by the total photoelectromotive force (7a + 7b + 7c + 7d) of the outputs of the respective light detection units.

As described above, according to this embodiment, the optical fiber 4 is arranged through the optical detector 4 at the center of the photodetector 6 which is composed of the photodetectors 6a, 6b, 6c and 6d divided into four parts. The photodetector 6 is scanned in the x and y directions so that the photoelectromotive forces 7a to 7d in the photodetector are equal, and then the photodetector 6 is moved in the z direction so that the incident light on the optical fiber 4 is maximized. Since the optical fiber 4 is aligned with the focal point 5 of the laser light by scanning at, the optical fiber can be quickly and surely aligned with the optical axis of the emitted light.

Further, when the photodetector 6 is scanned, the photoelectromotive forces 7a, 7b, 7c, 7d obtained from the photodetectors are summed to measure the optical output characteristic of the laser light as a spectral characteristic. It can be done at the same time as the measurement.

In the above-described embodiment, the photodetector 6 is composed of the photodetector sections divided into four, but the number of photodetector sections is not limited to this, and at least three or more are sufficient.

Next, a second embodiment of the present invention will be described. In this embodiment, a CCD 8 is used instead of the photodetector 6. That is, as shown in FIG. 2, the optical fiber 4 is arranged so as to penetrate the center of the CCD 8, the electromotive force of each output terminal (not shown) of the CCD 8 is monitored, and the optical fiber 4 is moved to a position where the value of each terminal is equal. By doing so, the optical axis of the laser beam 2b is aligned with the optical fiber 4. With this configuration, the same effect as that of the above embodiment can be obtained.

In each of the above embodiments, the optical fiber 4 is arranged at the center of the photodetector 6 or the CCD 8. However, the optical fiber 4 does not necessarily have to be arranged at the center of the above member, and the photodetector 6 is not necessary. Alternatively, the optical fiber 4 can be aligned with the optical axis of the laser beam 2b by performing signal processing so as to correct the position of the center of the CCD 8 and the position of the optical fiber 4.

In each embodiment, the laser beam 2 is focused by using the lens 3. However, when measuring light having a small divergence angle, the optical axis of the laser beam 2 is not focused by the lens. It may be introduced into the optical fiber 4.

[0018]

As described above, according to the photodetector of the present invention, the optical fiber is moved on the basis of the respective photoelectromotive forces of the plurality of light receiving regions of the photoelectric conversion unit, and the light to the optical fiber is moved. Since the positioning is performed so that the input is maximized, the optical fiber and the optical axis can be quickly aligned, and when the optical axis is aligned, the light generated in each light receiving area of the photoelectric conversion unit can be aligned. There is an effect that the light output characteristic can be detected from the electromotive force.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a photodetector according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the structure of a photodetector according to another embodiment of the present invention.

FIG. 3 is a schematic diagram showing a configuration of a conventional optical detection device using an optical fiber input method.

[Explanation of symbols]

 1 LD 2 Laser light 3 Lens 4 Optical fiber 6 Photodetector 8 CCD

[Procedure amendment]

[Submission date] April 17, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Next, the operation will be described. The laser light 2 a emitted from the LD 1 is condensed by the lens 3. The focused laser beam 2b is supplied to the four photo detectors 6a of the photo detector 6,
6b, 6c and 6d are detected and monitored by the photoelectromotive force 7a, 7b, 7c and 7d obtained from each photodetector. At this time, so that 7a = 7b = 7c = 7d,
The optical detector 6 x, by scanning in the y-direction, combined optical axis of the optical fiber 4 and the laser beam 2b, by further scanning in the z-direction input of the laser beam 2b in the optical fiber 4 becomes maximum focal Align as in 5.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

Next, a second embodiment of the present invention will be described. In this embodiment, a CCD 8 is used instead of the photodetector 6. That is, as shown in FIG. 2, the optical fiber 4 is arranged so as to penetrate the center of the CCD 8 and the electromotive force of each output terminal (not shown) of the CCD 8 is monitored to determine the x and y directions.
Then, the position where the light intensity is maximum is detected, and the optical fiber 4 is moved to that position, so that the optical axis of the laser beam 2b is aligned with the optical fiber 4. With this configuration, it is possible to obtain the same effect as that of the above-described embodiment , and the FFP
It is also possible to measure the characteristics .

Claims (1)

[Claims] 1. A photoelectric conversion unit having a plurality of light receiving regions in a light detection device for detecting light by introducing an emitted light by matching an optical fiber with an optical axis of the emitted light from a light source, and the photoelectric conversion unit. And an optical fiber fixed through the optical fiber, and the optical fiber is moved based on the photoelectromotive force in each light receiving region of the photoelectric conversion unit so that the optical axis of the emitted light is aligned with the optical fiber. An optical detection device characterized by the above.