JPH09113942A - Optical amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speedily and easily adjust the optical axis of light which is made incident on the gain area of the light amplifier by providing photodetector which detects the incidence position of the light nearby an optimum position of the incidence of the light on the grain area. SOLUTION: Photodetectors 6a and 6b are embedded nearby the optimum position of the incidence of external light 4 on the gain area 5a on the end surface of a light amplifier 5 which amplifies the light 4 to detect the incidence position of the light. Then the photodetectors 6a and 6b detect the external light 4 and the position shift between the optical axis of the external light 4 and the window of the gain area 5a of the light amplifier 5 is measured from the intensity distributions of the light detected by the photodetectors 6a and 6b. Consequently, while the photodetectors 6a and 6b detect the optical axis shift of the light 4 made incident on the gain area 5a, the optical axis is easily adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical amplifier that facilitates adjustment of the optical axis of incident light with respect to an optimum incident position in a gain region.

[0002]

2. Description of the Related Art Oscillation of a semiconductor laser occurs because spontaneous emission light is amplified in an active layer by a stimulated emission process as described in "Semiconductor Laser" (Baifukan, 1995). Due to the action, the semiconductor laser can be used as an optical amplifier having an amplifying action on the light injected from the outside. When a laser used as an optical amplifier is biased below a threshold, it is called a resonant laser amplifier, and when it is biased above a threshold and the amplifier itself is oscillating, it is called an injection locking amplifier.

FIG. 13 is an explanatory diagram when the optical output from the master laser is amplified by an optical amplifier. In FIG.
Is a master laser, 2 is an isolator, and 3 is an optical amplifier. An amplification factor G when the optical output from the master laser 1 is injected into the optical amplifier 3 having the end face reflectance R and the cavity length L (output signal power P _out from the optical amplifier 3 / input signal power P to the optical amplifier 3 _in ) is obtained as a result of multiple reflection in a Fabry-Perot resonator with optical gain, but the amplification factor Gs of a traveling-wave amplifier in which the end face reflectance R of both end faces can be neglected is exp (Γg−αi). Given by L. In this case, Γ is the light confinement rate, g is the optical gain of the active layer, and αi is the loss coefficient.

FIG. 14 is a schematic diagram showing the structure of a conventional optical amplifier which is such a traveling wave amplifier. In the figure, 3a is a gain region of the optical amplifier 3 which is a region for amplifying light injected from the outside through the window W, and 4 is light injected from the outside.

Next, the operation will be described. When the light 4 from the outside passes through the isolator 2 of the optical amplifier 3, the light 4 from the outside is gained in the gain region 3a, amplified, and output. In this case, since the light 4 from the outside needs to be accurately incident on the gain region 3a of the optical amplifier 3, the light 4 is injected from the outside to the micron-order window W for injecting the light into the gain region 3a of the optical amplifier 3. It is necessary to accurately match the optical axes of the light 4 from.

[0006]

Since the conventional optical amplifier is constructed as described above, in order to accurately guide light from the outside to the optical amplifier 3 and perform efficient amplification, it is irradiated from the outside. It is required to adjust the optical axis of the light 4 with respect to the window with high accuracy, but a position detecting means for knowing the positional relationship between the optical axis of the light 4 from the outside and the window of the gain region 3a is sufficient. In addition, there is a problem that it is not easy to perform highly accurate adjustment efficiently. Further, because the method of detecting the deviation amount of the optical axis adjustment is not sufficient, it is not easy to control the feedback of the deviation amount of the optical axis.

When the optical amplification is repeated a plurality of times, it is necessary to adjust the positional relationship between the optical axis of the irradiated and input light and the window of the gain region of the optical amplifier in each optical amplifier. There is a problem that the labor required for adjusting the optical axis increases in proportion to the number of optical amplifiers.

The present invention has been made to solve the above problems, and provides an optical amplifier capable of quickly and easily adjusting the optical axis of light incident on the gain region of the optical amplifier. With the goal.

[0009]

An optical amplifier according to a first aspect of the present invention comprises detection means for detecting the incident position of the light near the optimum incident position of the light with respect to the gain region. .

According to a second aspect of the present invention, there is provided an optical amplifier, wherein a plurality of photodetectors for detecting the incident light are provided in the vicinity of an incident window which defines an optimum incident position of the incident light on the gain region. Is provided with a detecting means.

An optical amplifier according to a third aspect of the present invention comprises a detecting means having a plurality of photodetectors arranged along a waveguide which is a gain region.

An optical amplifier according to a fourth aspect of the present invention is a plurality of optical amplifiers for detecting heat generated by the incident light in the vicinity of an incident window that defines an optimum incident position of the incident light on the gain region. The temperature measuring elements are arranged respectively.

An optical amplifier according to a fifth aspect of the present invention includes a reflector disposed near an entrance window that defines an optimum incident position of the incident light on the gain region, and a reflector for reflecting the incident light. A photodetector for detecting the light reflected by the reflector is provided as a detection means.

In the optical amplifier according to the sixth aspect of the present invention, the reflector is provided so as to be inclined at a predetermined angle toward the outside of the optical axis of the light incident on the entrance window with respect to the direction parallel to the entrance window. It is a thing.

An optical amplifier according to a seventh aspect of the present invention is the optical amplifier in which the reflector is provided with a predetermined angle inclining from the direction parallel to the incident window toward the optical axis of the light incident on the incident window. is there.

An optical amplifier according to an eighth aspect of the present invention includes a reflector disposed near an incident window that defines an optimum incident position of the incident light on the gain region, and a reflector for reflecting the incident light. An image sensor for detecting the light reflected by the reflector is provided as a detecting means.

An optical amplifier according to a ninth aspect of the present invention is provided with an optical distributor that reflects the light reflected by the reflector at a predetermined distribution ratio and guides it to the image sensor. is there.

An optical amplifier according to the tenth aspect of the invention is
A re-reflector that has a through hole through which incident light passes and further reflects the light reflected by the reflector to change the direction of the light reflected by the reflector and guide it to the image sensor. Is.

An optical amplifier according to the invention of claim 11 is
This is provided with a structure in which a reflector is formed on a part of the end surface of the optical amplifier body by coating.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. 1 is a schematic diagram showing the configuration of an optical amplifier according to a first embodiment of the present invention. In the figure, 5 is an optical amplifier, 5a is a gain region of the optical amplifier 5, and 6a and 6b are optical detectors (detection) for detecting the light 4 from the outside embedded in the end face of the optical amplifier 5 near the gain region 5a. Means).

Next, the operation will be described. In order to perform optical amplification, it is necessary to perform optical axis adjustment for accurately guiding the light 4 from the outside to the gain region 5a of the optical amplifier 5. Therefore, the light 4 from the outside is detected by the photodetectors 6a and 6b, and from the intensity distribution of the light detected by the photodetectors 6a and 6b, the optical axis of the light 4 from the outside and the gain of the optical amplifier 5 are obtained. The displacement of the area 5a from the window is measured. In this case, at least two photodetectors are provided near the window of the gain region 5a of the optical amplifier 5.

FIG. 2 is a photodetector according to the deviation of the optical axis of the light 4 from the outside when the photodetectors 6a and 6b of the optical amplifier 5 shown in the perspective view detect the light 4 from the outside, respectively. 6
2A is an output characteristic diagram of a and 6b, and FIG.
3 is a perspective view of FIG. 3, and W is a window (incident window) in the gain region.
2B and 2C are output characteristic diagrams of the photodetectors 6a and 6b. In FIGS. 2B and 2A, a is the gain region 5a of the optical amplifier 5 shown in FIG. The position of the photodetector 6a when the center of the window W is c, b is the position of the photodetector 6b, and the vertical axis is the output signal level of each photodetector 6a, 6b.

In the state where the optical axis of the light 4 from the outside, whose intensity distribution is axisymmetric, matches the window W of the gain region 5a, FIG.
As shown in (b), when the detection sensitivities of the photodetector 6a and the photodetector 6b are equal, the output signal levels of both detectors show the same value v, whereas the light 4 from the outside When the axis does not coincide with the gain region, the output signal levels of the photodetector 6a and the photodetector 6b show different values v1 and v2 as shown in FIG. FIG. 3C shows a state in which the optical axis of the light 4 from the outside is deviated from the position of the gain region 5a in the direction closer to the photodetector 6a.

Therefore, the optical axis of the light 4 from the outside is adjusted in the direction in which the output signal levels of the photodetectors 6a and 6b become equal, or the optical amplifier 5 is set to the light 4 from the outside.
2B, the difference between the output signal levels of the photodetectors 6a and 6b is adjusted to zero, so that the light 4 from the outside and the gain region 5a are adjusted. The positions of and can be adjusted easily and efficiently.

Although not shown in this embodiment described above, an automatic control mechanism for adjusting the output signal levels of the photodetectors 6a and 6b so that the difference between the output signal levels thereof becomes zero is provided from the outside. 4 is provided in the light source or the optical amplifier 5 that outputs 4 and the position of the light source or the optical amplifier 5 is automatically adjusted by operating the automatic adjustment mechanism constantly or as needed so that the difference becomes zero, It is also possible to always keep the position adjustment between the light 4 from and the window W of the gain region 5a in an optimum state.

Embodiment 2 FIG. FIG. 3 is a schematic diagram showing the configuration of the optical amplifier according to the second embodiment of the present invention. In the figure, 7 is an optical amplifier, 7a is a gain region of the optical amplifier 7, and 8a is
Reference numerals 8b and 8b denote temperature measuring elements (detection means) provided around the window W for allowing the light 4 from the outside to enter the gain region 7a, and are arranged on the end face of the optical amplifier 7. In this case, it is necessary to provide a plurality of temperature measuring elements around the window W, and in the case of a slit-shaped window, they are provided along the upper and lower long sides forming the slit, respectively, or each of the above-mentioned lengths. A plurality of temperature measuring elements are provided along the side.

Next, the operation will be described. In this embodiment, by the temperature measuring elements 8a and 8b provided around the window W of the gain region 7a of the optical amplifier 7, the deviation when the light 4 from the outside is incident on the gain region 7a of the optical amplifier 7 is prevented. It is measured as the temperature difference due to heat. That is, if the light 4 from the outside is deviated to the upper side with respect to the gain region 7a, the temperature measuring element 8
Since the output signal of a will generate a temperature detection output indicating a higher temperature than the output signal of the temperature measuring element 8b,
The optical axis of the light 4 from the outside may be adjusted so that the temperature detection outputs of the temperature measuring elements 8a and 8b become equal.

Although not shown in this embodiment described above, an automatic control mechanism for adjusting the temperature detection outputs of the temperature measuring elements 8a and 8b so that the difference between them is zero is provided by an external light source 4. Is provided to the light source or the optical amplifier 7 that outputs the light, and the position of the light source or the optical amplifier 7 is automatically adjusted by operating the automatic adjustment mechanism at all times or as necessary so that the difference becomes zero. It is also possible to always maintain the optimum position adjustment between the light 4 and the window W of the gain region 7a.

Embodiment 3 FIG. 4 is a schematic diagram showing the configuration of the optical amplifier according to the third embodiment of the present invention. In the figure, 9 is an optical amplifier, 9a is a gain region of the optical amplifier 9,
Reference numerals a and 10b are mirrors (reflectors) that are integrally provided on the end surface of the optical amplifier 9 near the window W of the gain region 9a at a predetermined angle to the optical axis side of the incident light and reflect external light 4. Is. Reference numeral 11a is a photodetector (detecting means) for detecting the external light 4 reflected by the mirror 10b, and 11b is a photodetector (detecting means) for detecting the external light 4 reflected by the mirror 10a.

Next, the operation will be described. Mirror 10
The light 4 from the outside reflected by a and 10b is the photodetector 11
b and 11a, respectively. In order to perform optical amplification, it is necessary to accurately guide the light 4 from the outside to the gain region 9a of the optical amplifier 9. Mirrors 10a and 10b of the optical amplifier 9
The external light 4 reflected by the light crosses the photodetector 11
b and 11a respectively, and each photodetector 11a, 1
From the difference in the output signal levels output from 1b, the deviation between the light 4 from the outside and the window of the gain region 9a of the optical amplifier 9 can be measured. Therefore, by adjusting the optical axis of the light 4 from the outside with respect to the window of the gain region 9a so as to eliminate the difference in the output signal levels output from the photodetectors 11a and 11b, it is possible to easily adjust the light from the outside under optimum conditions. The light 4 can be amplified. In addition, the mirrors 10a and 10b and the photodetector 11
It is possible to adjust the optical axis shift of the light incident on the gain region 9a with high accuracy according to the distances from b and 11a. Further, the mirrors 10a and 10b can be connected to the photodetectors 11a, 11b without extending the positions of the photodetectors 11a, 11b to the outside.
Since the distance to 11b can be set to be relatively long, the size of the device itself can be made compact.

Although not shown in this embodiment described above, an automatic control mechanism for adjusting the output signal levels of the photodetectors 11a and 11b so that the difference between the output signal levels becomes zero is provided from the outside. 4 is provided in the light source or the optical amplifier 9 that outputs 4 and a mechanism for integrally moving the optical amplifier 9 and the photodetectors 11a and 11b is provided.
The position of the light source or the optical amplifier 9 is automatically adjusted by operating the automatic adjusting mechanism at all times or when necessary so that the difference between the output signal levels of 11b becomes zero, and the light 4 from outside and the gain region. It is also possible to always keep the position adjustment with the window W of 9a in an optimum state.

Embodiment 4 FIG. FIG. 5 is a schematic diagram showing the configuration of the optical amplifier according to the fourth embodiment of the present invention. In the figure, 12 is an optical amplifier, 12a is a gain region of the optical amplifier 12, and 13a and 13b are coated in the vicinity of the gain region 12a of the optical amplifier 12.
Is a mirror (reflector) that is provided on the end surface of the mirror and is inclined outward by a predetermined angle to reflect the light 4 from the outside. Mirror 13
Reference characters a and 13b are provided on the inclined surface having a predetermined angle with respect to the end surface of the optical amplifier 12. Reference numeral 14a denotes a photodetector (detection means) for detecting the external light 4 reflected by the mirror 13a, and 14b denotes the external light 4 reflected by the mirror 13b.
Is a photodetector (detection means) for detecting.

Next, the operation will be described. Mirror 13
The light 4 from the outside reflected by a and 13b is a photodetector 14
a, 14b. In order to perform the optical amplification, it is necessary to guide the light 4 from the outside to the gain region 12a of the optical amplifier 12. The light 4 from the outside reflected by the mirrors 13a and 13b of the optical amplifier 12 is detected by the photodetectors 14a and 14b, respectively, and from the difference between the output signal levels output from the photodetectors 14a and 14b, The shift between the optical axis of the light 4 and the window W of the gain region 12a of the optical amplifier 12 can be measured. Therefore, by adjusting the optical axis of the light 4 from the outside with respect to the window W of the gain region 12a so as to eliminate the difference in the output signal levels output from the photodetectors 14a and 14b, it is possible to easily adjust the light from the outside under optimum conditions. The light 4 can be amplified. In addition, the mirrors 13a and 13b and the photodetectors 14a and 1
It is possible to adjust the optical axis shift of the light incident on the gain region 12a with high accuracy according to the distance from the lens 4b.

Although not shown in the above-described embodiment, an automatic control mechanism for adjusting the output signal levels of the photodetectors 14a and 14b so that the difference between the output signal levels of the photodetectors 14a and 14b becomes zero. The optical amplifier 12 and the photodetectors 14a, 14
b and the mechanism for moving integrally, and the photodetector 14
The position of the light source or the optical amplifier 12 is automatically adjusted by operating the automatic adjusting mechanism at all times or as necessary so that the difference between the output signal levels of a and 14b becomes zero. It is also possible to always maintain the optimum position adjustment between the gain region 12a and the gain region 12a.

Embodiment 5 FIG. FIG. 6 is a schematic diagram showing the configuration of the optical amplifier according to the fifth embodiment of the present invention. In the figure, 15 is an optical amplifier, 15a is a gain region of the optical amplifier 15, and 16 is a mirror (reflector) which is provided by coating the end surface of the optical amplifier 15 and reflects the light 4 from the outside. The mirror 16 is a gain region 15 of the optical amplifier 15.
It is provided on the end face excluding a. Reference numeral 17 denotes an optical distributor that guides the light, which has been distributed at a predetermined distribution ratio, to the external light 4 reflected by the mirror 16 to an image sensor (detection means) 19.

Next, the operation will be described. The external light 4 reflected by the mirror 16 is reflected by the light distributor 17 and guided to the image sensor 19. Since the image output signal level of the image sensor has a value corresponding to the intensity of the external light 4 reflected by the mirror 16, the image output signal level of the external light 4 reflected by the mirror 16 is shown in FIG. )
As shown in (2), the symmetrical state with substantially equal peak values is a state in which the optical axis of the light 4 from the outside and the gain region 15a coincide with each other. However, the image output signal processing of the image sensor different from that of the first embodiment is necessary, and for example, the relationship between the pixel position of the image sensor 19 and the image output signal level in the state where the optical axis adjustment is good is previously described. By prescribing, it is possible to determine the deviation between the optical axis of the light 4 from the outside and the gain region 15a based on the image output signal of the image sensor when the optical axis adjustment is good.

FIG. 7 shows the case where the optical axis of the light 4 from the outside coincides with the gain region 15a and the spot of the light 4 from the outside is accurately located in the window W of the gain region 15a of the optical amplifier 15. The image sensor 1 when the spot of the light 4 from the outside is deviated from the window W of the gain region 15a of the optical amplifier 15
It is explanatory drawing which shows the image output signal of FIG. The image sensor 19 in this case is described as a one-dimensional image sensor for the sake of description, but a two-dimensional image sensor is used to planarly adjust the deviation between the spot of the light 4 from the outside and the gain region 15a.

In FIG. 7A, 51 is an optical amplifier 15.
A spot of the light 4 from the outside accurately located in the window W of the gain region 15a of the optical amplifier 15;
The spot of the light 4 from the outside deviated from the window W of a is shown. 7B is an image output signal of the image sensor 19 when the spot of the light 4 from the outside is deviated from the gain region 15a of the optical amplifier 15, and FIG. 7C is the spot of the light 4 from the outside. Is the gain region 15 of the optical amplifier 15.
The image output signal of the image sensor 19 when accurately positioned at a is shown, where the spot 51 is the mirror 1
The portions of 6 appear as peaks P1 and P2 of the image output signal of the image sensor 19.

Therefore, when the image output signal of the image sensor 19 is in the state of FIG. 7B, the optical axis of the light 4 from the outside is moved upward, and the image output signal of the image sensor 19 is changed to that of FIG. ) Is adjusted.

Although not shown in this embodiment described above, an automatic control mechanism for adjusting the image output signal of the image sensor 19 to be as shown in FIG. 7C outputs the light 4 from the outside. The optical amplifier 15, the optical distributor 17, and the image sensor 19 are provided in the light source or the optical amplifier 15.
And the image sensor 19 are integrally movable.
The image output signal of FIG. 7C is always or automatically adjusted as needed so that the position adjustment of the light 4 from the outside and the gain region 15a is always kept in an optimum state. Since the image sensor is used, it is possible to adjust the position of the light 4 from the outside and the gain region 15a with high accuracy according to the number of pixels of the image sensor 19.

Embodiment 6 FIG. In the optical amplifier of this embodiment, a mirror having a through hole is used instead of the optical distributor described in the fifth embodiment. 8 is a perspective view showing an optical amplifier according to the sixth embodiment of the present invention. In FIG. 8, parts that are the same as or correspond to those in FIG. Reference numeral 18 denotes a mirror (reflector) arranged on the end face of the optical amplifier 15, and reference numeral 18 a denotes an entrance window formed at a position corresponding to the window W of the gain region 15 a of the mirror 18. Reference numeral 20 denotes a re-reflector, which again reflects the external light 4 reflected by the mirror 18 to cause the image sensor 19
Lead to. Reference numeral 20a is a through hole formed in the re-reflector 20 through which the light 4 from the outside passes.

Also in this embodiment, the position adjustment of the light 4 from the outside and the gain region 15a can be performed with high accuracy according to the number of pixels of the image sensor 19 as in the fifth embodiment.

Embodiment 7 FIG. In the optical amplifier of this embodiment, the mirror described in the third embodiment is provided independently of the optical amplifier. FIG. 9 shows a seventh embodiment of the present invention.
2 is a schematic diagram showing the configuration of the optical amplifier of FIG. In the figure, 2
1 is an optical amplifier, 21 a is a gain region of the optical amplifier 21, 22
Reference numerals a and 22b denote mirrors (reflectors) which are spaced apart from the end face of the optical amplifier 21 excluding the gain region 21a and are inclined at a predetermined angle on the optical axis side of the incident light. 24a
Is a photodetector (detection means) for detecting the external light 4 reflected by the mirror 22b, and 24b is a photodetector (detection means) for detecting the external light 4 reflected by the mirror 22a.

In this embodiment, the same effect as that of the third embodiment can be obtained. Although not shown in this embodiment described above, the photodetector 24
An automatic control mechanism for adjusting the difference between the output signal levels of a and 24b to be zero is provided in the light source or the optical amplifier 21 which outputs the light 4 from the outside, and is always provided so that the difference becomes zero. Alternatively, the position of the light source or the optical amplifier 21 is automatically adjusted by operating the automatic adjustment mechanism as necessary, and the position adjustment of the light 4 from the outside and the gain region 21a is always kept in an optimum state. It is also possible.
In this case, in order to match the optical axis of the light 4 from the outside with the window W of the gain region 21a, the position of the optical axis of the light 4 from the outside is adjusted, or the optical amplifier 21 and the mirrors 22a and 2a, 2 are arranged.
2b and the photodetectors 24a and 24b are mechanically moved integrally.

Embodiment 8. In the optical amplifier of this embodiment, the mirror described in the fourth embodiment is provided independently of the optical amplifier. FIG. 10 is a schematic diagram showing the structure of the optical amplifier according to the eighth embodiment of the present invention. In the figure,
26 is an optical amplifier, 26 a is a gain region of the optical amplifier 26, 2
7a and 27b are optical amplifiers 26 excluding the gain region 26a.
Is a mirror (reflector) which is arranged at a distance from the end surface of the mirror and is tilted outward by a predetermined angle. Reference numeral 28a is a photodetector (detection means) for detecting the external light 4 reflected by the mirror 27b, and 28b is a photodetector (detection means) for detecting the external light 4 reflected by the mirror 27a.

Also in this embodiment, the same effect as in the fourth embodiment can be obtained. In addition, although not shown in this embodiment described above, the photodetectors 28a, 2a
An automatic control mechanism for adjusting the difference between the output signal levels of 8b to be zero is provided in the light source or the optical amplifier 26 which outputs the light 4 from the outside, so that the difference becomes zero at all times or Operate the automatic adjustment mechanism as needed,
It is also possible to automatically adjust the position of the light source or the optical amplifier 26 so that the position adjustment of the light 4 from the outside and the gain region 26a is always kept in an optimum state.
In order to match the optical axis of the light 4 from the outside with the gain region 26a, the position of the optical axis of the light 4 from the outside is adjusted, or the optical amplifier 26, the mirrors 27a and 27b, and the photodetector 2 are arranged.
8a and 28b may be mechanically moved integrally.

Embodiment 9 FIG. In the optical amplifier of this embodiment, the mirror described in the fifth embodiment is provided independently of the optical amplifier. FIG. 11 is a schematic diagram showing the structure of the optical amplifier according to the ninth embodiment of the present invention. In the figure,
31 is an optical amplifier, 31a is a gain region of the optical amplifier 31, 3
Reference numerals 2a and 32b denote mirrors (reflectors) which are arranged in parallel to the end surface of the optical amplifier 31 excluding the gain region 31a and at a distance. Reference numeral 33 is a light distributor which distributes the light from the outside reflected by the mirrors 32a and 32b at a predetermined distribution ratio and guides it to an image sensor (detection means) 35.

Also in this embodiment, the same effect as that of the fifth embodiment can be obtained. Although not shown in this embodiment described above, the image sensor 35
7C is provided in the light source or the optical amplifier 31 which outputs the light 4 from the outside, and the optical amplifier 31 and the mirrors 32a, 3 are provided.
2b, the light distributor 33, and the image sensor 35 are provided with a mechanism capable of moving integrally, and the image output signal of the image sensor 35 is constantly or automatically adjusted as necessary so that the image output signal is as shown in FIG. , External light 4 and gain region 31a
It is also possible to always keep the position adjustments with and in the optimum state. Since the image sensor is used, the position adjustment between the light 4 from the outside and the window W of the gain region 31a is performed by the image sensor 35. It becomes possible to perform with high accuracy according to the number of pixels.

Embodiment 10 FIG. In the embodiment described above, the number of photodetectors has been described as two for the sake of description, but the number of photodetectors may be three or more, and as the number of photodetectors increases, they are incident on the window W of the gain region. The optical axis of the light 4 from the outside can be adjusted with higher accuracy.

Eleventh Embodiment FIG. 12 is a schematic diagram showing the structure of the optical amplifier according to the eleventh embodiment of the present invention. In the figure, 36 is an optical amplifier, 36a is a gain region of the optical amplifier 36, and 37 is a photodetector (detection means) which is embedded along the gain region 36a and is provided in the optical amplifier 36 to detect external light 4. ).

Next, the operation will be described. Gain area 36
The light 4 from the outside incident on a leaks from the gain region 36a to some extent, and thus the leaked light is detected by the photodetector 37 arranged along the gain region 36a. The output signal level of each photodetector 37 has different values when the light 4 from the outside is incident in parallel along the gain region 36a and when it is incident at a certain angle. From
In order that each photodetector 37 outputs an output signal level equal to the output signal level of each photodetector 37 when the light 4 from the outside is incident in parallel along the gain region 36a,
The optical axis can be easily adjusted by adjusting the optical axis of the light 4 from the outside or the position of the optical amplifier 36.

[0052]

As described above, according to the first aspect of the invention, the detecting means for detecting the incident position of the light is provided near the optimum incident position of the light with respect to the gain region. There is an effect that it is possible to easily perform the optical axis adjustment while detecting the optical axis shift of the light incident on the gain region by the detection means.

According to the second aspect of the invention, a plurality of photodetectors for detecting the incident light are arranged in the vicinity of the incident window that defines the optimum incident position of the incident light on the gain region. With this configuration, it is possible to easily detect the deviation between the incident window and the incident light by the output of the photodetector, and adjust the deviation of the optical axis of the light incident on the gain region. There is an effect that it can be easily performed based on the output of the photodetector.

According to the third aspect of the present invention, since the detecting means having a plurality of photodetectors arranged along the waveguide which is the gain region is provided, the incidence on the waveguide which is the gain region is performed. There is an effect that the deviation of the optical axis of the generated light can be accurately detected along the waveguide that is the gain region.

According to the invention described in claim 4, a plurality of temperature measurements for detecting the heat generated by the incident light in the vicinity of the incident window defining the optimum incident position of the incident light on the gain region. Since the elements are arranged, it becomes possible to easily detect the deviation between the incident window and the incident light by the output of the temperature measuring element, and the optical axis of the light incident on the gain region. There is an effect that the deviation can be easily adjusted based on the output of the temperature measuring element.

According to the fifth aspect of the present invention, a reflector disposed near an entrance window that defines an optimum incident position of the incident light on the gain region, and a reflector for reflecting the incident light, Since the photodetector that detects the light reflected by the reflector is provided as the detection means, the light is incident on the gain region with high accuracy according to the distance between the reflector and the photodetector. This has the effect of making it possible to adjust the deviation of the optical axis of light.

According to the invention of claim 6, the reflector is
Since it is arranged so as to be inclined at a predetermined angle on the side facing the outer side of the optical axis of the light incident on the incident window from the direction parallel to the incident window, depending on the distance between the reflector and the photodetector. There is an effect that it is possible to adjust the optical axis shift of the light incident on the gain region with high accuracy.

According to the invention of claim 7, the reflector is
Since it is arranged so as to be inclined at a predetermined angle on the side facing the optical axis of the light incident on the entrance window rather than the direction parallel to the entrance window, high accuracy depending on the distance between the reflector and the photodetector. It is possible to adjust the optical axis shift of the light incident on the gain region, and further, the distance from the reflector to the photodetector is comparatively large without expanding the arrangement position of the photodetector to the outside. Since it can be set long, the size of the apparatus itself can be made compact.

According to the eighth aspect of the present invention, a reflector disposed near an entrance window that defines an optimum incident position of the incident light on the gain region, and a reflector for reflecting the incident light, Since the image sensor for detecting the light reflected by the reflector is provided as the detecting means, the optical axis deviation of the light incident on the gain region with high accuracy according to the number of pixels of the image sensor is detected. It has the effect of making adjustments possible.

According to the ninth aspect of the invention, since the light distributor which distributes the light reflected by the reflector at a predetermined distribution ratio and reflects the light to the image sensor is provided, the image sensor of the image sensor is provided. The degree of freedom in the arrangement position is improved, and the optical axis deviation of the light incident on the gain region can be adjusted with high accuracy according to the number of pixels of the image sensor.

According to the tenth aspect of the present invention, there is a through hole through which incident light passes, the direction of the light reflected by the reflector is further reflected by the light reflected by the reflector. Since it is configured to include a re-reflector that guides the image sensor, the degree of freedom regarding the arrangement position of the image sensor is improved, and the light is incident on the gain region with high accuracy according to the number of pixels of the image sensor. There is an effect that it is possible to adjust the deviation of the optical axis of the reflected light.

According to the eleventh aspect of the present invention, since the reflector is coated on a part of the end face of the optical amplifier main body, the reflector is integrated with the optical amplifier main body and the strength is sufficiently maintained. It is possible to attach and arrange the light in such a state that there is an effect that it is possible to accurately adjust the deviation of the optical axis of the light incident on the gain region.

[Brief description of the drawings]

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

FIG. 2 is an output characteristic diagram when the photodetectors of the optical amplifier shown in the perspective view according to the first embodiment of the present invention respectively detect light from the outside.

FIG. 3 is a schematic diagram showing a configuration of an optical amplifier according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing a configuration of an optical amplifier according to a third embodiment of the present invention.

FIG. 5 is a schematic diagram showing a configuration of an optical amplifier according to a fourth embodiment of the present invention.

FIG. 6 is a schematic diagram showing a configuration of an optical amplifier according to a fifth embodiment of the present invention.

FIG. 7 is an explanatory diagram showing an image output signal of the image sensor of the optical amplifier according to the fifth embodiment of the present invention.

FIG. 8 is a perspective view showing a configuration of an optical amplifier according to a sixth embodiment of the present invention.

FIG. 9 is a schematic diagram showing the structure of an optical amplifier according to a seventh embodiment of the present invention.

FIG. 10 is a schematic diagram showing the structure of an optical amplifier according to an eighth embodiment of the present invention.

FIG. 11 is a schematic diagram showing the structure of an optical amplifier according to a ninth embodiment of the present invention.

FIG. 12 is a schematic diagram showing the structure of an optical amplifier according to an eleventh embodiment of the present invention.

FIG. 13 is an explanatory diagram showing amplification of an optical output from a master laser by an optical amplifier.

FIG. 14 is a schematic diagram showing a configuration of a conventional optical amplifier.

[Explanation of symbols]

4 Light from outside, 5, 7, 9, 12, 15, 21, 21
6,31,36 optical amplifier, 5a, 7a, 9a, 12
a, 15a, 21a, 26a, 31a, 36a gain region, 6a, 6b, 11a, 11b, 14a, 14b, 2
4a, 24b, 28a, 28b, 37 Photodetector (detecting means), 8a, 8b Temperature measuring element (detecting means), 10
a, 10b, 13a, 13b, 16, 18, 22a, 2
2b, 27a, 27b, 32a, 32b mirror (reflector), 17,33 light distributor, 19,35 image sensor (detection means), 20 re-reflector, 20a through hole.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Sato 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Sanryo Electric Co., Ltd.

Claims (11)

[Claims] 1. An optical amplifier having an amplifying effect on light incident on a gain region from the outside, comprising detection means for detecting the incident position of the light near the optimum incident position of the light on the gain region. An optical amplifier characterized by being provided. 2. The detecting means is a plurality of photodetectors for detecting the incident light, which are arranged in the vicinity of an incident window that defines an optimum incident position of the incident light on the gain region. The optical amplifier according to claim 1, which is characterized in that. 3. The optical amplifier according to claim 1, wherein the detection means includes a plurality of photodetectors arranged along the waveguide that is the gain region. 4. A plurality of temperature measuring elements for detecting heat generated by the incident light, the detecting means being disposed in the vicinity of an incident window that defines an optimum incident position of the incident light on the gain region. The optical amplifier according to claim 1, wherein: 5. A reflector for reflecting the incident light, which is arranged in the vicinity of an incident window that defines an optimum incident position of the incident light on the gain region, and a reflector for reflecting the incident light. The optical amplifier according to claim 1, further comprising a photodetector that detects the emitted light. 6. The reflector is provided so as to be tilted at a predetermined angle toward a side facing the outside of the optical axis of the light incident on the entrance window with respect to a direction parallel to the entrance window. The optical amplifier described. 7. The reflector according to claim 5, wherein the reflector is provided so as to be inclined at a predetermined angle toward a side facing the optical axis of the light incident on the incident window with respect to a direction parallel to the incident window. Optical amplifier. 8. The detecting means includes a reflector disposed near an incident window that defines an optimum incident position of the incident light on the gain region, and a reflector that reflects the incident light, and a reflector that reflects the incident light. The optical amplifier according to claim 1, further comprising: an image sensor that detects the emitted light. 9. A light distributor is provided, which reflects the light distributed at a predetermined distribution ratio with respect to the light reflected by the reflector, changes the direction of the distributed light, and sends the light to an image sensor. The optical amplifier according to claim 8. 10. A through hole through which incident light passes,
9. The optical amplifier according to claim 8, further comprising a re-reflector that further reflects the light reflected by the reflector to change the direction of the light and sends the light to the image sensor. 11. The reflector according to claim 5, wherein the reflector is a reflector formed by coating on a part of an end face of the optical amplifier body.
An optical amplifier according to the item.