JPH08248259A - Method and device for assembling optical parts - Google Patents

Abstract

PURPOSE: To make it possible to mount optical parts with good accuracy and reproducibility by fixing the optical parts at a desired angle in accordance with the intensity of the passed light measured while the optical part and analyzer are rotated around the axis of an optical fiber by changing the wavelength of light source light. CONSTITUTION: A light source 3 for generating the light which is variable in wavelength and has a finite extinction ratio is used in order to change the wavelength of the incident light on the polarization plane maintaining optical fiber 1. The optical parts 2 and the analyzer 5 are held with a prescribed angle at the exit end of the polarization plane maintaining optical fiber 1 and are mounted rotatably around the axis of the polarization plane maintaining optical fiber 1. The light from the light source 3 is made incident on the incident end 31 of the polarization plane maintaining optical fiber 1. The intensity of the light past the optical parts 2 and the analyzer 5 is measured while the wavelength of the light from the light source 3 is changed and the optical parts 2 and the analyzer 5 are rotated around the axis of the polarization plane maintaining optical fiber 1. The optical parts 2 are fixed with the desired angle to the exit end 30 of the polarization plane maintaining optical fiber 1 in accordance with the observed intensity of the light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to assembly and evaluation of an apparatus using a polarization-maintaining optical fiber mainly used in the fields of optical communication and optical measurement.

[0002]

2. Description of the Related Art An ordinary optical fiber is manufactured so that its refractive index is distributed symmetrically with respect to the light guiding direction (hereinafter referred to as z direction), and linearly polarized light is guided. In this case, there is a problem that a slight refractive index distribution is inevitably generated due to a slight temperature distribution or external stress, and the polarization plane fluctuates. Therefore, in the heterodyne or homodyne system in which a plurality of lights are mixed to extract a beat signal, there is a problem that the reception sensitivity becomes extremely unstable.

Therefore, what has been developed is a polarization-maintaining optical fiber having a structure in which even the light of the same wavelength has a different refractive index which the light perceives depending on the polarization direction. At present, several types of structures have been proposed, but each has a structure that is non-axisymmetric with respect to the z axis. For example, the core may be oval rather than circular, or the core may be formed with stress applying portions for compressing or stretching the core on both sides. Due to their structure, they have two polarization-maintaining principal axes (x-axis and y-axis) orthogonal to each other in the cross section perpendicular to the z-axis, and a linearly polarized wave having a polarization plane in this direction. When light is incident, its plane of polarization is preserved. This is because the refractive index perceived by light differs depending on the polarization direction, which causes the anisotropy of the propagation constant to release the degeneracy of the energy of the light, and the mode with the polarization plane in the x-axis direction of the polarization-maintaining optical fiber and the y-axis. This is because mode conversion between a mode having a plane of polarization in the direction is less likely to occur. Therefore, the larger the difference in refractive index between the x-axis direction and the y-axis direction (called B value, which will be described later), the better the performance as a polarization-maintaining optical fiber. Naturally, the better the polarization maintaining performance of a fiber, the more precisely the polarization direction of the incident light must match the polarization maintaining main axis direction of the polarization maintaining optical fiber.

Therefore, it is a very important problem in connecting the polarization-maintaining optical fibers to know with high accuracy which direction the polarization-maintaining main axis of the polarization-maintaining optical fiber faces. Connection is divided into a case where fusion is mainly performed and a case where connectors are attached and the connectors are connected to each other through adapter parts. inside that,
When a connector is used, it can be easily attached and detached, and since the connector with high precision and high durability has been recently developed and spread, its use is expanding. In this case, the shape of the connector is usually non-axisymmetric with respect to the z-axis of the polarization-maintaining optical fiber, and the polarization-maintaining main axis direction of the polarization-maintaining optical fiber having a circular outer shape is the shape of the connector. Can be easily recognized from. Also, when the connectors are connected to each other, the angle play is small, and the angles are controlled with extremely high precision. For this reason, matching and connecting the polarization-maintaining main axes of the polarization-maintaining optical fiber is limited to how accurately the angle between the polarization-maintaining optical fiber and the connector is controlled.

Conventionally, the most general method for grasping the polarization-maintaining principal axis direction of a polarization-maintaining optical fiber is to observe the end face of the polarization-maintaining optical fiber by enlarging it with a microscope or the like and to know its direction. As an alternative method, there is a method of utilizing light interference fringes. This is an interference fringe formed by stripping off the coating on the tip of a polarization-maintaining optical fiber and injecting linearly polarized light from just beside the polarization-maintaining optical fiber (direction that makes 90 ° with the z-axis). The pattern is projected on a screen, and the polarization-maintaining optical fiber is rotated about the z-axis to find the position where the interference pattern becomes symmetrical. This is because the interference fringe pattern becomes bilaterally symmetric when the incident path of light incident from the side surface coincides with the polarization-maintaining main axis direction of the polarization-maintaining optical fiber.

Further, a method is known in which linearly polarized light is incident from one end of a polarization-maintaining optical fiber and the polarization extinction ratio of the light emitted from the other end is measured to determine the polarization-maintaining axis direction. There is. In this case, in principle, the polarization extinction ratio of the outgoing light becomes infinite only when the polarization direction of the incoming light on the incident side and the polarization-maintaining principal axis direction of the polarization-maintaining optical fiber completely match. The polarization direction of is the polarization-maintaining principal axis direction of the polarization-maintaining optical fiber at the entrance end, and the polarization direction of the outgoing light is the polarization-maintaining principal axis direction of the polarization-maintaining optical fiber at the exit end. It is considered.

The polarization direction preserving principal axis direction of the polarization preserving optical fiber has been grasped by the above method.

[Problems to be Solved by the Invention]

However, the method of observing the end face of the polarization-maintaining optical fiber by enlarging it with a microscope and determining the polarization-preserving direction is simple, but high accuracy cannot be expected.
The method of observing the interference fringes by injecting linearly polarized light from the side surface of the polarization-maintaining optical fiber is also difficult to quantitatively control because it is judged from the pattern of the interference fringes, and many operations can be performed with a certain accuracy. Difficult to do. Furthermore, the polarization extinction ratio of the light emitted from the other end is maximized by rotating the polarization-maintaining optical fiber around the axis while injecting the linearly polarized light from one end of the polarization maintaining fiber. In the method of aligning the angles in the directions, stress is applied to the polarization-maintaining optical fiber by the operation of rotating the polarization-maintaining optical fiber. The refractive index difference from the y-axis direction) is changed. The fluctuation of the B value during the work is not preferable for the reason described below. In addition, it is practically impossible to produce completely linearly polarized light, that is, light with an infinite polarization extinction ratio, and when light with a finite extinction ratio is incident on the polarization-maintaining optical fiber. However, with only a single wavelength, there is a possibility that it will be adjusted to an incorrect angle for the reason described below, and its handling is extremely careful.

[0009]

Therefore, the present invention provides means for solving the above-mentioned problems based on the following phenomena discovered by the inventor.

When light is incident on the polarization-maintaining optical fiber 1 and the polarization extinction ratio of the light from the polarization-maintaining optical fiber 1 is measured, this becomes a simple function of the wavelength of the light and periodically changes. I found out that Here, the polarization extinction ratio means the ratio of the intensity of light in the strongest direction and the intensity in the weakest direction (both polarization planes are orthogonal to each other).

The function of wavelength is not limited to the polarization extinction ratio, but more generally, the intensity of light passing through the analyzer 5 set at a certain angle is periodic as a function of wavelength. It was also found that the fluctuation fluctuated to (Figs. 6 and 7). Of course, if the total intensity of light is detected except for the analyzer 5, it is always constant.

Further, not only the wavelength but also the length of the polarization-maintaining optical fiber 1 and the B value of the polarization-maintaining optical fiber 1 (the difference in refractive index between the x-axis direction and the y-axis direction of the polarization-maintaining optical fiber) are shown. It was also discovered that a variable fluctuates periodically.

Furthermore, the light passing through the analyzer 5 is detected only when the angle of the analyzer for receiving the light passing through the polarization-maintaining optical fiber 1 completely matches the polarization-maintaining main axis of the polarization-maintaining optical fiber 1. It was found that the strength did not fluctuate.

Therefore, all the inventions described in the above claims utilize the correlation between the change of the wavelength in the polarization-maintaining optical fiber and the intensity of the light passing through the analyzer 5 at a certain angle, which was discovered by the present inventor. is there.

The invention described in claim 1 is an assembling method of an optical component utilizing the above phenomenon. First, in order to change the wavelength of light incident on the polarization-maintaining single-mode fiber 1, first, a light source 3 that generates light having a finite extinction ratio and a variable wavelength is prepared. Light with a finite extinction ratio means light that is neither perfectly circularly polarized nor linearly polarized. Secondly, the optical component 2 to be attached to one end of the polarization-maintaining optical fiber 1 (hereinafter referred to as the exit end 30) and the analyzer 5 are held at a predetermined angle, and the axis of the polarization-maintaining optical fiber 1 is Attach it rotatably around. Thirdly, the light from the light source 3 is supplied to the other end of the polarization-maintaining optical fiber 1 (hereinafter referred to as the incident end 31).
Say. ). Fourth, while changing the wavelength of the light from the light source 3 and rotating the optical component 2 and the analyzer 5 around the axis of the polarization-maintaining optical fiber 1, the light passing through the optical component 2 and the analyzer 5 Measure the strength. At this time, the light undergoes the intensity modulation depending on the angle of the analyzer 5, and the intensity modulation is observed only when the angle of the analyzer 5 completely coincides with the polarization-maintaining main axis 14 of the polarization-maintaining optical fiber 1. Absent.
Fifth, the optical component 2 is fixed to the one end 30 of the polarization-maintaining optical fiber 1 at a desired angle based on the observed light intensity.

A second aspect of the present invention is an optical component assembling method utilizing the above phenomenon. A second object of the present invention is to accurately match the angle between the so-called support means and the analyzer. First, in order to change the wavelength of the light incident on the polarization-maintaining optical fiber 1, first, a light source 3 that generates light having a finite extinction ratio and a variable wavelength is prepared. Second
In addition, a means 8 for supporting the optical component 2 at the exit end 30 of the polarization-maintaining optical fiber 1 and around the axis of the polarization-maintaining optical fiber 1 is held at a predetermined angle with the polarization-maintaining optical fiber 1. While installing. The means 8 for supporting here means a holder used for supporting the optical component 2. At the same time, the analyzer 5 to be attached is attached rotatably around the axis of the polarization-maintaining optical fiber 1 via the holder which is the supporting means 8. Thirdly, the light from the light source 3 is made incident on the incident end 31 of the polarization-maintaining optical fiber 1. Fourthly, the intensity of the light passing through the analyzer 8 and the means 8 for changing the wavelength of the light from the light source 3 and supporting the analyzer 5 while rotating it about the axis of the polarization-maintaining optical fiber 1 is measured. . At this time, the light is subjected to intensity modulation depending on the angle of the analyzer 5, and the angle of the analyzer 5 changes depending on the angle.
Intensity modulation is not observed only when it completely matches the polarization-maintaining principal axis 14 of. Fifth, the analyzer 5 is fixed at a desired angle to the supporting means 8 based on the observed light intensity.

The third aspect of the present invention is a method for detecting the relative angle between the polarization-maintaining optical fiber 1 and the optical component 2, which also utilizes the above phenomenon. First, in order to change the wavelength of light incident on the polarization-maintaining optical fiber 1, first, a light source 3 that generates light having a finite extinction ratio with a variable wavelength is prepared. Secondly, the optical component 2 and the analyzer 5 are held at the output end 30 of the polarization-maintaining optical fiber 1 at a predetermined angle and attached to the polarization-maintaining optical fiber 1. Unlike the invention according to claim 1, the present invention does not aim at accurately aligning the polarization-maintaining optical fiber 1 and the optical component 2, and the optical component 2 does not polarize the polarization-maintaining optical fiber 1. Since the purpose is to detect how much the wavefront-maintaining spindle 14 is deviated, the optical component 2 and the analyzer 5 are rotatably mounted around the axis of the polarization-maintaining optical fiber 1. Does not need. Thirdly, the light from the light source 3 is made incident on the incident end 31 of the polarization-maintaining optical fiber 1. Fourth, while changing the wavelength of the light from the light source 3, the intensity of the light that has passed through the optical component 2 and the analyzer 5 is measured. The relative angle between the polarization-maintaining optical fiber 1 and the optical component 2 can be detected by the change in the measured intensity.

The invention according to claim 4 is a method of detecting the relative angle between the so-called supporting means 8 and the analyzer 5, which also utilizes the above phenomenon. First, in order to change the wavelength of light incident on the polarization-maintaining optical fiber 1, first, a light source 3 that generates light having a finite extinction ratio with a variable wavelength is prepared. Secondly, the means 8 for supporting the optical component 2 around the axis of the polarization-maintaining optical fiber 1 at the exit end 30 of the polarization-maintaining optical fiber 1 is provided at a predetermined angle with the polarization-maintaining optical fiber 1. Attach while holding. At the same time, the analyzer 5 is attached around the axis of the polarization-maintaining optical fiber 1 via the supporting means 8. In the present invention, unlike the invention described in claim 2, the supporting means 8 and the analyzer 5 are provided.
Since it is not intended to accurately align and, but is intended to detect how much the supporting means 8 is displaced with respect to the analyzer 5, the rotation around the axis of the polarization-maintaining optical fiber 1 is detected. It is not necessary that the supporting means 8 and the analyzer 5 are rotatably mounted. The light from the light source 3 is made incident on the incident end 31 of the polarization-maintaining optical fiber 1. The intensity of the light passing through the means 8 for changing and supporting the wavelength of the light from the light source 3 and the analyzer 5 is measured. The relative angle between the supporting means 8 and the analyzer 5 can be detected by the change in the measured intensity.

The invention described in claim 5 is a method for measuring the characteristics of the polarization-maintaining optical fiber 1 which also utilizes the above phenomenon. First, in order to change the wavelength of the light incident on the polarization-maintaining optical fiber 1, first, a light source 3 that generates light having a finite extinction ratio and a variable wavelength is prepared. Secondly, at the exit end 30 of the polarization-maintaining optical fiber 1 and at a predetermined angle around the axis of the polarization-maintaining optical fiber 1, the analyzer 5
Attach. In the present invention, unlike the inventions described in claims 1 and 2, the light emitted from the polarization-maintaining optical fiber 1 is received by the analyzer 5, and the polarization plane changes from the change in the light intensity due to the change in wavelength. Since the purpose is to measure the characteristics of the storage optical fiber 1, it is not necessary to use the optical component 2 and it is essential that the analyzer 5 is rotatably attached around the axis of the polarization-maintaining optical fiber 1. do not do. Thirdly, the light from the light source 3 is made incident on the incident end 31 of the polarization-maintaining optical fiber 1. Fourthly, the wavelength of the light from the light source 3 is changed and the intensity of the light passing through the analyzer 5 is measured. Due to the change in the measured intensity, the polarization-maintaining optical fiber 1
To measure the characteristics of.

The invention described in claim 6 is an optical component assembling apparatus which also utilizes the above phenomenon. The structure of the present invention is as follows. A light source 3 that emits light having a finite extinction ratio with a variable wavelength, and an optical component 2 that should be attached to an emission end 30 of a polarization-maintaining optical fiber 1 that makes this light incident on an incident end 31 have a predetermined angle. And the analyzer 5 attached in
A means 4 for rotatably attaching the optical component 2 and the analyzer 5 to the exit end 30 of the polarization-maintaining optical fiber 1 and about the axis of the polarization-maintaining optical fiber 1, and changing the wavelength of light from the light source 3. And a measuring device 6 for measuring the intensity of light passing through the optical component 2 and the analyzer 5 while rotating the optical component 2 and the analyzer 5 around the axis of the polarization-maintaining optical fiber 1, and the measuring device 6 Polarization-maintaining optical fiber 1 based on output signal
Means 7 for fixing the optical component 2 to the emitting end 30 of the optical component 2 at a desired angle
An optical component assembling apparatus including and. Here, the means 7 for fixing at a desired angle does not mean a specific device, but means fixing an optical component to the emitting end 30 of the optical fiber by a method such as bonding. Further, here, the means 4 that is rotatably attached around the axis of the polarization-maintaining optical fiber is
It does not mean an independent device, but the external structure of the analyzer. That is, when the structure of the analyzer is divided into an analyzer part that receives light from the polarization-maintaining optical fiber and another part that is outside the analyzer and that fixes the analyzer to a certain plane, If you fix the part to a certain plane,
The light receiving portion is rotatable, and the analyzer 5 is rotatable when the light receiving portion is rotated.
Since the analyzer 5 and the optical component 2 are coupled to each other, it can be said that the optical component is also rotatable. Further, here, the light undergoes intensity modulation depending on the angle of the analyzer 5,
No intensity modulation is observed only when the angle of the analyzer 5 completely matches the polarization-maintaining main axis 14 of the polarization-maintaining optical fiber 1.

The invention described in claim 7 is an optical component assembling apparatus which also utilizes the above phenomenon. The structure of the present invention is as follows. A light source 3 that emits light having a finite extinction ratio and a variable wavelength, and an optical component attached at a predetermined angle to an emission end 30 of a polarization-maintaining optical fiber 1 that injects this light into an incident end 31. 2, a means 8 for supporting 2 and a means 4 for rotatably mounting around the axis of the polarization-maintaining optical fiber 1 on the means 8 for supporting the analyzer 5 to be mounted,
Means 8 for changing the wavelength of the light from the light source 3 and supporting the analyzer 5 while rotating it around the axis of the polarization-maintaining optical fiber 1 and a measuring device 6 for measuring the intensity of the light passing through the analyzer 5. And the means 7 for fixing the analyzer 5 at a desired angle to the means 8 for supporting it based on the output signal of the measuring device 6. Here again, as in claim 6, the rotatably mounting means 4 refers to the external structure of the analyzer. Here, the light is intensity-modulated depending on the angle of the analyzer 5, and the angle of the analyzer 5 changes depending on the angle.
Intensity modulation is not observed only when it is perfectly aligned with the polarization-maintaining principal axis of.

The invention described in claim 8 is a detecting device for detecting the relative angle between the polarization-maintaining optical fiber 1 and the optical component 2, which also utilizes the above phenomenon. The structure of the present invention is as follows. A light source 3 that emits light having a finite extinction ratio with a variable wavelength, and an optical component 2 that should be attached to an emission end 30 of a polarization-maintaining optical fiber 1 that makes this light incident on an incident end 31 have a predetermined angle. A polarization-maintaining optical fiber 1 including an analyzer 5 attached in 1 and a measuring device 6 that changes the wavelength of light from a light source 3 and measures the intensity of light that has passed through the optical component 2 and the analyzer 5. It is a detection device that detects a relative angle with respect to the optical component 2. Unlike the invention according to claim 6, the present invention does not aim at accurately aligning the polarization-maintaining optical fiber 1 and the optical component 2, and the optical component 2 is a polarization-maintaining optical fiber 1. This is a device for detecting how much the wavefront-preserving main axis is deviated. Therefore, it is not necessary to measure the intensity while rotating the analyzer 5 around the axis of the polarization-maintaining optical fiber 1.

The invention described in claim 9 is the detection device for detecting the relative angle between the supporting means 8 and the analyzer 5, which also utilizes the above phenomenon. The structure of the present invention is as follows. A light source 3 that emits light having a finite extinction ratio with a variable wavelength, and an emission end 30 of a polarization-maintaining optical fiber 1 that enters this light into an incident end 31, and a polarization-maintaining optical fiber An analyzer 5 attached to the means 8 for supporting the optical component 2 attached at a predetermined angle around the axis of 1, and a means 8 for changing and supporting the wavelength of the light from the light source 3 and the analyzer 5. This is a detection device for detecting the relative angle between the analyzer 8 and the means 8 for supporting the optical component, including the measurement device 6 for measuring the intensity of the light passing through. In the present invention, unlike the invention described in claim 6, the supporting means 8 and the analyzer 5 are not aimed at aligning the supporting means 8 and the analyzer 5, and the supporting means 8 and the analyzer 5 have the polarization-maintaining optical fiber 1 This device is intended to detect the degree of deviation from the polarization-maintaining principal axis of. Therefore, it is not necessary to measure the intensity while rotating the analyzer 5 around the axis of the polarization-maintaining optical fiber 1.

A tenth aspect of the present invention is a device for measuring characteristics of a polarization-maintaining optical fiber 1 which also utilizes the above phenomenon. The configuration of the present invention is as follows. A light source 3 that emits light having a finite extinction ratio with a variable wavelength, and an analyzer attached at a predetermined angle to the other end 30 of the polarization-maintaining optical fiber 1 that makes this light enter an incident end 31. 5 is a characteristic measuring device for a polarization-maintaining optical fiber 1 including a measuring device 5 for changing the wavelength of light from the light source 3 and measuring the intensity of light passing through the analyzer 5. In the present invention, claim 6
Unlike the invention described in (1) above, the light emitted from the polarization-maintaining single-mode fiber 1 is received by the analyzer 5, and the characteristics of the polarization-maintaining single-mode fiber 1 are measured from the change in the intensity of the light due to the change in the wavelength. Since it is intended, the optical component 2 is unnecessary, and it is not necessary to measure the intensity while rotating the analyzer 5 around the axis of the polarization-maintaining optical fiber 1.

[0025]

Next, the principle discovered by the inventor will be described below. The invention is all based on this principle.

First, in the module for outputting laser light using the polarization-maintaining optical fiber 1, the inventor has found that the polarization extinction ratio (TE / TM) fluctuates periodically as a function of wavelength, and reproduces even at the same wavelength. I found that I could not get sex. Subsequently, the inventor reproduced such a phenomenon by a simple calculation model described later, and revealed that the polarization extinction ratio of the light emitted from the polarization-maintaining optical fiber generally has wavelength dependence. . Let θ _O be the angle indicating the polarization direction of the outgoing light at the outgoing end 30 when the light enters the polarization plane-maintaining axis 14 with an angle of θ _i , and the intensity between the angle θ _O and the direction forming 90 ° with θ _O. Figure 2 shows the result of calculating the ratio as the polarization extinction ratio.
And shown in FIG. When θi deviates from 0 °, the extinction ratio on the output side naturally decreases, but when θ _o is 0 °, it always takes a constant value. On the other hand, when θ _O deviates from 0 °, the extinction ratio fluctuates as a function of wavelength. Especially when θ _O takes a value close to α, the extinction ratio of the fiber output light takes a value exceeding the extinction ratio of the LD itself. Sometimes. Further, since δ which is the cause of the fluctuation is also a function of the B value and the fiber length, the fluctuation of the ambient temperature and the stress applied to the fiber cause a change, and the phase of the fluctuation cycle appears to be out of phase. FIG. 4 shows an example in which parameters are set and calculated so as to match actual measurement data. That is, the polarization direction angular distribution of the intensity of the light emitted from the polarization-maintaining optical fiber 1 periodically fluctuates as a function of the B value, the wavelength, and the fiber length except in the direction of the polarization-maintaining principal axis 14 of the fiber. When the extinction ratio is measured using the analyzer 5, this phenomenon causes the extinction ratio to fluctuate unless accurate angle control is performed.

The operation common to all of claims 1 to 10 will be described below with reference to FIG. Here, in order to simplify the explanation, the extinction ratio of the polarization-maintaining optical fiber 1 and the analyzer 5 is set to infinity, and the loss and end face reflection in each are neglected. The extinction ratio of incident light is defined by the following formula.

[0028]

[Equation 1]

The polarization direction dependence of the intensity of the emitted light when this light is incident on the polarization-maintaining optical fiber 1 with an angle θi offset from the polarization-maintaining main axis 14 is as follows.

[0030]

[Equation 2]

In the model shown in FIG. 5, the x-axis and the y-axis are equal to the polarization-maintaining main axis 14 of the polarization-maintaining optical fiber 1. B is a peculiar value (birefringence index) representing the characteristics of the polarization-maintaining optical fiber 1, L is the fiber length, λ is the wavelength of light, and θo is the angle indicating the polarization direction at the exit end 30, which is actually Corresponds to the orientation of the analyzer. The intensity of light passing through the analyzer when an analyzer with zero loss and an infinite extinction ratio of infinity is installed at an angle of θo is P (θo). Moreover, it is approximated as | H | << | E | = 1.

Examples of the wavelength dependence of the polarization angle distribution of the intensity of the light emitted from the polarization-maintaining single-mode fiber 1 calculated using this equation are shown in FIGS. 6 (a), 6 (b), and 7 (a). ) Figure 7
It shows in (b). The horizontal axis represents the wavelength of the incident light, and the vertical axis represents the intensity of the emitted light, which is a relative value standardized with the intensity at θi = θo = 0 ° as 1. Here, the extinction ratio of the incident light is 40 dB, the fiber length is 2 m, and the B value of the polarization-maintaining optical fiber is 4.5 ×.
It is set as 10 ^-4 . FIG. 7A shows | E | in FIG.
When the planes of polarization completely match the planes of polarization-maintaining polarization-maintaining optical fiber, FIG. 6 (b), FIG. 7 (a), and FIG. The calculation results are obtained when the polarization-maintaining principal axes of the two are deviated from each other by 2 °, 5 °, and 10 °, respectively, and are 0 °, 2 °, 5 °, and 10 ° with respect to the polarization-preserving axes of the polarization-maintaining optical fiber. Corresponds to measuring the intensity via a tilted analyzer. As is clear from these figures, the measured intensity fluctuates with the wavelength fluctuation unless θo is 0, and the magnitude of the fluctuation increases as θo increases. When θi is 0 °, the fluctuation is small, but it does not completely disappear, and by chance θ
This method is effective even when i becomes 0 °. It is impossible for the angle θo to change regardless of the angle α = 0, that is, θi = 0 °, and when the polarization extinction ratio of the incident light is infinite. Moreover, the angle at which the polarization extinction ratio can be maximized is not always fixed to the polarization-maintaining main axis of the polarization-maintaining optical fiber, and the maximum intensity may be obtained when θo is not 0 °. However, if the angle is adjusted by relying on the polarization extinction ratio at a single wavelength, the wrong angle will be set. This deviation angle has a maximum value of ± α centering on θi = 0 °.

Further, when the B value slightly changes due to the stress applied to the polarization-maintaining optical fiber, the fluctuation of the ambient temperature, etc., FIG. 6 (a) FIG. 6 (b), FIG. 7 (a) FIG. 7 (b) The series of periodic fluctuations shown in Figure 2 has the characteristic that the phases of the cycles are shifted. From the above, when the frequency-modulated light with a finite polarization extinction ratio is incident on one end of the polarization-maintaining optical fiber and the light emitted from the other end is received through the analyzer, the received light is The intensity is intensity-modulated with an efficiency that depends on the angle between the polarization-maintaining principal axis of the polarization-maintaining optical fiber and the analyzer, and the angle between the polarization-maintaining principal axis of the polarization-maintaining optical fiber and the analyzer is 0. The efficiency becomes 0 only when the angle is °.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A shows the configuration of an embodiment common to all claims of the present invention. First, polarization-maintaining optical fiber 1
Then, let us consider the so-called panda fiber.
Hereinafter, unless otherwise specified, the fiber 1 means a panda fiber that is the polarization-maintaining optical fiber 1. This panda fiber is becoming the mainstream of the current polarization-maintaining optical fiber 1 because of its excellent polarization extinction ratio characteristic and low loss characteristic. The cross-sectional shape of the panda fiber 16 is shown in FIG.
Shown in The broken line 15 defines the analyzer direction 15. The core 1 with the clad 13 interposed on both sides of the core 11
1 is provided with a stress applying portion 12 for applying stress, and the polarization-preserving main axis 14 is in a direction in which these three members are arranged in a line and a direction forming 90 ° with them.

Next, as the connector 2 which is the optical component 2,
Consider the SC connector 2 which is widely used at present. Hereinafter, unless otherwise noted, the term “connector 2” means the SC connector which is the optical component 2. The SC connector 2 has a substantially rectangular cross section perpendicular to the z-axis which is the light emission direction, and has a projection on one of the two long sides to form an asymmetrical shape.

Further, as a light source 3 (hereinafter, referred to as a wavelength variable light source 3) that emits light having a tunable extinction ratio with a variable wavelength, a device generally called an external resonator type is used. Is widely used and can be used in the present invention, a multi-electrode type distributed feedback semiconductor laser (hereinafter, referred to as DFB-LD) and a multi-electrode distributed Bragg reflection semiconductor laser (hereinafter, DBR). -LD) is also usable, and in this embodiment, the DBR-LD is considered as the wavelength variable light source 3. Multi-electrode type D
In BR-LD and multi-electrode type DFB-LD, the wavelength changes depending on the injection current value, so the wavelength shift speed is fast,
Workability improves because measurement can be completed in a short time. For this reason,
It is easy to improve the accuracy further by averaging by repeating the measurement many times. Especially multi-electrode type DBR-LD
Is easy to control the oscillation wavelength and oscillation output independently, and is suitable for applying only frequency modulation while keeping the output constant.

(Embodiment of the operation of the invention of claim 1) First,
The variable wavelength light source 3 described above is prepared. This variable wavelength light source 3
Generates light with a finite extinction ratio as well as a variable wavelength. Next, the connector 2 and the analyzer 5 are attached to the emitting end 30 of the fiber 1 around the fiber 1 at a predetermined angle. Fiber 1 of this connector 2 and analyzer 5
Specifically, the attachment to the emission end 30 is as follows. That is, the place of attachment is on the waveguide axis of the fiber 1, the propagating light of the fiber 1 is in a positional relationship of passing through the connector 2 and the analyzer 5 in this order, and the waveguide axis of the fiber 1 and the connector 2 are arranged. And the optical axis of the analyzer 5 must be the same. Further, it is premised that the angle between the connector 2 and the analyzer 5 is accurately controlled via the supporting means 8. Then, the light from the variable wavelength light source 3 is made incident on the incident end 31 of the fiber 1. The light emitted from the variable wavelength light source 3 propagates in the fiber 1 and reaches the emission end 30. Further, the measuring device 6 is configured to change the wavelength of the light from the variable wavelength light source 3 and rotate the connector 2 and the analyzer 5 around the axis of the fiber 1 while measuring the intensity of the light passing through the connector 2 and the analyzer 5. Measurement is performed by the light receiver 60. Here, around the axis is specifically the fiber 1
This means rotating around the waveguide axis of. Further, the analyzer 5 receives the light emitted from the emitting end 30 of the fiber 1 and transmits only the light having the polarization plane in the direction that coincides with the direction of the analyzer 5. Finally, the connector 2 is fixed to the emitting end 30 of the fiber 1 at a desired angle based on the intensity of light detected by the light receiver 60.

When the wavelength of the incident light is changed by the variable wavelength light source 3, the intensity of the light passing through the analyzer 5 exhibits a periodic fluctuation with respect to the wavelength according to the principle described in the operation. When the angle of the analyzer 5 is changed, the amplitude of the fluctuation of the intensity also changes, and if the total intensity of the incident light is always constant with respect to the change of the wavelength, the fluctuation cannot be detected at a certain angle at all. At this time, the angle of the analyzer 5 and the angle of the polarization-maintaining main axis 14 of the fiber 1 are the same, and the optical component 2 is connected to the fiber 1 at this position.
It may be fixed by pouring an adhesive to the emitting end 30 of the.

Although the above is an example of the case of manual operation, it is also possible to use the data processing / device control means 10 and the analyzer angle control means 9 as shown in FIG. 1 (b). . That is, the data processing / device control means 1
0 sends a wavelength control signal to the wavelength tunable light source 3, and the light receiver 60
The intensity value sent from is read to determine the amplitude of the wavelength and intensity variations. Next, the analyzer 5 is moved to the analyzer angle control means 9.
The angle control signal of is sent and the amplitude of intensity fluctuation is calculated again. By repeating this operation, the connector 2 may be fixed at an angle at which the amplitude of the fluctuation of the intensity becomes the smallest.

Further, a multi-electrode type DF is used for the variable wavelength light source 3.
When a B-LD or a multi-electrode DBR-LD is used, a wavelength shift of μ seconds or less is possible at a high speed, and the angle control can be performed at an extremely high speed by the automatic control as in this example. Become.

(Embodiment of Claim 2) Next, an embodiment of the method of aligning the angle between the means 8 for supporting the optical component and the analyzer 5 will be described. The means 8 for supporting is S
Use as a C connector holder. Hereinafter, unless stated otherwise, the term holder 8 means the SC connector holder that is the means 8 for supporting. Unlike another mainstream FC connector, the SC connector is fixed by simply inserting it into a holder and has almost no freedom of rotation around the waveguide axis, which makes it particularly suitable for polarization-maintaining optical fibers.
Therefore, accuracy is required to control the mounting angle of the holder. The present embodiment relates to the angle alignment of the analyzer 5 and the holder 8 fixedly attached to the analyzer 5 by using the fiber 1 and the connector 2 fixed to the fiber 1 with high accuracy. First, a fiber 1 having a connector 2 fixed at one end with high precision is prepared, and the connector 2 is fitted and held in a holder 8 to be attached. Analyzer 5 in this state
Tentatively rotatably fixed to the light incident position, and light from the variable wavelength light source 3 having a finite extinction ratio is incident from the other end of the fiber 1. The fiber 1 is fixed as much as possible. Then, after propagating in the fiber 1 to reach one end and passing through the connector 2 and the holder 8, the intensity of the light, which is only the component having a specific polarization plane through the analyzer 5, is detected by the photodetector 60. Then, while changing the wavelength, observe how the light intensity changes. When the direction of the analyzer 5 and the direction of the polarization-maintaining main axis 14 of the fiber 1 do not match, the intensity of the detected light shows a periodic fluctuation depending on the wavelength. Here, it can be considered that the polarization preserving main axis 14 of the fiber 1 and the connector 2 are completely in the same direction. Is correct. Therefore, rotate the analyzer 5 to find the angle at which the light intensity does not change,
If the holder 8 is fixed at that position, the analyzer 5 and the holder 8
The angle with can be attached with extremely high accuracy. As in the case of the first aspect, these steps can be performed at high speed and accurately by using arithmetic / control means such as a step motor for controlling the rotation or a personal computer. Further, in a device such as a polarization extinction ratio measurement module that freely rotates the analyzer 5 with respect to the holder 8, and in the application where the absolute angle reference and the orientation of the holder 8 need to be accurately matched, The following procedure is simpler than the procedure of. That is, the analyzer 5 is rotated with respect to a certain wavelength to measure the analyzer angle dependence of the intensity corresponding to P (θo) in Formula 2, and then the analyzer 5 is rotated again with another wavelength. Also measure the light intensity. Drawing a graph with the horizontal axis representing the tentative angle of the analyzer 5 and the vertical axis representing the intensity and searching for the intersection of the two curves, the tentative angle indicates the true angle of the analyzer. Therefore, the angle scale may be displayed with the direction set to 0 °. Furthermore, if the incident angle side of the fiber 1 is controlled by using a polarizer or the like, the accuracy can be further improved.

(Example of Operation of Claim 3) Next, an example of a method of detecting the relative angle between the polarization-maintaining optical fiber 1 and the optical component 2 of Claim 3 will be described. In this embodiment, the output end 30 of the fiber 1 and the connector 2 are mounted on the same optical axis and at a certain angle to be detected, and the means 8 for supporting the connector 2 and the analyzer 5 are accurately angled. Controlled. The mutual positional relationship is similar to that of the embodiment of claim 1 described above. Light having a finite extinction ratio propagates through the fiber 1 and sequentially passes through the connector 2 and the analyzer 5, and only the light having a certain plane of polarization determined by the angle of the analyzer 5 is received by the photodetector 60. Its intensity is detected.
Here, if the wavelength of the light incident on the fiber 1 is changed,
The intensity of the light received by the light receiver 60 generally varies periodically as a function of wavelength. The amplitude is determined by the extinction ratio of the incident light, the angle between the polarization plane when the light enters the fiber 1 and the polarization-maintaining main axis 14 of the fiber (θi described above), and the angle between the main axis and the analyzer 5 (previously described). Θo) and the Of these, the amplitude becomes 0 according to the formula 2 only when θo is 0. Therefore, it can be seen that the analyzer 5 and the polarization-maintaining main axis 14 of the fiber 1 are aligned with each other, and the supporting means already known The angle formed by the connector 2 and the polarization-maintaining main axis 14 of the fiber 1 can be known from the angle formed by 8 and the analyzer 5. Further, if θi can be freely controlled, it is clear that more accurate measurement can be performed.

Based on the idea of the invention, instead of changing the wavelength, the amplitude is a function of the temperature and stress of the fiber,
Further, if it can be freely controlled as a function of the fiber length, it is possible to cause the same phenomenon according to Equation 2.

(Embodiment of Claim 4) Next, an embodiment of an angle evaluation method between the means 8 for supporting the optical component and the analyzer 5 described in Claim 4 will be described. SC fixed accurately
The angle of the SC connector holder attached to the analyzer shall be detected using a PANDA fiber having a connector at one end. The same procedure as in the embodiment of claim A is performed, and the light of the variable wavelength light source is incident from the other end of the fiber, and the intensity of the light after passing through the analyzer is detected by the light receiver 60.
If the intensity changes corresponding to the wavelength change, the angle between the holder and the analyzer is deviated. In order to estimate the degree of deviation, if the angle on the incident side is accurately controlled or the incident angle is swept, then θo can be found from Equation 2, and θo indicates the magnitude of the angular deviation.
In the case of a polarization extinction ratio measurement module, etc., the dependence of the intensity on the analyzer angle is measured for two or more wavelengths, and the angle at which the detected intensity does not change even when the wavelength changes matches the angle reference. Find out if

(Example of operation of claim 5) Next, claim 5
An example of the method for measuring the characteristics of the polarization-maintaining single-mode fiber 1 described in 1) will be described. Here, the fiber 1 and the analyzer 5 whose characteristics are to be measured are the polarization plane-maintaining spindle 14 of the fiber 1.
And the analyzer 5 are fixed at an angle such that they do not become zero. The presence or absence of the connector 2 does not matter. The light propagating through the fiber 1 passes through the analyzer and is received by the photodetector 60, which is the same as the first and second embodiments. As described above, when the wavelength of the incident light is changed, the output of the light passing through the analyzer 5 changes periodically, but in the present embodiment, attention is paid to the cycle of the output fluctuation with respect to the wavelength. That is, in order to know the most important B value as the characteristic of the polarization-maintaining single-mode fiber 1, if the fiber length L is precisely measured, the B value can be obtained by measuring the wavelength difference for one cycle of the output fluctuation. You can know exactly. This is because it is clear from Equation 2 above that the wavelength difference is the product of B and L. For laser wavelength measurement, the femtometer (10
The accuracy of ^-15 m) is obtained, and the measurement accuracy of the B value can be improved depending on the measurement accuracy of the fiber length. On the other hand, even if there is a fiber that is known to have a certain B value and it is desired to measure the fiber length L, the value of the fiber length L can be known if the product of B and L is obtained by the above method. .

(Embodiment of claim 6) Next, an embodiment of the optical component assembling apparatus according to claim 6 will be described. The configuration is the same as that listed in claim 1. Variable wavelength light source 3
The light incident from propagates through the fiber 1, passes through the connector 2 and the analyzer 5 in this order, and only light having a certain polarization plane determined by the angle of the analyzer 5 passes through the analyzer 5 and is received by the photodetector 60. The light is received and its intensity is detected. A holder 8 is attached to the analyzer 5 under precise angle control so that the connector 2 held by the holder 8 can be rotated together with the analyzer 5 about the waveguide axis of the fiber 1. ing. Therefore, when the wavelength of the light emitted from the variable wavelength light source 3 is changed, the detected intensity changes periodically as a function of the wavelength. At this time, it is desirable that the B value is fixed as much as possible and operated in a short time so that the B value does not change due to temperature or stress. Multi-electrode DBR-L as variable wavelength light source 3
If D is used, the wavelength can be controlled independently of the output by changing the combination of currents injected into the electrodes of the LD, continuous wavelength sweeping is possible, and the wavelength shift is 1
Since it can be completed within μ seconds, the data shown in FIGS. 6 and 7 can be instantaneously measured. This measurement is performed by setting the analyzer 5 at a certain angle, and when the amplitude is grasped, the analyzer 5 is then slightly rotated to set a different angle, and the relationship between the wavelength and the output is examined again. At this time, if the amplitude is larger, the analyzer 5 is rotated in the opposite direction, and if it is smaller, it is further rotated in the same direction. When this work is repeated, the angle finally converges to 0. This is the state of θo = 0 °, and if an adhesive is injected into the joint between the fiber 1 and the connector 2 in this state, a polarization-preserving main shaft 14 of the fiber 1 and a connector-attached fiber in which the directions of the connector 2 are aligned are obtained. Can be made. As shown in FIG. 1B, a series of operations uses a step motor with a communication function to rotate the analyzer 5, and the light receiver 60 and the wavelength tunable light source 3 can also be controlled through the communication function. If it is used, the calculation / control means such as a personal computer is used to transmit the setting of the wavelength to control the light source, receive the intensity signal of the light from the light receiver 60 for the wavelength at that time, and calculate the amplitude. It is also possible to rotate the step motor to check the change in the amplitude, and repeat these operations until the amplitude is minimized to automatically adjust the angle.

(Embodiment of Claim 7) Next, an embodiment of an apparatus for assembling the optical component supporting means 8 and the analyzer 5 with good angle control will be described. The configuration is the same as that listed in claim 2. That is, the connector 2 fixed accurately is fitted into the holder 8 to which the fiber 1 having the emitting end 30 is to be attached to fix the whole, and the holder 8 is rotatably temporarily fixed to the analyzer 5. Then, the light of the variable wavelength light source 3 is made incident from the incident end 31 of the fiber 1, and it is observed how the intensity of the light passing through the analyzer 5 changes with respect to the wavelength. The analyzer 5 and the holder 8 are fixed at such an angle.
Alternatively, the analyzer 5 is rotated with respect to two or more certain wavelengths, and the holder 8 is fixed according to the angle at which the detected intensities become equal.

(Embodiment of claim 8) Next, an example of an angle evaluation apparatus for the polarization-maintaining optical fiber 1 and the optical component 2 according to claim 8 will be described. The main constituent elements are the same as those recited in claim 3. However, in this example, the incident end 31 of the fiber 1 is
The light of the variable wavelength light source 3 is incident from the above, and the angular deviation between the connector 2 attached to the output end 30 and the polarization preserving main axis 14 of the fiber 1 is evaluated. A holder 8 whose angle is accurately controlled is attached to the analyzer 5,
It is assumed that the connector 2 held by the holder 8 exactly matches the angle with the analyzer 5. Of the light incident from the variable wavelength light source 3, only light having a specific polarization plane is received by the light receiver 60 by the analyzer 5, and the intensity thereof is detected. As described above, when the wavelength tunable light source 3 is controlled to change the wavelength, the intensity of the detected light changes and the light intensity periodically changes as a function of the wavelength. If the amplitude of the fluctuation is 0, it can be seen that the polarization preserving main axis 14 of the fiber and the direction of the connector 2 are completely the same, and if they are not 0, they are deviated. In order to estimate the magnitude of the deviation, the angle between the analyzer 5 and the holder 8 is changed under precise control, the angle at which the amplitude becomes 0 is searched for, and the difference from the original angle is checked to determine the polarization plane. The misalignment between the storage spindle 14 and the connector 2 is shown. Further, the incident end 31 of the variable wavelength light source 3
Polarization plane preservation spindle 14 between the polarization direction of light and the fiber 1
The angle with the direction of
Θo can also be estimated by sweeping. If both are combined, accurate measurement with less error becomes possible. In either method, the rotating unit is controlled by a step motor having a communication function, and the variable wavelength light source 3 and the light receiver 60 also have a communication function. It is needless to say that if is controlled, high-speed and accurate work can be performed.

(Embodiment of Claim 9) Next, an embodiment of the apparatus for evaluating the mounting angle between the means 8 for supporting the optical component and the analyzer 5 will be described. The configuration is the same as that listed in claim 4. That is, the fiber 1 having the connector 2 which is fixed with high precision at the emitting end 30 is fitted into the holder 8 to be evaluated, and the light of the tunable light source 3 enters from the incident end 31 of the fiber 1 and passes through the analyzer 5. Observing how the intensity of the light fluctuates with respect to the wavelength, the angles are correct if there is no periodic fluctuation with respect to the wavelength, and the angles are deviated if there is fluctuation. The magnitude of the deviation can be estimated from the calculation by the above-mentioned formula 2 by accurately grasping the angle on the incident side or by sweeping the incident angle. Alternatively, the angle of the analyzer 5 is swept with respect to light of two or more wavelengths, and the deviation is obtained with an absolute reference being an angle at which the detection intensity does not change even if the wavelengths differ.

(Embodiment of claim 10) Next, an example of a characteristic evaluation device for a polarization-maintaining optical fiber according to claim 10 will be described. In this example, it is assumed that the connector 2 is not provided. The configuration is almost the same as that listed in claim 2. The emitting end 30 of the fiber 1 is rotatably held with respect to the analyzer 5, and is arranged so that the emitted light from the fiber 1 enters the analyzer 5. However, rotating the fiber 1 is not preferable because it may cause fluctuations in the B value.
It is better to use an analyzer that can be rotated with as much control as possible. As described above, when the wavelength of the incident light is changed, the intensity of the light passing through the analyzer 5 changes periodically with respect to the wavelength. If the wavelength is changed in the finest steps possible and the amount of wavelength difference in one period of fluctuation is obtained with respect to the fiber whose fiber length L is accurately known, the B value can be calculated by the above-mentioned formula 2. In order to improve the measurement accuracy, the analyzer 5 may be rotated and the analyzer may be adjusted to an angle at which the amplitude of the intensity fluctuation is as large as possible. Further, by using an arithmetic means such as a personal computer, it is possible to regress the obtained data into a function to obtain a more reliable numerical value. It goes without saying that the fiber length L of a fiber having a clear B value can be measured with the same configuration and formula.

[0051]

The following effects can be obtained by using the relationship between the wavelength and the intensity of emitted light in the polarization-maintaining optical fiber discovered by the inventor of the present invention. First, it becomes possible to quantitatively grasp the deviation of the mounting angle between the polarization-maintaining main axis of the polarization-maintaining optical fiber and the optical component by the numerical value of the fluctuation of the light intensity, and the accurate mounting can be performed with good reproducibility. I can do it now. In addition, it became possible to perform the work quickly and easily by automatically controlling the entire device. Secondly, it became possible to accurately grasp the attachment angle between the polarization-maintaining optical fiber and the optical component. Thirdly, it has become possible to measure the characteristics (B value, length) of the polarization-maintaining optical fiber in a short time with high accuracy and by a method that can be easily automated.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of the present invention.

FIG. 2 is a diagram showing the dependence of TE / TM on θi.

FIG. 3 is a diagram showing θo dependence of TE / TM.

FIG. 4 is a diagram showing comparison between measured data and calculated values.

FIG. 5 is a calculation model diagram for explaining the operation of the present invention.

FIG. 6 is a calculation result diagram illustrating the operation of the present invention.

FIG. 7 is a calculation result diagram illustrating the operation of the present invention.

FIG. 8 is a schematic diagram of an SC connector and a panda fiber.

[Explanation of symbols]

 1 Polarization-maintaining optical fiber. 2 Optical parts. 3 Wavelength variable light source. 4 Rotating means. 5 Analyzer. 6 Measuring device. 7 Means for fixing at a desired angle. 8. Supporting means. 9 Analyzer angle control means. 10 Data processing / device control means. 11 cores. 12 Stress applying part. 13 Clad. 14 Polarization preservation axis. 15 Analyzer direction. 16 panda fiber. 30 Emitting end. 31 Entrance end. 60 Light receiver.

Claims (10)

[Claims] 1. A step of preparing a light source for generating light having a finite extinction ratio with a variable wavelength, and mounting the light source on one end of a polarization-maintaining optical fiber and around the axis of the polarization-maintaining optical fiber. Holding the optical component and the analyzer at a predetermined angle and rotatably mounting them, injecting the light from the light source into the other end of the polarization-maintaining optical fiber, and the wavelength of the light from the light source. And measuring the intensity of light that has passed through the optical component and the analyzer while rotating the optical component and the analyzer about the axis of the polarization-maintaining optical fiber, and Fixing the optical component to one end of the polarization-maintaining optical fiber at a desired angle based on the above method. 2. A step of preparing a light source for generating light having a finite extinction ratio and having a variable wavelength, and a light source at one end of the polarization-maintaining optical fiber and around the axis of the polarization-maintaining optical fiber. The means for supporting the component is attached while being held at a predetermined angle with the polarization-maintaining optical fiber, and the analyzer to be attached via the supporting means is rotatably attached around the axis of the polarization-maintaining optical fiber. A step of causing light from the light source to enter the other end of the polarization-maintaining optical fiber; a wavelength of the light from the light source being changed; and the analyzer around the axis of the polarization-maintaining optical fiber. Measuring the intensity of the light that has passed through the supporting means and the analyzer while rotating, and fixing the analyzer to the supporting means at a desired angle based on the intensity of the light. light A method of assembling the goods. 3. A step of preparing a light source for generating light having a tunable extinction ratio and having a variable wavelength, and a light source at one end of the polarization-maintaining optical fiber and around the axis of the polarization-maintaining optical fiber. Holding and attaching the component and the analyzer at a predetermined angle, causing the light from the light source to enter the other end of the polarization-maintaining optical fiber, and changing the wavelength of the light from the light source. A method of detecting a relative angle between a polarization-maintaining optical fiber and an optical component, the optical component and the step of measuring the intensity of light passing through the analyzer. 4. A step of preparing a light source for generating light having a tunable extinction ratio and having a variable wavelength, and a light source at one end of the polarization-maintaining optical fiber and around the axis of the polarization-maintaining optical fiber. Mounting means for supporting the component while holding the polarization maintaining fiber at a predetermined angle, and mounting an analyzer around the axis of the polarization maintaining optical fiber via the supporting means; From the light source to the other end of the polarization-maintaining optical fiber, and changing the wavelength of the light from the light source and measuring the intensity of the light passing through the supporting means and the analyzer. A method of detecting the relative angle between the supporting means and the analyzer. 5. A step of preparing a light source for generating light having a tunable extinction ratio with a variable wavelength, and a step of providing a light source at one end of a polarization-maintaining optical fiber and around an axis of the polarization-maintaining optical fiber. Of the light from the light source to the other end of the polarization-maintaining optical fiber, changing the wavelength of the light from the light source, and changing the wavelength of the light from the light source. A method for measuring the characteristics of a polarization-maintaining optical fiber, including the step of measuring the intensity. 6. A light source (3) which emits light having a finite extinction ratio with a variable wavelength and an optical component to be attached to one end of a polarization-maintaining optical fiber which makes the light incident on the other end thereof. (5) attached at an angle of, and a means (4) for attaching the optical component and the analyzer to one end of the polarization-maintaining optical fiber and rotatably about the axis of the polarization-maintaining optical fiber. ) And changing the wavelength of the light from the light source, and rotating the optical component and the analyzer around the axis of the polarization-maintaining optical fiber, and the intensity of the light passing through the optical component and the analyzer. Assembly of an optical component including a measuring device (6) for measuring the optical component, and means (7) for fixing the optical component to the other end of the polarization-maintaining optical fiber at a desired angle based on an output signal of the measuring device. apparatus. 7. A light source (3) which emits light having a finite extinction ratio and whose wavelength is variable, and a light source (3) attached to one end of a polarization-maintaining optical fiber which makes the light incident on the other end at a predetermined angle. Means (8) for supporting the optical component, means (4) for rotatably mounting the analyzer to be mounted around the axis of the polarization-maintaining optical fiber to the means for supporting, and Measuring means (6) for changing the wavelength and measuring the intensity of the light passing through the analyzer while supporting the analyzer while rotating the analyzer around the axis of the polarization-maintaining optical fiber, and the measurement. An apparatus for assembling an optical component, comprising means (7) for fixing the analyzer at a desired angle to the supporting means based on an output signal of the apparatus. 8. A light source (3) which emits light having a finite extinction ratio with a variable wavelength, and a polarization-maintaining light at one end of a polarization-maintaining optical fiber which makes the light incident on the other end. An analyzer (5) attached at a predetermined angle to an optical component attached around the axis of the fiber, and changing the wavelength of light from the light source, and the intensity of light passing through the optical component and the analyzer. A detector for detecting the relative angle between the polarization-maintaining optical fiber and the optical component, including a measuring device (6) for measuring 9. A light source (3) which emits light having a finite extinction ratio with a variable wavelength, and a polarization-maintaining light at one end of a polarization-maintaining optical fiber which makes the light incident on the other end. An analyzer (5) attached to a means for supporting an optical component attached at a predetermined angle around the axis of the fiber, and a means for changing and supporting the wavelength of light from the light source and the analyzer. A detection device for detecting a relative angle between a means for supporting an optical component and a analyzer, which includes a measuring device (6) for measuring the intensity of the transmitted light. 10. A light source (3) which emits light having a finite extinction ratio and having a variable wavelength, and a polarization-maintaining optical fiber at one end of the polarization-maintaining optical fiber which enters the light at one end. An analyzer (5) mounted at a predetermined angle around the axis of, and a measuring device (6) for changing the wavelength of light from the light source and measuring the intensity of light passing through the analyzer.
A polarization-maintaining optical fiber characteristic measuring device including and.