JPH04145401A - Light variable delay device - Google Patents

Abstract

PURPOSE:To change the propagation delay time of an optical signal only by the control of a uniaxial direction and to offer a small-sized and simple device by integrating and fixing an input optical fiber and a collimating lens, and an output optical fiber and a condenser lens in a primary cylinder and a secondary cylinder, respectively. CONSTITUTION:The optical signal outputted from the input optical fiber 11 which is fixed in a primary sleeve 15 is converted into the parallel rays of light by the collimating lens 12 which is fixed in the sleeve 15 and propagated in the space of the primary cylinder 17, then condensed by the condenser lens 13 which is fixed in a secondary sleeve 16 and inputted in the output optical fiber 14 which is fixed in the sleeve 16. In order to adjust a delay distance, an adjusting nut 19 is rotated in a desired direction. The locking ring 192 of the nut 19 is rotatably held by the guides 182 and 183 of the secondary cylinder 18. The cylinder 17 is moved in an axial direction by having the guiding groove 171 guided on the guiding rail 181 of the cylinder 18. Thus, the spatial propagation distance of the parallel rays of light by the lens 12 is adjusted.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to a light beam that changes the distance between a collimating lens and a condensing lens that face each other, that is, the spatial propagation distance of parallel light, only by parallel movement in the -axis direction. This invention relates to a variable delay device.

(Prior Art) FIG. 2 is a diagram schematically showing the configuration of a conventional variable optical delay device. In Fig. 2, 1 is an input optical fiber, 2 is a collimating lens, 3 is a condensing lens, 4 is an output optical fiber, 5 is a primary fine movement table, 6 is a secondary fine movement table, 7 is a tertiary fine movement table, and 8 is a fourth fine movement table. Next is the micro-motion table. Here, the primary fine movement table 5 to the fourth fine movement table 8 are arranged in the translational direction of Xe'l-2 in the orthogonal coordinate system set in FIG. The angular direction of θ2 is controllable, and is adjusted so that the collimating lens 2 converts the light into parallel light and the condensing lens 3 condenses the light with low loss.

In such a configuration, an optical signal propagates through the input optical fiber 1 fixed to the primary fine movement table 5 and output from one end face of the input optical fiber 1, which is transmitted through the collimating lens 2 fixed to the secondary fine movement table 6.
is converted into parallel light.

The optical signal converted into parallel light by the collimating lens 2 is propagated through space and then condensed by the condensing lens 3 fixed to the tertiary fine movement table 7 again.

This focused optical signal is input to the output optical fiber 4 fixed to the quaternary fine movement table 8, and after propagating through the output optical fiber 4, is output.

In this configuration, the primary fine movement table 5 and the secondary fine movement table 6 (or
By moving the tertiary fine movement table 7 and the quaternary fine movement table 8) by the same distance in two directions and changing the spatial propagation distance of parallel light,
It functions as an optical variable delay device using input/output fibers 1 and 4 as input/output terminals.

(Problems to be Solved by the Invention) However, the conventional variable optical delay device described above requires four 6-axis fine movement tables, which has the disadvantage that the overall configuration becomes large.

Furthermore, since it is necessary to move two fine movement tables when adjusting the delay distance, there is a drawback that readjustment of the optical system is required.

The present invention has been made in view of the above circumstances, and its purpose is to provide a small and simple optical variable delay device that can change the propagation delay time of an optical signal by controlling only in the -axis direction. be.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an input optical fiber for transmitting an input optical signal, and converts the optical signal emitted from the input optical fiber into parallel light. a collimating lens; a primary sleeve that fixes the input optical fiber and the collimating lens; and a primary cylinder with the primary sleeve fixed near one end surface so that parallel light from the collimating lens travels toward the other end surface. , a secondary cylinder having an outer diameter smaller than the inner diameter of the primary cylinder inserted from the other end surface side of the primary cylinder, a condensing lens for condensing parallel light from the collimating lens, and the condensing lens. an output optical fiber for outputting the light condensed by the condenser lens, and fixing the condensing lens and the output optical fiber;
The apparatus also includes a secondary sleeve fixed to one end surface of the secondary cylinder, and a position adjustment mechanism for adjusting the relative positions of the primary cylinder and the secondary cylinder in the axial direction.

(Function) According to the present invention, the input optical fiber and the collimating lens, and the output optical fiber and the condensing lens are integrated by the primary sleeve and the secondary sleeve, respectively. Further, these two sleeves are fixedly mounted on a primary cylinder and a secondary cylinder, which are cylinders having different large and small diameters, respectively.

At this time, the primary sleeve and the secondary sleeve are inserted into the primary cylinder such that the input and output end surfaces of the collimating lens and the condensing lens face each other.

This insertion depth is adjusted only on the cylindrical axis by the position adjustment mechanism, thereby changing the spatial propagation distance of the parallel light by the collimating lens.

(Embodiment) FIGS. 1 and 3 are diagrams showing an embodiment of the optical variable delay device according to the present invention, and FIG. 1 is a cross-sectional view showing the overall configuration;
FIG. 3 is an enlarged perspective view of a primary cylinder and a secondary cylinder according to the present invention.

In the figure, 11 is an input optical fiber, and 12 is a collimating lens, which converts the optical signal output from the input optical fiber 11 into parallel light. A condenser lens 13 condenses the parallel light produced by the collimator lens 12.

Reference numeral 14 denotes an output optical fiber, into which the optical signal focused by the condensing lens 13 is inputted to one end and outputted from the other end.

Reference numeral 15 denotes a primary sleeve, on one end of which the output end of the collimating lens 12 is terminated and fixed so that their axes coincide with each other, and the input end of the collimating lens 12 and one end of the input optical fiber 11 are arranged to face each other. One end of the input optical fiber 11 is fixed.

Reference numeral 16 denotes a secondary sleeve, on one end of which the input end face of the condenser lens 13 is terminated and fixed so that the input end face of the condenser lens 13 closely matches each other, and the output end face of the condenser lens 13 and the output optical fiber 14 are fixed.
One end side of the output optical fiber 14 is fixed such that one end surface of the output optical fiber 14 faces each other.

Reference numeral 17 denotes a primary cylinder, which has an inner diameter larger than the outer diameter of the primary sleeve 15, and has a guide rail 181 of a secondary cylinder 18, which will be described later, in the longitudinal direction from one end side to the other end side of the inner wall in a direction parallel to the axis. A guide groove 171 is formed to guide the guide. Further, a thread groove 172 is formed extending from the center of the outer wall to the end surface on the other end side, and is engaged with a thread groove 191 of an adjustment nut 19, which will be described later.

On one end side of this primary cylinder 17, a primary sleeve 15 is provided.
The collimator lens 12 is inserted and fixed so that the axes thereof coincide with each other and the output end surface of the collimator lens 12 faces the opening on the other end side.

A secondary cylinder 18 has an outer diameter slightly smaller than the inner diameter of the primary cylinder 17, and has a guide groove 171 of the primary cylinder 17 in the longitudinal direction extending from one end of the outer wall to the vicinity of the other end. A guide rail 181 for guiding is formed. Further, guides 182 and 183 are formed on the other end side edge and on the edge edge of the guide rail 181 to rotatably lock a locking ring 192 of an adjustment nut 19, which will be described later.

On one end side of this secondary cylinder 18, a secondary sleeve 16 is provided.
The axes are made to coincide with each other, and the termination surface and one end surface of the condenser lens 13 are terminated and fixed.

Reference numeral 19 denotes an adjustment nut, which has a threaded groove 191 that threads into the threaded groove 172 of the primary cylinder 17 from one end to the center, and has guides 182 and 183 of the secondary cylinder 18 at the other end.
A locking ring 192 is formed to be locked to.

Next, a method of assembling the variable optical delay device shown in FIG. 1 will be explained.

First, the input optical fiber 11 and collimating lens 12 are fixed at predetermined positions on the primary sleeve 15 and integrated, and the output optical fiber 14 and the condensing lens 13 are fixed at predetermined positions on the secondary sleeve 16 and integrated. become

Next, the primary sleeve 15 is inserted from one end side of the primary cylinder 17 so that the output end surface of the collimating lens 12 faces the opening on the other end side and the axes coincide with each other, and the primary sleeve 15 is placed in a predetermined position.
For example, it is fixed with adhesive.

Also, insert the secondary sleeve 16 from the other end side of the secondary cylinder 18, terminate the end surface with the condenser lens 13 and one end surface, and use adhesive so that the axes coincide. Fix it.

Next, the secondary cylinder 18 is connected to the primary cylinder 17 from the other end side, and the collimating lens 1 fixed to the primary cylinder 17 side is
The condenser lens is inserted so that the output end face of No. 2 and the input end face of the condenser lens face each other.

Next, the screw groove 191 and the screw groove 17 of the primary cylinder 17 are inserted so as to cover the adjustment nut 19 from the other end of the secondary cylinder 18.
2 are screwed together, the locking ring 192 is positioned approximately at the center of the guide 183 of the secondary cylinder 18 and the other end surface, and then the guide 182 is attached to the periphery of the other end of the secondary cylinder 18. Assembly is complete.

Next, the operation of the above configuration will be explained.

An optical signal propagating through the input optical fiber 11 fixed to the primary sleeve 15 and output from one end face thereof is converted into parallel light by the collimating lens 12 also fixed to the primary sleeve 15 .

The optical signal converted into parallel light by the collimating lens 12 is propagated through the space along the central axis of the primary cylinder 17, and then condensed by the condensing lens 13 fixed to the secondary sleeve 16 again. This focused optical signal is input from one end of the output optical fiber 14, which is also fixed to the secondary sleeve 16, and is output from the other end after propagating through the output optical fiber 14.

Here, when adjusting the delay distance, use the adjustment nut 19.
Rotate it in the desired direction. At this time, adjust nut 19
The locking ring is connected to the guide 182 of the secondary cylinder 18 and the guide 1
83, so that the adjusting nut 1
9 freely rotates around the outer periphery of the secondary cylinder 18 at a fixed position.

Thereby, the guide groove 171 of the primary cylinder 15 is guided by the guide rail 181 of the secondary cylinder 18, and the primary cylinder 15 moves in the axial direction. As the primary cylinder 15 moves in the axial direction, the distance between the output end surface of the collimating lens 12 and the input end surface of the condensing lens 13 becomes smaller or larger.

In this way, the spatial propagation distance of the parallel light through the collimating lens 12 is adjusted to an arbitrary value.

As explained above, according to this embodiment, the input optical fiber 11, the collimating lens 12, and the output optical fiber 1
4 and the condensing lens 13 are integrated, and these are fixed to the partial cylinder 17 and the secondary cylinder 18, so the spatial propagation distance of parallel light can be changed simply by adjusting the axis direction, which is different from the conventional method. As in, x, y, z, θ1. A fine movement table for position adjustment in the θ2 direction is not required. Therefore, there are advantages in that adjustment is easy and the optical system can be significantly downsized.

Here, the effect of miniaturization of this optical system is expressed by variable delay distance (L
) 5 cm and will be quantitatively considered below.

First, in the conventional technology shown in Fig. 2, the dimensions of the four fine movement tables (X direction x y direction x z direction) are at least 5 cm
(To) About X5cgo. Therefore, variable delay distance L
= 5 cm, the optical system will be large, about 5 cgn x 5 cm x 25 cm, even if the diameter of the lens is ignored.

On the other hand, in this example, there is no large mechanism such as a fine movement table, and the size of the optical system is L = 5ca, which reduces the loss of parallel light.
It is determined by the diameter of the lens for propagating space.

This loss is due to the diameter spread (dD) of parallel light due to diffusion: dD=(λ/D)−L (λ: wavelength, D: diameter of parallel light, L: parallel light propagation distance). In order to keep the loss low (dD/
D) is suppressed to a few %, λ = 1.3 μm, L = 5
If it is cm, then D=1 angle. Therefore, in this embodiment, a Greenrod lens with a diameter of about 1 cm can be used, and the diameter of the cylinder can be about 1 cm at most.

Therefore, in this embodiment, the entire optical system is 1 crnX1
csX10csn, and the volumetric capacity can be reduced to about 1/60 compared to the conventional technology.

(Effects of the Invention) As described above, according to the present invention, the human-powered optical fiber and the collimating lens are integrated into the primary sleeve, the output optical fiber and the condensing lens are integrated into the secondary sleeve, and these are integrated into the hollow cylinder. Since it is fixed to the secondary cylinder, the spatial propagation distance of parallel light can be changed simply by adjusting the -axis direction.

Therefore, there are advantages in that it is easy to adjust the spatial propagation distance of the optical signal converted into parallel light by the collimating lens, and the optical system and, in turn, the apparatus can be significantly downsized.

[Brief explanation of drawings]

tJ1 is a sectional view showing an embodiment of the optical variable delay device according to the present invention, FIG. 2 is a configuration diagram of a conventional optical variable delay device, and FIG. 3 is an enlarged view of the primary cylinder and secondary cylinder according to the present invention. FIG. In the figure, 11... Input optical fiber, 12... Collimating lens, 13... Condensing lens, 14... Output optical fiber, 15... Primary sleeve, 16... Secondary sleeve, 17 ... - Missing cylinder, 18 ... Secondary cylinder, 19 ... Adjustment nut.

Claims (1)

[Scope of Claims] An input optical fiber for transmitting an input optical signal, a collimating lens for converting the optical signal output from the input optical fiber into parallel light, and a primary lens for fixing the input optical fiber and the collimating lens. a primary cylinder in which the primary sleeve is fixed near one end surface so that the parallel light from the collimating lens travels toward the other end surface; and a primary cylinder inserted from the other end surface side of the primary cylinder. a secondary cylinder having an outer diameter smaller than the inner diameter; a condensing lens for condensing the parallel light from the collimating lens; and an output optical fiber for outputting the light condensed by the condensing lens; fixing the condenser lens and the output optical fiber, and
A variable optical delay characterized by comprising: a secondary sleeve fixed to one end surface side of a secondary cylinder; and a position adjustment mechanism for adjusting the relative position of the primary cylinder and the secondary cylinder in the axial direction. Device.