JPS6145232A - Acoustooptic device - Google Patents

Abstract

PURPOSE:To reduce characteristic variation which is caused by stress strain from a fitting part by coupling a housing and the fitting plate with each other by plural arrays of coupling means perpendicular to the lengthwise direction of the housing, and limiting the array width of the coupling means within a specific range. CONSTITUTION:The fitting plate 31 is provided at the outside of the housing 30 where the optical system is fiexed. The housing 30 and fitting plate 31 are coupled with each other by coupling screws 33. The coupling screws are arrayed at right angles to the lengthwise direction of the housing 30 and intervals B of the screw arrays in the housing lengthwise direction are <=1/3 time as large as intervals A of fitting holes 32 used to fix this acoustooptic device to equipment in the housing lengthwise direction. Consequently, the optical system is never strained by stress strain from the fitting part, so characteristic variation is reduced to stabilize the performance and improve the reliability.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an acousto-optic device.

(Conventional structure and its problems) Acousto-optic elements that utilize the light diffraction phenomenon caused by ultrasonic waves have traditionally been used by inputting light beams radiated into space, but in recent years, with the development of optical fibers, An acousto-optic device was proposed in which light is input through an optical fiber and transmitted light and diffracted light are extracted from another optical fiber.
A prototype is being produced.

Figure 1 shows a structural diagram of an acousto-optical device that inputs and outputs light through an optical fiber.l is an input terminal for ultrasonic excitation energy, and 2 is an input terminal for ultrasonic excitation energy input from input terminal 1 to an ultrasonic transducer. This is an impedance matching section for efficiently sending the signal to 3. 4 is an acousto-optic medium;
An ultrasonic transducer 3 is bonded to the ultrasonic transducer 3, and an ultrasonic reflecting surface 5 is provided to prevent ultrasonic waves from being reflected along the same path as surfaces 7a and 7b through which light enters and exits. Further, 6 indicates a region where ultrasonic waves exist.

Light is first input from the input optical fiber 8.

The light beam is shaped after passing through the input light coupling optical element 9, enters the light entrance surface 7a of the acousto-optic medium 4, and reaches the region 6 where the ultrasonic waves are present. At this time, if the angle between the normal to the incident light wavefront and the ultrasonic wavefront matches θ given by the following equation, the diffracted light 15
occurs.

θ, 4λ/(2nA) λ: Incident light wavelength n: Refractive index of the acousto-optic medium A: Ultrasonic wavelength The diffraction light 15 is guided to the diffraction optical fiber 12 via the diffraction light coupling optical element 13. Further, when the ultrasonic wave is not present in the light transmission region, the diffracted light 15 is not generated and the transmitted light 14 is guided to the transmitted light output optical fiber 10 via the transmitted light coupling optical element 11. Further, the ultrasonic reflecting surface 5 is arranged so that the ultrasonic waves emitted from the ultrasonic transducer 3 are reflected on the opposing surface and do not return along the same path and disturb the normal optical diffraction phenomenon.

When attempting to manufacture an acousto-optic device that inputs and outputs light using an optical fiber as described above, the acousto-optic device is housed in one housing, and the input optical fiber 8 that inputs light into the acousto-optic device is housed in one housing. Input light coupling optical cable 91 diffraction light output optical fiber 2, diffraction light coupling optical element 13. The transmitted light output optical fiber 101, the transmitted light coupling optical element 11, etc. are arranged and fixed, but in such an acousto-optic 8 device, the maximum performance depends on the accuracy of setting the mechanical positional relationship between the constituent parts. That's the point.

Even if each component part is placed and fixed with sufficient accuracy during manufacturing, when the casing is actually attached to the equipment and used, the casing may experience distortion characteristics due to stress from the mounting parts. This was a problem from a practical point of view because it caused a lot of heat.

(Object of the Invention) In view of the above-mentioned drawbacks, an object of the present invention is to provide an acousto-optic device in which changes in characteristics caused by distortion of the casing due to stress from the part to which the acousto-optic device is attached are very small. shall be.

(Structure of the Invention) In order to achieve this object, the acousto-optic device of the present invention includes an input optical fiber, an input light coupling optical element, an acousto-optic element, a transmitted light output optical fiber, a transmitted light coupling optical element,
It has a housing for fixing the diffraction light coupling optical element and the diffraction light output optical fiber, and a mounting plate provided on the outside of the housing,
The casing and the mounting plate are connected by a plurality of rows of connecting means arranged perpendicularly to the longitudinal direction of the casing, and the array width of the connecting means is such that the width of the arrangement is such that the mounting plate is connected to the mounting plate for mounting the acousto-optic device. It has a structure in which the spacing between the mounting means provided on the plate is 173 or less.

With this configuration, it is possible to realize an acousto-optic device in which changes in characteristics caused by stress strain from the mounting portion are extremely small, which is a problem when the acousto-optic device according to the present invention is actually used.

(Description of Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a plan view of the internal configuration of an acousto-optic device according to an embodiment of the present invention, FIG. 3 is a side view, and FIG. 4 is a bottom view.

2, 3, and 4, 21 is an acousto-optic element, 24 is an input optical fiber, and 25 is an input optical fiber 2.
4 is an input optical coupling optical element for coupling the light guided to the acousto-optic element, 23 is an input terminal for ultrasonic excitation energy for driving the acousto-optic element, and 22 is an impedance matching part through which Ultrasonic excitation energy is supplied to the acousto-optic element.

The light transmitted through the acousto-optic element is guided to the transmitted light output optical fiber 29 via the transmitted light coupling optical element 28,
On the other hand, the diffracted light generated by the acousto-optic element is guided to the diffracted light output optical fiber 27 via the diffracted light coupling optical elements 26a and 26b, which include one or more input optical fibers, input light coupling optical elements, and acousto-optic elements. , a transmitted light coupling optical element, a transmitted light output optical fiber, a diffracted light coupling optical element, and a diffracted light output optical fiber are fixed to the housing 30. Further, a mounting plate 31 is provided on the outside of the casing, and the casing and the mounting plate are connected by connecting screws 33. However, the connecting screws are connected by a row of screws arranged perpendicularly to the longitudinal direction of the casing, and the interval A between the rows of screws in the longitudinal direction of the casing is 1 for fixing the acousto-optic device according to the present invention to a device. The following condition is satisfied for the above-mentioned distance B in the longitudinal direction of the housing between the mounting holes 32 used in the process.

(A/B)≦(1/3) (Effects of the Invention) As described above, according to the present invention, when fixing the acousto-optic device SEI, . . . Since the bending moment generated by The practical effects of having high reliability and performance stability as a new functional device are significant.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an acousto-optic device that inputs and outputs light through an optical fiber, FIG. 2 is a plan cross-sectional view of an acousto-optic device according to an embodiment of the present invention, FIG. 3 is a side view of the same, and FIG. The figure is a bottom view of the same. 21... Acousto-optic element, 22... Impedance matching section, 23... Input terminal for ultrasonic excitation energy, 2
4... Input optical fiber, 25... Input light coupling optical element, 26a, 26b... Diffractive light coupling optical element,
27... Diffraction light output optical fiber, 28... Transmitted light coupling optical element, 29... Transmitted light output optical fiber, 3
o...Housing, 31...Mounting plate, 32...Mounting hole,
33...Connecting screw. Figure 1 Figure 2

Claims (2)

[Claims] (1) An acousto-optic element having a transducer for ultrasonic excitation in a part of an acousto-optic medium, an input optical fiber that guides incident light, and a light emitted from the input optical fiber that is shaped into the acousto-optic medium. an input light coupling optical element that enters, a transmitted light coupling optical element for guiding the light transmitted through the acousto-optic element to the transmitted light output optical fiber, and a transmitted light coupling optical element for guiding the light diffracted by the acousto-optic element to the diffracted light output optical fiber. a diffractive light coupling optical element, the acousto-optic element, the input optical fiber, the input light coupling optical element, the transmitted light output optical fiber, the transmitted light coupling optical element, the diffraction light output optical fiber, and the diffraction light coupling optical element. and a mounting plate provided on the outside of the housing, the housing and the mounting plate being coupled by a plurality of rows of coupling means arranged perpendicularly to the longitudinal direction of the housing. Construction of acousto-optic device. (2) The acousto-optic device according to claim 1, wherein the arrangement width of the coupling means is 1/3 or less of the interval between the mounting means for mounting the acousto-optic device.