CN1547048A - Tunable Fabri-Paro cavity filter and preparation method thereof - Google Patents

Abstract

The invention is a kind of tunable Fabry-Perot cavity filter and the manufacturing method. The filter includes an input fiber, an output fiber, a cylinder shell out of the piezoelectric ceramic pipe, the upper and the subjacent ends of the cylinder shell has a upper cover and a subjacent cover, one end of the piezoelectric ceramic pipe is connected to the subjacent cover; another end and the upper cover are adhered with a piece of equal plating lens; the upper and the subjacent cover have a light out hole and a light-in hole, there sets a piece of collimating lends on the upper cover and the subjacent cover, the lens are at the holes. The collimate lends and the fibers are fixed, two pieces of parallel plating lens are pasted on the upper cover and the piezoelectric ceramic pipe; the piezoelectric ceramic pip is connected to the subjacent cover directly; the cylinder shell is fixed on the subjacent cover; the upper cover is fixed at the piezoelectric ceramic pipe tightly. The invention uses fiber collimator and high reverse lends plated lends to form a Fabry-Perot cavity, to replace the fiber end surface plating, reduces the difficulty and the cost.

Description

Tunable Fabry-Perot cavity filter and its preparation method

technical field

The invention relates to an optical device, in particular to a tunable Fabry-Perot cavity filter and a preparation method.

technical background

In recent years, as the preparation technology of fiber gratings has become more mature, it is easy to form large-scale production, and people's research on optical sensing has become more in-depth and extensive. Because the fiber grating sensor has a compact structure, it is easy to integrate and embed measurement, and it uses intrinsic wavelength coding for the sensing information, which is free from electromagnetic noise and light intensity fluctuations, and it is easy to use multiplexing (wavelength division, time division, space division) The technology realizes the quasi-distributed multi-point measurement of various sensing quantities (stress, temperature, strong magnetic field, etc.), and has broad application prospects in the safety monitoring of civil, aviation, ship, electric power and petroleum fields. However, the high cost of the system due to the difficulty in demodulating wavelength-coded signals limits its popularization and application. At present, the methods and devices for encoding and demodulating wavelength signals include: matched fiber grating filter method, unbalanced Mach-Zehnder interferometer method, edge filter method, and tunable Fabry-Perot cavity method. Among them, the tunable Fabry-Perot cavity (FFPF) method uses a single optical fiber and utilizes multi-beam interference, which has the advantages of small insertion loss, good sensitivity, high light energy utilization rate, and simple operation. However, the currently used tunable Fabry-Perot cavity method is formed by inserting two optical fibers coated on the end face into a glass capillary. Since the outer diameter of the optical fiber is 125 μm and the diameter of the capillary is 200 μm, it is necessary to insert the optical fiber It is very difficult to ensure that the coated end face of the optical fiber is not damaged in the glass capillary, and the process of coating the end face of the optical fiber is also very complicated, so its manufacturing process is complicated and the cost is high, which limits its application.

Contents of the invention

The technical problem to be solved by the present invention is to provide a tunable Fabry-Perot cavity filter with simple structure, simple production process, low cost and stable performance and its production method.

The technical solution of the present invention to solve the technical problem is: a tunable Fabry-Perot cavity filter, comprising an input optical fiber, an output optical fiber, a piezoelectric ceramic tube and a cylindrical shell placed outside the piezoelectric ceramic tube, The upper and lower ends of the cylindrical shell have an upper cover and a lower cover respectively; one end of the piezoelectric ceramic tube is connected to the lower cover, and the other end and the inner wall of the upper cover are respectively pasted with a piece of coated lens parallel to each other; the upper and lower covers have light holes respectively. and the light inlet, a collimating lens is respectively installed on the outer walls of the upper cover and the lower cover, and the collimating lens is located at the positions of the light outlet and the light inlet.

The preparation method of the present invention is as follows: the collimating lens and the incident and outgoing optical fibers are respectively fixed on the fixtures on both sides of the cylindrical shell through a small sleeve to ensure the coaxiality of the two sections of optical fibers; Paste on the upper cover and the piezoelectric ceramic tube; connect the piezoelectric ceramic tube vertically to the lower cover, pay attention to the alignment of the center hole; fasten the cylindrical shell on the lower cover with screws; tighten the upper cover with screws Fixed on the piezoelectric ceramic tube.

The working principle of the present invention is: after the input optical fiber passes through the optical fiber collimator, it becomes equal light and enters two parallel mirrors coated with a high reflection film, that is, the Fabry-Perot cavity, and reflects back and forth in it to form multi-light interference. The transmitted light after the Fabry-Perot cavity is collected into the output fiber by the fiber collimator and output. At the same time, the ceramic tube formed by stacking multi-layer ring-shaped piezoelectric ceramics is pasted behind the coated lens for cavity length tuning, so as to obtain the function of wavelength tuning.

The present invention uses an optical fiber collimator and a Fabry-Perot cavity formed by coating a high-reflection film lens to replace the coating on the end face of the optical fiber, which reduces the difficulty and cost of the manufacturing process, so the production process is simple and the cost is low. The inventive device has high cost performance and can be widely used in optical fiber sensing systems.

Description of drawings

Fig. 1 is the structural representation of the present invention

specific implementation plan

As shown in the figure, a tunable Fabry-Perot cavity filter includes an input optical fiber 10, an output optical fiber 1, a ceramic tube 6 and a cylindrical shell 5 that is sleeved on the ceramic tube, and on the cylindrical shell 5 , the lower end has upper cover 4 and lower cover 7 respectively, and one end of ceramic tube 6 links to each other with lower cover 7; The other end of ceramic tube 6 and the inner wall of upper cover 4 are respectively pasted a piece of coated lens 11,12 parallel to each other; There are a light exit hole 3 and a light entry hole 8, and a collimator lens 2, 9 is respectively installed on the outer walls of the upper cover 4 and the lower cover 7, and the collimation lenses 2, 9 are respectively located at the positions of the light exit hole 3 and the light entry hole 8.

The preparation method of the present invention is: fix the collimating lens 2, 9 and the incident optical fiber respectively on the clamps on both sides of the barrel-shaped casing 5 through a small sleeve to ensure the coaxiality of the two sections of optical fiber; The coated lenses 11 and 12 are attached to the upper cover 4 and the piezoelectric ceramic tube 6 respectively; the piezoelectric ceramic tube 6 is vertically connected to the lower cover 7, paying attention to the alignment of the center hole; the barrel-shaped shell 5 is fastened by screws On the lower cover 7; the upper cover 4 is fastened on the piezoelectric ceramic tube 6 by screws.

Claims (2)

1, a kind of tunable Fabry-Perot cavity wave filter is characterized in that described wave filter comprises input optical fibre, output optical fibre, piezoelectric ceramic tube and is enclosed within the outer cylindrical housing of piezoelectric ceramic tube, and the cylindrical housing upper and lower end has loam cake and lower cover respectively; One end of piezoelectric ceramic tube links to each other with lower cover, and its other end and loam cake inwall are pasted the coequal plated film lens of a slice respectively; Light hole and light well are arranged respectively on the upper and lower cover, on loam cake and following cover outer wall a slice collimation lens is housed respectively, collimation lens is positioned at light hole and light well position.

2, the described tunable Fabry of a kind of production claim 1-Perot cavity filtered method is characterized in that: with collimation lens with go out incident optical and be separately fixed on the anchor clamps on cylindrical housing both sides by a small casing, guarantee the right alignment of two sections optical fiber; Two plated film lens that are parallel to each other are affixed on respectively on loam cake and the piezoelectric ceramic tube; Piezoelectric ceramic tube is vertically connected on down covers, focal point hole involutory; Cylindrical housing is fastened on down by screw covers; Loam cake is fastened on the piezoelectric ceramic tube by screw.