CN204101811U - Adjustable optic fibre F-P wave filter - Google Patents

Abstract

The utility model relates to a kind of adjustable optic fibre F-P wave filter, comprise physical construction, piezoelectric ceramics, input optical fibre and output optical fibre, it is parallel relatively that input optical fibre and output optical fibre are fixed on physical construction upper surface, and form resonator cavity, it is characterized in that: fix piezoelectric ceramics by integrated machine structure and keep the resonator cavity that input optical fibre and output optical fibre are formed.Described input optical fibre and output optical fibre are single-mode fiber.The beneficial effects of the utility model are: because physical construction is integrated machining, ensure that the stability of structure and long-term durable row, also increase to the optically-coupled precision with input optical fibre and output optical fibre.

Description

Adjustable optic fibre F-P wave filter

Art

The utility model relates to a kind of adjustable optic fibre F-P (Fabry-Perot) wave filter.

Background technology

In Fiber Optical Communication System, need the wavelength to transmitting optical signal, power and signal to noise ratio (S/N ratio) to measure in real time. adjustable optic fibre F-P wave filter be in Fiber Optical Communication System in a Primary Component. its principle of work utilizes resonance effects, the light of the specific wavelength only allowing wideband light source to send transmits to low-loss in a fiber, and the light of other wavelength of filtering.

Meanwhile, adjustable optic fibre F-P wave filter is also the core devices of Fibre Optical Sensor demodulating system, for differentiating the wavelength variations of Fibre Optical Sensor return signal, thus realizes the fast demodulation of optical fiber sensing system.

Existing a kind of optical fibre Fabry-perot (Fabry-Perot) wave filter is made up of two single-mode fibers, piezoelectric ceramics and physical constructions, as shown in Figure 1, reflectance coating is coated with at the parallel relative end face of single-mode fiber, single-mode fiber is fixed on mechanical parts, piezoelectric ceramics two ends are also connected on mechanical parts, and input optical fibre and output optical fibre are aimed at and formed resonator cavity.Stretched by triangular wave or sawtooch sweep control circui piezoelectric ceramics and change the object that cavity length reaches change projection wavelength.Because physical construction and piezoelectric ceramics are that the form of adhesion is so be exactly inevitably the stability problem of the endurance issues brought such as glue long-term creep and optical fiber alignment.

Solve the problem to overcome, permanance on holding structure and stability, the structure of another kind of adjustable filter as shown in Figure 2, in such an embodiment, the as a whole materials processing of physical construction forms, this ensure that the precision of processing, and be fixedly completed by the elastic construction of physical construction itself between physical construction and piezoelectric ceramics.Because the creeping property of solid metal itself is significantly smaller than any bonded adhesives, so just overcome structural permanance and stability problem like this.

Utility model content

The purpose of this utility model is to provide a kind of adjustable optic fibre F-P (Fabry-Perot) wave filter, overcomes the deficiency of above-mentioned aspect in existing product.

The purpose of this utility model is achieved through the following technical solutions:

A kind of adjustable optic fibre F-P (Fabry-Perot) wave filter, comprise physical construction, piezoelectric ceramics, input optical fibre and output optical fibre, it is parallel relatively that input optical fibre and output optical fibre are fixed on physical construction upper surface, and form resonator cavity, it is characterized in that: fix piezoelectric ceramics by integrated machine structure and keep the resonator cavity that input optical fibre and output optical fibre are formed.

Described input optical fibre and output optical fibre are single-mode fiber.

The end face of described input optical fibre and output optical fibre plates high-reflecting film through polishing.

The reflectivity of highly reflecting films is between 99.0%-99.9%.

The beneficial effects of the utility model are:

1, because physical construction is that a block of material overall processing forms and ensure that machining precision;

2, due to piezoelectric ceramics and physical construction is fixedly completed by the elastic part of physical construction, so do not worry the permanance that the creep effect brought by glue bond causes and stability problem.

Accompanying drawing explanation

With reference to the accompanying drawings the utility model is described in further detail below.

Fig. 1 is the structural representation of a kind of wave filter of the prior art;

Fig. 2 is the structural representation of embodiment in adjustable optic fibre F-P (Fabry-Perot) wave filter described in the utility model embodiment;

Embodiment

Embodiment

As shown in Figure 2, a kind of adjustable optic fibre F-P (Fabry-Perot) wave filter described in the utility model embodiment, comprise input optical fibre 3 and output optical fibre 4, input optical fibre 3 and output optical fibre 4 are single-mode fiber, input optical fibre 3 is parallel with the end face of output optical fibre 4 relatively, and form resonator cavity, piezoelectric ceramics 2 is provided with in the resonator cavity be made up of input optical fibre 3 and output optical fibre 4, the end face of described input optical fibre 3 and output optical fibre 4 is through polishing, and high-reflecting film 5 is directly coated with on end face, the reflectivity of highly reflecting films 5 is between 99.0%-99.9%, the interval between two highly reflecting films 5 is regulated to reach the wavelength regulating transmitted light by the voltage that changes on piezoelectric ceramics 2.

Optical fiber filter is made up of single-mode fiber, and the opposing end surface of optical fiber grinds to form high-quality surface, and two surfaces of catoptron are aligned to a completely parallel resonator cavity, are referred to as Fabry-Perot Etalon.This resonator cavity has wavelength selection function, and when a branch of broad band light beam incides in this resonator cavity, only have the light of some special wavelength could through resonator cavity, from another root beam projecting, and the light of other wavelength is all repelled by resonator cavity, through peak be referred to as free spectral range through peak-to-peak wavelength interval, (FSR:Free Spectrum Range):

$\mathrm{FSR}=\frac{{\mathrm{\λ}}^2}{2\mathrm{nd}}---\left(1\right)$

The size of free spectral range determines primarily of the refractive index n of the distance d between two catoptrons and medium therebetween. (1), in formula: λ is wavelength, for air dielectric, n=1, free spectral range then can be expressed as:

FSR＝λ ²/2d (2)，

Change the size that spacing d just can change FSR, namely can change the position of transmitance.

Piezoelectric ceramics (PZT) is used to the distance between fine setting two catoptrons; When adding that a sawtooth voltage is on piezoelectric ceramics, just can be through the continuous scanning of rate, becoming adjustable Fabry-Perot Etalon wave filter.Overall with BW (Band Width) between the half-shadow of transmitance can be similar to the ratio of free spectral range and be denoted as:

FSR/BW＝F (3)，

F is a constant, and be referred to as acutance (Finesse), it determines primarily of the reflectivity R of reflective coating:

$F=\frac{\mathrm{\π}\sqrt{R}}{1-R}---\left(4\right)$

Different reflectivity determines different acutancees, for the fiber Fabry-Perot filter with specific reflectance, free spectral range be certain with the ratio of transmitance live width, so these two amounts can not independently be chosen.

The present invention fixes input optical fibre 3 and output optical fibre 4 and piezoelectric ceramics 2 and reaches by designing a kind of reliable and stable physical construction 1 and improve the stability of whole device and the object of long-term reliability.

Claims (5)

1. an adjustable optic fibre F-P wave filter, comprise physical construction (1), piezoelectric ceramics (2), input optical fibre (3) and output optical fibre (4), it is parallel relatively that input optical fibre (3) and output optical fibre (4) are fixed on physical construction (1) upper surface, and form resonator cavity, it is characterized in that: fix piezoelectric ceramics (2) by integrated machine structure (1) and keep the resonator cavity that input optical fibre (3) and output optical fibre (4) are formed.

2. adjustable optic fibre F-P wave filter according to claim 1, is characterized in that: described input optical fibre (3) and output optical fibre (4) are single-mode fiber.

3. adjustable optic fibre F-P wave filter according to claim 1 and 2, is characterized in that: fix piezoelectric ceramics (2) by integrated machine structure (1) and keep the resonator cavity that input optical fibre (3) and output optical fibre (4) are formed.

4. adjustable optic fibre F-P wave filter according to claim 3, is characterized in that: described input optical fibre (3) and output optical fibre (4) are coated with highly reflecting films (5).

5. adjustable optic fibre F-P wave filter according to claim 3, is characterized in that: the reflectivity of described highly reflecting films (5) is between 99.0%-99.9%.