CN104729494A - Resonant hollow-core photonic crystal fiber gyroscope and application - Google Patents

Abstract

The invention discloses a resonant hollow-core photonic crystal fiber gyroscope and application. The resonant hollow-core photonic crystal fiber gyroscope is composed of a hollow-core photonic crystal fiber, a fiber coupler, a light source, a photoelectric detector A and a photoelectric detector B; the hollow-core photonic crystal fiber and the fiber coupler form a resonant cavity, meanwhile, the light source, the photoelectric detector A and the photoelectric detector B are connected with the fiber coupler through a pigtail, and thus, an integral gyroscope optical path is formed. Compared with the existing resonant fiber gyroscope, the resonant hollow-core photonic crystal fiber gyroscope provided by the invention has the advantages of simple structure, miniatured size and strong adaptive capacity to environment.

Description

A kind of resonant mode hollow photonic crystal fiber gyroscope and application

Technical field

The present invention proposes a kind of resonant mode hollow photonic crystal fiber gyroscope, relate to photonic crystal fiber, optical fibre gyro instrument, especially resonance type optical fiber gyro field.

Background technology

Interference type optical fiber gyroscope is a kind of all solid state gyroscope instrument, have that reliability is high, the life-span be long, dynamic range is large, vibrate insensitive, volume is little, lightweight, be applicable to the feature produced in enormous quantities, and very high precision can be reached.But when in the face of engineer applied, optical fibre gyro also also exists the shortcomings such as environmental sensitivity is excessive, especially when outside exists temperature variation, the performance index of optical fibre gyro often will decline an order of magnitude.By structure optimization and the winding method improving fiber optic loop, and improve input scheme and take outer shield component, environmental suitability can be solved to a certain extent, but also bring a series of accessory problems such as cost is high, volume is large, quality is heavy, power consumption is high, start-up time is long, reliability is low simultaneously.

Resonance type optical fiber gyro is integrated with the advantage of laser gyro and interference type optical fiber gyroscope, and can form gyro light path with shorter optical fiber, when equal accuracy, its fiber lengths is only 1/10 ~ 1/100 of interfere type, and size also can be less than laser gyro.

But resonance type optical fiber gyro does not still realize mass production at present, hinder its main cause to high precision and practical development to comprise non-linear Kerr effect, the drift that the STRESS VARIATION caused by temperature causes and random polarization are coupled the polarization nonreciprocity caused.

In laser gyro, light beam transmits in the resonator cavity of vacuum, therefore there are not the problems referred to above, and interference type optical fiber gyroscope can adopt wide spectrum light source effectively to suppress Kerr effect and the nonreciprocal error of polarization.But in current resonance type optical fiber gyro, but lack suitable solution always because resonator cavity itself is made up of real core fibre, Kerr effect, polarization coupled impact and temperature sensitivity all excessive, additional upper light source adopts narrow-linewidth laser light source, and these problems can be made more serious.

Summary of the invention

In order to break through existing resonance type optical fiber gyro engineer applied and practical on bottleneck, the object of this invention is to provide a kind of resonance type optical fiber gyro based on hollow-core photonic crystal fiber and application.

The present invention is based on the Bragg diffraction principle of hollow-core photonic crystal fiber.Specifically, light beam does not transmit in media as well, but transmits in atmosphere, thus the impact of environment on optical fiber is limited in extremely low scope.

Technical scheme of the present invention is as follows:

A kind of resonant mode hollow photonic crystal fiber gyroscope, hollow-core photonic crystal fiber, fiber coupler, light source, A photodetector and B photodetector, light source outputs to fiber coupler, clockwise and counterclockwise two-way is divided into transmit, oscillation circuit is formed in hollow-core photonic crystal fiber, one curb loop and is spread into A photodetector clockwise, and another curb loop and spread into B photodetector counterclockwise.

The fibre core of described hollow-core photonic crystal fiber is air or vacuum, dependence Bragg diffraction principle propagation light beam.

Described fiber coupler is 3X2 fiber coupler, light source access port access light source tail optical fiber, A detector access port access A photodetector tail optical fiber, B detector access port access B photodetector tail optical fiber, one end of A optical fiber input port access hollow-core photonic crystal fiber, the other end of B optical fiber input port access hollow-core photonic crystal fiber; Coupling eyeglass also containing plating high-reflecting film in fiber coupler, mates with hollow-core photonic crystal fiber and forms resonator cavity.

Described light source is the LASER Light Source of narrow linewidth, high coherence.

Described A photodetector is fiber spectrometer.

Described B photodetector is fiber spectrometer.

Resonant mode hollow photonic crystal fiber gyroscope described in basis obtains a method for annular light path angular velocity of rotation,

Resonance type optical gyroscope resonance frequency difference with the pass of angular velocity of rotation is:

$\mathrm{\Δv}=\frac{4A}{\mathrm{\λL}}\·\mathrm{\Ω}$

In formula, Δ ν is that resonance frequency is poor, and Ω is angular velocity of rotation, and λ is the wavelength in vacuum, the area that A surrounds for resonant optical path, and L is annular light path physical length.

The application of resonant mode hollow photonic crystal fiber gyroscope in inertial navigation field described in a kind of basis.

Beneficial effect of the present invention is: the feature that the present invention utilizes hollow-core photonic crystal fiber guide-lighting in atmosphere, to largely reducing in optical fibre gyro environment to the impact of optical fiber sensing ring; Resonant mode hollow photonic crystal fiber gyroscope compact conformation of the present invention in addition, is conducive to the miniaturization of resonance type optical fiber gyro and practical.

Accompanying drawing explanation

Fig. 1 is the structural representation of resonant mode hollow photonic crystal fiber gyroscope;

Fig. 2 is fiber coupler structure discrete component perspective diagram;

Fig. 3 is fiber coupler Standard body perspective diagram;

In figure, 1 is hollow-core photonic crystal fiber, and 2 is fiber couplers, and 3 is light sources, 4 is A photodetectors, 5 is B photodetectors, and 201 is light source access ports, and 202 is A detector access ports, 203 is B detector access ports, 204 is A optical fiber input ports, and 205 is B optical fiber input ports, and 206 is the coupling eyeglasses plating high-reflecting film.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described.

The resonance type optical fiber gyro that appears as of hollow-core photonic crystal fiber provides a kind of technical scheme.This optical fiber is different from traditional fiber, and light beam is not rely on total reflection principle to transmit in hollow-core photonic crystal fiber, but Bragg diffraction principle.In other words, light beam can fetter in atmosphere by hollow-core photonic crystal fiber, but not in medium.Such benefit is, greatly can reduce the measuring error caused by environmental sensitivity of optical fiber itself, and the high precision for optical fibre gyro exports and provides guarantee.

Principle of work of the present invention is: light source outputs to fiber coupler from tail optical fiber, enters hollow-core photonic crystal fiber, and a curb loop and propagated clockwise, and another curb loop and propagated counterclockwise.According to Sagnac principle, the annular light path of rotation can cause the light path of clockwise and counterclockwise two-way light path to change, thus changes the resonance frequency in two-way light path.Two fiber spectrometers are accessed at the delivery outlet of fiber coupler, detect the spectrum of clockwise light path and counterclockwise light path output light respectively, the angular velocity of rotation of annular light path can be calculated by the frequency-splitting detecting light intensity minimum point (i.e. resonance frequency).

Resonant mode hollow photonic crystal fiber gyroscope proposed by the invention effectively can advance miniaturization and the practicalization of resonance type optical fiber gyro.

Embodiment

With reference to Fig. 1, a kind of resonant mode hollow photonic crystal fiber gyroscope comprises: hollow-core photonic crystal fiber 1, fiber coupler 2, light source 3, A photodetector 4, B photodetector 5.Wavelength be the light source 3 of 1550nm by light source access port 201 input optical fibre coupling mechanism, then input hollow-core photonic crystal fiber 1 by A optical fiber input port 204 and B optical fiber input port 205, coordinate the coupling eyeglass 206 of plating high-reflecting film to form loop checking installation.Export light and enter A photodetector 4 and B photodetector 5 through A detector access port 202 and B detector access port 203.

With reference to Fig. 2,3, fiber coupler 2 is metal aluminum design, and bonding agent or threaded hole can be adopted to encapsulate.Inner coupling eyeglass 206 is for being coated with the smooth glass substrate of metallic reflective coating (as golden film, silverskin etc.).

The light wave that two beam reversals propagate is propagated in annular light path, and a branch of is that a branch of is counterclockwise clockwise.When annular light path is static, for the light that both direction is propagated, its light path is consistent, and this also means that the resonance frequency of two-beam ripple is identical.When annular light path is rotated around the sensitive axes perpendicular to holding plane, due to Sagnac effect, the light wave propagation path that both direction is propagated is no longer equal, defines optical path difference, thus bringing resonance frequency difference, the frequency-splitting detected by two photodetectors calculates angular velocity of rotation.

Resonance type optical fiber gyro resonance frequency difference with the pass of angular velocity of rotation is:

$\mathrm{\Δv}=\frac{4A}{\mathrm{\λL}}\·\mathrm{\Ω}$

In formula, Δ ν is that resonance frequency is poor, and Ω is angular velocity of rotation, and λ is the wavelength in vacuum, the area that A surrounds for annular light path, and L is annular light path physical length.Measure the resonant frequency difference value of annular light path, the velocity of rotation of annular light path can be calculated.

Claims (8)

1. a resonant mode hollow photonic crystal fiber gyroscope, it is characterized in that, it comprises: hollow-core photonic crystal fiber (1), fiber coupler (2), light source (3), A photodetector (4) and B photodetector (5), light source (3) outputs to fiber coupler (2), clockwise and counterclockwise two-way is divided into transmit, oscillation circuit is formed in hollow-core photonic crystal fiber (1), one curb loop and is spread into A photodetector (4) clockwise, another curb loop and is spread into B photodetector (5) counterclockwise.

2. resonant mode hollow photonic crystal fiber gyroscope according to claim 1, is characterized in that, the fibre core of described hollow-core photonic crystal fiber (1) is air or vacuum, dependence Bragg diffraction principle propagation light beam.

3. resonant mode hollow photonic crystal fiber gyroscope according to claim 1, it is characterized in that, fiber coupler (2) is 3X2 fiber coupler, light source access port (201) access light source (1) tail optical fiber, A detector access port (202) access A photodetector (4) tail optical fiber, B detector access port (203) access B photodetector (5) tail optical fiber, one end of A optical fiber input port (204) access hollow-core photonic crystal fiber (1), the other end of B optical fiber input port (205) access hollow-core photonic crystal fiber (1); Coupling eyeglass (206) also containing plating high-reflecting film in fiber coupler (2), mates with hollow-core photonic crystal fiber (1) and forms resonator cavity.

4. resonant mode hollow photonic crystal fiber gyroscope according to claim 1, is characterized in that, described light source (3) is the LASER Light Source of narrow linewidth, high coherence.

5. resonant mode hollow photonic crystal fiber gyroscope according to claim 1, is characterized in that, described A photodetector (4) is fiber spectrometer.

6. resonant mode hollow photonic crystal fiber gyroscope according to claim 1, is characterized in that, described B photodetector (5) is fiber spectrometer.

7. the resonant mode hollow photonic crystal fiber gyroscope according to any one of claim 1 ?6 obtains a method for annular light path angular velocity of rotation, it is characterized in that,

Resonance type optical gyroscope resonance frequency difference with the pass of angular velocity of rotation is:

$\mathrm{\Δ\ν}=\frac{4A}{\mathrm{\λL}}\text{\·\Ω}$

In formula, Δ ν is that resonance frequency is poor, and Ω is angular velocity of rotation, and λ is the wavelength in vacuum, the area that A surrounds for resonant optical path, and L is annular light path physical length.

8. the application of resonant mode hollow photonic crystal fiber gyroscope in inertial navigation field according to any one of claim 1 ?6.