CN203688846U - Three-port light circulator - Google Patents

Abstract

The utility model discloses a three-port light circulator. The three-port light circulator comprises a double-fiber collimator, a first beam splitting/combining crystal, a first polarization converter set, a light beam loop device, a second polarization converter set, a second beam splitting/combining crystal and a single-fiber collimator which are sequentially aligned on a vertical axis of the light circulator, wherein the light beam loop device is a crystal polarization splitting prism formed by a single-block birefringence crystal of which three wedge angle faces are processed and taken as three light through end faces, a light axis of the crystal polarization splitting prism is in an incident face, the light axis of the crystal polarization splitting prism and the vertical axis have an included angle, azimuths of the three light through end faces are alpha1, alpha2 and alpha3, and the azimuth theta of the light axis is in matching with a light beam cross coupling angle beta of the double-fiber collimator. According to the three-port light circulator, the single-block crystal prism is taken as a light loop part, so a light loop device formed by multiple routine optical elements is avoided, and thereby the dimension is reduced, assembly is convenient, product performance is effectively improved, and cost is further reduced.

Description

A kind of three port photocirculators

[technical field]

The utility model relates to the optical passive component of optical fiber telecommunications system, relates in particular to a kind of three port photocirculators.

[background technology]

Three port photocirculators are the optical passive components that include three ports, and light beam, from the first port input of circulator, will be exported from the second port, but can not export from the first port from the light of the second port input, but from the 3rd port output.Optical circulator is arranged on to optical fiber one end, just can makes the two-beam of reverse transmission each other in same optical fiber be separated into different ports in this optical fiber end.Therefore can be by optical channel that originally can only one-way transmission rapidly and very easily become the optical channel of transmitted in both directions, thus increase light transmission capacity at double.Therefore, optical circulator is widely used in the fields such as wavelength division multiplexer, Erbium-Doped Fiber Amplifier (EDFA), optical add/drop multiplexer, dispersion compensator.

The typical structure of optical circulator can be divided into optical splitting/combining apparatus, polarization form converter and light beam loop device three major parts.Wherein, Part I, optical splitting/combining apparatus, is generally the beam splitter that monolithic birefringece crystal is made, and light beam can be divided into the orthogonal linearly polarized light of two bundle polarization states, or by the photosynthetic light beam of restrainting into of the orthogonal linear polarization of two bundle polarization states; The second part is polarization converted device, can be by the polarization state of linearly polarized light perpendicular isolated optical splitting/combining apparatus two bundle polarization states respectively by certain angle rotation.It is made up of two crystal half-wave plates and half Faraday rotation sheet conventionally.No matter Part I and the second part, principle of work, still, from applying, are all shaped, different companies and R&D institution there is no too large difference at these two parts.

The 3rd part is light beam walking along the street device, also be the parts of core the most in optical circulator, it not only needs the light beam of different linear polarization to transmit by different light rebroadcast links, also must be able to make the two-beam of different linear polarization mutually mate with the light beam cross-couplings angle of double-fiber collimator with certain angle simultaneously.Different companies and different R&D institutions, all done sizable work and research to these parts, utilizes different optical elements, or the combination of optical element, completes the function of this part.But some shortcoming inevitably all in actual use.Performance and the cost of product are affected.

The patent of optical circulator aspect is many at present, and optical loop device is wherein all by multiple optical element combination Cheng Ze substantially, as U.S. Pat 6049426A, US6052228A, US6822793B2, they all adopted two independently wollaston prism as light beam go in ring device; Chinese patent ZL01127772.6, adopts a wollaston prism and two optical wedge gusset plate combinations; Chinese patent ZL01263562.6, adopts two polarization splitting prisms that crystal angle of wedge sheet is combined into.These optical loop devices are owing to having adopted multiple optical elements as optical loop device, and its structure is more complicated, and equipment adjustment is also more difficult, and cost is also higher, and reliability is poor.

[summary of the invention]

The purpose of this utility model is just to overcome the above-mentioned shortcoming of existing optical circulator, and a kind of three port photocirculators are provided, and has simplified the structure of light beam loop device, reduces assembly difficulty, improves the reliability of product and reduces costs.

For achieving the above object, the technical solution adopted in the utility model is: a kind of three port photocirculators, comprise the double-fiber collimator on the longitudinal axis that is sequentially arranged in this optical circulator, the first beam splitting/close Shu Jingti, first group of polarization form converter, light beam loop device, second group of polarization form converter, the second beam splitting/close Shu Jingti and single optical fiber calibrator, wherein: described light beam loop component is to have processed three crystal polarization splitting prisms that angle of wedge face forms as three logical light end faces by monolithic birefringece crystal, wherein the first logical light end face and the second logical light end face are positioned at the same end face of this birefringece crystal, threeway light end face is positioned at the other end of this birefringece crystal, and the first logical light end face, the second logical light end face, the position angle of the 3rd smooth end face is respectively α 1, α 2, α 3, the optical axis of this crystal polarization splitting prism has angle in the plane of incidence and with longitudinal axis, is designated as Axis Azimuth angle θ, the azimuth angle alpha 3 of the azimuth angle alpha 1 of described Axis Azimuth angle θ, the first logical light end face, the azimuth angle alpha 2 of the second logical light end face, the 3rd smooth end face matches with the staggered coupling of the light beam angle beta of described double-fiber collimator.

Further, the azimuth angle alpha 3 of the azimuth angle alpha 2 of the azimuth angle alpha 1 of described Axis Azimuth angle θ, the first logical light end face, the second logical light end face, the 3rd smooth end face is determined by following calculating with the relation of the staggered coupling of the light beam angle beta of described double-fiber collimator:

$\mathrm{\&beta;}1:=\mathrm{\&alpha;}1-a\sin [{\left(\frac{{\mathrm{<figure-callout\; id="2"\; label="no"\; filenames="HDA0000457409270000011.png,HDA0000457409270000012.png"\; state="\{\{state\}\}">no</figure-callout>}}^2\&CenterDot;{\mathrm{ne}}^2}{{\mathrm{<figure-callout\; id="2"\; label="no"\; filenames="HDA0000457409270000011.png,HDA0000457409270000012.png"\; state="\{\{state\}\}">no</figure-callout>}}^2\&CenterDot;{\sin \left(\mathrm{\&theta;e}\right)}^2+{\mathrm{ne}}^2\&CenterDot;{\cos \left(\mathrm{\&theta;e}\right)}^2}\right)}^{\frac{1}{2}}\&CenterDot;\sin [\mathrm{\&alpha;}1-(\mathrm{\&theta;e}-\mathrm{\&theta;})\left]\right]$

$\mathrm{\&beta;}2:=a\sin [\mathrm{no}\&CenterDot;\sin [\mathrm{\&alpha;}2-(\mathrm{\&alpha;}3-a\sin \left(\frac{\sin \left(\mathrm{\&alpha;}3\right)}{\mathrm{no}}\right))\left]\right]-\mathrm{\&alpha;}2$

Wherein, the O optical index that no is described birefringece crystal, ne is the refractive index of described birefringece crystal E light, β 1 and β 2 are the emergence angle of light after described crystal polarization splitting prism, and β 1=β 2=β/2, and β/2 are the intersection half-angle of two accurate devices of optical fiber.Wherein, θ _ethe wave vector direction of propagating in described birefringece crystal for E light and the angle of described birefringece crystal optical axis, and θ _ecan try to achieve by following equation:

${\left(\frac{{\mathrm{no}}^2\&CenterDot;{\mathrm{ne}}^2}{{\mathrm{<figure-callout\; id="2"\; label="no"\; filenames="HDA0000457409270000011.png,HDA0000457409270000012.png"\; state="\{\{state\}\}">no</figure-callout>}}^2\&CenterDot;{\sin \left(\mathrm{\&theta;e}\right)}^2+{\mathrm{ne}}^2\&CenterDot;{\cos \left(\mathrm{\&theta;e}\right)}^2}\right)}^{\frac{1}{2}}\&CenterDot;\sin [\mathrm{\&alpha;}3-(\mathrm{\&theta;e}-\mathrm{\&theta;})]:=\sin \left(\mathrm{\&alpha;}3\right)$

Further, the birefringece crystal of described light beam loop component is YVO4 birefringece crystal, and, the Axis Azimuth angle of described crystal polarization splitting prism and the position angle of three logical light end faces are respectively θ=45 °, α 1=4.29 °, α 2=7.28 °, α 3=5.706 ° when the angle of the crossing β=3.0 of the accurate device of two optical fiber °.

Three port photocirculators of the present utility model, owing to adopting monolithic crystal prism as optical loop parts, the optical loop device of having avoided conventional many optical element combination to become, simplify the structure of light beam loop device, reduce size, also be convenient to assembling, effectively improved properties of product, and improved the reliability of product and reduce costs.

[accompanying drawing explanation]

Fig. 1 is the stereographic map of the utility model three port photocirculators.

Fig. 2 is the structure vertical view of the utility model three port photocirculators.

Fig. 3 is the structure side view of the utility model three port photocirculators.

Fig. 4 a and Fig. 4 b are that the polarization state of the utility model three port photocirculators changes schematic diagram.

Fig. 5 is the polarization splitting prism schematic diagram of the utility model embodiment tri-port photocirculators.

[embodiment]

Below in conjunction with accompanying drawing and concrete embodiment, the utility model is described further.

As shown in Figure 1 to Figure 3, the utility model three port photocirculators comprise double-fiber collimator 1 on the longitudinal axis that is sequentially arranged in this optical circulator, the first beam splitting/close Shu Jingti 2, first group of polarization form converter 3, light beam loop device 4, second group of polarization form converter 5, the second beam splitting/close Shu Jingti 6 and single optical fiber calibrator 7.

Wherein:

Described double-fiber collimator 1, one tail optical fiber is the first port A, for the input end of light beam, another tail optical fiber is the 3rd port C, for the output terminal of light beam;

Described the first beam splitting/close Shu Jingti 2, can be made by YVO4 birefringece crystal, for light beam being divided into two bunch polarized lights or being light beam by two bunch polarization combiners;

Described first group of polarization form converter 3, by two half-wave plate 31(32) and a Faraday rotation sheet 33 form, the polarization direction of two bunch polarized lights is rotated respectively;

Described light beam loop component 4 is to have processed three crystal polarization splitting prisms that angle of wedge face forms as three logical light end faces by monolithic birefringece crystal, wherein the first logical light end face 41 and the second logical light end face 42 are positioned at the same end face of this birefringece crystal, the 3rd smooth end face 43 is positioned at the other end of this birefringece crystal, and the first position angle that leads to light end face 41, the second logical light end face 42, the 3rd smooth end face 43 is respectively α 1, α 2, α 3; The optical axis of this crystal polarization splitting prism has angle in the plane of incidence and with longitudinal axis, is designated as Axis Azimuth angle θ; The azimuth angle alpha 3 of the azimuth angle alpha 1 of described Axis Azimuth angle θ, the first logical light end face 41, the azimuth angle alpha 2 of the second logical light end face 42, the 3rd smooth end face 43 matches with the staggered coupling of light beam angle (light beam intersecting angle) β of described double-fiber collimator 1;

Described second group of polarization form converter 5, by two half-wave plate 51(52) and a Faraday rotation sheet 53 form, the polarization direction of two bunch polarized lights is rotated respectively;

Described the second beam splitting/close Shu Jingti 6, can be made by YVO4 birefringece crystal, for light beam being divided into two bunch polarized lights or being light beam by two bunch polarization combiners;

Described single optical fiber calibrator 7, its tail optical fiber is the second port B, for the input/output terminal of light beam.

As shown in Fig. 4 a, Fig. 4 a is the polarization state variation diagram of light beam from the first port A to the second port B transmitting procedure, when light beam is from the light of the random polarization state of the first port A input during through the first beam splitting/close the YVO4 birefringece crystal of Shu Jingti 2, be separated into the orthogonal line polarisation of two bundle polarization states, enter respectively half-wave plate 31 and half-wave plate 32; Half-wave plate 31 and half-wave plate 32 counterclockwise respectively rotate 45 ° by the plane of polarization of this two bunch polarized light along one clockwise one, the polarization state of two bunch polarisations is parallel to each other (see Fig. 4 a 2.) from mutually vertically becoming, then logical light Faraday rotation sheet 5, makes the plane of polarization of this two bunch polarized light all be rotated in a clockwise direction 45 °.After now two-beam enters light beam loop component 4, because its linearly polarized light is E light with respect to the birefringece crystal of light beam loop component 4, through superrefraction, be horizontal light beam output (seeing the forward arrow of Fig. 2) by original light beam school obliquely.And then through identical optically-active structure, the polarization state of two light beams is again vertical, after the second beam splitting/close Shu Jingti 6, second group of polarization form converter 5, be combined into a branch ofly, be that single optical fiber calibrator receives.

As shown in Figure 4 b, Fig. 4 b is the polarization state variation diagram of light beam from the second port B to the 3rd port C transmitting procedure.In the time that light is inputted from the second port B, light is after the second beam splitting/close Shu Jingti 6, second group of polarization form converter 5, because Faraday rotation sheet 53 has characteristics of non-reciprocity, obtain and the orthogonal two bunch polarized lights of 4. polarization state of Fig. 4 a (see Fig. 4 b 4.).This two bunch polarized light is O light with respect to the birefringece crystal of light beam loop component 4, after superrefraction output, and has angle from the input beam of the first port A.

Be illustrated in figure 5 the polarization splitting prism schematic diagram of three port photocirculators, calculate the Axis Azimuth angle θ of birefringece crystal and the azimuth angle alpha 1 of three logical light end faces, α 2, α 3, the coupling angle beta of itself and double-fiber collimator 1 is matched.Its computing formula is as follows:

$\mathrm{\&beta;}1:=\mathrm{\&alpha;}1-a\sin [{\left(\frac{{\mathrm{<figure-callout\; id="2"\; label="no"\; filenames="HDA0000457409270000011.png,HDA0000457409270000012.png"\; state="\{\{state\}\}">no</figure-callout>}}^2\&CenterDot;{\mathrm{ne}}^2}{{\mathrm{<figure-callout\; id="2"\; label="no"\; filenames="HDA0000457409270000011.png,HDA0000457409270000012.png"\; state="\{\{state\}\}">no</figure-callout>}}^2\&CenterDot;\sin {\left(\mathrm{\&theta;e}\right)}^2+{\mathrm{ne}}^2\&CenterDot;\cos {\left(\mathrm{\&theta;e}\right)}^2}\right)}^{\frac{1}{2}}\&CenterDot;\sin [\mathrm{\&alpha;}1-(\mathrm{\&theta;e}-\mathrm{\&theta;})\left]\right]$

$\mathrm{\&beta;}2:=a\sin [\mathrm{no}\&CenterDot;\sin [\mathrm{\&alpha;}2-(\mathrm{\&alpha;}3-a\sin \left(\frac{\sin \left(\mathrm{\&alpha;}3\right)}{\mathrm{no}}\right))\left]\right]-\mathrm{\&alpha;}2$

Wherein, no is the O optical index of the birefringece crystal of described light beam loop component 4, and ne is the refractive index of the birefringece crystal E light of described light beam loop component 4, θ _ethe wave vector direction of propagating in the birefringece crystal of light beam loop component 4 for E light and the angle of this birefringece crystal optical axis, and θ _etried to achieve by following equation:

${\left(\frac{{\mathrm{no}}^2\&CenterDot;{\mathrm{ne}}^2}{{\mathrm{<figure-callout\; id="2"\; label="no"\; filenames="HDA0000457409270000011.png,HDA0000457409270000012.png"\; state="\{\{state\}\}">no</figure-callout>}}^2\&CenterDot;{\sin \left(\mathrm{\&theta;e}\right)}^2+{\mathrm{ne}}^2\&CenterDot;\cos {\left(\mathrm{\&theta;e}\right)}^2}\right)}^{\frac{1}{2}}\&CenterDot;\sin [\mathrm{\&alpha;}3-(\mathrm{\&theta;e}-\mathrm{\&theta;})]:=\sin \left(\mathrm{\&alpha;}3\right)$

β 1 and β 2 are the emergence angle of light after the birefringece crystal of this light beam loop component 4, and β 1=β 2=β/2, and are the intersection half-angle of two accurate devices of optical fiber.The light of output can well receive for double-fiber collimator 1 like this, from the 3rd port C output, finally realize the loop transfer function of optical circulator.

For example, it is the double-fiber collimator of 3.0 ° for the light beam angle of the crossing, and when the birefringece crystal of described light beam loop component is YVO4 birefringece crystal, calculate according to above formula, the optical axis of YVO4 crystal polarization splitting prism and three logical light surface azimuths can be: θ=45 °, α 1=4.29 °, α 2=7.28 °, α 3=5.706 °.Can certainly be the combination of other angle, all can as long as meet the combination of above-mentioned inclusive all combination angles.

In sum, three port photocirculators of the present utility model, owing to adopting monolithic crystal prism as optical loop parts, the optical loop device of having avoided conventional many optical element combination to become, the structure of having simplified light beam loop device, has reduced size, is also convenient to assembling, effectively improve properties of product, and improved the reliability of product and reduce costs.

Below be only the explanation to the utility model embodiment; rather than restriction to protection domain; the change of any unsubstantiality; as change birefringece crystal material; deflection θ, the α 1 of the optical axis in polarization splitting prism and three logical light faces, α 2, α 3 etc., within should dropping on the claim protection domain of the utility model patent.

Claims (3)

1. a port photocirculator, comprise the double-fiber collimator on the longitudinal axis that is sequentially arranged in this optical circulator, the first beam splitting/close Shu Jingti, first group of polarization form converter, light beam loop device, second group of polarization form converter, the second beam splitting/close Shu Jingti and single optical fiber calibrator, it is characterized in that: described light beam loop component is to have processed three crystal polarization splitting prisms that angle of wedge face forms as three logical light end faces by monolithic birefringece crystal, wherein the first logical light end face and the second logical light end face are positioned at the same end face of this birefringece crystal, threeway light end face is positioned at the other end of this birefringece crystal, and the first logical light end face, the second logical light end face, the position angle of threeway light end face is respectively α 1, α 2, α 3, the optical axis of this crystal polarization splitting prism has angle in the plane of incidence and with longitudinal axis, is designated as Axis Azimuth angle θ, the azimuth angle alpha 3 of the azimuth angle alpha 1 of described Axis Azimuth angle θ, the first logical light end face, the azimuth angle alpha 2 of the second logical light end face, the 3rd smooth end face matches with the staggered coupling of the light beam angle beta of described double-fiber collimator.

2. three port photocirculators as claimed in claim 1, is characterized in that: the azimuth angle alpha 3 of the azimuth angle alpha 1 of described Axis Azimuth angle θ, the first logical light end face, the azimuth angle alpha 2 of the second logical light end face, the 3rd smooth end face is determined by following calculating with the relation of the staggered coupling of the light beam angle beta of described double-fiber collimator:

$\mathrm{\&beta;}1:=\mathrm{\&alpha;}1-a\sin [{\left(\frac{{\mathrm{no}}^2\&CenterDot;{\mathrm{ne}}^2}{{\mathrm{no}}^2\&CenterDot;\sin {\left(\mathrm{\&theta;e}\right)}^2+{\mathrm{ne}}^2\&CenterDot;\cos {\left(\mathrm{\&theta;e}\right)}^2}\right)}^{\frac{1}{2}}\&CenterDot;\sin [\mathrm{\&alpha;}1-(\mathrm{\&theta;e}-\mathrm{\&theta;})\left]\right]$

$\mathrm{\&beta;}2:=a\sin [\mathrm{no}\&CenterDot;\sin [\mathrm{\&alpha;}2-(\mathrm{\&alpha;}3-a\sin \left(\frac{\sin \left(\mathrm{\&alpha;}3\right)}{\mathrm{no}}\right))\left]\right]-\mathrm{\&alpha;}2;$

Wherein, the O optical index that no is described birefringece crystal, ne is the refractive index of described birefringece crystal E light, β 1 and β 2 are the emergence angle of light after described crystal polarization splitting prism, and β 1=β 2=β/2, and β/2 are the intersection half-angle of two accurate devices of optical fiber, and, θ _ethe wave vector direction of propagating in described birefringece crystal for E light and the angle of described birefringece crystal optical axis, θ _etry to achieve by following equation:

${\left(\frac{{\mathrm{no}}^2\&CenterDot;{\mathrm{ne}}^2}{{\mathrm{no}}^2\&CenterDot;{\sin \left(\mathrm{\&theta;e}\right)}^2+{\mathrm{ne}}^2\&CenterDot;\cos {\left(\mathrm{\&theta;e}\right)}^2}\right)}^{\frac{1}{2}}\&CenterDot;\sin [\mathrm{\&alpha;}3-(\mathrm{\&theta;e}-\mathrm{\&theta;})]:=\sin \left(\mathrm{\&alpha;}3\right).$

3. three port photocirculators as claimed in claim 2, it is characterized in that: the birefringece crystal of described light beam loop component is YVO4 birefringece crystal, and, the Axis Azimuth angle of described crystal polarization splitting prism and the position angle of three logical light end faces are respectively θ=45 °, α 1=4.29 °, α 2=7.28 °, α 3=5.706 ° when the angle of the crossing β=3.0 of the accurate device of two optical fiber °.

Images