CN202025159U

CN202025159U - Optical circulator with compact structure

Info

Publication number: CN202025159U
Application number: CN2011201379657U
Authority: CN
Inventors: 王冬寒; 徐云兵; 蔡宏铭; 王健; 林锦绣; 陈斯杰; 林斌
Original assignee: Photop Technologies Inc
Current assignee: Photop Technologies Inc
Priority date: 2011-05-04
Filing date: 2011-05-04
Publication date: 2011-11-02
Anticipated expiration: 2021-05-04

Abstract

The utility model discloses an optical circulator with a compact structure. A three-port optical circulator provided by the embodiment of the utility model comprises a single-optical fiber collimating device and a double-optical fiber collimating device, double refraction crystal, a half-wave plate, and magneto-optical crystal, wherein a beam loop circuit part adopts a special polarization dispersion prism formed through bonding two pieces of wedge double refraction crystal with mutually perpendicular optical axes, so as to effectively replace a Wollaston prism or a ridge prism, realize specific angle matching of the double-optical fiber collimating device, facilitate adjustment, and effectively improve finished product ratio. Meanwhile, the entire optical circulator requires few elements, is convenient to process, and has a small size, so that the structure is more compact and the stability is excellent. The utility model further comprises a four-port circulator employing the special polarization dispersion prism.

Description

A kind of compact type optical circulator

Technical field

The utility model relates to the optical passive component of optical fiber telecommunications system, relates in particular to a kind of compact type optical circulator.

Background technology

Optical circulator is a kind of nonreciprocity optical passive component, and it can make light signal only along the port sequential delivery of regulation, has a wide range of applications at optical communication field.For the polarization independent type optical circulator, people such as Matsumoto and Fujii just did a large amount of research as far back as late nineteen seventies to the early 1990s, proposed multiple structure, they all are the characteristics of non-reciprocity that utilize magneto-optical crystal, adopt discrete birefringece crystal of polylith and optically-active element to form.Fig. 1 is a kind of typical structure of optical circulator, is designed by M.Koga.It can be divided into branch actinic light (D﹠amp; M) 104,105, polarization converted (P﹠amp; O) 102,103 and light beam loop component (BCC) 101 three parts, wherein divide actinic light 104,105 and light beam loop component 101 can adopt polarization spectroscope (PBS) or birefringece crystal, the polarization converted parts often are made up of reciprocity and nonreciprocity optical rotation plate, the nonreciprocity optical rotation plate can use the magneto-optical crystal of palpus externally-applied magnetic field or carry the magneto-optical crystal in magnetic field, and the reciprocity optical rotation plate can use half-wave plate or natural gyrotropi crystal.

In the design in early days, each input/output terminal all adopts a single fiber collimating apparatus 106, makes the oversize of entire device, makes difficulty, poor stability.The thought that is used for circulator with alternative two the single fiber collimating apparatuss of a double-fiber collimator has well solved the problems referred to above.But because input and output two light beams of double-fiber collimator and not parallel, but have a specific angle, therefore all using one in these circulators is parallel element with this intersection light beam school.In some patents in early days, place a roof prism or one and half height prism wedge or wollaston prisms at A place, the position of structure shown in Figure 1, they all are used for directional light is produced an angle that mates with double-fiber collimator, and the single fiber collimating apparatus that two of left end can be arranged in parallel replaces with a double-fiber collimator like this.But roof prism used herein and prism wedge, two light beams that are coupled are incided respectively on the different logical light faces, this needs the incidence point spacing of two light beams bigger, therefore the birefringece crystal required size that uses in the light beam loop component is longer, and very high to light beam incidence point status requirement.Adopting wollaston prism is to have utilized the polarization characteristic of light beam in the loop, but amount of crystals increases stability decreases.

Summary of the invention

The purpose of this utility model is to provide a kind of compact conformation that is applied in the optical system, good stability, the novel optical circulator of being convenient to regulate.

For achieving the above object, the technical scheme that the utility model proposed is: a kind of compact type optical circulator is characterized in that comprise: input/output port comprises a double-fiber collimator 201 and a single fiber collimating apparatus 212; Divide the actinic light parts, comprise a pair of YVO4 birefringece crystal 202,211; The optically-active parts comprise two cover magneto-optical crystal 205,208 and four half-wave plates 203,204,209,210; The light beam loop component comprises the polarization splitting prism that is formed by two birefringent wedge crystal 2s, 06,207 bonding; The optical axis of described two birefringent wedge crystal 2s 06,207 is orthogonal; Described light beam loop component is three port light beam loop components.Perhaps described I/O mouth also can be made of two double-fiber collimators, and described light beam loop component is changed to four port light beam loop components, can constitute the optical circulator of four ports.

Further, the staggered coupling angle of the angle of wedge of described polarization splitting prism and optical axis azimuth angle alpha, β, γ, θ and double-fiber collimator is complementary.

Preferably, in three-port circulator, α=5.4 °, β=4.0 °, γ=5.0 °, θ=48 °; In four-port circulator, α=3.63 °, β=2.85 °, γ=5.0 °, θ=88 °.

Further, place the light beam loop component in the middle of the described two cover magneto-optical crystals 205,208; Described a pair of YVO4 birefringece crystal 202,211 lay respectively at two cover magneto-optical crystals 205,208 two ends, separately near an end face of magneto-optical crystal 205,208 respectively viscose glue two half-wave plates 203,204 are arranged, 209,210, the other end of one of them birefringece crystal 202 and double-fiber collimator 201 couplings, another birefringece crystal 211 and single fiber collimating apparatus 212 couplings.

The utility model mainly utilizes a branch of linearly polarized light to have the principle of different refractivity in the birefringece crystal of the same race of different optical axis directions, design philosophy with walk-off type birefringece crystal and wollaston prism combines cleverly, and the special angle light beam of double-fiber collimator output can be matched well.It as the light beam loop component in the optical circulator, in conjunction with dividing actinic light, polarization converted parts, has been realized a kind of optical circulator simple for structure.The required component number of this circulator entire device is few, easy to process, and size is little, make its compact conformation, good stability, be convenient to regulate.

Description of drawings

Fig. 1 is the circulator theory structure synoptic diagram of prior art;

Fig. 2 is the structure vertical view of the utility model circulator;

Fig. 3 is the structure side view of the utility model circulator;

Fig. 4 is that the polarization state of the utility model circulator changes synoptic diagram;

Fig. 5 is the polarization splitting prism synoptic diagram of the utility model embodiment three-port circulator;

Fig. 6 is the polarization splitting prism synoptic diagram of the utility model embodiment four-port circulator.

Embodiment

Below in conjunction with the drawings and specific embodiments, the utility model is described further.

As Fig. 2 or shown in Figure 3, the utility model circulator comprises a single fiber collimating apparatus 212(TEC optical fiber cable), YVO4 birefringece crystal 211, half-wave plate 209,210, magneto-optical crystal 208, birefringent wedge crystal 2 07, birefringent wedge crystal 2 06(optical axis and birefringent wedge crystal 2 07 optical axis be orthogonal), magneto-optical crystal 205, half-wave plate 203,204, YVO4 birefringece crystal 202, a double-fiber collimator 201(TEC optical fiber cable).

Fig. 2 is a theory structure vertical view of the present utility model, and Fig. 3 is its side view.The light path of this structure relates to the change of polarization state.When the light of random polarization state when 1 port is imported, the polarization state of each mark position is seen Fig. 4 (a) among Fig. 3; When light when 2 ports are imported, the polarization state of each mark position is seen Fig. 4 (b) among Fig. 2.From the light of the random polarization state of port one input through birefringece crystal 202, the polarization state horizontal separation of wherein orthogonal two kinds of compositions comes, 203,204 is half-wave plate, this two bunch polarization polarization surface is rotated counterclockwise 45 ° (see Figure 34 a) 2.), then by magneto-optical crystal 205, make this two bunch polarized light be rotated in a clockwise direction 45 ° respectively, that orthogonal so originally two bundle polarization polarization state of light become is parallel (see Fig. 4 (a) 3.).Because this moment, the relative birefringent wedge crystal 2 06 of polarization state of two-beam was an o light, and birefringece crystal 207 is an e light relatively, is level through superrefraction with the transmission direction school under original oblique, and then through identical optically-active structure, the polarization state of two light beams is vertical again, is combined into a branch of single fiber collimating apparatus 212 receptions that are through birefringece crystal 211.After the light process optical rotation plate group 208,209,210 of port 2 inputs, because magneto-optic has characteristics of non-reciprocity, obtain two perpendicular bunch polarized lights of 4. polarization state with Fig. 4 (a) (see figure (b) 4.), the relative birefringece crystal 207 of this two bunch polarized light is an o light, relatively birefringent wedge crystal 2 06 be an e light, has angle after superrefraction output and from the input beam of port one.As shown in Figure 5, be the polarization splitting prism synoptic diagram of three-port circulator, calculate the angle of wedge beta, gamma of birefringent wedge crystal 2 06 and the azimuth angle theta of birefringece crystal 207 optical axises, α, for example α=5.4 °, β=4.0 °, γ=5.0 °, θ=48 ° ,The coupling angle of itself and double-fiber collimator is complementary.The emergence angle ω 1=ω 2 of light behind two birefringent wedge crystal exports light like this and will from port 3 outputs, finally realize the loop transfer function of circulator well for double-fiber collimator 201 receives.

Be illustrated in figure 6 as the polarization splitting prism synoptic diagram of four-port circulator, in four port polarization splitting prisms, the optical axis of first birefringent wedge Amici prism 301 is parallel with surface level, and the optical axis of the optical axis of second Amici prism 302 and first Amici prism 301 is orthogonal, and the deviation of any beam split angle promptly takes place at the plane of incidence.Calculate the corresponding angle of wedge and optical axis position angle, for example α=3.63 °, β=2.85 °, γ=5.0 °, θ=88 ° ,The angle of input and output optic angle degree and double-fiber collimator is complementary, can realizes the loop transfer function of four-port circulator.

Although specifically show and introduced the utility model in conjunction with preferred embodiment; but the those skilled in the art should be understood that; in the spirit and scope of the present utility model that do not break away from appended claims and limited; the various variations that the utility model is made are protection domain of the present utility model in the form and details.

Claims

1. a compact type optical circulator is characterized in that, comprising: input/output port comprises a double-fiber collimator and a single fiber collimating apparatus; Divide the actinic light parts, comprise a pair of YVO4 birefringece crystal; The optically-active parts comprise two cover magneto-optical crystal and four half-wave plates; The light beam loop component comprises the polarization splitting prism that is formed by two birefringent wedge crystal bondings; The optical axis of described two birefringent wedge crystal is orthogonal; Described light beam loop component is the polarization splitting prism of three port light beam loop components.

2. a kind of compact type optical circulator as claimed in claim 1 is characterized in that: described I/O mouth comprises two double-fiber collimators; Described light beam loop component is the polarization splitting prism of four port light beam loop components.

3. a kind of compact type optical circulator as claimed in claim 1 or 2 is characterized in that: the staggered coupling angle of the angle of wedge of described polarization splitting prism and optical axis azimuth angle alpha, β, γ, θ and double-fiber collimator is complementary.

4. a kind of compact type optical circulator as claimed in claim 1 is characterized in that: place the light beam loop component in the middle of the described two cover magneto-optical crystals; Described a pair of YVO4 birefringece crystal lays respectively at the two ends of two cover magneto-optical crystals, separately near an end face of magneto-optical crystal respectively viscose glue two half-wave plates are arranged, the other end of one of them birefringece crystal and double-fiber collimator coupling, another birefringece crystal and single fiber collimating apparatus coupling.

5. a kind of compact type optical circulator as claimed in claim 3 is characterized in that: in the three-port circulator, and the described angle of wedge and optical axis azimuth angle alpha=5.4 °, β=4.0 °, γ=5.0 °, θ=48 °.

6. a kind of compact type optical circulator as claimed in claim 3 is characterized in that: in the four-port circulator, and the described angle of wedge and optical axis azimuth angle alpha=3.63 °, β=2.85 °, γ=5.0 °, θ=88 °.