CN2514562Y - Ring optical path device - Google Patents

Abstract

The utility model discloses a three-port circulator with close conformation which is formed by employing a double-fiber collimator, a single-fiber collimator, a double-wedge-angle glass block, a double birefringent crystal, and a Wollaston prism to make pairs. The light input from a port 1 is transformed into single polarized light, and is reflected via a special glass block, and then is refracted by the Wollaston prism, and finally goes into a port 2 by way of a centralized beam. The polarization state caused at the time the light from the port 2 is transmitted to the Wollaston prism is vertical to the polarization state caused at the time the light from the port 1 is transmitted to the same Wollaston prism, and then both the light are refracted via the other end of the Wollaston prism to go into a port 3 by way of a centralized beam. Because the utility model employs the double-fiber collimator, the volume of the whole device realizes miniaturization. The utility model is also characterized by the employment of the small double birefringent crystal, the Wollaston prism and the double-wedge-angle glass block, which can greatly reduce the cost compared with the tranditional circulators which employ large double birefringent crystals, thereby the utility model has great practicality and latent capacities.

Description

A kind of novel circulator

Affiliated technical field

This novel ring of light device field that relates to optical-fibre communications.Optical circulator is widely used at optical-fibre communications fields such as optical fiber bidirectional communication, optical fiber dispersion compensation, image intensifers, especially refers to a kind of tight type, optical circulator cheaply.

Background technology

In optical circulator, pursuit tight type, small size, low-cost configuration are the main trend of various designs recent years.Most typical structure is patent US5909310 (Kwita), and its structure light path principle as shown in Figure 1.

The characteristics of this typical structure are to have adopted wollaston prism and double-fiber collimator, with 1 in traditional circulator design, 2,3 passage independent separate states merge and utilize identical several crystal jointly, materials such as crystal have so not only been saved, and two collimaters of original two ports are merged into a double-fiber collimator, and reduced device volume greatly, realized the tight miniaturization of circulator.But the shortcoming of this typical structure is its cost, because its material therefor costs an arm and a leg, has seriously limited its application.If can effectively reduce its cost, just can be widely used.

Summary of the invention

The purpose of this utility model provides a kind of can significantly reducing cost, and takes into account a kind of novel circulator of its compactness and small size simultaneously.

The purpose of this utility model is achieved in that the three-port circulator that adopts double-fiber collimator, single fiber collimater, folding wedge angle glass blocks, birefringece crystal, wollaston prism pairing to form tight structure.Mainly be that the input light from port one is become single polarisation,, close bundle entry port 2 again by the wollaston prism refraction again through the reflection of special glass piece.Polarization state when polarization state and light from port one incident reach same specific wollaston prism when the light of port 2 incidents reaches wollaston prism is vertical, reflects through the other end of wollaston prism again and closes bundle entry port 3.

Because this novel double-fiber collimator that adopted, so the entire device volume has been realized miniaturization, these novel another part characteristics are to adopt fritter birefringece crystal, wollaston prism and folding wedge angle glass blocks, adopt the bulk birefringece crystal to compare with traditional endless row device, can significantly reduce cost, thereby have very big practical value and potentiality.

Description of drawings

Further describe in conjunction with example and accompanying drawing now

Fig. 1 is existing United States Patent (USP) light channel structure principle;

Fig. 2 (a) is the utility model port one → port 2 light path front views;

Fig. 2 (b) is the utility model port one → port 2 light path vertical views;

Fig. 2 (c) is the utility model port 2 → port 3 light path front views;

Fig. 2 (d) is the utility model port 2 → port 3 light path vertical views;

Fig. 3 (a) is the utility model port one → port 2 part index paths;

Fig. 3 (b) is the utility model port 2 → port 3 part index paths;

Fig. 4 is the utility model mechanical assembly drawing.

Embodiment

This novel principle sees shown in Fig. 2 (a), Fig. 2 (b), Fig. 2 (c), Fig. 2 (d), Fig. 2 (a) wherein, and Fig. 2 (b) is respectively the light path front view of port one → port 2, vertical view.Fig. 2 (c), Fig. 2 (d) is respectively front view, the vertical view of port 2 → port 3.

As Fig. 2 (a) is the light path front view of circulator port one → port 2, arranges light here and can be decomposed into parallel paper of polarization state and two kinds of vertical papers.202,215,201 are optical fiber cable, are respectively port one, port 2, port 3.203 is two optical fiber capillaries, and 204 is lenticule, and 203 and 204 constitute double-fiber collimator, 205 is birefringece crystal, and 206 is faraday's revolving fragment, 207A, 207B is two 1/2 wave plates of splicing mutually, and its optical axis respectively becomes 22.5 ° of angles with the handing-over seam, shown in the 207B of Fig. 2 (a) top.208 is folding wedge angle glass blocks, and 209A, 209B are wollaston prism, 210A, 210B is same 207A, 1/2 wave plate of 207B structure, and its optical axis is for the splicing seams symmetry and become 22.5 ° of angles, 211 is faraday's revolving fragment, 212 is birefringece crystal, and 213 is lenticule, and 214 is the single fiber head, 213,214 constitute the single fiber collimater.

Analysis chart 2 (a) optical path change at first, light enter from port one that double-fiber collimator is collimated to be directional light, will be decomposed into the orthogonal polarised light of two bundles, a branch of parallel paper, a branch of vertical paper from the directional light of collimater outgoing by birefringece crystal 205.Faraday's revolving fragment 206,1/2 wave plate 207A, 207B are combined into one.Wherein, for faraday's revolving fragment 206, frontlighting road direction is seen the time by counterclockwise rotating 45 °, 1/2 wave plate 207A, 207B optical axis direction and between them splicing be seamed into 22.5 °, it is the light of identical polarization direction that this wave plate combined body is restrainted the orthogonal phototransformation of polarization states to two.Fig. 2 (a1) represents the direction of rotation and the 1/2 wave plate 207A of faraday's revolving fragment 206 respectively, the optical axis direction of 207B (along the light path direction of advance), Fig. 2 (a2) represents that respectively light enters faraday's revolving fragment 206 preceding polarization directions, enter faraday's revolving fragment 206 rear polarizer directions and enter 1/2 wave plate 207A, 207B rear polarizer direction, we can be birefringece crystal 205, faraday's revolving fragment 206,1/2 wave plate 207A, 207B makes up A as optical function, can be decomposed into the directional light behind a branch of collimation two bundles and be separated from each other on the spaces, polarization state is identical and perpendicular to the optical function combination of paper.Two-beam is through making up B by folding wedge angle glass blocks 208 and the optical function that wollaston prism 209A, 209B constitute, the identical light light path in front view of this two bundle polarization does not change, be embodied in light path generation deviation in the vertical view 2 (b), describe when this will narrate Fig. 2 (b) below.The identical light of two bundle polarization states passes through 1/2 wave plate 210A, to become the mutual orthogonal polarized light of two bundles behind 210B and the faraday's revolving fragment 211 again, just polarization state is just in time opposite when passing through birefringece crystal 205,210A wherein, 210B is the same 207A of 1/2 wave plate structure, the 207B optical axis direction is also identical, Fig. 2 (a3), represent 1/2 wave plate 210A, the optical axis direction of 210B, the direction of rotation of faraday's revolving fragment 211, Fig. 2 (a4) expression enters 1/2 wave plate 210A, light polarization before the 210B, light beam is by 1/2 wave plate 210A, 210B rear polarizer attitude and by faraday's revolving fragment 211 rear polarizer attitudes.Light arrives birefringece crystal 212 by 1/2 wave plate 210A, 210B and faraday's revolving fragment 211 backs, synthesizes the orthogonal light beam of a branch of polarization state through birefringece crystal 212, shown in Fig. 2 (a).Here can regard 1/2 wave plate 210A, 210B and faraday's revolving fragment 211 as one group of optical function combination C, it is combined into the identical light of two bundle polarizations with the orthogonal light of a branch of polarization state again.213,214 constitute the single fiber collimater, receive the light by birefringece crystal 212.Circulator is realized from port one to port 2 function thus.

We see Fig. 2 (b) again, and this is from vertical view analysis 2 light courses from the port one to the port.Pass the combination of A group optics from the port one emergent light with certain drift angle, from vertical view, going up two-beam separately at Fig. 2 (a) becomes a projection that overlaps here, and deviation does not take place.208 is folding wedge angle glass blocks, and establishing the angle of wedge is γ, and when the port one of double-fiber collimator, 2 advance the light time simultaneously, is θ by A optics combination two-beam angle.Arriving folding wedge angle glass blocks 208 light beams is the light of same polarization state, it enters wollaston prism 209A after the glass blocks total reflection of folding wedge angle, the 209B light beam reflects once more, wollaston prism 209A, the 209B optical axis direction is seen shown in Fig. 2 (b), establishes wollaston prism 209A, and the angle of wedge of 209B is α, refractive index is no and ne, and its relational expression can be written as:

n*sin(arcsin(sin(φ/2)/n)+2*γ)＝sin(θ/2) (1)

φ=arcsin[(n wherein _o-n _e) tan α], n is 208 refractive index.

We are analysis chart 2 (c), two groups of index paths of Fig. 2 (d) again, and its expression light enters the index path that arrives optical fiber 201 (port 3) from optical fiber 215 (port 2).Make up by C group optics from the directional light of capable collimater 213 outgoing of monochromatic light, this moment, C group optics combination function was with identical from the light of the lenticule 204 outgoing optical function during by the combination of A group optics, and the polarization state when frontlighting road direction that different is is seen polarization state and organized optical element by A is just vertical.Promptly for Fig. 2 (c), the parallel paper of its polarization state, just in time perpendicular with the situation of Fig. 2 (a).By the two-beam of C group optics combination, go up direction at Fig. 2 (c) during again by B group optical element and do not change.(Fig. 2 (c1), be respectively along optical path direction and see faraday's revolving fragment 211, direction of rotation and the optical axis direction of 1/2 wave plate 210A, 210B, two-beam was by faraday's revolving fragment 211 preceding polarization directions when three figure among Fig. 2 (c2) were respectively the frontlighting road, by faraday's revolving fragment 211 polarization rears to, by polarisation of light direction behind 1/2 wave plate 210A, the 210B).Light enters the combination of A group optics after making up by B group optics, (two identical light beams of polarization can be converted into the orthogonal optical module of polarization state), be combined into a branch of light through birefringece crystal 205 again and enter lenticule 204, to optical fiber 201, it is port 3, C group function among A group same Fig. 2 of function this moment (a) is promptly closed Shu Zuoyong.Fig. 2 (c3) represents 1/2 wave plate 207A when optical path direction respectively, the direction of rotation of the optical axis direction of 207B and 206 pairs of light polarizations of faraday's revolving fragment, three figure of Fig. 2 (C4) represent that respectively two bundle polarised lights advance 1/2 wave plate 207A, before the 207B, enter 1/2 wave plate 207A, after the 207B and advance light beam polarization direction after faraday's revolving fragment 206.

Fig. 2 (d) expression light is overlooked index path from port 2 inputs during by C group, B group, A group optical element.Similar Fig. 2 of this light path (b), different is by among Fig. 2 (d) during optics combination C polarization state perpendicular to paper, by Wo Lasi prism 209B, the downward deviation of 209A rear polarizer light, again by the folding wedge angle glass blocks 208 back light total reflections deviation that makes progress, behind A, light beam closes bundle and enters optical fiber 1, and promptly port 3.

In conjunction with Fig. 2 (b), 2 (d) as can be seen, the effect of wollaston prism 209A, 209B is in the light path: when light when port one is imported, in Fig. 2 (b), show as parallel paper light, by the time still be parallel paper, upwards be angled to horizon light, when light during from port 2 input, in Fig. 2 (d), show as vertical paper light by the time still be vertical paper, deviation downwards.Like this, the structure of this patent realizes the function of three-port circulator, and promptly the port one port 2; Port 2 ports 3.

This another novel structure is that the folding wedge angle glass blocks 308 of the folding wedge angle glass blocks 208 of the B function combinations among Fig. 2 and wollaston prism 209 usefulness different angles and birefringece crystal 309 are replaced, as shown in Figure 3.Wherein Fig. 3 (a) is the part index path of port one to port 2, and the light that sends from 1/2 wave plate 207 is directional light through glass blocks 308 total reflections of folding wedge angle, and polarization state is parallel to paper, is the E anaclasis through birefringece crystal 309, is coupled in the port 2 again.Fig. 3 (b) is the port 2 part index path to port 3, and the polarization state of light of sending from 1/2 wave plate 210 is O light when birefringece crystal 309 perpendicular to paper, and total reflection takes place parallel inciding on the folding wedge angle glass blocks 308, is coupled in the port 3 again.

Because this novel double-fiber collimator that adopted, so the entire device volume has been realized miniaturization, another characteristics of this patent are all to adopt wollaston prism and optical prism, adopt the bulk birefringece crystal to compare with the traditional endless device, can significantly reduce cost, thereby have very big practical value and potentiality.

This new mechanical installation diagram as shown in Figure 4, optical fiber cable is respectively circulator port 3, port one, port 2,403,422 is optical fiber cable rubber sheath, 404,424 for the end sleeve pipe, 405 is double-fiber collimator, 406 is scolding tin, 407 is metal-coating, 408A, 408B; 413A, 413B; 417,418 respectively is one group of wollaston prism, and 409,412,416 is glass blocks, and 410,415 is the faraday's revolving fragment that carries magnetic field, 411A, and 411B, 414A, 414B are 1/2 wave plate, 425 is the metallic packaging sheet.The fixing epoxy glue bonding that all adopts of optical element and shell.

Claims (2)

1. novel circulator, form by double-fiber collimator (203,204) single fiber collimater (213,214) and setting optical element between the two, it is characterized in that between the collimater, three optical function combination A, B, C also being provided with birefringece crystal, folding wedge angle glass blocks, wollaston prism form the three-port circulator of tight structure, wherein:

A is made up of birefringece crystal (205), faraday's revolving fragment (206) and two 1/2 wave plates (207A, 207B);

B is by folding wedge angle glass blocks (208) and wollaston prism (209A, 209B);

C is made up of with birefringece crystal (212) two 1/2 wave plates (210A, 210B), faraday's revolving fragment (211).

2. a kind of novel circulator according to claim 1 is characterized in that described optical function combination B can be made up of folding wedge angle glass blocks (308) and birefringece crystal (309).

Images