CN2485662Y

CN2485662Y - Optical fiber separator

Info

Publication number: CN2485662Y
Application number: CN 01238275
Authority: CN
Inventors: 吴砺; 凌吉武; 陈铭星; 刘淑云; 宁海洋
Original assignee: Casix Inc
Current assignee: Casix Inc
Priority date: 2001-06-11
Filing date: 2001-06-11
Publication date: 2002-04-10
Anticipated expiration: 2011-06-11

Abstract

A kind of novel fibre optic isolater is equipped with birefringent filter in the first optical fiber head light output end, is equipped with the identical birefringent filter of two panels thickness in the second optical fiber head light end face, every with a thickness of 0.3-1mm. It is equipped with self-focusing lens between farad power revolving fragment and birefringent filter, wherein the birefringent filter on the first optical fiber head is every birefringent filter on the second optical fiber head

Times, fibre optic isolater is assembled into collimator. The utility model is first to make extraordinary collimator, adds Faraday rotation piece, finally realizes and be assembled into isolator. The optical axis of crystal can be rotated by collimator and realize adjusting in the utility model structure, the opposite position of optical axis makes isolator reach maximum isolation degree on specified wavelength between crystal, to improving yield rate, while shortening Production Time, thus the utility model have in production it is biggish with potentiality.

Description

A kind of novel fibre optic isolater

This novel fibre optic isolater that relates to optical passive component in a kind of optical-fibre communications.

Fibre optic isolater has two big main flows at present, and a kind of is to adopt birefringece crystal angle of wedge sheet (seeing patent USP5446578), and another kind of structure is seen Fig. 1, wherein, 201,206 is optical fiber collimator, 202,204,205 is birefringece crystal, and 203 are faraday's revolving fragment (seeing patent USP 5825950).

Fig. 2 (a), 2 (b) 2 (c) they are this isolator principle of work synoptic diagram of Fig. 1, the orientation of the optical direction optical axis of crystal projection of Fig. 2 (a) expression isolator core, and crystal 2 04,205 length are a, crystal 2 02 length is Described crystal wafer optical axis is the light at optical direction O, and E light produces the direction of maximum walk-off angle, as adopting YVO ₄Crystal, optical axis and the incident ray left and right sides at 45 optical axis direction, Fig. 2 (b), 2 (c) represent forward and reverse index path respectively, the interior strigula of circle is represented polarization state among the figure.Dashed circle represents that light do not get back to the origin-location, the light that is the origin-location is shown in Fig. 2 (c), and the emergent light of collimating apparatus 201 is divided into O light and E light behind birefringece crystal 202,203 is faraday's revolving fragment, O light, E light all are rotated counterclockwise 45 ° through out-of-date, relative 202 optical axises of 204 optical axis angle at 45, and relative 202 optical axises of 205 optical axis become 135 ° of angles, O light separately and E light are through 204, close bundle 205, collimated device 206 receives, and light path is shown in Fig. 2 (b).

Fig. 2 (c) expression light passes through 205 successively from collimating apparatus 206 reverse outgoing, 204,203,202 polarization state, light beam is divided into O light through 205, E light, oppositely through 45 ° of the equidirectional again rotations of faraday's revolving fragment, because it is at 45 between 204 and 202 optical axises, faraday's revolving fragment is identical with forward light sense of rotation among Fig. 2 (b) to the sense of rotation of reverse incident light, therefore backward beam arrives 202 o'clock polarization states and the middle forward light of Fig. 2 (b) and becomes 90 ° of angles 202 o'clock polarization state, O light then, no longer return after E light passes 202, shown in Fig. 2 (c), so just reach light beam reverse isolation purpose by the former road of Fig. 3 (b).

Yet such scheme adopts seldom in actual applications, because for guaranteeing the isolation of isolator, the length of crystal 2 02 is as using YVO ₄Crystal thickness a generally needs 6.5mm, cost height like this, thereby reduced its using value.

This novel purpose is: design a kind of novel fibre optic isolater, be lowered under the prerequisite that assurance light can well be isolated, to adapt to the demand in market.

The following structure of this novel employing realizes above-mentioned purpose, is provided with the birefringece crystal sheet at the first optical fiber head light output end, is equipped with two birefringece crystal sheets that thickness is identical at the second optical fiber head light end face, and every thickness is 0.3-1mm.Be equipped with GRIN Lens between farad power revolving fragment and birefringece crystal sheet, wherein birefringece crystal sheet on first optical fiber head is an every birefringece crystal sheet on second optical fiber head

Doubly, in two birefringece crystal sheets on second optical fiber head, wherein the birefringece crystal sheet away from second optical fiber head can be 1/2 wave plate, another sheet still is the birefringece crystal sheet, and thickness is identical with birefringece crystal sheet thickness on first optical fiber head, and wherein birefringece crystal sheet optical axis becomes 22.5 ° with 1/2 wave plate optical axis on second optical fiber head.

Adopt the as above fibre optic isolater of structure fabrication, wherein birefringece crystal sheet thickness is 0.3-1mm, and rescinded angle is approximately 1 * 1mm and gets final product, and saves greatly than the birefringece crystal sheet material in the prior art, thereby has reduced manufacturing cost.The optical axis of crystal can rotate by collimating apparatus and realize that the relative position of optical axis makes isolator reach the maximum isolation degree on the wavelength of appointment between the adjusting crystal in this structure, thereby improved yield rate, shortened Production Time simultaneously, so this structure there is very big application potential in actual use.

Specify below in conjunction with accompanying drawing:

Fig. 1 is the prior art optical structure chart.

Fig. 2 (a) and (b), (c) are Fig. 1 fundamental diagram.

Fig. 3 is this novel optical structural drawing.

Fig. 4 (a) and (b), (c) are Fig. 3 fundamental diagram.

Fig. 5 is this novel another structural drawing.

Fig. 6 (a) and (b), (c) are Fig. 5 fundamental diagram.

Fig. 7 is this new structure figure.

Among Fig. 3 (a), 401 is first optical fiber head, and 408 is second optical fiber head, 402,406,407 is birefringece crystal, and 402 thickness is 406,407

Doubly, 403,405 is GRIN Lens, and 404 is faraday's revolving fragment.Same Fig. 1 of ultimate principle that this is novel, but structure has had fundamental difference.In Fig. 3, be that birefringece crystal is placed between optical fiber head and the GRIN Lens, be close on the optical fiber head.See that along incident direction 406 optical axis direction and 402 optical axis direction angle at 45,406 optical axis direction become 90 ° of angles with 407 optical axis direction, 404 turn clockwise 45 °, see Fig. 4 (a).Fig. 4 (b), Fig. 4 (c) represent the synoptic diagram of light positive to, reverse optical path polarization state of light and position respectively, be divided into O light and E light from the emergent light of optical fiber head 401 by two sides parallel double refracting crystal 402, and be d1 at crystal exit end spaces, O light that separates and E light pass through faraday's revolving fragment 404 through GRIN Lens collimation back, the polarization direction turns clockwise 45 °, because of the scioptics twin-beam exchanges position up and down, light beam is through 406,407 close bundle again enters optical fiber, sees Fig. 4 (b).

In 4 (c) from 408 emergent lights by after 402, can not get back in 401 optical fiber similar Fig. 3 of principle (c), no longer stating here more.

The structure of Fig. 3 and the fundamental difference of Fig. 1 are birefringece crystal 402,406, and 407 thickness d only needs 0.3～1mm, and the cross section is about about 1 * 1mm and gets final product.So just reduce the cost of crystalline material greatly.

The structure of Fig. 5 is similar to Fig. 3, and just 506 is 1/2 wave plate, and the same position in Fig. 3 is a birefringece crystal.Among Fig. 5,501 is the single fiber head, 502 is birefringece crystal, and 503 is lenticule, and 504 is faraday's revolving fragment, 505 is lenticule, 506 is 1/2 wave plate, and 507 is birefringece crystal, and 508 is the single fiber head, Fig. 6 (a) is the projecting direction of each crystal light path optical axis on optical direction, and Fig. 6 (b), (c) are respectively isolator positive and negative direction light path light polarization and change in location.

In Fig. 5, crystal 5 02 equates that with crystal 5 07 thickness this point is different with Fig. 4 situation, and wave plate 506 optical axises become 22.5 ° (seeing Fig. 5 (a)) with 502 optical direction optical axis directions.Note O light among Fig. 5 (c), 5 (c), E light crosses by twin-beam on two lens front positions and the upper-lower position exchange, and its principle and noted earlier similar no longer repeats.

Among Fig. 7,601,602 is optical fiber cable, 603,604 is optical fiber cable rubber sheath, and 605 is the isolator shell, 606,607 is the optical fiber head of being made by glass capillary, 608,609 is the birefringece crystal sheet, 621 is 1/2 wave plate or birefringece crystal, and 610,611 is the lenticule of collimating apparatus, 612,613 is glass bushing, is used to locate collimating apparatus optical fiber head and lens, 614,615 is the filled gold overcoat, 616 is scolding tin, and 617 are the fixing metal bridge of collimating apparatus, and 618 is silica gel, 619 is magnet ring, and 620 is faraday's revolving fragment.

Claims

1. novel fibre optic isolater, form by optical fiber, two optical fiber heads, faraday's revolving fragment etc., it is characterized in that: be equipped with the birefringece crystal sheet at the first optical fiber head light output end, be equipped with two birefringece crystal sheets that thickness is identical at the second optical fiber head light end face, every thickness is 0.3-1mm, be equipped with GRIN Lens between farad power revolving fragment and birefringece crystal sheet, wherein birefringece crystal sheet on first optical fiber head is an every birefringece crystal sheet on second optical fiber head Doubly.

2. a kind of novel fibre optic isolater according to claim 1, it is characterized in that: in two birefringece crystal sheets on second optical fiber head, wherein the birefringece crystal sheet away from second optical fiber head can be 1/2 wave plate, another sheet still is the birefringece crystal sheet, and thickness is identical with birefringece crystal sheet thickness on first optical fiber head, and wherein birefringece crystal sheet optical axis becomes 22.5 ° with 1/2 wave plate optical axis on second optical fiber head.