CN1874195B - Multiplexing / demultiplexing ROADM based on TFF - Google Patents
Multiplexing / demultiplexing ROADM based on TFF Download PDFInfo
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- CN1874195B CN1874195B CN200610019486A CN200610019486A CN1874195B CN 1874195 B CN1874195 B CN 1874195B CN 200610019486 A CN200610019486 A CN 200610019486A CN 200610019486 A CN200610019486 A CN 200610019486A CN 1874195 B CN1874195 B CN 1874195B
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Abstract
Multiplexer/demultiplexer ROADM based on TFF includes a film filter A, and a pair of light collimator placed at same optical path in front of and behind the film filter A. Characters are that normal line of film filter A is oblique placed on optical path; film filter A and film filter B are placed in parallel; filter A and filter B is a pair of film interference filter with same even thickness; being placed behind the filter B, reflector is perpendicular to optical path. Features are: filtering wavelength of filtering unit is adjustable, and east and simple implementation for processing and controlling mechanical parts.
Description
Technical field
The present invention relates to a kind of reconfigurable light path multiplexing demultiplexing device (ROADM) up and down.Specifically, relate to the ROADM of a kind of based thin film interference filter (TFF) technology.This reconfigurable light path multiplexing demultiplexing device up and down can be widely used in optical WDM communication system, various optical network system and the gating and the exchange in optical signal transmission path in All-Optical Communication Network.
Background technology
In fiber optic transmission system and optical network system, the development of wavelength-division multiplex technique (WDM) provides an effective way that makes full use of fiber bandwidth.This technology adopts the method for the light carrier of a plurality of different wave lengths of transmission in an optical fiber, shown in Fig. 1 (1), light signal by the single wavelength of single wavelength laser array output, the mixed light signal that forms a branch of multi-wavelength via multiplexed optical wave after with repeated use of device transmits in same optical fiber, so just make entrained and information transmitted amount increase at double on the optical fiber, the unit bandwidth transmission cost reduces greatly.The required Primary Component of this technology is exactly optical wavelength multiplexing device and demodulation multiplexer, and shown in Fig. 1 (2), the optical wavelength demodulation multiplexer is exactly that the light signal of the single wavelength in each road is separated from multiplexed light signal, for road use up and down, is a branch wave process; The optical wavelength multiplexing device is its inverse process, is the individual wave process that closes.And the main devices of making optical wavelength multiplexing/demodulation multiplexer at present is to utilize film interference filter (TFF) and array waveguide grating (AWG), and wherein the former is the most ripe at present, uses also the widest a kind of technology, and convenient, flexible advantage is arranged; And the latter is a present main developing direction, has to be convenient to integrated advantage.
A Primary Component as wavelength-division multiplex system of future generation is exactly ROADM, and the light signal by its system can selectively receive and send some wavelength channel from multiplexed light signal does not influence the transmission of other wavelength channels simultaneously again.Operation principle according to smooth multiplexing demultiplexing device above-mentioned, we can be according to its partial waves and close up and down multiplexing demultiplexing device (ROADM) of reconfigurable light path that wave process designs a kind of practicality, to reach any wavelength of multiplexed light signal are realized the process that road is up and down selected.Wherein, because film interference filtering technique (TFF) is the most ripe at present, on production and cost, certain advantage is arranged so use it to constitute ROADM.
The existing many trials of ROADM design of past based thin film interference filter technology.These schemes at first all be based on the Bell laboratory 70～eighties of last century about the invention of GRIN Lens rod and application process thereof (US4111524, US4474424).Its schematic diagram as shown in Figure 2, its structure comprises the film filter of a fixed wave length, the a pair of optical collimator that is symmetrical in the film filter placement, what wherein be connected to the multipath light signal input is the twin-core optical collimator, the other end then is a single core optical collimator.
Its operation principle is that the light signal of multichannel wavelength is coupled to a twin-core optical collimator via optical fiber, comes out the back for the collimation directional light after a branch of diffusion behind the flashlight process optical collimator, shines fixed wave length (as λ
2) film filter on, film filter transmission λ
1The light signal of wavelength is exported through behind single core optical collimator of the other end, and the light signal that will remain wavelength with and the small former twin-core optical collimator of angular deviation reflected back, be coupled to another root optical fiber by it again and export.The breadboard patent of Bell at first can realize one three port OADM (light path multiplexing demultiplexing device up and down) device, and it can selectively receive the light signal of a wavelength channel, and keeps the light signal continuation transmission of other wavelength channels.If the light signal of the residue wavelength that this optical fiber is contained is introduced next fixing filter unit, just the λ that can leach
2Light signal, through too much organizing filter unit (as 8 groups), just can leach the light signal of 9 road wavelength. so just can realize the function of a demodulation multiplexer, and the function of multiplexer is its inverse process. the filter wavelength of the filter unit of this scheme is fixed, and does not have adjustability.
Improved plan is as shown in Figure 3 on the basis of the breadboard patent of Bell in Japan Tyke, mountain (SANTAK) company.This scheme uses the film filter of non-uniform thickness to realize ROADM, the film thickness of this film filter is gradual change rather than identical, diverse location is because its film thickness difference causes the interference difference that causes, can transmission leaches the lightwave signal of different wave length.This scheme advantage is only to use a pair of optical collimator, just can leach wavelength optical signals, use motor that this film filter is carried out push-and-pull then, feasible incident light through optical collimator shines the film position at the different-thickness of this non-uniform film filter, thereby leaches different light signals.The light signal that leaches is exported via single core optical collimator, and the light signal of reflection passes to another root optical fiber output via the twin-core optical collimator.The filter wavelength of the filter unit of this scheme is not fixed, and is adjustable within a large range.
The shortcoming of this scheme is to adopt motor push-and-pull film filter heterogeneous to realize filtering of different wavelengths, and control precision requires high, and the angular deviation on the direction can not be arranged, and is very high to the processes specification requirement of mechanical part.Equally very high to the requirement of the preparation of design of the film of film system and Thin Film Filter heterogeneous simultaneously.
Summary of the invention
The objective of the invention is to overcome the shortcoming and defect that prior art exists, the multiplexing demultiplexing device of a kind of based thin film interference filter technology (TFF) is provided, the filter wavelength of its filter unit is adjustable, and is simple to the processing and the control of mechanical part simultaneously, is easy to realize.
Technical scheme of the present invention is: the multiplexing demultiplexing device ROADM of based thin film interference filter TFF, comprise a film filter A, one is opposite to before and after the film filter A and the optical collimator on same light path, it is characterized in that: the normal slope of film filter A is placed in light path, film filter B and the parallel placement of film filter A, film filter B is used for film filter A, receive film filter B and film filter A and be the film interference filter of a pair of identical uniform thickness, place speculum behind the film filter B, speculum is perpendicular to light path.
The multiplexing demultiplexing device ROADM of aforesaid based thin film interference filter TFF is characterized in that: also comprise optical circulator M; Be used to import multipath light signal;
Optical circulator M, film filter A, are opposite to the optical circulator N that places behind single core optical collimator, film filter B, speculum and the speculum of film filter A front and back and constitute one group of filter unit;
Many group filter units are arranged, and the output of the optical circulator M of last group of filter unit connects the input of the optical circulator M of the one group of filter unit in back.
The multiplexing demultiplexing device ROADM of aforesaid based thin film interference filter TFF is characterized in that: film filter A, is opposite to the speculum of placing behind optical collimator, film filter B and the film filter B of film filter A front and back and constitutes one group of filter unit; Many group filter units are arranged;
Being positioned at the preceding optical collimator of film filter A is the twin-core optical collimator, is used to import multipath light signal; The optical collimator that is positioned at behind the film filter A is single core optical collimator; The output of the twin-core optical collimator of last group of filter unit connects the input of the twin-core optical collimator of the one group of filter unit in back.
Operation principle of the present invention: arrive tilted-putted uniform thickness film interference filter A after the multiplexed light signal in outside (as 40 tunnel) is via optical circulator and single core optical collimator (or twin-core optical collimator) after, film filter A leaches λ
iSingle core optical collimator output that the light signal of wavelength is placed via another symmetry. output is realized the selection on road up and down of this wavelength light signal by an optical circulator. the light signal of the residue of this film filter A reflection simultaneously wavelength is to the film light filter B of another parallel placement, two film filters are identical, and remaining that the two is parallel. such two film filters have identical filtering characteristic at the light signal incidence point of identical incident angle, the light signal of residue wavelength just can arrive the completely reflecting mirror of placing perpendicular to reflected light path through reflection back once more like this. after being reflected by two film filters successively by same light path after through the completely reflecting mirror reflection, gets back to light signal single core optical collimator of input and optical circulator after export by another root optical fiber, so just finished the separation of one tunnel wavelength light signal. in the time of need leaching the light signal of another road wavelength, change the angle of inclination of the non-uniform film filter of two parallel placements, promptly change the incident angle of light of film filter, so just can leach another road light signal. by rotating two parallel film filters, the angle that constantly changes incident light just can realize the branch wave process of ROADM.
And be its inverse process to the ripple that closes of light signal.With the light signal of single wavelength, arrive the input of single core optical collimator via the right-hand member optical circulator after, the incident angle of light of the film filter by adjusting two parallel placements just can be realized the multiplex process to the different wave length light signal.
The present invention has the following advantages:
1. simple in structure, be easy to realize.Determine the road up and down of each road wavelength light signal by stepping motor, can regulate dynamically and gating light path up and down, use very flexible.The selective light number of channel according to actual needs, maximum can realize that the road up and down of 40 road light signals selects.Use optical circulator at filtering output end, make single wavelength light signal in same group of filtering device, just can realize on the road up and down, simplify the structure.What system adopted is uniform film filter, and cost is low.The technology maturation of current thin film filter, stable performance, the insertion loss is low, so the loss of whole system is also lower.
2. optic path is simple, owing to used completely reflecting mirror to make filtered light signal to turn back to input according to original route, so just make that two optical collimators can both fixed placement, do not need the process that moves and follow the trail of light signal, make the stable higher of light path, reduced the difficulty of light path debugging, also made to be more prone to realize on the technology.
3. owing to used the twin-stage film filter during each filtering, so the light signal filtering to single wavelength after twice filtering is more thorough, upload once more when being multiplexed in the multipath light signal at same wavelength light signal like this, caused with frequently crosstalking in system with greatly reducing, make channel isolation improve greatly.
In a word, ratio of performance to price height of the present invention uses flexibly, and wide application prospect may be arranged.
Description of drawings
The wave separater process of closing of the multiplexing demultiplexing device of Fig. 1-wdm system.
Fig. 2-Bell Lab is based on the OADM system construction drawing of twin-core optical collimator.
Fig. 3-Tyke, Japanese mountain SANTAK company is based on the ROADM scenario-frame design drawing of TFF technology.
The structural representation of Fig. 4-of the present invention-group filter unit embodiment 1.
Fig. 5-three groups of filter unit embodiment 2 structural representations of the present invention.
Fig. 6-three groups of filter unit embodiment 3 structural representations of the present invention.
Fig. 7 (1)-transmittance graph when incident angle 4.8 is spent.
Fig. 7 (2)-transmittance graph when incident angle 12.2 is spent.
Fig. 7 (3)-transmittance graph when incident angle 12.2 is spent.
Fig. 8 (1)-transmittance graph when incident angle 4.8 is spent.
Fig. 8 (2)-transmittance graph when incident angle 14.9 is spent.
Fig. 8 (3)-transmittance graph when incident angle 14.9 is spent.
Embodiment
Embodiment 1: the structure of one group of filter unit embodiment of the present invention as shown in Figure 4, utilize the film interference filter of a pair of identical uniform thickness to be placed in parallel in input path with certain angle of inclination, single core optical collimator, a completely reflecting mirror and two optical circulators of being equipped with a pair of symmetry placement again constitute one group of filter unit.
Embodiment 2: structure as shown in Figure 5, and each group light filter unit all adopts structure similarly to Example 1, and difference is, with the reflection output port of first group of filter unit, is connected to second group of light filter unit.Whole system utilizes two to three groups of such filter units just can realize that (1528nm～1561nm) optical channel closes ripple and divide wave process to the whole C wave band.
Embodiment 3: adopt structure as shown in Figure 6, each group filter unit symmetry is placed two optical collimators, the multiple wavelength optical signal input uses the twin-core optical collimator, single wavelength light signal output part after every group of filtering unit filters uses a single core optical collimator and an optical circulator, makes the road up and down of single wavelength light signal just can finish in same group of filtering device.Two identical homogeneous film filters are realized twice filtering with the parallel placement of certain angle tilt, and filtering for the second time can effectively reduce the same frequency of system and crosstalk.The incident angle of light of the film filter by changing two parallel placements just can realize that the filtering of different wave length light signal is to realize its road up and down.Completely reflecting mirror is basically perpendicular to reflected light path and places (because the characteristics of twin-core optical collimator make the extremely small angle tilt that is placed with of completely reflecting mirror, angle tilt is at 0.1～3.0 degree), filtered flashlight is repeatedly reflected after the twin-core optical collimator is coupled in another root optical fiber exports, and enter next filter unit.Adopt a plurality of filter units (two or three) just can realize to the whole C wave band (optical channel among the 1528nm～1561nm) arbitrarily up and down the road select, also can select to use wherein certain or certain several filter units according to actual needs, make the flexibility of system and alternative be greatly improved.
1, operation principle of the present invention is:
Arrive tilted-putted uniform thickness film interference filter after the multiplexed light signal in outside (as 40 tunnel) is via optical circulator and single core optical collimator after, film filter leaches λ
iSingle core optical collimator output that the light signal of wavelength is placed via another symmetry.Output is realized the selection on road up and down of this wavelength light signal by an optical circulator.The light signal of the residue of this film filter reflection simultaneously wavelength is to the film light filter of another parallel placement, and two film filters are identical, and remains that the two is parallel.Such two film filters have identical filtering characteristic at the light signal incidence point of identical incident angle, and the light signal that remains wavelength like this is through just arriving the completely reflecting mirror of placing perpendicular to reflected light path after the reflection once more.After being reflected by two film filters by same light path successively through completely reflecting mirror reflection back, gets back to light signal single core optical collimator of input and optical circulator after, so just finished the separation of one tunnel wavelength light signal by another root optical fiber output.In the time of need leaching the light signal of another road wavelength, change the angle of inclination of the non-uniform film filter of two parallel placements, promptly change the incident angle of light of film filter, so just can leach another road light signal.By rotating two parallel film filters, the angle that constantly changes incident light just can realize the branch wave process of ROADM.
And be its inverse process to the ripple that closes of light signal.With the light signal of single wavelength, arrive the input of single core optical collimator via the right-hand member optical circulator after, the incident angle of light of the film filter by adjusting two parallel placements just can be realized the multiplex process to the different wave length light signal.
Each group filter unit can be realized about 13 according to design needs (being that system uses three groups or two groups of filter units) or the road up and down of 20 channels is selected, by reusing three groups or two groups of above-mentioned ROADM filter units, whole system can be implemented in the whole C wave band (road up and down arbitrarily of 40 tunnel single wavelength light signals of 1528nm～1561nm), realize the function of reconfigurable smooth bifurcated multiplexer, as shown in Figure 5.
2, filter design and performance
The filter that the design uses is to require design according to having certain dynamic tilt incident angle tuning range.Can use three groups or two groups of filter units to finish tunable filtering by design to the whole C wavelength band.
According to the design of using three groups of filter units, its tunable wavelength scope of every group should be 11 nm, can satisfy the tuning of 13 to 14 channels.The dynamic-tuning angular range of each group is from 4.8 degree～12.3 degree.In tunable range, the pass band width of its transmission curve is greater than 0.4nm, and cut off band width is less than 1.2nm, and ripple coefficient approaches 0, and the Polarization Dependent Loss maximum is less than 0.03dB.Satisfy the needs of 100G dwdm system fully.With first group of filter unit is example, and its tunable wavelength scope is 1561nm～1550nm.At initial incident angle is 4.8 when spending, and corresponding centre wavelength is 1561nm; When incident angle be tuned to 12.2 when spending, its centre wavelength moves on to 1550nm.Simulation result as shown in Figure 7.
By Fig. 7 (3) as seen its maximum PDL value less than 0.03dB.
Same, the tunable wavelength scope of second group of filter unit is from 1550nm～1539nm; The tunable wavelength scope of the 3rd group of filter unit is from 1539nm～1528nm.
According to the design of using two groups of filter units, its tunable wavelength scope of every group should be 16 or 17nm, and every group can be satisfied the tuning of 20 channels.The dynamic-tuning angular range of each group is from 4.8 degree～14.9 degree.In tunable range, the pass band width of its transmission curve is greater than 0.4nm, and cut off band width is less than 1.2nm, and the Polarization Dependent Loss maximum is less than 0.03dB.Satisfy the needs of 100G dwdm system fully.
With second group of filter unit is example, and its tunable wavelength scope is 1545nm～1528nm.At initial incident angle is 4.8 when spending, and corresponding centre wavelength is 1545nm; When incident angle be tuned to 14.9 when spending, its centre wavelength moves on to 1528nm.Simulation result as shown in Figure 8.
By Fig. 8 (3) as seen its maximum PDL value less than 0.03dB.
Same, the tunable wavelength scope of first group of filter unit is from 1561nm～1545nm.
Claims (3)
1. the multiplexing demultiplexing device ROADM of based thin film interference filter TFF, comprise a film filter A, one is opposite to before and after the film filter A and the optical collimator on same light path, it is characterized in that: the normal slope of film filter A is placed in light path, film filter B and the parallel placement of film filter A, film filter B is used for film filter A, receive film filter B and film filter A and be the film interference filter of a pair of identical uniform thickness, place speculum behind the film filter B, speculum is perpendicular to light path.
2. the multiplexing demultiplexing device ROADM of based thin film interference filter TFF as claimed in claim 1 is characterized in that: also comprise optical circulator M; Be used to import multipath light signal;
Optical circulator M, film filter A, are opposite to the optical circulator N that places behind single core optical collimator, film filter B, speculum and the speculum of film filter A front and back and constitute one group of filter unit;
Many group filter units are arranged, and the output of the optical circulator M of last group of filter unit connects the input of the optical circulator M of the one group of filter unit in back.
3. the multiplexing demultiplexing device ROADM of based thin film interference filter TFF as claimed in claim 1 is characterized in that: film filter A, is opposite to the speculum of placing behind optical collimator, film filter B and the film filter B of film filter A front and back and constitutes one group of filter unit;
Many group filter units are arranged;
Being positioned at the preceding optical collimator of film filter A is the twin-core optical collimator, is used to import multipath light signal; The optical collimator that is positioned at behind the film filter A is single core optical collimator; The output of the twin-core optical collimator of last group of filter unit connects the input of the twin-core optical collimator of the one group of filter unit in back.
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| CN200610019486A CN1874195B (en) | 2006-06-29 | 2006-06-29 | Multiplexing / demultiplexing ROADM based on TFF |
| US11/819,530 US7821712B2 (en) | 2006-06-29 | 2007-06-28 | Thin film tunable optical filter |
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| CN200610019486A CN1874195B (en) | 2006-06-29 | 2006-06-29 | Multiplexing / demultiplexing ROADM based on TFF |
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| CN100451703C (en) * | 2006-12-18 | 2009-01-14 | 武汉光迅科技股份有限公司 | Tri-port depolarizing tunable optical filter based on TFF |
| CN103837934B (en) * | 2012-11-22 | 2016-01-20 | 福州高意通讯有限公司 | A kind of optical fiber circulator |
| CN114252960A (en) * | 2020-09-25 | 2022-03-29 | 华为技术有限公司 | Adjustable optical add/drop multiplexer |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1588148A (en) * | 2004-09-09 | 2005-03-02 | 上海交通大学 | Tunable wave length selection/locking light dense wave division complex combining wave/channel splitting filter |
| KR20050037016A (en) * | 2003-10-17 | 2005-04-21 | 주식회사 나놉스 | Tunable optical filter and method of manufacture |
| CN1632633A (en) * | 2003-12-24 | 2005-06-29 | 招远招金光电子科技有限公司 | Low polarization-related loss optical filter with adjustable wavelength in a wide range |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20050037016A (en) * | 2003-10-17 | 2005-04-21 | 주식회사 나놉스 | Tunable optical filter and method of manufacture |
| CN1632633A (en) * | 2003-12-24 | 2005-06-29 | 招远招金光电子科技有限公司 | Low polarization-related loss optical filter with adjustable wavelength in a wide range |
| CN1588148A (en) * | 2004-09-09 | 2005-03-02 | 上海交通大学 | Tunable wave length selection/locking light dense wave division complex combining wave/channel splitting filter |
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