CN2726219Y

CN2726219Y - Apparatus for inhibiting ASE noise power in preamplifier

Info

Publication number: CN2726219Y
Application number: CNU2004200460628U
Authority: CN
Inventors: 陈麒; 谢红; 张文斗; 赵欣
Original assignee: O Net Communications Shenzhen Ltd
Current assignee: O Net Technologies Shenzhen Group Co Ltd
Priority date: 2004-05-24
Filing date: 2004-05-24
Publication date: 2005-09-14
Anticipated expiration: 2014-05-24

Abstract

The utility model relates to an apparatus for inhibiting ASE power in preamplifier. An ASE filter is used in the preamplifier, and a film layer for inhibiting 1530 nm wavelength is plated on the middle film of the ASE filter to attenuate a part of the ASE power of the wave band neighboring the 1530 nm firstly; thus, the signal wavelength can be easily identified by the tunable filter without increasing the noise figure of the preamplifier; simultaneously the control software is simplified, and the control speed and the accuracy are improved.

Description

The device that in preamplifier, suppresses the ASE noise power

Technical field

The utility model relates to suppress in a kind of optical communication the device of noise, particularly is applied to reduce in the optical communication device of ASE noise.

Background technology

In the optical communication technique field, in order to amplify the small-signal after the long Distance Transmission, improve the receiving sensitivity and the signal to noise ratio of system, can before receiving equipment, introduce preamplifier usually.Its basic structure as shown in Figure 1, flashlight is after main optical path 1 amplifies, isolate by 2 pairs of backlights of isolator, 3 pairs of signals of tunable optic filter are discerned, coupler 4 and photodiode 7 are used for filtered light signal is monitored, 5 of adjustable attenuators are used for signal light intensity is decayed, and are monitored and feed back by coupler 6 and photodiode 8.Usually preamplifier is operated in the range of linearity, the erbium fibre is in the higher level of population inversion, when less and wavelength is within 1540nm to the 1560nm scope when the EDFA input power, when scanning in the long scope of all-wave with tunable optic filter 3, because near the spontaneous radiation power the 1530nm is very high, almost suitable with signal light power, will occur.Situation as shown in Figure 2 can detect two peak values at the whole C wave band, i.e. ASE noise waves peak value 11 and signal wave peak value 12.Because tunable filter 3 comes identification signal by detecting crest value, such two crest values can influence normal signal and judge think noise ASE 11 by mistake to be actual optical signal.For solving this contradiction, generally can be by following approach:

1. discern by the measurement of slope or bandwidth.Like this, certainly will cause the complicated of Control Software and control rate is slowed down, producing unusual chance increases, thereby reduces its accuracy.

2. adopt special erbium fibre to improve the curve of spectrum, make that the interior gain spectrum of whole bandwidth is more smooth, so just can guarantee that with interior peak value be the flashlight peak value.But this mechanism is that reduction number average particle reflecting level is achieved by use high-dopant concentration erbium fibre, and its cost is to increase noise factor.

Summary of the invention

In order to address the above problem, the utility model provides a more effective device to suppress the ASE noise power, makes signal wavelength more easy to identify.

To achieve these goals, the utility model has used an ASE filter in the preamplifier light path, near the ASE noise power of the wave band 1530nm can be suppressed based on the ASE filter of TTF technology.The ASE filter places between optical isolator and the tunable filter.In optical transmission process, the ASE filter at first can carry out near the ASE noise the 1530nm part decay 3-5dB, and its peak value is descended, and like this, tunable optic filter just can identify signal at an easy rate.

Because adopt said method and device, the utility model has been simplified Control Software, has improved control rate and accuracy, do not increase the noise factor of putting in advance simultaneously, guaranteed the signal to noise ratio of putting in advance.

Description of drawings

Below in conjunction with accompanying drawing the utility model is further specified.

Fig. 1 is put secondary index path in advance for what use in the prior art;

Fig. 2 is without the light amplifier gain distribution schematic diagram of ASE noise suppressed in the prior art;

Fig. 3 is put secondary index path in advance for what use in the utility model;

Fig. 4 is the light amplifier gain distribution schematic diagram after the ASE noise suppressed in the utility model;

Fig. 5 is an ASE filter graph architecture in the utility model;

Fig. 6 is the embodiment schematic diagram when the two-stage light channel structure is arranged;

Fig. 7 is another embodiment schematic diagram when the two-stage light channel structure is arranged.

Embodiment

Below in conjunction with accompanying drawing the utility model suppresses the ASE noise power in preamplifier device is described further.

Among Fig. 3 to Fig. 5, the main optical path 1 in the optical transmission process, the optical device that connects successively is an optical isolator 2 thereafter, ASE filter 10, tunable filter 3, optical coupler 4, adjustable attenuator 5, optical coupler 6 is output at last.When the signal light power after amplifying through main optical path 1 is less, as shown in Figure 4, two light that peak power is suitable can occur, one is to be spontaneous radiation (ASE) noise 11 of peak value with 1530nm, and another is the actual signal light 12 between 1540nm-1560nm.Before the utility model comprised that an ASE filter 10 places the light path of tunable filter 3, described ASE filter 10 comprised a diaphragm 14, and the film that its surface is coated with decay 1530nm wavelength power can carry out effective attenuation with near the ASE noise the 1530nm.When having spontaneous radiation (ASE) noise 11 and actual signal light 12 simultaneously by behind the ASE filter 10, wherein spontaneous radiation (ASE) noise 11 promptly can be attenuated, obtain image intensifer distribute power 13, the peak value of actual signal ripple 12 is compared with ASE noise 13 and is just seemed apparent in view, is discerned by tunable filter 3 easily.Like this, solved signal identification and filtering problem in simple mode, and the noise factor of can deterioration not putting in advance, the signal to noise ratio of putting in advance guaranteed.In addition, optical coupler 4 divides a part to photodiode 7 light signal, and so that the light signal after the ASE filter process is monitored, optical coupler 6 and photodiode 8 are used for output light is monitored.

Fig. 6 to Fig. 7 is another embodiment of the present utility model, if situation is placed in the position of the ASE filter 10 of its expression when the two-stage light channel structure is arranged.Fig. 6 represents that ASE filter 10 can place two-

stage light path

21 and 22, and between the tunable filter 3, Fig. 7 represents that ASE filter 10 can also place between two-

stage light path

21 and 22, can suppress the ASE noise power equally.

The above person is the utility model most preferred embodiment only, is not to be used to limit scope of the present utility model, and all equivalences of being done according to the utility model claim change or modify, and are all the utility model and contain.

Claims

1. device that in preamplifier, suppresses the ASE noise power, comprise optical isolator, tunable filter, flashlight is identified at the tunable filter place, it is characterized in that, before the tunable filter light path, increase an ASE filter, the ASE noise power at ASE filter attenuation ASE crest place makes its output smooth.

2. as claims 1 described device that suppresses ASE power in preamplifier, it is characterized in that the ASE filter comprises a diaphragm, described diaphragm is the diaphragm of the ASE noise power at decay ASE crest place.