CN102566194A - Broadband wavelength converter based on high-nonlinearity flattened-dispersion optical fibers and converting method of broadband wavelength converter - Google Patents

Abstract

The invention relates to a broadband wavelength converter based on high-nonlinearity flattened-dispersion optical fibers, which comprises a signal light input optical path, a continuous light source, a continuous light input optical path and a Sagnac interference ring. The Sagnac interference ring comprises high-nonlinearity flattened-dispersion optical fibers, a first coupler and a second coupler, wherein the first coupler is used for transmitting continuous light to the Sagnac interference ring, and the second coupler is used for coupling signal light to be converted with the continuous light outputted by the first coupler and transmitting to the Sagnac interference ring. The invention further relates to a converting method of the broadband wavelength converter, which includes: using the second coupler to receive the signal lights to be converted; using the first coupler to receive the continuous light in a target conversion wavelength; and using the first coupler to output wavelength-converted signal light and the original-wavelength signal light. The broadband wavelength converter and the converting method have the advantages that wavelength conversion with wavelength interval more than 50nm can be realized; the converter is quick in response speed and can reach femtosecond level theoretically; the length of the Sagnac interference ring is only 10m; and the broadband wavelength converter is compact in structure, cost-saving and low in power consumption.

Description

Broadband wavelength converter and conversion method based on high nonlinear dispersion flat fiber

technical field

The invention relates to the technical field of all-optical signal processing and the technical field of nonlinear fiber optics, in particular to a broadband wavelength converter and a conversion method based on high nonlinear dispersion flat optical fiber.

Background technique

Information technology is developing at a speed beyond people's imagination. At the same time, people's demand for communication quality and experience is increasing. Therefore, higher requirements are put forward for communication technology. The all-optical intelligent reconfigurable communication network is recognized as the next-generation communication method to solve the communication bottleneck. In an all-optical intelligent reconfigurable communication network, in order to make full use of network resources, it is necessary to dynamically adjust the resources to reduce network congestion and improve the reconfigurability and intelligence of the optical network. Currently, the technologies for realizing all-optical wavelength conversion mainly include cross-gain modulation (XGM), cross-phase modulation (XPM), and four-wave mixing (FWM). Cross-gain modulation is a gain saturation effect in active devices, and semiconductor optical amplifiers (SOAs) are the most widely used devices for generating cross-gain modulation. However, due to the limitation of carrier recovery time in SOA, the response speed of this kind of all-optical wavelength converter is generally on the order of nanoseconds, which will limit the further improvement of the all-optical wavelength conversion speed. XPM and FWM are two third-order nonlinear effects with femtosecond-level response speed, which are ideal for ultra-high-speed all-optical wavelength conversion, and have attracted great attention from scientific and technological workers from all over the world. The core of the optical fiber is very small, so that its third-order nonlinear coefficient is very large, and when the optical signal propagates in the optical fiber, the distance between the two is long, so the XPM or FWM effect can be well realized. In addition, the optical fiber-based All-optical wavelength converters are naturally compatible with optical communication systems and can minimize insertion loss.

Found through document retrieval, Sarker, B. et al published a paper entitled "All-optical wavelength conversion based on cross-phase modulation (XPM) on Photonics Technology Letters (Photonics Technology Letters, 2002, Vol. ) in a single-mode fiber and a Mach-Zehnderinterferometer. It consists of a 2km long standard single-mode fiber and a Mach-Zehnder interferometer. Due to the small nonlinear coefficient of the standard single-mode fiber and the uneven dispersion, the wavelength conversion efficiency of this structure is not high, and the wavelength conversion width is only 20nm, which is difficult to meet the needs of broadband all-optical conversion.

After patent search, it was found that the application number is 200480025229.5, and the title is "All-optical wavelength converter based on semiconductor optical amplifier with Sagnac interferometer with asymmetric position". The device uses a Sagnac (Sagnac) interference loop, and places an SOA on an asymmetrical position of the loop, and utilizes the SOA and the Sagnac loop to jointly complete the wavelength conversion of the input signal. As mentioned before, the working speed of SOA is limited by the recovery time of carriers, so the working speed of the device is only on the order of nanoseconds, and the placement of SOA in the device requires an accurate offset, and an inappropriate offset A large amount will cause the conversion effect to fail to meet the design requirements.

Therefore, the existing all-optical wavelength converter needs to be improved in both the switchable wavelength width and the conversion speed to meet the requirements.

Contents of the invention

The technical problem to be solved by the present invention is: in order to overcome the deficiencies in the switchable wavelength width and conversion speed of the existing all-optical wavelength converter, the present invention provides a broadband wavelength converter based on high nonlinear dispersion flat optical fiber and its conversion method, the present invention can realize wavelength conversion with a wavelength interval of more than 50nm, and the conversion speed can theoretically reach femtosecond level, and the conversion speed of picosecond level is observed in the embodiment.

The technical scheme adopted by the present invention to solve the technical problem is: a broadband wavelength converter based on a high nonlinear dispersion flat optical fiber, which has a signal light input optical path for adjusting the polarization state and power of the signal light to be converted, a continuous light source and a The continuous light input optical path for adjusting the polarization state and power of the continuous light, the continuous light source is connected with the continuous light input optical path, and also has a Sagnac interference ring, and the Sagnac interference ring includes a high nonlinear dispersion flat fiber, which is used for the continuous The light is passed to the first coupler on the Sagnac interference ring and is used to couple the signal light to be converted with the continuous light output by the first coupler and pass it to the second coupler on the Sagnac interference ring. The second coupler is arranged at On the Sagnac interference ring between the high nonlinear dispersion flat fiber and the first coupler, the signal light input optical path communicates with the second coupler, and the continuous light input optical path communicates with the first coupler.

In order to control the polarization state of the optical signal in the Sagnac interference ring, the Sagnac interference ring also has at least one third polarization controller, and the third polarization controller and the second coupler are respectively located in the high nonlinear dispersion flat optical fiber on both sides.

In order to control the polarization state of the signal light to be converted and the continuous light used to control the target conversion wavelength, the signal light input optical path has at least one first polarization controller, and the continuous light input optical path has at least one second polarization controller .

In order to meet the needs of broadband all-optical wavelength conversion and increase the width of wavelength conversion, the nonlinear coefficient of the high nonlinear dispersion flat fiber is ≥11(KmW) ^-1 , and the dispersion coefficient: 0≤GVD<1.5ps/km/nm , length ≤ 10m.

Preferably, the first coupler is a four-port optical power coupler with a splitting ratio of 50:50, the first end is the input end, connected to the continuous light source; the second end is the output of the transformed signal light terminal; the third terminal and the fourth terminal are respectively the first component output terminal for outputting the first component signal and the second component output terminal for outputting the second component signal, and both the third terminal and the fourth terminal interfere with Sagnac The ring communicates; the running directions of the first component signal and the second component signal on the Sagnac interference ring are opposite.

Preferably, in cooperation with the first coupler, the second coupler is a three-port optical power coupler with a splitting ratio of 10:90, the first end is the 90% input end, and the output end of the signal light input optical path connection; the second end is a 10% input end, which is connected with the third end or the fourth end of the first coupler; the third end is an output end for outputting coupled signals, and communicates with a high nonlinear dispersion flat optical fiber.

A broadband wavelength conversion method based on high nonlinear dispersion flat optical fiber, Sagnac interference ring is set, and described Sagnac interference ring includes high nonlinear dispersion flat optical fiber, a first coupler, a second coupler and at least one polarization controller, The second coupler is arranged on the Sagnac interference ring between the high nonlinear dispersion flat fiber and the first coupler;

receiving the signal light to be converted after the polarization state and power adjustment is entered into the second coupler;

The continuous light received through the polarization state and power adjustment enters the first coupler, the wavelength of the continuous light is the same as the wavelength of the target conversion, and the continuous light is divided into a clockwise component and an anticlockwise component in the Sagnac interference ring;

The clockwise component or counterclockwise component of the first coupler is coupled with the signal light received by the second coupler and then input into the high nonlinear dispersion flat fiber to generate a phase modulation signal;

The phase modulation signal and the counterclockwise component or the clockwise component reach the first coupler at the same time, and the signal light with converted wavelength and the original wavelength signal light are output from the first coupler.

During the conversion process, adjust the polarization controller to make the output signal of the Sagnac interference ring the strongest.

In order to select the converted signal, the wavelength-converted signal light output from the first coupler and the original wavelength signal light are input to the filter to obtain the wavelength-converted signal light.

The beneficial effects of the present invention are that the broadband wavelength converter and conversion method based on high nonlinear dispersion flat optical fiber of the present invention have the following advantages:

1. With a wide wavelength conversion width, the signal can be transferred to a wavelength that is more than 50nm away from the signal light wavelength;

2. Ultra-fast response speed, which can theoretically reach femtosecond level;

3, compact structure, cost saving, compared with the existing all-optical wavelength converter based on Sagnac interference ring, the ring length of existing Sagnac ring needs hundreds of meters to thousands of meters, the ring length of Sagnac ring of the present invention Only 10m;

4. Low power consumption. Compared with the existing all-optical wavelength converter based on the Sagnac interference ring, the power consumption of the present invention is at least 3dB lower.

5. The high nonlinear dispersion flat fiber does not require a special offset, which is convenient to use, and the conversion effect is not easily affected by the position offset of the high nonlinear dispersion flat fiber in the later stage.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a schematic structural diagram of an optimal embodiment of a broadband wavelength converter based on a high nonlinear dispersion flat fiber in the present invention.

In the figure 1, erbium-doped fiber amplifier (EDFA), 2, the first polarization controller, 3, the first optical power attenuator, 4, adjustable laser, 5, the second EDFA, 6, the second polarization controller, 7 , second optical power attenuator, 8, second coupler, 9, first coupler, 10, high nonlinear dispersion flat fiber, 11, third polarization controller, 12, filter, 13, autocorrelator, 14. Spectrum analyzer.

Fig. 2 is the spectrum before wavelength conversion in the best embodiment of the broadband wavelength converter based on high nonlinear dispersion flat fiber of the present invention.

Fig. 3 is the spectrum after wavelength conversion in the optimal embodiment of the broadband wavelength converter based on high nonlinear dispersion flat fiber of the present invention.

Fig. 4 is the signal light pulse before wavelength conversion in the best embodiment of the broadband wavelength converter based on high nonlinear dispersion flat fiber of the present invention.

Fig. 5 is the signal light pulse output after wavelength conversion in the optimal embodiment of the broadband wavelength converter based on high nonlinear dispersion flat fiber of the present invention.

Detailed ways

The present invention is described in further detail now in conjunction with accompanying drawing. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, so they only show the configurations related to the present invention.

As shown in FIG. 1 , it is a schematic structural diagram of an optimal embodiment of a broadband wavelength converter based on a high nonlinear dispersion flat fiber in the present invention. It has a signal light input optical path for adjusting the polarization state and power of the signal light to be converted, a continuous light source, and a continuous light input optical path for adjusting the continuous light polarization state and power. The signal light input optical path has a first erbium-doped fiber amplifier 1, The first polarization controller 2 and the first optical power attenuator 3, the continuous light input optical path has the second erbium-doped fiber amplifier 5, the second polarization controller 6 and the second optical attenuator 7 in sequence, and the continuous light source is an adjustable laser 4, the tunable laser 4 is connected with the second erbium-doped fiber amplifier 5, and also has a Sagnac interference ring, and the Sagnac interference ring includes a high nonlinear dispersion flat optical fiber 10, and is used to transmit continuous light to the first coupler on the Sagnac interference ring 9 and the second coupler 8 used to couple the signal light to be converted with the continuous light output by the first coupler 9 and pass it to the Sagnac interference ring, the high nonlinear dispersion flat fiber 10 and the first coupler 9 in Sagnac Symmetrically arranged on the interference ring, the second coupler 8 is arranged on the Sagnac interference ring between the high nonlinear dispersion flat fiber 10 and the first coupler 9, the first optical power attenuator 3 is connected with the second coupler 8, and the second The second optical attenuator 7 is connected with the first coupler 9 .

There is also a third polarization controller 11 on the Sagnac interference ring, and the third polarization controller 11 and the second coupler 8 are respectively located on both sides of the high nonlinear dispersion flat optical fiber 10 .

The first coupler 9 is a four-port optical power coupler with a splitting ratio of 50:50, and the first end 901 is an input end connected to the second optical attenuator 7; the second end 902 is an output end of the converted signal light, Connected with the filter 12; the third terminal 903 and the fourth terminal 904 are respectively the first component output terminal for outputting the first component signal and the second component output terminal for outputting the second component signal, the third terminal 903 and the Both the fourth terminals 904 communicate with the Sagnac interference ring; the running directions of the first component signal and the second component signal on the Sagnac interference ring are opposite, the first component signal runs counterclockwise, and the second component signal runs clockwise.

The second coupler 8 is a three-port optical power coupler with a splitting ratio of 10:90, and the first end 801 is a 90% input end connected to the output end of the first optical power attenuator 3; the second end 802 is 10% The input end is connected to the fourth end 904 of the first coupler 9 ; the third end 803 is an output end for outputting coupled signals, and communicates with the high nonlinear dispersion flat optical fiber 10 . The third terminal 903 of the first coupler 9 is connected to the third polarization controller 11 .

The pulse signal to be converted is amplified by the first erbium-doped fiber amplifier 1, and then its polarization state is adjusted by the first polarization controller 2, so that the output signal of the signal light input optical path is the strongest, and then the signal is converted by the first optical power attenuator 3 The optical power is adjusted to 8dBm, and finally the second coupler 8 couples 90% of the signal power from port 801 to port 803 and enters the Sagnac interference ring. The wavelength of the continuous light output by the tunable laser 4 is adjusted to the target wavelength that the signal light needs to be converted to. In this embodiment, the target converted wavelength is 1510nm, and is amplified by the second erbium-doped fiber amplifier 5, and then controlled by the second polarization The polarizer 6 controls its polarization state, so that the output signal of the continuous light input optical path is the strongest, then the continuous light power is adjusted to 8dBm by the second optical attenuator 7, and then the continuous light is equally divided by its 901 port by the first coupler 9 To ports 903 and 904, two paths of light running clockwise and counterclockwise are formed. Port 904 of the first coupler is connected to port 802 of the second coupler. 10% of the power of the light output by the 904 port is coupled to the 803 port through the second coupled 802 port, and is input into the high nonlinear dispersion flat optical fiber 10 together with the signal light coupled from the 801 port, and the signal light and the continuous light are in the The high nonlinear dispersion flat optical fiber 10 interacts to produce a cross-phase modulation effect, thereby changing the phase of the continuous light running clockwise, and the continuous light running clockwise and the continuous light running counterclockwise carrying phase information, in the first meet in the coupling 9, and finally transfer the signal carried by the signal light to the continuous light, adjust the third polarization controller 11, so that the output signal at the 902 port is the strongest, and it is output by the 902 port of the first coupler 9, and the output light Divided into two paths, one path passes through a filter to filter out the signal light with converted wavelength, and then input to the autocorrelator 13; the other path is directly input to the spectrum analyzer 14.

The high nonlinear dispersion flat fiber used in this embodiment has a nonlinear coefficient of 11 (KmW) ^-1 , a dispersion coefficient of 0.5<GVD<1.5 ps/km/nm, and a length of 10 m.

In this embodiment, the signal light is converted from a wavelength of 1560nm to 1510nm, and the conversion results are shown in Figures 2-5, wherein Figures 2 and 3 illustrate that the wavelength conversion has been successfully realized in the frequency domain, and Figures 4 and 5 are from In the time domain, the realization of wavelength conversion is explained, and it can be seen that the conversion speed reaches the order of picoseconds. In Fig. 5, after the wavelength conversion of the signal light, the pulse is broadened to some extent, and those skilled in the art know that this is only due to the effect of the filter; Meet the communication requirements.

Inspired by the above-mentioned ideal embodiment according to the present invention, through the above-mentioned description content, relevant workers can make various changes and modifications within the scope of not departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, but must be determined according to the scope of the claims.

Claims (9)

1. broad band wavelength transducer based on the high non-linearity Dispersion Flattened Fiber; Has the continuous light input light path that is used to adjust flashlight input light path, the continuous light source of flashlight polarization state to be transformed and power and is used to adjust continuous light polarization state and power; Described continuous light source is connected with the continuous light input light path; It is characterized in that: also have the Sagnac interference ring; Described Sagnac interference ring comprises high non-linearity Dispersion Flattened Fiber (10), be used for continuous light is delivered to first coupling mechanism (9) on the Sagnac interference ring and is used for the continuous light coupling of flashlight to be transformed and first coupling mechanism (9) output and is delivered to second coupling mechanism (8) on the Sagnac interference ring; Second coupling mechanism (8) is arranged on the Sagnac interference ring between high non-linearity Dispersion Flattened Fiber (10) and first coupling mechanism (9); Described flashlight input light path is communicated by letter with second coupling mechanism (8), and the continuous light input light path is communicated by letter with first coupling mechanism (9).

2. the broad band wavelength transducer based on the high non-linearity Dispersion Flattened Fiber as claimed in claim 1; It is characterized in that: also have at least one the 3rd Polarization Controller (11) on the described Sagnac interference ring, described the 3rd Polarization Controller (11) and second coupling mechanism (8) lay respectively at the both sides of high non-linearity Dispersion Flattened Fiber (10).

3. the broad band wavelength transducer based on the high non-linearity Dispersion Flattened Fiber as claimed in claim 1; It is characterized in that: described flashlight input light path has at least one first Polarization Controller (2), has at least one second Polarization Controller (6) in the continuous light input light path.

4. the broad band wavelength transducer based on the high non-linearity Dispersion Flattened Fiber as claimed in claim 1 is characterized in that: nonlinear factor>=11 (KmW) of described high non-linearity Dispersion Flattened Fiber (10) ^-1, abbe number: 0≤GVD＜1.5ps/km/nm, length≤10m.

5. like each described broad band wavelength transducer in the claim 1 to 4 based on the high non-linearity Dispersion Flattened Fiber; It is characterized in that: described first coupling mechanism (9) is that splitting ratio is the four port luminous power coupling mechanisms of 50:50; First end (901) is an input end, is connected with described continuous light source; Second end (902) is the output terminal of flashlight after the conversion; The 3rd end (903) and the 4th end (904) are respectively first component output terminal and the second component output terminal that is used to export the second component signal that is used to export first component signal, and the 3rd end (903) and the 4th end (904) all communicate with the Sagnac interference ring; Described first component signal is opposite with the traffic direction of second component signal on the Sagnac interference ring.

6. the broad band wavelength transducer based on the high non-linearity Dispersion Flattened Fiber as claimed in claim 5; It is characterized in that: described second coupling mechanism (8) is that splitting ratio is the three port luminous power coupling mechanisms of 10:90; First end (801) is 90% input end, is connected with the output terminal of flashlight input light path; Second end (802) is 10% input end, is connected with the 3rd end (903) or the 4th end (904) of first coupling mechanism (9); The 3rd end (803) communicates with high non-linearity Dispersion Flattened Fiber (10) for being used to export the output terminal of coupled signal.

7. broad band wavelength transform method based on the high non-linearity Dispersion Flattened Fiber is characterized in that:

The Sagnac interference ring is set; Described Sagnac interference ring comprises high non-linearity Dispersion Flattened Fiber (10), first coupling mechanism (9), second coupling mechanism (8) and at least one Polarization Controller (11), and second coupling mechanism (8) is arranged on the Sagnac interference ring between high non-linearity Dispersion Flattened Fiber (10) and first coupling mechanism (9);

The flashlight to be transformed that receives through polarization state and power adjustment gets into second coupling mechanism (8);

The continuous light that receives through polarization state and power adjustment gets into first coupling mechanism (9), and described continuous light wavelength is identical with the wavelength of object transformation, in the Sagnac interference ring, continuous light is divided into clockwise component and counterclockwise component;

Be input in the high non-linearity Dispersion Flattened Fiber (10) after the flashlight coupling that the clockwise component of first coupling mechanism (9) or counterclockwise component and second coupling mechanism (8) receive, produce phase modulated signal;

Phase modulated signal and counterclockwise component or clockwise component arrive first coupling mechanism (9) simultaneously, from first coupling mechanism (9) output transform the flashlight and the former wavelength signals light of wavelength.

8. the broad band wavelength transform method based on the high non-linearity Dispersion Flattened Fiber as claimed in claim 1 is characterized in that: in the conversion process, adjustment Polarization Controller (11) makes the output signal of Sagnac interference ring the strongest.

9. the broad band wavelength transform method based on the high non-linearity Dispersion Flattened Fiber as claimed in claim 1; It is characterized in that: the conversion that will from first coupling mechanism (9), export the flashlight and the former wavelength signals light of wavelength be input to wave filter (12), the flashlight of wavelength that obtained conversion.

Images