CN203119913U - All-optical format conversion device with wavelength multicasting function - Google Patents

Abstract

The utility model discloses an all-optical format conversion device with a wavelength multicasting function. A RF signal source transmits a radio frequency signal with a repetition frequency of 10GHz. The radio frequency signal is transmitted to a mode-locked semiconductor laser for performing active mode locking. The mode-locked semiconductor laser transmits ultra-short pulse sequence with a repetition frequency of 10GHz as pump light. After an erbium-doped fiber amplifier performs power amplification on the pump light, a water filter 1 filters spontaneous radiation noise. After the pump light passes a polarization controller PC2, the pump light is optically coupled with a NRZ signal to be converted. A polarization controller PC1 on a branch circuit of the NRZ signal light is used for adjusting polarization state of the light beam. After the pump light and the NRZ signal light are coupled, the coupled light is transmitted into an overhigh-power erbium-doped fiber amplifier for power amplification. Then the amplified light enters a 50-meter photonic crystal fiber. Four-wave mixing effect between the signal light and the pump light is generated in the photonic crystal fiber. Two narrow-band optical wave filters are used for respectively filtering the sidebands, thereby obtaining a format conversion signal. Simultaneously wavelength conversion is completed and a wavelength multicasting function is realized.

Description

A kind of full optical code type conversion apparatus with set of wavelengths multicast function

Technical field

The utility model relates to all-optical network interfacing field, in particular a kind of full optical code type conversion apparatus with set of wavelengths multicast function.

Background technology

Along with video request program, the continuous appearance of network medical treatment equiband enhanced multimedia business, people increase year by year to the demand of the network bandwidth, wavelength division multiplexing (WDM) is two kinds of topmost signal multiplexing modes in the optical fiber telecommunications system with time division multiplexing (OTDM), the former generally adopts nonreturn to zero code (NRZ) form, because it has channel wavelength spacing closely, higher spectrum efficiency, stronger time jitter and chromatic dispersion tolerance, be mainly used in metropolitan area network and Access Network, the latter generally adopts NRZ (RZ) form, because it has little duty ratio, higher polarization mode dispersion tolerance, good anti-line nonlinearity damage ability, be highly suitable for the long Distance Transmission of two-forty, be mainly used in backbone network.Wavelength division multiplexing (WDM) being combined with time division multiplexing (OTDM) technology, give full play to both advantages, is the developing direction of following photonic network.In such system, the different piece of network will have different format modulation signals, therefore, the all-optical network interfacing that can organically the different piece in the optical-fiber network (wide area network/metropolitan area network/Access Network) be combined becomes the research focus day by day, causes people's extensive concern.Full light NRZ is exactly one of key technology of above-mentioned all-optical network interface to the sign indicating number type switch technology of RZ, it can effectively avoid the opto-electronic conversion of lengthy and tedious poor efficiency, break through the operating rate limit of conditional electronic device, to be applicable to that in the light territory NRZ sign indicating number that transmits is converted to the RZ sign indicating number that is suitable for transmitting in wide area network in metropolitan area network/Access Network, thereby finish the conversion from WDM to OTDM, realize functionality, network interface, therefore have important practical value.And full-light multicast can send to a plurality of destination nodes with same information by synchronization, can support video request program, and network medical treatment equiband enhanced multimedia business for saving network cost, improves network efficiency and has important function.

At present, realize that full light NRZ can be divided into two kinds to the sign indicating number type switch technology of RZ, first kind is the scheme that adopts the photoelectricity combination, the main optical-electronic oscillator that relies on, high-frequency electronic devices such as phase-modulator, have apparatus expensive and be subjected to drawback such as electronic device " speed bottleneck " restriction, second kind is the mode that adopts full light, realizes based on various nonlinear optical effects.Further can be divided into cross-gain modulation in the based semiconductor image intensifer, cross-phase modulation, cross polarization modulation, four-wave mixing effect; Based on cross-phase modulation in the dispersion shift highly nonlinear optical fiber, the cross polarization modulation, four-wave mixing effect, produce effect based on periodically poled lithium niobate waveguide cascade and frequency/difference frequency, based on the cross-phase in silicon nanowires modulation or four-wave mixing effect, based on the narrow-band filtering effect of silicon-based micro ring resonator etc.Wherein, four-wave mixing effect has signal bit rate and the transparent advantage of modulation format, therefore receives much attention.It further can be divided into two classes, the first kind is to adopt individual signals light and pump light, improve its input power simultaneously, utilize the high-order four-wave mixing effect together with the various nonlinear effects in the optical fiber, produce a plurality of new frequency components, realize that single many NRZ of arriving change to RZ sign indicating number type, another kind of for utilizing a plurality of flashlights and pump light to interact, only based on the single order four-wave mixing effect, produce a plurality of four wave mixing sidebands, finish single many NRZ of arriving and change to RZ sign indicating number type.But four-wave mixing effect inefficiency in the semiconductor optical amplifier, traditional dispersion shift highly nonlinear optical fiber need again pump light and flashlight are arranged near the zero-dispersion wavelength of fiber, satisfy phase-matching condition, have limited the flexibility of sign indicating number type switch technology.Emerging photonic crystal fiber, by compact arranged nanometer level microporous composition the on two-dimensional directional, by changing the shape and size of micropore, can control CHROMATIC DISPERSION IN FIBER OPTICS and nonlinear characteristic flexibly, avoided the drawback of conventional optical fibers fully, be very suitable for as full optical signal processor part.Simultaneously, owing to be all optical fibre structure, fully based on the work of the third-order non-linear mechanism in the optical fiber, have simple in structurely, response speed is fast, dependable performance, and be easy to and advantages such as existing commercialization ultrahigh speed optical fiber telecommunications system is connected, have development prospect very much.

The utility model content

Technical problem to be solved in the utility model is to provide a kind of full optical code type conversion apparatus with set of wavelengths multicast function at the deficiencies in the prior art.

The technical solution of the utility model is as follows:

A kind of full optical code type conversion apparatus with set of wavelengths multicast function comprises RF signal source, mode locking semiconductor laser, erbium-doped fiber amplifier, first filter, Polarization Controller PC1, Polarization Controller PC2, crosses high power erbium-doped fiber amplifier, photonic crystal fiber, second filter, the 3rd filter; The RF signal source is used for sending the radiofrequency signal that repetition rate is 10GHz, mode locking semiconductor laser is used for described radiofrequency signal is carried out active mode locking, and to send repetition rate be that the ultrashort pulse sequence of 10GHz is served as pump light, erbium-doped fiber amplifier is used for pump light is carried out power amplification, first filter is used for the pump light after the power amplification is leached spontaneous emission noise, Polarization Controller PC2 is used for regulating the pumping polarization state of light, and Polarization Controller PC1 is used for regulating the polarization state of NRZ signal to be converted; Injected the high power erbium-doped fiber amplifier after NRZ flashlight to be converted and the pump light coupling and carry out power amplification, 50 meters photonic crystal fibers are used for taking place four-wave mixing effect, and second filter, the 3rd filter are used for leaching sideband.

The utility model is at ultra high-speed optical sub-network application background, a kind of code type conversion apparatus is proposed, adopt the nonlinear optics principle in the novel optical fiber, broken through the rate limit of " photoelectricity light " sign indicating number type transducer on the one hand, overcome the based semiconductor image intensifer on the other hand, electroabsorption modulator, the periodically poled lithium niobate wave-guide efficiency is low, Insertion Loss is big, tradition highly nonlinear optical fiber wavelength arranges inflexible drawback, has the conversion efficiency height, response speed is fast, advantages such as operating wavelength range is wide, simultaneously, can also finish the all-optical wave-length multicast functionality, can support the multimedia service in the advanced WDM/OTDM mixed light sub-network, have important practical value.

The utility model utilizes the four-wave mixing effect in the dispersion flattene high non-linear photon crystal optical fiber, realized that first speed is that the NRZ of 10Gbit/s changes to RZ sign indicating number type, the sign indicating number type transducer operation wavelength wideband adjustable of design, and in the conversion of sign indicating number type, realize wavelength conversion and binary channels set of wavelengths multicast function, had important function for the development of ultrahigh speed WDM/OTDM mixed light sub-network.

Description of drawings

Fig. 1 is the NRZ-RZ sign indicating number type transducer fundamental diagram based on four-wave mixing effect;

Fig. 2 is the internal structure based on the NRZ-RZ sign indicating number type transducer of four-wave mixing effect;

Fig. 3 is the example device that realizes the conversion of sign indicating number type based on four-wave mixing effect in the high non-linear photon crystal optical fiber;

Embodiment

Below in conjunction with specific embodiment, the utility model is elaborated.

Embodiment 1

A kind of energy realizes that full light NRZ is to the sign indicating number type conversion method of RZ, and in the conversion of sign indicating number type, can finish the full-light multicast function, concrete principle such as Fig. 1: the flashlight that carries data message is that the continuous light of λ s produces through modulation by wavelength, be NRZ code data stream, pump light is the narrow pulsewidth light pulse sequence of wavelength X p, can regard complete " 1 " the RZ sign indicating number of the less bit of duty ratio as, with both couplings, further inject high linear photon crystal optical fiber after the power amplification, because photonic crystal fiber dispersion flattene, in wideer wave-length coverage, all can satisfy phase-matching condition, obvious four-wave mixing effect takes place, cause producing two bundle ideler frequency light at flashlight and pump light both sides, because pump light is bit " 1 " ultrashort light pulse entirely, do not carry any information, and the four wave mixing effect is equivalent to an AND gate, therefore, cause two contained information of sideband and flashlight identical, for no other reason than that pump light is the less relatively burst pulse of duty ratio, make the numeric data code type of ideler frequency light correspondence become the RZ sign indicating number by the NRZ in the primary signal light, realized single to two sign indicating number type conversions.Left figure among Fig. 1, (a) for before four wave mixing takes place, the frequency domain spectrum after the four wave mixing is for taking place in (b), right figure (c) (d) (e) is corresponding time-domain signal light λ s (f), pump light λ p, the time domain waveform of ideler frequency light λ I1 and ideler frequency light λ I2.

Code type conversion apparatus of the present utility model as shown in Figure 2, the RF signal source is sent the radiofrequency signal that repetition rate is 10GHz, the injecting lock mould semiconductor laser carries out active mode locking to it, it is that the ultrashort pulse sequence of 10GHz is served as pump light that mode locking semiconductor laser sends repetition rate, pulsewidth is 1.9ps, centre wavelength is λ p, (EDFA) carries out power amplification to pump light at erbium-doped fiber amplifier, use filter 1 to leach spontaneous emission noise subsequently, after passing through Polarization Controller PC2 subsequently, with NRZ flashlight coupling to be converted, the polarization state that Polarization Controller PC1 on the NRZ flashlight branch road is used for regulating this light beam is to guarantee two-beam four wave mixing best results in high non-linear photon crystal optical fiber.Injected high power erbium-doped fiber amplifier (HP-EDFA after the two coupling, Keopsys company produces, operating wavelength range 1535nm-1565nm, saturation output power 34dBm, noise figure is less than 6dB) carry out power amplification, after enter 50 meters photonic crystal fibers, because flashlight and pumping light power higher (power 25dBm), four-wave mixing effect taking place in photonic crystal fiber, produce two sidebands in its both sides, uses two narrow band optical filters (filter 2 and filter 3) that sideband is leached respectively, just obtain a yard type switching signal, simultaneously, finish the wavelength conversion, realized the set of wavelengths multicast function.

The utility model adopts novel dispersion flattene high non-linear photon crystal optical fiber as core devices, the non linear coefficient that optical fiber is bigger has shortened required fiber lengths greatly, make the sign indicating number type transducer of institute's utility model compare with conventional optical fibers, anti-vibration, polarization property strengthen, system is more easy of integration, simultaneously, use less input power just can produce stronger non linear coefficient, greatly reduce system power dissipation.On the other hand, since the optical fiber dispersion that adopts smooth, it all has obvious four-wave mixing effect in wideer wave-length coverage, make that designed sign indicating number type transducer broad band wavelength in 19 nanometer range is tunable, and has binary channels set of wavelengths multicast function, optimum multicast signal ER and the Q factor are higher than 10dB and 7 respectively, and whole system is all optical fibre structure, is convenient to be connected with the existing fiber communication system.

Should be understood that, for those of ordinary skills, can be improved according to the above description or conversion, and all these improvement and conversion all should belong to the protection range of the utility model claims.

Claims (1)

1. full optical code type conversion apparatus with set of wavelengths multicast function, it is characterized in that, comprise RF signal source, mode locking semiconductor laser, erbium-doped fiber amplifier, first filter, Polarization Controller PC1, Polarization Controller PC2, cross high power erbium-doped fiber amplifier, photonic crystal fiber, second filter, the 3rd filter; The RF signal source is used for sending the radiofrequency signal that repetition rate is 10GHz, mode locking semiconductor laser is used for described radiofrequency signal is carried out active mode locking, and to send repetition rate be that the ultrashort pulse sequence of 10GHz is served as pump light, erbium-doped fiber amplifier is used for pump light is carried out power amplification, first filter is used for the pump light after the power amplification is leached spontaneous emission noise, Polarization Controller PC2 is used for regulating the pumping polarization state of light, and Polarization Controller PC1 is used for regulating the polarization state of NRZ signal to be converted; Injected the high power erbium-doped fiber amplifier after NRZ flashlight to be converted and the pump light coupling and carry out power amplification, 50 meters photonic crystal fibers are used for taking place four-wave mixing effect, and second filter, the 3rd filter are used for leaching sideband.

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