WO2013097384A1 - Ultra-dense wavelength-division multiplexing system and method - Google Patents

Abstract

A wavelength-division multiplexing system and method. The wavelength-division multiplexing system comprises: an N number of optical frequency comb wavelength-division subsystems used for outputting combined signals, where N is an integer greater than or equal to two, and a coupler used for combining into a single-route signal by interleaved multiplexing the combined signals outputted by the N number of optical frequency comb wavelength-division subsystems. Each optical frequency comb wavelength-division multiplexing subsystem comprises: an optical frequency comb, a demultiplexer used for isolating a K number of optical carrier signals from the combs, where K is an integer greater than or equal to one, a K number of modulators connected to output ends of the demultiplexer, and a multiplexer connected to all output ends of the K number of modulators. The technical solution utilizes the multiple optical frequency comb wavelength-division multiplexing subsystems to implement ultra-dense wavelength-division multiplexing, and is easy to implement.

Description

 Ultra-dense wavelength division multiplexing system and method

Technical field

 The present invention relates to the field of optical communications, and in particular, to an ultra-dense wavelength division multiplexing system and method.

Background technique

 In a wavelength division multiplexing (WDM) system of a passive optical network (PON), an optical line terminal OLT needs to generate a downlink data signal of multiple users.

 At present, there are two main methods: one is integrated on-chip by a multi-channel distributed feedback laser and a modulator, and then the multiplexed signals are coupled into the same fiber for transmission; the other is to use a single optical frequency comb. An optical carrier signal of multiple equal-interval frequencies is generated, each optical carrier signal is modulated, and the multiple modulated signals are coupled into the same optical fiber for transmission.

 Both of these programs have their own drawbacks. For the first method, since the frequency shift of each laser belongs to a random process independent of each other, after photoelectric modulation, each signal spectrum may be aliased when the combined wave is output to the optical fiber; and for the ultra-dense wavelength division multiplexing system, The number of carriers required is even hundreds, which results in a large number of lasers and modulators on the integrated chip. There is currently no integrated chip that satisfies this requirement. For the second method, the optical carrier signals of multiple equal-interval frequencies separated from the optical frequency comb are not easy to be spectrally shifted, and the implementation of the splitting is simple, but due to the limitation of the related art, it is difficult to generate by a single optical frequency comb. With hundreds of optical carrier signals, the existing optical frequency comb can not meet the requirements of ultra-dense wavelength division multiplexing.

Summary of the invention

 The present invention provides an ultra-dense wavelength division multiplexing system and method for implementing ultra-dense wavelength division multiplexing using an optical frequency comb.

 In order to solve the above technical problems, the present invention uses the following technical solutions:

 A wavelength division multiplexing system, the wavelength division multiplexing system is an ultra-dense wavelength division multiplexing system, comprising N optical frequency comb wavelength division multiplexing subsystems and couplers, wherein N is an integer greater than or equal to 2, wherein :

N said optical frequency comb wavelength division multiplexing subsystems are configured to: output a multiplexed signal; The coupler is configured to: interlace and multiplex the combined signals of the N optical frequency band division multiplexing subsystems to form a combined signal;

 Wherein, the N optical frequency combo division multiplexing subsystems comprise an optical frequency comb, a splitter, K modulators and a combiner, and K is an integer greater than or equal to 1, wherein:

 The splitter is configured to: separate K optical carrier signals from the optical frequency comb;

 K modulators are connected to the splitter output;

 The combiner is coupled to the K modulator outputs.

 Optionally, the frequency intervals of the K optical carrier signals are equal.

 Optionally, the wavelength division multiplexing system further includes:

 N lasers, wherein the output signal of each laser is a seed source of an optical frequency comb multiplex sub-system.

 Optionally, the frequency spacing of the N lasers is equal, wherein the frequency spacing of the K optical carrier signals is equal to N times the frequency interval of the N lasers.

 Optionally, the wavelength division multiplexing system further includes a laser, a seed source optical frequency comb and a splitter, wherein:

 The seed source optical frequency comb is connected to the laser output end;

 The splitter is configured to: separate N equal-frequency-interval optical carrier signals from the seed light source optical comb; wherein each of the N optical carrier signals is an optical frequency comb The seed source of the sub-multiplexing subsystem.

A method for implementing wavelength division multiplexing, the method for implementing ultra-dense wavelength division multiplexing, comprising the following steps:

 Separating K optical carrier signals from N optical frequency combs, respectively, is an integer greater than or equal to 2, and Κ is an integer greater than or equal to 1;

 Performing a trickle modulation on one of the optical carrier signals;

Combining the optical carrier signals modulated by the chirp circuit to obtain a chirped multiplexed signal; and interpolating and multiplexing the combined multiplexed signals to synthesize one signal. Optionally, the K optical carrier signals are K equal frequency interval optical carrier signals.

 Optionally, the method further includes:

 Set up one laser;

 The output signals of each of the different lasers are used as seed sources for different optical frequency combs.

 Optionally, the method further includes:

 The frequency intervals of the lasers are set to be equal, wherein a frequency interval of the one of the lasers is equal to 1/Ν of a frequency interval of the optical carrier signals.

 Optionally, the method further includes:

 Setting the optical frequency comb of the laser and the seed source;

 Using the output signal of the laser as a seed source of the optical frequency comb of the seed source;

 Separating the optical carrier signals of equal frequency intervals from the optical frequency comb of the seed source; respectively, respectively, each of the different optical carrier signals of the optical carrier signals as one of the optical frequency combs Seed light source for different optical frequency combs.

In the above technical solution, the optical frequency comb wavelength division multiplexing subsystem comprises an optical frequency comb, a splitter that separates multiple independent optical carrier signals from the optical frequency comb, and a combiner that synthesizes multiple independent optical carrier signals, thereby ensuring each The multiplexed signal output by the optical frequency comb-wave division multiplexing subsystem may include a plurality of optical carrier signals; and the plurality of optical frequency-combined-wavelength division multiplexing subsystem output signals are coupled to realize a dense wave of the optical wave signal Sub-multiplexing, simple implementation; In addition, for each optical-frequency comb-wavelength division multiplexing subsystem, since the combined multiplexed signal that does not require its output contains several hundred optical carrier signals, the optical frequency comb existing in the related art Both the generation and the splitter can be used in the optical frequency band division multiplexing subsystem in the embodiment of the present invention, so that the technical solution is more easily popularized and used. BRIEF abstract

 1 is a composition diagram of an ultra-dense wavelength division multiplexing system according to the embodiment;

 2 is a composition diagram of an ultra-dense wavelength division multiplexing system according to an application example;

3 is a composition diagram of another ultra-dense wavelength division multiplexing system according to an application example; 4 is a spectrum diagram after wavelength division multiplexing using the ultra-dense wavelength division multiplexing system of the application example; FIG. 5 is a spectrum diagram after wavelength division multiplexing using a single optical frequency comb;

 FIG. 6 is a flowchart of the ultra-dense wavelength division multiplexing method of the embodiment. Preferred embodiment of the invention

 In order to make the objects, the technical solutions and the advantages of the present invention more clearly, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments of the present application may be arbitrarily combined with each other. These combinations are all within the scope of the invention.

 FIG. 1 is a composition diagram of an ultra-dense wavelength division multiplexing system according to the embodiment.

 The system includes N optical frequency comb wavelength division multiplexing subsystems and couplers, and N is an integer greater than or equal to 2, where:

 N said optical frequency comb wavelength division multiplexing subsystems are configured to: output a multiplexed signal;

 The coupler is configured to: interleave and multiplex the N combined signals output by the optical frequency band division multiplexing subsystem to be combined into one signal;

 The optical frequency band division multiplexing subsystem further includes an optical frequency comb, a splitter, K modulators and a combiner, wherein:

 The splitter is configured to: separate K optical carrier signals from the optical frequency comb, K is an integer greater than or equal to 1; wherein, the frequency intervals of the K optical carrier signals may be equal;

 K modulators are connected to the output of the branching filter;

 The combiner is coupled to the K modulator outputs.

In order to provide a seed light source for the above optical frequency comb, the system may further comprise N lasers, wherein each laser is a seed light source of an optical frequency comb wavelength division multiplexing subsystem; the frequency spacing of the N lasers may be equal, K The frequency spacing of the optical carrier signals is equal to N times the N laser frequency intervals; or may further include a laser, a seed source optical frequency comb connected to the single laser output, and being arranged to be separated from the seed source optical frequency comb a splitter of N equal-frequency-interval optical carrier signals; wherein each of the N optical carrier signals is an optical-frequency comb-wavelength division multiplexing subsystem The optical frequency comb provides a seed light source, and a solution for providing a seed light source for the optical frequency comb in the related art can be used in the present embodiment. The optical frequency comb in this embodiment may include an intensity modulator IM for receiving a seed light source from an external device such as the laser or seed light source comb described above; a phase modulator PM cascading with the intensity modulator IM And a microwave source that supplies microwave power to the intensity modulator IM and the phase modulator PM.

 The intensity modulator IM described above can flatten the frequency envelope generated by the optical frequency comb to avoid a large power difference between the optical carrier signals separated by the splitter.

 Since the output signal of the phase modulator PM satisfies the Bessel function form, the depth of the phase modulation can be changed by increasing the input power of the microwave source, and then the values of the Bessel functions of each order are changed to obtain a plurality of higher-order frequency components. Prepare for ultra-dense wavelength division multiplexing.

 However, in actual implementation, since the available microwave source power is limited, or it is desirable to control the output power of the microwave source for cost reasons, the microwave source power with respect to the number of phase modulator cascades may be a monotonically decreasing function. This feature sets a plurality of sequentially arranged phase modulators PM in the optical frequency comb.

Two application examples are given below for the above embodiment to further clarify the present invention.

 Application example 1

 FIG. 2 is a composition diagram of an ultra-dense wavelength division multiplexing system according to an application example.

 The system comprises five optical frequency comb wavelength division multiplexing subsystems for outputting a combined wave signal, a coupler for interpolating and multiplexing the combined wave signals output by the five optical frequency band division multiplexing subsystems, and 5 For each laser, the output signal of each laser is a seed source of an optical frequency combo-wavelength division multiplexing subsystem, and each laser output signal has a frequency interval of 5 GHz.

 Wherein, each optical frequency comb wavelength division multiplexing subsystem further comprises:

An optical frequency comb, a splitter for separating 27 optical carrier signals from the optical comb, 27 modulators connected to the output of the splitter, and connected to the output of the 27 modulators Combiner. among them:

 For optical frequency υ:

 The interior includes an intensity modulator IM, two sequentially cascaded phase modulators PM connected to the output of the intensity modulator IM, and a microwave source that provides microwave power for the IM and the two PMs; in this application example The half-wave voltages of the intensity modulator IM and the phase modulator PM are 5V and 4V, respectively, and the microwave source is transmitted to the intensity modulator IM. The microwave input powers of the two cascaded phase modulators PM are 24dBm, 31.58dBm and 28.62, respectively. dBm. The intensity input of the intensity modulator IM and the two phase modulators PM can be set to 1 times, 3 times and 2 times the half-wave voltage of the respective modulator.

 Of course, in this application example, the number of phase modulator PMs in the optical frequency comb may also be one. In this case, the microwave input amplitude of the phase modulator PM needs to be set to be five times the modulator half-wave voltage. Both of the optical combs of the structure can produce a spectrum containing an optical carrier signal number of 27, an optical carrier signal with a frequency spacing of 25 GHz, and an amplitude jitter of less than 2 dB.

 For a splitter for separating 27 optical carrier signals from an optical comb: it may be an array based waveguide grating.

 For 27 modulators connected to the splitter: Each modulator can modulate the optical carrier signal using a non-return-to-zero code NRZ.

Application example 2

 FIG. 3 is a composition diagram of another ultra-dense wavelength division multiplexing system according to an application example.

 The system comprises the system comprising five optical frequency comb wavelength division multiplexing subsystems for outputting a combined wave signal, and a coupler for interpolating and multiplexing the combined wave signals output by the five optical frequency combo wavelength division multiplexing subsystems. The system further includes a laser, a seed source optical frequency comb connected to the laser output end, and a splitter for separating five optical carrier signals from the seed source optical frequency comb, in the five optical carrier signals Each optical carrier signal is a seed light source of an optical frequency comb-wave division multiplexing subsystem, and the frequency intervals of the five optical carrier signals are 5 GHz. among them,

 The configuration of the optical frequency comb wavelength division multiplexing subsystem is the same as the configuration in the application example 1;

The seed light source comb includes an intensity modulator IM connected to the output end of the IM Connected to an intensity modulator PM, and a microwave source that supplies microwave power to the IM and PM; in this application example, the half-wave voltages of the intensity modulator IM and the phase modulator PM are also 5V and 4V, respectively, and the microwave source The input to the intensity modulator IM, the microwave input power of the phase modulator PM is 30 dBm and 25.6 dBm, respectively. The microwave input amplitudes of the intensity modulator IM and the phase modulator PM can be set to be twice and 1.5 times the half-wave voltage of the respective modulators.

 It can be clearly seen from the above application example 1 and application example 2 that the signal output by the coupler of the ultra-dense wavelength division multiplexing system having the above structure can include 5*27=135 optical carrier signals in the 3 dB bandwidth range, as shown in the figure. 4; far more than 27 optical carrier signals obtained in a 3dB bandwidth range using a single optical frequency comb, as shown in Figure 5; and the optical frequency comb from the optical frequency band division multiplexing subsystem in the system The splitter that separates 27 optical carrier signals only requires a channel spacing of 25 GHz. The existing splitter can satisfy this requirement and is simple to implement.

FIG. 6 is a flowchart of the ultra-dense wavelength division multiplexing method of the embodiment.

 5601: Separating K optical carrier signals from N optical frequency combs, N is an integer greater than or equal to 2, and K is an integer greater than or equal to 1;

 The frequency spacing between the K optical carrier signals can be equal;

 In order to provide a seed light source for the optical frequency comb, N lasers can also be provided, and the output signals of each different laser are used as seed light sources of different optical frequency combs; the frequency intervals of the set N lasers can also be equal, the frequency of N lasers The interval is equal to 1/N of the frequency interval of the K optical carrier signals;

 Or setting the laser and seed source optical frequency comb; using the output signal of the laser as the seed light source of the seed source optical frequency comb; separating N equal-frequency-interval optical carrier signals from the seed source optical frequency comb, respectively, from N light Each of the different optical carrier signals separated in the carrier signal is used as a seed source for each of the N optical frequency combs.

 5602. Perform K-channel modulation on the K optical carrier signals.

 S603, combining the optical carrier signals modulated by the K channel;

 S604. Perform an inter-multiplexing and multiplexing of the N-way multiplexed signals to synthesize one signal.

One of ordinary skill in the art will appreciate that all or part of the steps in the above methods may be passed through the program. The instructions are related to hardware completion, and the program can be stored in a computer readable storage medium such as a read only memory, a magnetic disk, or an optical disk. Optionally, all or part of the steps of the foregoing embodiments may also be implemented by using one or more integrated circuits. Accordingly, each module/unit in the foregoing embodiment may be implemented in the form of hardware, or may use software functions. The form of the module is implemented. The invention is not limited to any specific form of combination of hardware and software.

 It is to be understood that the invention may be embodied in other forms and modifications without departing from the spirit and scope of the invention.

Industrial Applicability In the above technical solution, the optical frequency comb wavelength division multiplexing subsystem includes an optical frequency comb, a splitter that separates multiple independent optical carrier signals from the optical frequency comb, and a combiner that synthesizes multiple independent optical carrier signals. Therefore, it is ensured that the multiplexed signal outputted by each optical frequency band division multiplexing subsystem can include multiple optical carrier signals; and the plurality of optical frequency combo multiplexed subsystem output signals are coupled to realize the optical signal Dense wavelength division multiplexing, simple implementation; In addition, for each optical frequency comb wavelength division multiplexing subsystem, since the multiplexed signal that does not require its output contains hundreds of optical carrier signals, the related art exists. The optical frequency comb generation and the demultiplexer can be used in the optical frequency combo wavelength division multiplexing subsystem in the embodiment of the present invention, so that the technical solution is more easily popularized and used. Therefore, the present invention has strong industrial applicability.

Claims

Claim

 A wavelength division multiplexing system, the wavelength division multiplexing system is an ultra-dense wavelength division multiplexing system, comprising N optical frequency comb wavelength division multiplexing subsystems and couplers, and N is an integer greater than or equal to 2 , among them:

N said optical frequency comb wavelength division multiplexing subsystems are configured to: output a multiplexed signal;

 The coupler is configured to: interleave and multiplex the N combined signals output by the optical frequency band division multiplexing subsystem to be combined into one signal;

 Wherein, the N optical frequency combo division multiplexing subsystems comprise an optical frequency comb, a splitter, K modulators and a combiner, and K is an integer greater than or equal to 1, wherein:

 The splitter is configured to: separate K optical carrier signals from the optical frequency comb;

 K modulators are connected to the splitter output;

 The combiner is coupled to the K modulator outputs.

 2. The wavelength division multiplexing system according to claim 1, wherein

 The frequency intervals of the K optical carrier signals are equal.

 3. The wavelength division multiplexing system according to claim 1 or 2, wherein the wavelength division multiplexing system further comprises: N lasers, wherein each of the laser output signals is an optical frequency comb wavelength division multiplexing subsystem Seed light source.

 4. The wavelength division multiplexing system according to claim 3, wherein

 The frequency spacing of the N lasers is equal, wherein the frequency intervals of the K optical carrier signals are equal to N times the frequency interval of the N lasers.

 5. The wavelength division multiplexing system according to claim 1 or 2, wherein the wavelength division multiplexing system further comprises a laser, a seed source optical frequency comb and a demultiplexer, wherein:

 The seed source optical frequency comb is connected to the laser output end;

 The splitter is configured to: separate N equal-frequency-interval optical carrier signals from the seed light source optical comb; wherein each of the N optical carrier signals is an optical frequency comb The seed source of the sub-multiplexing subsystem.

6. A method for implementing wavelength division multiplexing, the method for implementing ultra-dense wavelength division multiplexing, comprising the following steps: Separating K optical carrier signals from N optical frequency combs respectively, N is an integer greater than or equal to 2, and Κ is an integer greater than or equal to 1;

 Performing a trickle modulation on one of the optical carrier signals;

 The optical carrier signals modulated by the chirps are combined to obtain a chirped multiplexed signal; and the multiplexed signals of the spurs are interleaved and multiplexed to synthesize one signal.

 7. The method of claim 6 wherein:

 The one of the optical carrier signals is an optical carrier signal of equal frequency intervals.

 8. The method of claim 6 or 7, the method further comprising:

 Set up one laser;

 The output signals of each of the different lasers are used as seed sources for different optical frequency combs.

 9. The method of claim 8, the method further comprising:

 The frequency intervals of the lasers are set to be equal, wherein a frequency interval of the one of the lasers is equal to 1/Ν of a frequency interval of the optical carrier signals.

 10. The method of claim 6 or 7, the method further comprising:

 Setting the optical frequency comb of the laser and the seed source;

 Using the output signal of the laser as a seed source of the optical frequency comb of the seed source;

 Separating the optical carrier signals of equal frequency intervals from the optical frequency comb of the seed source; respectively, respectively, each of the different optical carrier signals of the optical carrier signals as one of the optical frequency combs Seed light source for different optical frequency combs.