CN116632641A - A new self-oscillating optical frequency comb generator - Google Patents

Abstract

The invention discloses a new self-oscillating optical frequency comb generator, an OEO loop A, which is used in conjunction with a continuous spectrum laser and a photoelectric oscillator to generate an optical frequency comb; the signal separation component is passed through a 1x15 optical demultiplexer A is connected to the OEO loop A to generate real and imaginary signals; the transmission channel is connected to the signal separation component through a 1x15 optical demultiplexer B for signal transmission; the decoding component is connected to the transmission channel and used To restore the real part and imaginary part signals and perform decoding processing; wherein, the OEO loop A includes a single-mode optical fiber A, a PIN photodetector, an electric amplifier A and a bandpass Bessel filter; The error vector size, bit error rate, symbol error rate and Q factor of the received signal of the 300Gbps 116-QAM transmission receiving channel transmitted over the uncompensated optical fiber link of the standard single-mode fiber are strong, and their clear constellation diagram is strong, which is very important in coherent optical communication. high applicability.

Description

A new self-oscillating optical frequency comb generator

technical field

The invention belongs to the technical field of communication, in particular to a new self-oscillating optical frequency comb generator.

Background technique

Under the premise that the transmission capacity of optical fiber communication continues to increase, in order to obtain high data rates, increasing the number of WDM channels has received a lot of attention.

However, this approach also increases the complexity of the optoelectronic conversion and will result in much higher data rates than the optoelectronic transmitter and receiver can handle.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a new self-oscillating optical frequency comb generator, which solves the above-mentioned problems.

To achieve the above object, the present invention is achieved through the following technical solutions: a new self-oscillating optical frequency comb generator, comprising:

OEO loop A is used in conjunction with a continuum laser and an optoelectronic oscillator to generate an optical frequency comb;

The signal separation component is connected to the OEO loop A through a 1x15 optical demultiplexer A to generate real and imaginary signals;

The transmission channel is connected to the signal separation component through a 1x15 optical demultiplexer B for signal transmission;

A decoding component, connected to the transmission channel, is used to restore the real part and imaginary part signals and perform decoding processing;

Wherein, the OEO loop A includes a single-mode optical fiber A, a PIN photodetector, an electrical amplifier A and a bandpass Bessel filter, the PIN photodetector is connected to the electrical amplifier A and the single-mode optical fiber A, and the The single-mode fiber A is connected to the external signal and the connection spectrum laser, the band-pass Bessel filter is connected to the photoelectric oscillator, and the single-mode fiber is connected to the signal separation component through the 1×15 optical demultiplexer A.

On the basis of the above technical solutions, the present invention also provides the following optional technical solutions:

Further technical solution: the signal separation component includes a rectangular optical filter, a 16QAM modulator A and a beam splitter A, the rectangular optical filter is connected to a single-mode optical fiber A through a 1x15 optical demultiplexer A, and the splitter Beamer A is connected to the transmission channel through a 15x1 optical multiplexer.

A further technical solution: the transmission channel includes a loop structure of a single-mode fiber B and a photoelectric amplifier B, the single-mode fiber B is connected to the beam splitter A through a 15x1 optical multiplexer, and the photoelectric amplifier is connected to the single-mode fiber Mode fiber B connection.

Further technical solution: the decoding component includes a 90° optical mixer, a DSP digital signal processing module, a decision module and a 16QAM receiver, the DSP digital signal processing module is connected with the decision module and the 90° optical mixer, and the 90° ° The optical mixer is connected to the single-mode fiber B through a 1x15 optical demultiplexer B, and the decision module is connected to the 16QAM receiver.

A further technical solution: also includes: a homodyne receiving structure connected to a single-mode optical fiber B through a 1x15 optical demultiplexer B to generate a new self-oscillating optical frequency comb, and the homodyne receiving structure includes a photoelectric oscillator B, OEO loop B, single-mode fiber C and 1x15 optical demultiplexer C, the OEO loop B has the same structure as OEO loop A, and the OEO loop B is connected to the photoelectric oscillator B and 1x15 optical demultiplexer B connection.

A further technical solution: the input bit stream of the 16QAM modulator A is generated by a pseudo-random bit sequence generator.

A further technical solution: the beam splitter A is a beam splitter injected into the in-phase light modulator and the four-phase light modulator.

A further technical solution: the loop structure of the single-mode fiber B includes 80km of single-mode fiber per loop and cooperates with a photoelectric amplifier with an optical gain of 18dB. The loop structure of the single-mode fiber B uses three loops in total.

Beneficial effect

The invention provides a new self-oscillating optical frequency comb generator, which has the following advantages compared with the prior art

Beneficial effect:

1. In the OFC generation scheme, the microwave signal is replaced by a generated optoelectronic oscillator, which defines the frequency spacing between the generated carriers. In total, 15 carriers are generated, of which the center carrier on the receiving side is used for Generate Local Oscillator Optical Frequency Comb (LO-OFC), left and right carrier for 1 single-mode fiber A6QAM data modulation of 80km to 240km single-mode fiber, transmit 300Gbps116- over uncompensated fiber link of 80km to 240km standard single-mode fiber The error vector magnitude, bit error rate, symbol error rate and Q-factor of the received signal of the receive channel of QAM transmission and its clear constellation diagram strongly support the applicability of the proposed scheme in coherent optical communication.

Description of drawings

Fig. 1 is a schematic diagram of the self-oscillating optical frequency comb generation scheme of the present invention and its deployment in a coherent 16QAM transmission network.

Fig. 2 shows the generation result (a) of the OFC generation scheme of the present invention and the generation of a local oscillator (b) to generate an optical frequency comb.

Fig. 3 is the simulation result and constellation diagram of the present invention carrier 193.08THz and 193. single-mode optical fiber B12 THz in 80km to 240km optical fiber transmission.

Fig. 4 is the error vector magnitude and Q factor of the present invention.

Notes on reference signs: 1. Photoelectric oscillator A; 2. Continuous spectrum laser; 3. Band-pass Bessel filter; 4. Electric amplifier; 5. PIN photodetector; 6. Single-mode fiber A; 7. Optics Demultiplexer A; 8. Rectangular optical filter; 9. Beam splitter A; 10. 16QAM modulator A; 11. Optical multiplexer; 12. Single-mode fiber B; 13. Optical demultiplexer B; 14. 90° optical hybrid; 15. DSP digital signal processing module; 16. Judgment module; 17. 16QAM receiver; 18. Photoelectric oscillator B; 19. Optical demultiplexer C; 20. OEO loop B.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The specific implementation of the present invention will be described in detail below in conjunction with specific embodiments.

Referring to Figures 1-4, a new self-oscillating optical frequency comb generator is provided for an embodiment of the present invention, including:

The OEO loop A is used in conjunction with the continuum laser 2 and the photoelectric oscillator A1 to generate an optical frequency comb;

The signal separation component is connected to the OEO loop A through the 1x15 optical demultiplexer A7 to generate real and imaginary signals;

The transmission channel is connected to the signal separation component through a 1x15 optical demultiplexer B for signal transmission;

A decoding component, connected to the transmission channel, is used to restore the real part and imaginary part signals and perform decoding processing;

Wherein, the OEO loop A includes a single-mode optical fiber A6, a PIN photodetector 5, an electric amplifier A4 and a bandpass Bessel filter 3, and the PIN photodetector 5 is connected with the electric amplifier A4 and the single-mode optical fiber A6 , the single-mode optical fiber A6 is connected to the external signal and the connection spectrum laser, the band-pass Bessel filter 3 is connected to the photoelectric oscillator A1 device, and the single-mode optical fiber is connected to the signal separation component through the optical demultiplexer A7 of 1×15 connect.

Specifically, the signal separation component includes a rectangular optical filter 8, a 16QAM modulator A10, and a beam splitter A9, the rectangular optical filter 8 is connected to a single-mode optical fiber A6 through a 1x15 optical demultiplexer A7, and the 16QAM The modulator A10 is connected with the beam splitter A9, and the beam splitter A9 is connected with the transmission channel through a 15x1 optical multiplexer 11, and the input bit stream of the 16QAM modulator A10 is generated by a pseudo-random bit sequence generator (PRBS) , the beam splitter A9 is a beam splitter injected into the in-phase light modulator and the four-phase light modulator. The OEO loop A cooperates with the continuum laser 2 and the optical frequency comb generated by the photoelectric oscillator A1 to be decomplexed through the 1x15 optical demultiplexer A7, and the decomplexed signal passes through the rectangular optical filter 8 that filters the signal successively And the 16QAM modulator A10, the signal passing through the 16QAM modulator A10 is divided into a real part and an imaginary part (I and Q) by a fractionator A.

Specifically, the transmission channel includes a loop structure of a single-mode optical fiber B12 and a photoelectric amplifier, and the single-mode optical fiber B12 is connected to the beam splitter A9 through a 15x1 optical multiplexer 11, and the photoelectric amplifier is connected to the single-mode optical multiplexer 11. The optical fiber B12 is connected, and the photoelectric amplifier is connected to the decoding component through an optical demultiplexer B13 of 1x15. The loop structure of the single-mode optical fiber B12 includes 80km single-mode optical fiber and cooperates with the optical gain of the photoelectric amplifier. The optical gain of the single-mode optical fiber B12 is 18dB. The mode fiber B12 loop structure uses a total of three spanning rings. The purpose of this setting is to maintain the transmission advantage by adopting the loop structure of the single-mode optical fiber B12 and the optical amplifier B maintaining the gain of the optical signal.

In the above example, those skilled in the art should know that the number of cross-rings of the loop structure of the single-mode optical fiber B12 is set according to requirements, rather than just set to three.

Specifically, the decoding assembly includes a 90° optical mixer 14, a DSP digital signal processing module 15, a decision module 16 and a 16QAM receiver 17, and the DSP digital signal processing module 15 is connected with the decision module 16 and the 90° optical mixer 14 The 90° optical hybrid 14 is connected to the single-mode fiber B12 through the 1x15 optical demultiplexer B13, and the decision module 16 is connected to the 16QAM receiver 17. The 90° optical hybrid 14 is connected to the 1x15 optical demultiplexer B to receive the signal and restore the real and imaginary parts (I and Q) of the signal, and transmit it to the DSP digital signal processing module 15 for DSP off-line processing, and then make a decision , and the judged signal is decoded by a 16QAM modulator.

Specifically, it also includes: a homodyne receiving structure, connected to a single-mode fiber B12 through a 1x15 optical demultiplexer B13, for generating a new self-oscillating optical frequency comb, and the homodyne receiving structure includes a photoelectric oscillator B18, The OEO loop B20 and the 1x15 optical demultiplexer C19, the OEO loop B20 has the same structure as the OEO loop A, and the OEO loop B20 is connected to the photoelectric oscillator B18 and the 1x15 optical demultiplexer B13. Using an optical homodyne receiver structure, where the local oscillator (LO) source is replaced by the same OFC source used at the transmitter end, as shown in Figure 1, however, the laser source is replaced by a center carrier frequency (193.1THz), the center The carrier frequency is reserved for generating the LO self-oscillating OFC source.

In the embodiment of the present invention, the OEO loop A receives one of the signals separated into two channels, and cooperates with the photoelectric oscillator A1 and the continuum laser 2 to generate an optical frequency comb, and the generated optical frequency comb passes through a 1x15 optical demultiplexer A7 carries out the decomplexing process and the signal after decomplexing passes through the rectangular optical filter 8 and the 16QAM modulator A10 that filter the signal successively, and the signal through the 16QAM modulator A10 is divided into a real part and an imaginary part (I and Q), using 15x1 optical multiplexer 11 to jointly modulate the carrier and inject data into the transmission channel and transmit the signal to the decoding component through the transmission channel. The transmission channel adopts the loop structure of single-mode fiber B12 and maintains the optical signal gain The optical amplifier B is used to maintain the transmission advantage, and the optical demultiplexer B with the same number of channels is used in the decoding component to separate the optical signal and identify each carrier, and the identified carrier is transmitted to the 90° optical mixer 14 to restore the signal Real part and imaginary part (I and Q), and transmit to DSP digital signal processing module 15 and carry out DSP off-line processing, then judge, the signal after the judgment is decoded by 16QAM receiver 17, simultaneously at the optical separation of receiving end The signal passes through a homodyne receiving structure containing an OEO loop A whose local oscillator (LO) source is replaced by the same OFC source used at the transmitter end, the laser source being replaced by a center carrier frequency ( 193.1THz), the center carrier frequency is reserved for generating the LO self-oscillating OFC source.

The simulation results are shown in Figure 2. The generated comb contains 15 carrier frequencies and has a high carrier-to-noise ratio. The resulting OFC and self-oscillating local oscillator results can be seen in Figure 2. As can be seen, the amplitude difference varies from left to right. These carriers are filtered using a rectangular optical filter 8 and individually passed through a 16QAM modulator with 20Gb data rates overlaid on each carrier. The filtered signal is split into real and imaginary parts (I and Q) using beam splitters injected into in-phase and quadrature-phase (IQ) optical modulators. The signals from both ends are combined using an optical combiner to produce the desired 16QAM signal.

The system proposed in this patent performs well in terms of bit error rate, symbol error rate and Q factor. Figure 3 shows the BER performance of the proposed scheme with different fiber spans. It can be seen that this scheme provides the best results for 80km and 160km fiber transmission, and the BER value at 240km is still below the threshold. Additionally, the constellation diagrams for Channel 1 and Channel 2 can also be seen in the inset of Figure 3. Meanwhile, the error vector magnitude, bit error rate, symbol error rate and Q factor of the receiving channel can be seen in Fig. 4. From the obtained results, it can be concluded that the proposed OFC generation scheme has the potential to be deployed in 1 single-mode fiber A6QAM coherent optical communication systems with fiber spans ranging from 80 km to 240 km.

The invention is based on the SO-OFC generator on the OLT and ONU side, replaces the laser array on the OLT side as a transmitter, and acts as a local oscillator source on the ONU side. Compared with conventional LiNbO3 MZMs, EAM offers better performance in terms of lower power consumption and faster response. Meanwhile, EAMs have been widely used as transmitters in high-speed and long-distance optical communication systems due to their ease of integration with relatively small-sized lasers. Self-oscillating OFCs are generated by a cascaded configuration of EAMs and polarization controllers. The self-oscillating loop is configured by using a high-speed PIN photodetector, electrical amplifier 4, standard single-mode fiber and a bandpass Bessel filter 3. 20Gbps 16QAM data is modulated on each carrier and without using dispersion compensating fiber in the transmission line. At the receiving end, a Gaussian optical filter is used to identify the carrier signal, and a 16QAM receiver 17 is used to detect the in-phase and quadrature phases of the incoming signal.

In the OFC generation scheme of the present invention, the microwave signal is replaced by a generated optoelectronic oscillator, which defines the frequency spacing between the generated carriers, in total, 15 carriers are generated, where the center carrier on the receiving side is used for Generate Local Oscillator Optical Frequency Comb (LO-OFC), left and right carrier for 1 single-mode fiber A6QAM data modulation of 80km to 240km single-mode fiber, transmit 300Gbps116- over uncompensated fiber link of 80km to 240km standard single-mode fiber The error vector magnitude, bit error rate, symbol error rate and Q-factor of the received signal of the receive channel of QAM transmission and its clear constellation diagram strongly support the applicability of the proposed scheme in coherent optical communication.

It should be noted that in this document, relational terms such as first, second, etc., A and B are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these No such actual relationship or order exists between entities or operations. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (8)

1. A new self-oscillating optical frequency comb generator, further comprising:

the OEO loop A is matched with the continuous spectrum laser (2) and the photoelectric oscillator A (1) for use and is used for generating an optical frequency comb;

a signal separation component connected to the OEO loop a through an optical demultiplexer a (7) of 1x15 for generating real and imaginary signals;

the transmission channel is connected with the signal separation assembly through the optical demultiplexer B of 1x15 and is used for signal transmission;

the decoding component is connected with the transmission channel and is used for recovering the real part and the imaginary part signals and performing decoding processing;

the OEO loop A comprises a single-mode fiber A (6), a PIN photoelectric detector (5), an electric amplifier A (4) and a band-pass Bessel filter (3), wherein the PIN photoelectric detector (5) is connected with the electric amplifier A (4) and the single-mode fiber A (6), the single-mode fiber A (6) is connected with an external signal and a connection spectrum laser, the band-pass Bessel filter (3) is connected with the photoelectric oscillator A (1), and the single-mode fiber is connected with a signal separation assembly through an optical demultiplexer A (7) of 1x 15.

2. The new self-oscillating optical frequency comb generator according to claim 1, characterized in that the signal separation assembly comprises a rectangular optical filter (8), a 16QAM modulator a (10) and a beam splitter a (9), the rectangular optical filter (8) being connected to the single-mode optical fiber a (6) by a 1x15 optical demultiplexer a (7), the beam splitter a (9) being connected to the transmission channel by a 15x1 optical multiplexer (11).

3. The new self-oscillating optical frequency comb generator according to claim 1, characterized in that the transmission channel comprises a loop structure of a single-mode fiber B (12) and an optical amplifier B, the single-mode fiber B (12) being connected to the beam splitter a (9) by a 15x1 optical multiplexer (11), the optical amplifier being connected to the single-mode fiber B (12).

4. A new self-oscillating optical frequency comb generator according to claim 3, characterized in that the decoding assembly comprises a 90 ° optical mixer (14), a DSP digital signal processing module (15), a decision module (16) and a 16QAM receiver (17), the DSP digital signal processing module (15) being connected to the decision module (16) and to the 90 ° optical mixer (14), the 90 ° optical mixer (14) being connected to the single-mode optical fiber B (12) via a 1x15 optical demultiplexer B (13), the decision module (16) being connected to the 16QAM receiver (17).

5. The new self-oscillating optical frequency comb generator of claim 3, further comprising: a homodyne receiving structure connected with a single-mode optical fiber B (12) through an optical demultiplexer B (13) of 1x15 and used for generating a new self-oscillating optical frequency comb, wherein the homodyne receiving structure comprises an optoelectronic oscillator B (18), an OEO loop B (20) and an optical demultiplexer C (19) of 1x15, the OEO loop B (20) is identical to the OEO loop A in structure, and the OEO loop B (20) is connected with the optoelectronic oscillator B (18) and the optical demultiplexer B (13) of 1x 15.

6. The new self-oscillating optical frequency comb generator of claim 2, characterized in that the 16QAM modulator a (10) input bit stream is generated by a pseudo-random bit sequencer.

7. A new self-oscillating optical frequency comb generator according to claim 2, characterized in that the beam splitter a (9) is a beam splitter injected into an in-phase optical modulator and a four-phase optical modulator.

8. A new self-oscillating optical frequency comb generator according to claim 3, characterized in that the loop structure of the single-mode fiber B (12) comprises 80km of single-mode fiber per span loop and cooperates with the optical gain of the photo-amplifier by 18dB, and the loop structure of the single-mode fiber B (12) uses three spans in total.