CN103297016B

CN103297016B - Optical transmitter and optical communication method

Info

Publication number: CN103297016B
Application number: CN201210120329.2A
Authority: CN
Inventors: 莫今瑜; 李奕; 吕超
Original assignee: Oclaro Technology Ltd
Current assignee: Lumentum Technology UK Ltd
Priority date: 2012-03-01
Filing date: 2012-04-11
Publication date: 2020-06-19
Anticipated expiration: 2032-04-11
Also published as: CN103297016A

Abstract

An optical transmitter and an optical communication method, and a method and apparatus for performing an optical switching function are disclosed. The method comprises the following steps: generating a control signal according to a switching rule of a signal to be switched, wherein an 'l' state of the control signal corresponds to an on state of the switching device and a '0' state of the control signal corresponds to an off state of the switching device; performing an and operation on the generated control signal and the signal to be switched to obtain a switched signal; and outputting the switched signal. The present disclosure provides methods and apparatus that can eliminate the use of switching devices while still performing switching functions without any negative impact on system performance.

Description

Optical transmitter and optical communication method

Technical Field

The present disclosure relates to the field of digital communication/optical communication, and more particularly, to a method and apparatus for performing an optical switching function without a separate optical switching device, and an optical transmitter implemented for the switching function and an optical communication method without a separate optical switch.

Background

Switching devices are widely used in the field of electro-optical communications to perform signal switching functions. As the operating frequency of the switching device increases, problems such as transition time and jitter become more important.

For example, in an exemplary PIC (planar integrated circuit) system, TcMZ (Tunable compact Mach-Zehnder) may be used as a modulated wavelength Tunable laser. To obtain fast switching between wavelengths, a dual TcMZ laser system may be employed. Here, a high-speed optical switching device is required to switch the high-speed burst between the two TcMZ lasers in the nanosecond range in order to ensure that the high-speed burst is modulated onto the optical signal emitted from only one TcMZ laser at any one time, while no high-speed burst is modulated onto the optical signals emitted from the two TcMZ lasers during the guard time. For this reason, the following options are available.

The first option is to use SOA (semiconductor optical amplifier) or InP MZ as a shutter. When using an SOA as a shutter, there is an oscillation of about 4GHz and the transition time of the optical switching device from one stable state to another is about 1 us. When using an InP MZ as a shutter, there is a long lag in the optical power response, and the transition time of the optical switching device is about several tens of milliseconds. Therefore, the option of using SOA or InP MZ as a shutter cannot be applied to the high-speed tunable laser described above.

The second option is to use an external high speed optical switch. However, such high speed optical switching devices are very limited in their suppliers and therefore expensive. In addition, such optical switching devices require additional external drivers to manage the switching function and cannot ensure that the entire wavelength band is supported. Therefore, the option of using an external high-speed optical switch is not suitable for the high-speed tunable laser described above.

A third option is to use a non-linear polarization rotation method via the Kerr effect or SOA. This approach is involved in some research papers, but is not suitable for commercial exploitation.

Accordingly, there is a need for a method and apparatus for performing a switching function of a switching device when no switching device is required or existing switching device performance does not meet system requirements, and for an optical communication method and optical transmitter for switching an input signal between two or more cooperating optical transmitters without the use of an optical switch.

Disclosure of Invention

According to a first aspect of the present disclosure, a method is provided for performing an optical switching function without the need for a separate optical switching device. The method comprises the following steps: generating a control signal according to a switching rule of a signal to be switched, wherein a '1' state of the control signal corresponds to an on-state of the switching device and a '0' state of the control signal corresponds to an off-state of the switching device; performing an and operation on the generated control signal and the signal to be switched to obtain a switched signal; and outputting the switched signal.

According to a second aspect of the present disclosure, there is provided an apparatus that performs an optical switching function without a separate optical switching device. The device comprises the following components: a controller generating a control signal according to a switching rule of a signal to be switched, wherein a '1' state of the control signal corresponds to an on state of the switching device and a '0' state of the control signal corresponds to an off state of the switching device; and a logic unit coupled with the controller for performing an and operation on the generated control signal and the signal to be switched to obtain a switched signal and outputting the switched signal.

According to a third aspect of the present disclosure, an optical communication device is provided. The communication device includes: a controller generating one or more control signals according to a switching regulation of an input high-speed NRZ signal stream, wherein a "1" state of each control signal corresponds to an ON state of the optical switching device and a "0" state of each control signal corresponds to an OFF state of the optical switching device; a logic unit coupled to the controller for performing an AND operation on each control signal with the input high speed NRZ signal stream to obtain one or more switched high speed NRZ signal streams; one or more modulators coupled to the logic unit; and one or more lasers each coupled to one of the one or more modulators, wherein each modulator is configured to modulate a corresponding one of the one or more switched high speed NRZ signal streams onto an optical signal emitted from the laser coupled to that modulator.

According to a fourth aspect of the present disclosure, a light emitter is provided. The light emitter includes: a plurality of cooperative optical transmitters for modulating a plurality of electrical signals onto a plurality of optical signals, respectively; a control unit coupled to the plurality of coordinated optical transmitters for converting an input signal into a plurality of electrical signals and providing the plurality of electrical signals to the plurality of coordinated optical transmitters, wherein only one of the plurality of electrical signals carries the input signal at a time; and an optical combiner coupled to the plurality of coordinated optical transmitters for combining the modulated optical signals output from the plurality of coordinated optical transmitters into a single optical signal output for transmission.

According to a fifth aspect of the present disclosure, a method for optical communication is provided. The method comprises the following steps: converting an input signal into a plurality of electrical signals, wherein only one of the plurality of electrical signals carries the input signal at a time; modulating the plurality of electrical signals onto a plurality of optical signals, respectively, to obtain a plurality of modulated optical signals; and combining the plurality of modulated optical signals into a single optical signal output for transmission.

By using the method and apparatus of the present disclosure, switching functions can be performed, providing a simple and feasible alternative when no switching device is required or the performance of the switching device does not meet system requirements. Especially in high speed systems such as optical communication systems, where the operating frequency and/or transition time of the switching device adversely affects the system performance, the method and apparatus provided by the present disclosure can perform the switching function of the switching device instead of the switching device without any negative impact on the system performance.

Drawings

The present disclosure will now be described in detail by way of specific embodiments with reference to the accompanying drawings. The same or similar elements are denoted by the same reference numerals in the drawings, in which:

fig. 1 is a schematic diagram showing a conventional switching device S;

fig. 2 shows an exemplary switching rule of the switching device S;

fig. 3 illustrates an apparatus for performing a handover function according to an exemplary embodiment of the present disclosure;

FIG. 4 is a schematic illustration of control signals generated according to the exemplary switching rule shown in FIG. 2;

FIG. 5 illustrates an exemplary block diagram of a logic unit in the device shown in FIG. 3;

fig. 6 shows a flow chart of a method for performing a handover function according to an exemplary embodiment of the present disclosure;

FIG. 7 is an exemplary high speed system to which the present disclosure may be applied;

FIG. 8 is a schematic diagram of a portion of the signals within the high speed system of FIG. 7;

fig. 9 illustrates an optical transmitter according to an exemplary embodiment of the present disclosure; and is

Fig. 10 shows a flowchart of an optical communication method according to an exemplary embodiment of the present disclosure.

Detailed Description

Fig. 1 shows a schematic diagram of a conventional switching device. As shown in fig. 1, the switching device S can switch an Input terminal carrying an Input signal Input to one or more of the n output channels C1, C2, cnj-1, Cn under the control of the Enable signal Enable to switch the Input signal Input to one or more output channels according to the switching rule. It will be appreciated by those skilled in the art that although fig. 1 shows n output channels, there may be only one output channel, depending on the actual needs.

The Enable signal Enable corresponds to a switching rule of the switching device S, and the switching rule may be set according to actual needs. Fig. 2 presents one switching rule of the switching device S for exemplary, but not limiting, purposes. As shown in fig. 2, the switching device S is closed at time T1 to switch the signal Input onto the output channel C1, and is opened after a predetermined period of time; next, the switching device S is closed at time T2 to switch the signal Input onto the output channel C2, and is opened after a predetermined period of time; then, the switching device S is closed at time T3 to switch the signal Input onto the output channel C3, and is opened after a predetermined period of time; and so on. Thus, according to this switching rule, the switching device S switches the Input terminal carrying the Input signal Input on with the output channels C1, C2,. and Cn, respectively, for the time periods T1-T1 ', T2-T2 ',. and Tn-Tn ', and switches the Input terminal off with all the output channels for the remaining time periods.

Fig. 3 illustrates an apparatus 300 for performing a handover function according to an exemplary embodiment of the present disclosure. The apparatus 300 for performing a switching device switching function includes a controller 302 and a logic unit 304 coupled to the controller 302. The controller 302 generates a plurality of control signals En _1, En _2,. and En _ n according to an Enable signal Enable corresponding to a switching rule, and outputs the generated control signals En _1, En _2,. and En _ n to the logic unit 304. Each control signal includes two logic states "1" and "0", where state "1" corresponds to the closed state of the switching device S and state "0" corresponds to the open state of the switching device S. Fig. 4 is a waveform diagram illustrating a plurality of control signals generated by the controller 302 of fig. 3 according to the switching rule of fig. 2. As shown in fig. 4, since the switching device S turns on the input terminal and the output channel C1 only during the period T1-T1 ', the control signal En _1 for the output channel C1 is "1" only during the period T1-T1', and is "0" for the remaining periods. Also, since the switching device S turns on the input terminal and the output channel C2 only during the period T2-T2 ', the control signal En _2 for the output channel C2 is "1" only during the period T2-T2', and is "0" in the remaining periods. Accordingly, since the switching device S turns on the input terminal and the output channel Cn only in the time period Tn-Tn ', the control signal En _ n for the output channel Cn is "1" only in the time period Tn-Tn', and is "0" in the remaining time periods.

The controller 302 may be implemented by software, hardware, firmware, or a combination thereof. Such an implementation is readily available to those skilled in the art and, for the sake of brevity, will not be described in detail herein.

The logic unit 304 performs an and operation on each control signal from the controller 302 and the signal to be switched Input from the Input terminal to obtain a switched signal, and outputs the switched signal onto the corresponding output channels C1, C2. For example, when performing an and operation on the signal to be switched Input from the Input terminal and the control signal En _1 for the output channel C1, since the control signal En _1 is "1" for the time period T1-T1 'and "0" for the remaining time period, the switched signal obtained on the output channel C1 is the same as the signal to be switched Input before performing the and operation for the time period T1-T1', and is "0" for the remaining time period. Similarly, the resulting switched signal on the output channel C2 is the same as the signal to be switched Input before performing the and operation for the time period T2-T2', and is 0 for the remaining time periods; the resulting switched signal on the output channel Cn is the same as the signal to be switched Input before performing the and operation for the time period Tn-Tn', and is 0 for the remaining time periods.

In this way, the signal switching function of the switching device S shown in fig. 1 can be performed using the apparatus 300 shown in fig. 3 including the controller 302 and the logic unit 304.

Fig. 5 shows an exemplary block diagram of logic unit 304 in the form of an and gate. As shown, each output channel corresponds to an and gate, each and gate has two Input terminals, one Input terminal is used for inputting the signal to be switched Input, and the other Input terminal is used for inputting a corresponding control signal. Those skilled in the art will appreciate that the logic unit 304 shown in fig. 3 may also be implemented by other logic gates besides and gates, FPGAs, microprocessors, and software, firmware, or a combination thereof capable of performing and operations, according to actual needs. Such an implementation is readily available to those skilled in the art and, for the sake of brevity, will not be described in detail herein.

Fig. 6 shows a flowchart of a method for performing a handover function according to an exemplary embodiment of the present disclosure. In step 602, a signal to be switched Input is Input. One or more control signals are generated in step 604 according to the switching rules of the signal to be switched. Each control signal includes two logic states "1" and "0", where state "1" corresponds to the closed state of the switching device S and state "0" corresponds to the open state of the switching device S. At step 606, an and operation is performed on each generated control signal and the signal to be switched to obtain one or more switched signals, and the switched signals are output onto the corresponding output channels at step 608. When the control signal is "1", the switched signal resulting from the and operation is the same as the signal to be switched Input, and when the control signal is "0", the switched signal on the output channel is "0". Therefore, the signal switching function of the switching device can be performed by adopting the method of the present disclosure.

The application of the method and apparatus of the present disclosure to perform a high speed NRZ (non-return to zero) signal stream switching function in a high speed optical switching system instead of a high speed optical switching device is described below in conjunction with fig. 7 and 8.

Fig. 7 shows a schematic diagram of a high-speed tunable laser system 700 to which the methods and apparatus of the present disclosure may be applied. Fig. 8 shows a schematic diagram of a portion of the signals within the high-speed tunable laser system 700 shown in fig. 7. The high-speed tunable laser system 700 in fig. 7 can be implemented with a dual TcMZ transmitter and includes an apparatus 702 for performing the switching function of an optical switching device, two lasers 708 and 710, two

MZ modulators

714 and 716, and a combiner 712. The two MZ modulators operate according to a switching rule corresponding to the Enable signal Enable in fig. 8. Specifically, the switching rule of the optical switching device is as follows: the burst NRZ signal stream burst (ch w) is modulated onto the optical signal emitted from the laser 1 using the MZ modulator 1 in a time period T1-T1 ', the burst NRZ signal stream burst (ch x) is modulated onto the optical signal emitted from the laser 2 using the MZ modulator 2 in a time period T2-T2 ', the burst NRZ signal stream burst (ch y) is modulated onto the optical signal emitted from the laser 1 using the MZ modulator 1 in a time period T3-T3 ', the burst NRZ signal stream burst (ch z) is modulated onto the optical signal emitted from the laser 1 using the MZ modulator 2 in a time period T4-T4 ', and the two MZ modulators modulate 0 onto the optical signal output from the lasers 1 and 2 using the MZ modulator 2 in guard time periods T1 ' -T2, T2 ' -T3, and T3 ' -T4, where the guard time period may be, for example, 300 ns.

In accordance with the switching rules described above, the controller 704 included in the apparatus 702 for performing the switching function of the optical switching device may generate two control signals En _1 and En _2 as shown in fig. 8, wherein each control signal includes two logic states "1" and "0" corresponding to the closed state and the open state of the optical switching device, respectively. A logic unit 706 contained within the apparatus 702 for performing an optical switching function may perform an and operation on each of the two control signals En _1 and En _2 and the input burst signal stream, and generate two output signal streams Out _1 and Out _2 as shown in fig. 8, and then modulate the two output signal streams Out _1 and Out _2 onto optical signals emitted from the laser 1 and the laser 2 via MZ modulators 1 and 2, respectively. The two dimmed signals output by MZ modulators 1 and 2 may be combined into a combined modulated optical signal by combiner 712 for transmission.

As shown in fig. 8, the output signal stream Out _1 is a burst signal stream burst (ch w) in a time period T1-T1 ', a burst signal stream burst (ch y) in a time period T3-T3', and "0" in the remaining time period. Therefore, the MZ modulator 1 modulates the burst signal stream burst (ch w) and the burst signal stream burst (ch y) onto the optical signal emitted from the laser 1 in the time periods T1-T1 'and T3-T3', respectively, and modulates 0 onto the optical signal emitted from the laser 1 in the remaining time periods.

Similarly, the output signal stream Out _2 is the burst signal stream burst (ch x) at the time period T2-T2 ', the burst signal stream burst (ch z) at the time period T4-T4', and "0" at the remaining time period. Therefore, the MZ modulator 2 modulates the burst signal stream burst (ch x) and the burst signal stream burst (ch z) onto the optical signal emitted from the laser 2 in the time periods T2-T2 'and T4-T4', respectively, and modulates 0 onto the optical signal emitted from the laser 2 in the remaining time periods.

Thus, using the method and apparatus of the present disclosure, the signal switching function of the optical switching device can be performed for high speed NRZ signal streams in the tunable laser system shown in fig. 7.

Those skilled in the art will appreciate that although the controller 704 shown in figure 7 generates two control signals En _1 and En _2, the controller 704 may generate one or more control signals to switch the burst NRZ signal stream onto one or more modulators for transmission, depending on the actual needs, e.g., the number of lasers used. Likewise, the logic unit 706 shown in FIG. 7 may be implemented using the AND gate arrangement shown in FIG. 5.

Fig. 9 illustrates an optical transmitter 900 according to an exemplary embodiment of the present disclosure. The optical transmitter 900 comprises two coordinated

optical transmitters

908 and 910, a control unit 902 coupled to the coordinated

optical transmitters

908 and 910, and an optical combiner 912 coupled to the coordinated

optical transmitters

908 and 910. The control unit 902 converts an input signal, e.g. a high speed NRZ signal stream, into two electrical signals Out _1 and Out _2 and supplies the converted electrical signals Out _1 and Out _2 to the cooperative

optical transmitters

908 and 910, respectively, wherein only one of the converted electrical signals Out _1 and Out _2 carries the input signal at the same time. The cooperative

optical transmitters

908 and 910 modulate the electrical signals Out _1 and Out _2 onto respective optical signals and output the modulated optical signals to an optical combiner 912. Optical combiner 912 then combines the modulated optical signals output from coordinated

optical transmitters

908 and 910 into a single optical signal for transmission.

The cooperative optical transmitter 908 includes a laser 1 for generating an optical signal and an optical modulator 1 for modulating an electrical signal Out _1 onto the generated optical signal, and the cooperative optical transmitter 910 includes a laser 2 for generating an optical signal and an optical modulator 2 for modulating an electrical signal Out _2 onto the generated optical signal. In one embodiment, laser 1 and laser 2 may produce optical signals having different wavelengths, while in another embodiment, laser 1 and laser 2 may produce optical signals having the same wavelength. The optical modulators 1 and 2 may be MZ modulators, and when the electrical signals Out _1 and Out _2 are low level or "0", the modulated optical signals output from the optical modulators 1 and 2 may be zero.

The control unit 902 comprises a controller 904 and a logic unit 906 coupled to the controller 904. The controller 904 may generate two control signals En _1 and En _2 according to a conversion rule corresponding to the Enable signal Enable and input the generated control signals En _1 and En _2 to the logic unit 906.

At the same time, only one control signal is active, i.e.: its logic state is 1; during the guard period, none of the plurality of control signals En _1 and En _2 is active, i.e.: their logic state is 0. The guard period is a time interval between temporally adjacent control signals En _1 and En _ 2. The guard period is introduced to overcome transition times of software, hardware and/or firmware in the control unit 902 (e.g., transition times of gate circuits in the control unit 902), which may be between 1-999ns, such as about 300 ns. During the guard period, there is no input signal or the input signal is zero, and the converted electrical signals Out _1 and Out _2 are also zero.

The logic unit 906 converts the input signal into two electrical signals Out _1 and Out _2 according to the control signals En _1 and En _2, and provides each electrical signal to a corresponding cooperative optical transmitter, respectively. In one embodiment, the logic unit 906 may include an and operation logic circuit for performing an and operation on the input signal and each control signal to generate the electrical signals Out _1 and Out _2, wherein the and operation logic circuit may include an and gate as shown in fig. 5.

The conversion rule can be preset according to actual needs. FIG. 8 presents a transformation rule for exemplary, but not limiting purposes, namely: the input signal (ch w) is transmitted using the cooperative optical transmitter 908 during a time period T1-T1 ', the input signal (ch x) is transmitted using the cooperative optical transmitter 910 during a time period T2-T2 ', the input signal (ch y) is transmitted using the cooperative optical transmitter 908 during a time period T3-T3 ', the input signal (ch z) is transmitted using the cooperative optical transmitter 910 during a time period T4-T4 ', and the input signal (ch z) is transmitted without using any one of the cooperative

optical transmitters

908 and 910 during the guard time periods T1 ' -T2, T2 ' -T3, and T3 ' -T4 or the output of each cooperative optical transmitter is zero. Further, during the guard periods T1 ' -T2, T2 ' -T3, and T3 ' -T4, no input signal or the input signal is zero.

As shown in FIG. 8, the logic state of the control signal En _1 generated by the controller 904 is 1 during the time periods T1-T1 ' and T3-T3 ', and 0 during the time periods T1 ' -T3 and T3 ' -T4 '. The logic state of the control signal En _2 generated by the controller 904 is 1 during the time periods T2-T2 ' and T4-T4 ', and 0 during the time periods T1-T2 and T2 ' -T4. Accordingly, the electrical signal Out _1 generated by the logic unit 902 carries the input signal (ch w) in the time period T1-T1 ', carries the input signal (ch y) in the time period T3-T3 ', and does not carry the input signal in the time periods T1 ' -T3 and T3 ' -T4 ', that is: its logic state is zero; the electrical signal Out _2 generated by the logic unit 902 carries the input signal (ch x) during the time period T2-T2 ', carries the input signal (ch z) during the time period T4-T4 ', and does not carry the input signal during the time periods T1-T2 and T2 ' -T4, i.e.: its logic state is zero. Thus, the cooperative optical transmitter 908 modulates the electrical signal Out _1 carrying the input signal (ch w) and the input signal (ch y) onto the optical signal generated by the laser 1 using the optical modulator 1 during the time periods T1-T1 ' and T3-T3 ', respectively, while the outputs are zero during the time periods T1 ' -T3 and T3 ' -T4 '; the cooperative optical transmitter 910 modulates the electrical signal Out _2 carrying the input signal (ch x) and the input signal (ch z) onto the optical signal generated by the laser 2 using the optical modulator 2 during the time periods T2-T2 ' and T4-T4 ', respectively, while the output is zero during the time periods T1-T2 and T2 ' -T4.

Those skilled in the art will appreciate that although only two coordinated light emitters are shown in fig. 9, light emitter 900 may comprise a plurality of coordinated light emitters; accordingly, the controller 904 in the control unit 902 may generate a plurality of control signals according to a predetermined conversion rule, and the logic unit 906 may convert the input signal into a plurality of electrical signals according to the plurality of control signals.

Fig. 10 shows a flow chart of an optical communication method 1000 according to an exemplary embodiment of the present disclosure. At step 1002, an input signal, such as a high speed NRZ signal stream, is converted into two electrical signals Out _1 and Out _2, wherein only one of the converted electrical signals Out _1 and Out _2 carries the input signal at the same time. At step 1004, the electrical signals Out _1 and Out _2 are modulated onto the optical signals by two coordinated optical transmitters as shown in fig. 9, respectively, to obtain two modulated optical signals. The resulting modulated optical signals are then combined into a single optical signal output for transmission at step 1006.

The converting step 1002 includes generating control signals En _1 and En _2 according to a predetermined conversion rule, and converting the input signal into electrical signals Out _1 and Out _2 according to the generated control signals En _1 and En _ 2. The step of converting the input signal into the electric signal according to the control signal includes performing an and operation on the input signal and each control signal to generate electric signals Out _1 and Out _ 2. The modulating step 1004 includes generating two optical signals with two lasers in the coordinated optical transmitters and modulating electrical signals Out _1 and Out _2 onto the two optical signals, respectively, to obtain two modulated optical signals, wherein the generated optical signals may have the same or different wavelengths.

At the same time, only one control signal is active, i.e.: its logic state is 1; during the guard period, however, none of all the control signals En _1 and En _2 is active, i.e.: their logic state is 0. The guard period is a time interval between temporally adjacent control signals En _1 and En _ 2. The guard period is introduced to overcome the transition time of the software, hardware and/or firmware used, which may be between 1-999ns, for example, may be about 300 ns. During the guard period, there is no input signal or the input signal is zero, and the converted electrical signals Out _1 and Out _2 are also zero.

The conversion rule can be preset according to actual needs. In one exemplary conversion rule shown in fig. 8, an input signal (ch w) is transmitted using the cooperative light emitter 908 shown in fig. 9, for example, in a period T1-T1 ', an input signal (ch x) is transmitted using the cooperative light emitter 910 shown in fig. 9, for example, in a period T2-T2 ', an input signal (ch y) is transmitted using the cooperative light emitter 908 in a period T3-T3 ', an input signal (chz) is transmitted using the cooperative light emitter 910 in a period T4-T4 ', and the input signal is transmitted using none of the cooperative

light emitters

908 and 910 in a guard period T1 ' -T2, T2 ' -T3, and T3 ' -T4 or the output of each cooperative light emitter is zero.

As shown in FIG. 8, the logic state of the control signal En _1 is 1 during the time periods T1-T1 ' and T3-T3 ', and is 0 during the time periods T1 ' -T3 and T3 ' -T4 '. The logic state of the control signal En _2 is 1 during the time periods T2-T2 ' and T4-T4 ', and 0 during the time periods T1-T2 and T2 ' -T4. Accordingly, the electrical signal Out _1 carries the input signal (ch w) during the time period T1-T1 ', carries the input signal (ch y) during the time period T3-T3 ', and does not carry the input signal during the time periods T1 ' -T3 and T3 ' -T4 ', i.e.: its logic state is zero; the electrical signal Out 2 carries the input signal (ch x) during the time period T2-T2 ', carries the input signal (ch z) during the time period T4-T4 ', and does not carry the input signal during the time periods T1-T2 and T2 ' -T4, i.e.: its logic state is zero. Thus, the cooperative optical transmitter 908 modulates the electrical signal Out _1 carrying the input signal (ch w) and the input signal (ch y) onto its generated optical signal in the time periods T1-T1 ' and T3-T3 ', respectively, while outputting zero in the time periods T1 ' -T3 and T3 ' -T4 '; the coordinated optical transmitter 910 modulates the electrical signal Out _2 carrying the input signal (ch x) and the input signal (ch z) onto its generated optical signal at time periods T2-T2 ' and T4-T4 ', respectively, while the output is zero at time periods T1-T2 and T2 ' -T4.

Those skilled in the art will appreciate that in the optical communication method 1000 illustrated in fig. 10, an input signal may be converted into a plurality of electrical signals, and a plurality of optical signals may be generated by a plurality of coordinated optical transmitters and modulated onto corresponding optical signals.

Thus, the optical transmitter 900 and the optical communication method 1000 according to the present disclosure can switch input signals between two or more cooperative optical transmitters without using an optical switch.

Compared with the scheme adopting the high-speed switching device, the method and the device provided by the disclosure are not limited by the working frequency and the transition time of the switching device, and cannot generate oscillation in the signal switching process, so that the switching process is fast and stable, and the requirement on the frequency accuracy of the signal switching process in a high-speed system can be met. In addition, the method and the device provided by the disclosure are simple and easy to implement, and the required components can be purchased in the market, so that the method and the device are suitable for mass production.

The present disclosure has been described above with reference to specific embodiments, but the present disclosure is not limited to these specific embodiments. Those skilled in the art will appreciate that various modifications, substitutions, changes, and the like can also be made to the present disclosure. For example, one step or component in the above embodiments is divided into a plurality of steps or components to be implemented, or conversely, the functions of a plurality of steps or components in the above embodiments are implemented in one step or component. However, such variations are intended to be within the scope of the present disclosure, as long as they do not depart from the spirit of the present disclosure. In addition, some terms used in the specification and claims of the present application are not limiting, but are merely for convenience of description. Furthermore, all or a portion of the features described in one particular embodiment may be combined in another embodiment as may be desired and advantageous for practical purposes.

Claims

1. A method of performing a switching function of an optical switching device in an optical communication system, comprising the steps of:

generating a control signal according to a switching rule of a signal to be switched, wherein a '1' state of the control signal corresponds to an on-state of the optical switching device and a '0' state of the control signal corresponds to an off-state of the optical switching device;

performing an and operation on the generated control signal and the signal to be switched to obtain a switched signal; and

outputting the switched signal.

2. The method of claim 1, wherein the signal to be switched is a high speed NRZ signal stream.

3. An apparatus for performing a switching function of an optical switching device in an optical communication system, comprising:

a controller generating a control signal according to a switching rule of a signal to be switched, wherein a '1' state of the control signal corresponds to an on state of the optical switching device and a '0' state of the control signal corresponds to an off state of the optical switching device; and

and the logic unit is coupled with the controller and is used for carrying out AND operation on the generated control signal and the signal to be switched to obtain a switched signal and outputting the switched signal.

4. The apparatus of claim 3, wherein the signal to be switched is a high speed NRZ signal stream.

5. The apparatus of claim 3, wherein the logic cell comprises an AND gate.

6. An optical communication device comprising:

a controller generating one or more control signals according to a switching regulation of an input high-speed NRZ signal stream, wherein a "1" state of each control signal corresponds to an ON state of the optical switching device and a "0" state of each control signal corresponds to an OFF state of the optical switching device;

a logic unit coupled to the controller for performing an AND operation on each control signal with the input high speed NRZ signal stream to obtain one or more switched high speed NRZ signal streams;

one or more modulators coupled to the logic unit; and

one or more lasers each coupled to one of the one or more modulators,

wherein each modulator is configured to modulate a corresponding one of the one or more switched high speed NRZ signal streams onto an optical signal emitted from a laser coupled to the modulator.

7. The optical communication device of claim 6, wherein the logic unit comprises an AND gate.

8. The optical communication device of any one of claims 6-7, wherein the modulator is a MZ modulator.

9. An optical transmitter, comprising:

a plurality of cooperative optical transmitters for modulating a plurality of electrical signals onto a plurality of optical signals, respectively;

a control unit coupled to the plurality of coordinated optical transmitters for converting an input signal into a plurality of electrical signals and providing the plurality of electrical signals to the plurality of coordinated optical transmitters, wherein only one of the plurality of electrical signals carries the input signal at a time; and

an optical combiner coupled to the plurality of coordinated optical transmitters for combining the modulated optical signals output from the plurality of coordinated optical transmitters into a single optical signal output for transmission.

10. The optical transmitter of claim 9, wherein the control unit comprises:

a controller for generating a plurality of control signals; and

a logic unit for converting the input signal into the plurality of electrical signals according to the plurality of control signals and providing the plurality of electrical signals to the plurality of cooperative light emitters, respectively.

11. The optical transmitter of claim 10, wherein the controller generates the plurality of control signals according to a predetermined conversion rule.

12. The optical transmitter of claim 10, wherein only one of the plurality of control signals is active at a time, and none of the plurality of control signals is active during a guard period, wherein the guard period is a time interval between two temporally adjacent ones of the plurality of control signals.

13. The optical transmitter of claim 12, wherein each of the plurality of control signals is active when its logic state is 1.

14. The optical transmitter of any one of claims 10-13, wherein the logic unit comprises an and arithmetic logic circuit for performing an and operation on the input signal and each of the plurality of control signals to generate the plurality of electrical signals.

15. The optical transmitter of claim 14, wherein the and operational logic circuit comprises an and gate.

16. The optical transmitter of claim 12, wherein none or zero of the input signal occurs during the guard period.

17. The optical transmitter of claim 12 or 16, wherein each of the plurality of electrical signals is zero during the guard period.

18. An optical transmitter as claimed in claim 12 or 16, wherein the guard period is 1-999 ns.

19. The optical transmitter of claim 18, wherein the guard period is 300 ns.

20. The optical transmitter of any one of claims 9-13, wherein each of the plurality of coordinated optical transmitters comprises:

a laser for generating an optical signal; and

an optical modulator for modulating a respective one of the plurality of electrical signals onto the optical signal.

21. The optical transmitter of claim 20, wherein the optical modulator is a MZ modulator.

22. An optical transmitter according to any one of claims 9 to 13, wherein the input signal is a high speed NRZ signal stream.

23. The optical transmitter of any one of claims 9-13, wherein the number of the plurality of coordinated optical transmitters is 2.

24. The optical transmitter of any one of claims 9-13, wherein the optical signals generated from the plurality of cooperating optical transmitters have the same or different wavelengths.

25. A method for optical communication, comprising the steps of:

converting an input signal into a plurality of electrical signals, wherein only one of the plurality of electrical signals carries the input signal at a time;

modulating the plurality of electrical signals onto a plurality of optical signals, respectively, to obtain a plurality of modulated optical signals; and

combining the plurality of modulated optical signals into a single optical signal output for transmission.

26. The method of claim 25, wherein converting the input signal into a plurality of electrical signals comprises:

generating a plurality of control signals; and

converting the input signal into the plurality of electrical signals according to the plurality of control signals.

27. The method of claim 26, wherein the plurality of control signals are generated according to a predetermined conversion rule.

28. The method of claim 26, wherein only one of the plurality of control signals is active at a time, and none of the plurality of control signals is active during a guard period, wherein the guard period is a time interval between two temporally adjacent ones of the plurality of control signals.

29. The method of claim 28, wherein each of the plurality of control signals is active when its logic state is 1.

30. The method of any of claims 26-29, wherein converting the input signal into the plurality of electrical signals according to the plurality of control signals comprises:

performing an AND operation on each of the input signal and the plurality of control signals to generate the plurality of electrical signals.

31. The method of claim 28, wherein none or zero of the input signal occurs during the guard period.

32. The method of claim 28 or 31, wherein each of the plurality of electrical signals is zero during the guard period.

33. The method of claim 28 or 31, wherein the guard period is 1-999 ns.

34. The method of claim 33, wherein the guard period is 300 ns.

35. The method of any of claims 25-29, wherein modulating the plurality of electrical signals onto a plurality of optical signals, respectively, to obtain a plurality of modulated optical signals further comprises: generating the plurality of optical signals.

36. The method of any one of claims 25-29, wherein the input signal is a high speed NRZ signal stream.

37. The method of any one of claims 25-29, wherein the plurality of optical signals have the same or different wavelengths.

38. The method of any one of claims 25-29, wherein the number of the plurality of optical signals is 2.