Abstract:
An optoelectronic integrated apparatus, including a plurality of working optical source links, at least one spare optical source link, at least one spare data channel, and a protection control unit for detecting whether there is any working optical source link faulty. When detecting that a working optical source link is faulty, controlling a spare optical source link whose emission wavelength is the same as the faulty working optical source link to fulfill the functions of the faulty working optical source link and switching a data signal from the working data channel to a spare data channel. The spare optical source link is adapted to modulate the optical signal using the data signal from the spare data channel, and transmits the modulated optical signal. Reliability of the optoelectronic integrated apparatus is enhanced without increasing the maintenance cost.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/CN2007/070967, filed Oct. 26, 2007. This application claims the benefit of Chinese Application No. 200610142656.2, filed Oct. 27, 2006. The disclosures of the above applications are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to optical communication technologies and to an optoelectronic integrated apparatus and a method for protecting optoelectronic integrated apparatus. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Dense Wavelength-Division Multiplexing (DWDM) technology has become a dominant technology used in both long-haul and regional backbone transmission networks, and is gradually being introduced into Metropolitan Area Network (MAN). Conventional DWDM systems adopt separate encapsulation, i.e. fabricating linecards dedicated for one or more optical devices, and the linecards are inter-connected by fibers. 
     With developments in the technology, prices of optical devices are decreasing continuously. The cost of encapsulating an optical device typically remains high, and has become a bottleneck keeping the cost of the whole optical device high. Taking a laser as an example, the core of the laser may cost only several dollars, while the encapsulation may cost hundreds of dollars. 
     During the past few years, people have made efforts to integrate several optical devices, such as lasers and modulators on one semiconductor substrate to eliminate the cost generated by encapsulating each optical device separately. Meanwhile, the volumes of sub-modules, e.g. sub-modules for transmitting, receiving and monitoring in a DWDM system, are greatly reduced due to the reduction in encapsulation. 
     An optoelectronic integrated circuit is an apparatus in which several optical devices are integrated on a semiconductor substrate with corresponding periphery control circuits.  FIG. 1  is a schematic diagram of the interior structure of an optoelectronic integrated apparatus at the transmitting end in accordance with the prior art. Referring to  FIG. 1 , in order to transmit information through an optoelectronic integrated circuit, the optoelectronic integrated apparatus at the transmitting end includes in its interior a top-layer control unit, a data switching unit, an optical source link control unit, n optical source links and n data channels corresponding to the n optical source links, and a wavelength combining unit, in which the “n” refers to the number of optical source links or data channels.  FIG. 2  is a schematic diagram illustrating the data transmission using the data channels and the optical source links at the transmitting end of the optoelectronic integrated apparatus in the prior art. Referring to  FIGS. 1 and 2 , in practical service applications, each optical source link mainly includes an optical source and a modulator, and may also includes an optical link wiretapping (Tap) module. A link checking circuit in the optical source link control unit checks the performance of each optical source link by use of each corresponding Tap module, so that the optical source link control unit can adjust the optical source link suitably according to the result of checking, e.g. adjust the optical power in the optical source link.  FIG. 3  is a schematic diagram illustrating a structure of the optoelectronic integrated apparatus at the receiving end in the prior art. Referring to  FIG. 3 , the optoelectronic integrated apparatus at the receiving end mainly includes in its interior a wavelength de-combining unit, n optical receiving units and an electric data processing unit. 
     When the optoelectronic integrated apparatus at the transmitting end is in operation, the optical source in an optical source link generates and outputs an optical signal to the modulator, and a corresponding data channel outputs an electric signal to the modulator. The modulator then modulates the received optical signal and the electric signal to generate and output an optical signal to the wavelength combining unit. The wavelength combining unit combines the optical signals received from all the optical source links and then outputs the combined optical signals to the optoelectronic integrated apparatus at the receiving end. In the optoelectronic integrated apparatus at the receiving end, the wavelength de-combining unit de-combines the received optical signals and outputs the de-combined n-way optical signals to the corresponding optical receiving units respectively, and each optical receiving unit converts a received optical signal into an electric signal and then outputs the electric signal to the electric data processing unit. Then the electric data processing unit processes the electric signals according to a certain service processing procedure. 
     At present, optical signals are of many advantages over electric signals in information delivering, such as enhanced capability of anti-interference, higher transmission speed, and etc. Therefore, the optoelectronic integrated apparatus has been used widely. 
     There are presently, however, no effective protecting measures for the optoelectronic integrated apparatus at the moment. Each optical source link may be used as a working link for transmitting service data. Thereby, when a failure, e.g., an optical source fails to emit light or a modulator malfunctions, occurs in any optical source link in an optoelectronic integrated apparatus, the whole optoelectronic integrated apparatus can not function properly, and thus the reliability of the optoelectronic integrated apparatus is impaired. In order to restore the working of the optoelectronic integrated apparatus, measures such as replacement, should be adopted in the prior art. However, because the components of each optical source link in an optoelectronic integrated apparatus are integrated on the same substrate and are encapsulated along with all the others, the faulty optical source link can not be replaced individually. As a result, the whole optoelectronic integrated circuit has to be replaced, which increases the maintenance and repair cost greatly. 
     SUMMARY 
     Various embodiments provide a method for protecting optoelectronic integrated apparatus, in order to provide efficient protecting measures for optoelectronic integrated apparatus and enhance the reliability of the apparatus. An optoelectronic integrated apparatus is also provided. 
     The technical schemes according to various embodiments are illustrated as follows. 
     An optoelectronic integrated apparatus is provided, which includes: a protection control unit, a plurality of working optical source links, at least one spare optical source link, and at least one spare data channel corresponding to the at least one spare optical source link, in which 
     the protection control unit is adapted to detect whether there is any working optical source link faulty, and when detecting that a working optical source link is faulty, control a spare optical source link whose emission wavelength is the same as the faulty working optical source link to fulfill the functions of the faulty working optical source link, and switch the data signal from the working data channel of the faulty working optical source link to the spare data channel of the spare optical source link when detecting that the working optical source link is faulty; 
     the spare optical source link is adapted to modulate the optical signal generated by the spare optical source link using the data signal from the spare data channel, and transmit the modulated optical signal. 
     A method for protecting optoelectronic integrated apparatus is also provided, which includes: 
     detecting whether there is any working optical source link faulty in the optoelectronic integrated apparatus; and 
     when detecting that a working optical source link is faulty, controlling a spare optical source link which has the same emission wavelength as the faulty working optical source link to fulfill the functions of the faulty working optical source link, switching data from the working data channel corresponding to the faulty working optical source link to a spare data channel, modulating the optical signal generated in the spare optical source link using the electric signal output from the spare data channel, and transmitting the modulated optical signal. 
     As can be seen from the above, according to the embodiments, a fault of a working optical source link can be detected, and the service transmission, which was performed by the service data from the faulty working optical source link and the corresponding working data channel, can be implemented by use of a spare optical source link and a corresponding spare data channel. Therefore, the optoelectronic integrated apparatus functions properly even if the working optical source link fails, which provides effective protection for the optoelectronic integrated apparatus and enhances the reliability of the optoelectronic integrated apparatus. 
     Furthermore, in various embodiments, the spare wavelength-tunable optical source link and a corresponding spare data channel can transmit the service data for the faulty working optical source link and the corresponding data channel automatically without replacing the whole optoelectronic integrated apparatus as performed in the prior art. As a result, the maintenance cost of the optoelectronic integrated apparatus is reduced, and accordingly the maintenance workload of the maintenance worker is reduced because the maintenance will not be carried out manually. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a schematic diagram illustrating the interior structure of an optoelectronic integrated apparatus at the transmitting end in the prior art; 
         FIG. 2  is a schematic diagram illustrating data transmission by data channels and optical source links at the transmitting end of an optoelectronic integrated apparatus in the prior art; 
         FIG. 3  is a schematic diagram illustrating the structure of an optoelectronic integrated apparatus at the receiving end in the prior art; 
         FIG. 4A  is a schematic diagram illustrating the basic structure of an optoelectronic integrated apparatus in accordance with various embodiments; 
         FIG. 4B  is a schematic diagram illustrating the detailed structure of the optoelectronic integrated apparatus in accordance with various embodiments; 
         FIG. 5A  is a schematic diagram illustrating a structure of a wavelength combining unit in an optoelectronic integrated apparatus in accordance with various embodiments; 
         FIG. 5B  is a schematic diagram illustrating another structure of a wavelength combining unit in the optoelectronic integrated apparatus in accordance with various embodiments; 
         FIG. 6  is a flowchart illustrating the process for protecting the optoelectronic integrated apparatus according to various embodiments; 
         FIG. 7  is a schematic diagram illustrating a structure for transmitting data using data channels and optical source links of an optoelectronic integrated apparatus at the transmitting end in accordance with various embodiments; 
         FIG. 8  is a schematic diagram illustrating another structure for transmitting data using data channels and optical source links of an optoelectronic integrated apparatus at the transmitting end in accordance with various embodiments; and 
         FIG. 9  is a schematic diagram illustrating a structure of a wavelength-tunable optical source link. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     Various embodiments provide a method for protecting optoelectronic integrated apparatus, which includes: checking whether there is a fault in each of the working optical source links in the optoelectronic integrated apparatus at the transmitting end; when a fault of a working optical source link is detected, controlling a spare wavelength-tunable optical source link and a corresponding spare data channel to transmit the service data which were being transmitted by the faulty working optical source link and the working data channel corresponding to the faulty working optical source link. 
     According to various embodiments of the optoelectronic integrated apparatus.  FIG. 4A  is a schematic diagram illustrating the basic structure of the optoelectronic integrated apparatus. Referring to  FIG. 4A , the optoelectronic integrated apparatus according to various embodiments mainly includes: a protection control unit, a plurality of working optical source links and working data channels corresponding to the plurality of working optical source links, and one or more spare optical source links which are wavelength-tunable and spare data channels corresponding to the one or more spare optical source links in the interior of the apparatus. 
     The protection control unit detects faults of the working optical source links. When a fault of a working optical source link is detected, the protection control unit activates a wavelength-tunable spare optical source link and a spare data channel corresponding to the wavelength-tunable spare optical source link, and manages a switching process which switches an electric signal from the working data channel of the faulty working optical source link to the spare data channel of the activated spare optical source link. 
     The spare data channel of the activated spare optical source link transmits the received electric signal to the activated spare optical source link. The activated spare optical source link, after being activated, generates an optical signal from the wavelength-tunable optical source, modulates the generated optical signal using the electric signal received from the spare data channel and outputs the modulated optical signal. 
       FIG. 4B  is a schematic diagram illustrating the detailed structure of the optoelectronic integrated apparatus according to various embodiments. Referring to  FIGS. 4A and 4B , the protection control unit of the optoelectronic integrated apparatus in the embodiment includes: a top-layer control unit, and a data switching unit, a link monitoring unit and an optical source link control unit. 
       FIG. 5A  is a schematic diagram illustrating a structure of a wavelength combining unit in the optoelectronic integrated apparatus according to various embodiments. Referring to  FIG. 5A , as the spare optical source link adopts a wavelength-tunable optical source, the wavelength combining unit of the optoelectronic integrated apparatus in the embodiment includes in its interior: a first wavelength combiner connected to all working ports each of which corresponds to a working optical source link respectively; a second wavelength combiner connected to each spare port corresponding to each working optical source link respectively; and a third wavelength combiner connected to both the first wavelength combiner and the second wavelength combiner, in which, 
     the first wavelength combiner is adapted to receive optical signals from each working optical source link via each connected working port, combine and then transmit the received optical signals to the third wavelength combiner; 
     the second wavelength combiner is adapted to tune the central wavelength to accord with the emission wavelength of the faulty working optical source link, connect to the activated spare optical source link via the spare port corresponding to the faulty working optical source link, combine the optical signals received from the spare port corresponding to the faulty working optical source link and then transmit the combined signal to the third wavelength combiner; and 
     the third wavelength combiner is adapted to combine all the received optical signals and then output the combined signal to an optoelectronic integrated apparatus at the receiving end. 
       FIG. 5B  is a schematic diagram illustrating another structure of the wavelength combining unit of the optoelectronic integrated apparatus according to various embodiments. Referring to  FIG. 5B , as the spare optical source link adopts an wavelength-tunable optical source, the wavelength combining unit includes in the interior: a first wavelength combiner connected to each working port corresponding to each working optical source link respectively, a second wavelength combiner connected to one or more spare ports, and a third wavelength combiner connected to both the first wavelength combiner and the second wavelength combiner, wherein 
     the first wavelength combiner is adapted to receive optical signals from each working optical source link via each connected working port, combine the received optical signals and then transmit the combined signal to the third wavelength combiner; 
     the second wavelength combiner is adapted to adjust the temperature of the second wavelength combiner so as to tune the central wavelength of a first spare port among the spare ports to accord with the emission wavelength of the faulty working optical source link, connect to the activated spare optical source link via the first spare port, combine the optical signal received from the first spare port and then transmit the combined signal to the third wavelength combiner; and 
     the third wavelength combiner is adapted to combine all the received optical signals and then transmit the combined signal to an optoelectronic integrated apparatus at the receiving end. 
     According to various embodiments, each working optical source link or each spare optical source link mainly includes an optical source, and may also include a modulator, a detecting unit and a light absorber, in which the detecting unit may be, for example, a Tap. 
       FIG. 6  is a flowchart illustrating the process of protecting an optoelectronic integrated apparatus according to an embodiment. According to various embodiments and referring to  FIGS. 4A ,  4 B,  5 A,  5 B,  6 , and  7 , one or more wavelength-tunable spare optical source links and spare data channels corresponding to the one or more wavelength-tunable spare optical source links are reserved in the optoelectronic integrated apparatus. As shown in  FIG. 7 , a detecting unit is set in each working optical source link. The process of protecting an optoelectronic integrated apparatus by using the optoelectronic integrated apparatus provided by the embodiment is shown as follows. 
     Block  601 : In the optoelectronic integrated apparatus at the transmitting end, a detecting unit in a working optical source link, for example a Tap unit, receives the optical signal output from the working optical source link, and outputs the received optical signal to a link monitoring unit. 
     A Tap may output a portion, e.g. 5%, of the energy of the received optical signal to the link monitoring unit. 
     Block  602 : In the optoelectronic integrated apparatus at the transmitting end, the link monitoring unit analyzes the optical signal output from each Tap of each optical source link, examines the performances of the working optical source links, and outputs the monitored performance information to the optical source link control unit. 
     Block  603 : In the optoelectronic integrated apparatus at the transmitting end, the optical source link control unit determines whether each working optical source link is faulty in accordance with the received monitored performance information of each working optical source link, and transmits the fault information of the faulty source link to the top-layer control unit when determining a working optical source link, e.g. the first working optical source link among the working optical source links, is faulty. 
     It should be noted that, detecting the fault of the working optical source links is carried out in conjunction with the structure of the optoelectronic integrated apparatus at the transmitting end shown in  FIG. 7  from Block  601  to Block  603 . In combination with the structure of the optoelectronic integrated apparatus at the transmitting end shown in  FIG. 8 , if the detecting unit functions after the combining procedure of the wavelength combining unit, the monitoring process from Block  601  to Block  603  may be replaced by the following process. 
     The detecting unit, e.g. a Tap, receives the combined optical signal output from the wavelength combining unit, and outputs the received optical signal to the link monitoring unit. The detecting unit may output a portion, such as 5%, of the energy of the received optical signal to the link monitoring unit. The link monitoring unit analyzes the spectrum and the optical power of the optical signal output from the detecting unit of each optical source link or analyzes a optical track signal of each optical source link and transmits the analysis result of the spectrum and optical power or the analysis result of the optical track signal of each optical source link to the optical source link control unit. The optical source link control unit detects performance changes in the spectrum and optical power or performance changes in the optical track signal of each optical source link in accordance with the received analysis result, so as to determine whether each working optical source link is faulty. When determining that the first working optical source link among the working optical source links is faulty, the optical source link control unit transmits the fault information of the faulty working optical source link to the top-layer control unit. When utilizing a optical track signal, it is necessary to add a optical track signal to an optical source in each optical source link in advance, for example, adding low frequency interference of different frequencies to the optical source in different optical source links. 
     Block  604 : In the optoelectronic integrated apparatus at the transmitting end, the top-layer control unit transmits an indication to the optical source link control unit for activating a first spare wavelength-tunable optical source link among the spare wavelength-tunable optical source links after receiving the fault information of the first working optical source link. 
     If several spare wavelength-tunable optical source links and spare data channels corresponding to the several spare wavelength-tunable optical source links are preset in the optoelectronic integrated apparatus, the first spare wavelength-tunable optical source link and the spare data channel corresponding to the first spare wavelength-tunable optical source link described herein and hereafter are selected according to priorities preset by the top-layer control unit for each spare optical source link and the spare data channel corresponding to the spare optical source link, or optionally selected from all the preset spare optical source links and spare data channels corresponding to the preset spare optical source links by the top-layer control unit; or selected from all the preset spare optical source links and the spare data channels corresponding to the preset spare optical source links according to other policies preset by the top-layer control unit. 
     Block  605 : In the optoelectronic integrated apparatus at the transmitting end, the optical source link control unit deactivates the first working optical source link and activates the first spare wavelength-tunable optical source link on receiving the indication for activating the first spare optical source link, and transmits an indication for tuning the wavelength of the first spare optical source link to accord with the emission wavelength of the first working optical source link to the spare optical source link. 
     When there is a light absorber in each optical source link, the optical source link control unit may also activate the light absorber in the first working optical source link. The light absorber in the first working optical source link absorbs the optical signal output from the first working optical source link after being activated, so as to ensure that the first working optical source link generates no interference optical signal after being faulty. 
     Block  606 : In the optoelectronic integrated apparatus at the transmitting end, when activated, the wavelength-tunable optical source in the first spare optical source link tunes its emission wavelength to accord with the emission wavelength of the first working optical source link; and the link monitoring unit examines the performance of the first spare optical source link and transmits the monitored performance information of the first spare optical source link to the optical source link control unit. 
     Block  607 : In the optoelectronic integrated apparatus at the transmitting end, the optical source link control unit determines whether the first spare optical source link reaches a stable state in accordance with the received monitored performance information of the first spare optical source link. The optical source link control unit transmits the stable state indication of the first spare optical source link to the top-layer control unit when determining the first spare optical source link reaches a stable state. 
     In Block  607 , when determining the first spare optical source link has not reached a stable state, the optical source link control unit may transmit an indication of an unstable state to the link monitoring unit, and the link monitoring unit controls the light absorber in the first spare wavelength-tunable optical source link to absorb the optical signal output from the first spare optical source link, so as to avoid interfering with other working links because the first spare optical source link has just begun to work and has not reached a stable state. The link monitoring unit deactivates the light absorber when the first spare optical source link reaches a stable state. 
     Block  608 : In the optoelectronic integrated apparatus at the transmitting end, on receiving a stable state indication of the first spare optical source link, the top-layer control unit transmits a switching indication to the data switching unit for switching the electric signal from the working data channel of the first working optical source link to the spare data channel of the first spare optical source link. 
     It should be noted that, in the above process, the top-layer control unit does not transmit the switching indication to the data switching unit until receiving the stable state indication for the first spare optical source link. In practical service applications, after receiving the fault information of the first working optical source link in Block  604 , the top-layer control unit may immediately transmit the switching indication to the data switching unit for switching the electric signal from the working data channel of the first working optical source link to the spare data channel of the first spare optical source link. 
     Block  609 : In the optoelectronic integrated apparatus at the transmitting end, on receiving the switch indication, the data switching unit switches the electric signal from the working data channel of the first working optical source link to the spare data channel of the first spare optical source link. 
     Block  610 : In the optoelectronic integrated apparatus at the transmitting end, the optical source in the first spare wavelength-tunable optical source link generates an optical signal of the same wavelength as that of the first working optical source link, modulates the generated optical signal using the electric signal output from the spare data channel of the activated spare optical source link, then transmits the modulated optical signal to the wavelength combining unit. 
     Block  611 : in the optoelectronic integrated apparatus at the transmitting end, the first wavelength combiner and the second wavelength combiner in the wavelength combining unit respectively receive and combine optical signals transmitted from the optical source links and transmit the combined optical signals to the third wavelength combiner. It should be noted that, in the above process, after receiving the fault information of the first working optical source link in Block  604 , the top-layer control unit transmits an indication to the wavelength combining unit of connecting the wavelength combining unit to the first spare optical source link. 
     Referring to  FIG. 5A , when the interior structure of the wavelength combining unit is as shown in  FIG. 5A , after receiving the connected indication, the wavelength combining unit connects the spare port of the first working optical source link in the wavelength combining unit with the first spare wavelength-tunable optical source link. Thus, in Block  611 , in various embodiments, the wavelength combining unit may receive the optical signal output from each optical source link, and the implementation may include the following steps. The second wavelength combiner in the wavelength combining unit tunes its central wavelength to accord with the wavelength of the first working optical source link, connects to the first spare wavelength-tunable optical source link via a first spare port corresponding to the first working optical source link, and combines the optical signal received from the spare port corresponding to the first working optical source link, and then transmits the combined optical signal to the third wavelength combiner. The first wavelength combiner receives the optical signal transmitted from each working optical source link via each connected working port, and combines the received optical signal and then transmits the combined optical signal to the third wavelength combiner. 
     Referring to  FIG. 5B , when the interior structure of the wavelength combining unit is as shown in  FIG. 5B , after receiving the connected indication, the wavelength combining unit connects the spare port corresponding to the first working optical source link in the wavelength combining unit with the first spare wavelength-tunable optical source link. Thus, in Block  611 , in various embodiments, the wavelength combining unit may receive the optical signal output from each optical source link, which may be implemented as according to the following steps. The second wavelength combiner in the wavelength combining unit may include a temperature control sub-unit. The temperature control sub-unit adjusts the temperature to tune central wavelength of the first spare port to accord with the emission wavelength of the first working optical source link. The second wavelength combiner connects to the first spare wavelength-tunable optical source link via the first spare port, combines the optical signal received from the first spare port and then transmits the combined signal to the third wavelength combiner. The first wavelength combiner receives the optical signal transmitted from each working optical source link via each connected working port, and combines the received optical signal and then transmits the combined optical signal to the third wavelength combiner. 
     It should be noted that, in various embodiments, a 1×N optical switch may be included between each spare wavelength-tunable optical source link and the second wavelength combiner. Accordingly, the first wavelength-tunable spare optical source link connects, via the 1×N optical switches, to the spare port which is connected to the second wavelength combiner, wherein N is larger than or equal to the number of the spare ports. Alternatively, in various embodiments, an optical splitter and an optical switch may be set between each spare wavelength-tunable optical source link and the second wavelength combiner, in which case the first wavelength-tunable spare optical source link connects, via the optical splitter and the optical switch, to the spare port which is connected to the second wavelength combiner. 
     Block  612 : In the optoelectronic integrated apparatus at the transmitting end, the third wavelength combiner in the wavelength combining unit combines the optical signal from the first wavelength combiner and the optical signal from the second wavelength combiner, and transmits the combined optical signal to the optoelectronic integrated apparatus at the receiving end. 
     The optoelectronic integrated apparatus at the receiving end receives the optical signal subsequently. According to various embodiments, the first spare optical link may tune the emission wavelength of the optical source to accord with the emission wavelength of the first working optical source link. Thus, the last optical signal output from the optoelectronic integrated apparatus at the transmitting end is the same as the optical signal transmitted from the first working optical source link before being faulty. In this way, there is no alterations made to the optoelectronic integrated apparatus at the receiving end, and the detailed receiving process is same as that of the optoelectronic integrated apparatus at the receiving end in the prior art. 
     It should be noted that, in the above process according to some embodiments, the protecting process implemented by the protection control unit in the interior of the optoelectronic integrated apparatus at the transmitting end may also be implemented by an existing top-layer control unit, a data switching unit and an optical source link control unit. In practical service applications, the protection control unit, according to other embodiments, may also be a new functional unit in the interior of the optoelectronic integrated apparatus, and the principle of protecting the optoelectronic integrated apparatus is the same as that of the above embodiments. 
     According to some embodiments, the emission wavelength of each spare wavelength-tunable optical source link may be pre-tuned to accord with the average value of the emission wavelengths of all the working optical source links. The spare optical source links are in an inactive state and the optical signals output of all the spare optical source links are shutdown. When the first working optical source link fails, the optoelectronic integrated apparatus at the transmitting end activates the selected spare wavelength-tunable optical source link, switches the data from the working data channel of the faulty working optical source link to the spare data channel of the selected spare optical source link, and modulates the optical signal generated from the selected spare optical source link by using the electric signal output from the spare data channel of the selected spare optical source link, then transmits the modulated optical signal to the wavelength combining unit. 
     Furthermore, according to the above embodiments, the detecting unit, e.g. a Tap, and the link monitoring unit collaboratively monitor the performance of the working optical source links. In practical service applications, monitoring the performance of the working optical source link may be achieved by other measures, and the principle of the detailed process is the same as that of the process provided by the above embodiment. 
     According to some embodiments, the working data channels and the spare data channels may be set in two respective apparatuses or be incorporated in one apparatus. 
     Moreover, according to some embodiments, the light absorber has two functions. One is to monitor the optical power of the whole link according to the optical power absorbed by the light absorber when the optical source link in which the light absorber is located, functions properly. The other function is to absorb almost all of the optical signals in the optical source link where the light absorber is located when the optical source link is faulty, and this is done by applying a control signal, generally a voltage signal, to the light absorber so that the whole faulty optical source link is shut down. The light absorber may be an optical switch or PIN tube or other element. When the light absorber is a PIN tube, it can detect the output power of the optical signal when applied a positive voltage, and absorb the optical signal when applied a negative voltage. 
     Furthermore, in some embodiments, the wavelength combining unit may be an AWG or N×1 wavelength multiplexer and etc. 
     According to some embodiments, each wavelength-tunable optical source link includes a wavelength-tunable optical source. The tunable range of the wavelength is so wide that it can cover the spectrum of all the working optical source links. The wavelength-tunable optical source may be implemented in pluralities of ways, for example by adopting SG-DBR and GCSR to adjust the circuit. There are two ways to integrate the wavelength-tunable optical source. One is to generate the wavelength-tunable optical source together with the fixed-wavelength optical source while fabricating the optoelectronic integrated circuit, wherein the wavelength-tunable optical source link is as shown in  FIG. 9  (prior art), and the black parts in  FIG. 9  are the controlling pins on which leads are welded to be connected to outside pins of the optoelectronic integrated circuit. The other is to produce a laser with a wavelength-tunable optical source by other technical measures and mount the laser on the generated semiconductor base. 
     In addition, according to some embodiments, the working optical source links and the spare optical source links may be located on the same integrated circuit board or on respective integrated circuit boards. 
     Moreover, the above embodiments are described in detail in conjunction with the optoelectronic integrated apparatus. In practical service applications, the method according to some embodiments may not rely on the optoelectronic integrated apparatus described herein, in which case the principle of the processing is the same as that of the procedure provided by the above described embodiments, except that the optoelectronic integrated apparatus at the transmitting end performs the steps of the above embodiments without specified functional unit in the interior of the optoelectronic integrated apparatus at the transmitting end. 
     In general, the above are only various embodiments and are not intended to limit the protection scope. Any modification, equivalent replacement and improvement made under the principle of the present teachings should be included in the protection scope.