Optical transceiver module and optical communication system

Abstract

The present disclosure relates to mitigation of temperature variation and crosstalk in silicon photonic interconnects. An optical transceiver module includes a light source configured to emit light, a transmitter resonator configured to transmit an optical signal from the light source, a temperature sensor configured to detect a temperature of the transmitter resonator, and a controller circuit. The controller circuit is configured to obtain a first temperature variation value based on the detected temperature, and encode the first temperature variation value in an outgoing data stream via the transmitter resonator.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to optical communications. BACKGROUND

[0002] Optical networks typically include optical transmitters, optical receivers, and optical fibers connected therebetween. To increase transmission capacity, a wavelength division multiplexing (WDM) approach is introduced. The WDM approach allows transmission of multiple wavelengths in a single physical optical fiber, thereby increasing transmission bandwidth. Optical interconnections in optical networks can be based on silicon photonics using resonator-type modulators. The resonator-type modulators can be ring resonators including a set of waveguides in which at least one waveguide can be a closed loop coupled to at least an optical input port and an optical output port. Since the resonator-type modulators are compatible with the manufacturing process of integrated circuits, the resonator-type modulators have various application potentials in optical communication networks. SUMMARY

[0003] According to one aspect of the present disclosure, there is provided an optical transceiver module comprising: a light source configured to emit light; a transmitter resonator configured to transmit an optical signal from the light source; a temperature sensor configured to detect a temperature of the transmitter resonator; a controller circuit configured to: obtain a first temperature change value based on the detected temperature; and encode the first temperature change value in an outgoing data stream via the transmitter resonator; a receiver resonator configured to receive an incoming data stream; and a heater coupled to the receiver resonator to adjust a temperature of the receiver resonator, wherein the controller circuit is further configured to: extract a second temperature change value from the incoming data stream; and control the heater to adjust the temperature of the receiver resonator based on the second temperature change value.

[0004] According to another aspect of the present disclosure, there is provided an optical transceiver module comprising: a receiver resonator configured to receive an incoming data stream; a heater coupled to the receiver resonator to adjust a temperature of the receiver resonator; and a controller circuit configured to: extract a first temperature change value from the incoming data stream; and control the heater to adjust the temperature of the receiver resonator based on the first temperature change value, wherein: the receiver resonator is configured to receive incoming data signals in a plurality of input optical channels, each of the input optical channels operating at a different wavelength; and the controller circuit is further configured to: extract crosstalk data encoded in respective data signals in respective optical channels; and subtract the crosstalk data from data signals received prior to the respective data signals.

[0005] According to yet another aspect of the disclosure, there is provided an optical communication system comprising a transmitter module and a receiver module coupled to each other via one or more optical cables, wherein the transmitter module comprises: a light source configured to emit light; a transmitter resonator configured to transmit an optical signal from the light source; a temperature sensor configured to detect a temperature of the transmitter resonator; and a transmitter controller circuit configured to: obtain a first temperature variation value based on the detected temperature; and encode the first temperature variation value in a data stream via the transmitter resonator; and wherein the receiver module comprises: a receiver resonator configured to receive the data stream; a heater coupled to the receiver resonator to adjust a temperature of the receiver resonator; and a receiver controller circuit configured to: extract the first temperature variation value from the data stream; and control the heater to adjust the temperature of the receiver resonator based on the first temperature variation value. BRIEF DESCRIPTION OF DRAWINGS

[0006] The disclosure is described in detail according to one or more different embodiments with reference to the following drawings. The drawings are provided for illustrative purposes only and only depict typical or example embodiments.

[0007] Figure 1 FIG. 1 illustrates an optical communication system according to one example embodiment.

[0008] Figure 2 FIG. 2 is a flowchart illustrating a method for providing a temperature parameter of a transmitter ring resonator to a receiver module in an optical communication system according to one example embodiment.

[0009] Figure 3 FIG. 3 is a flowchart illustrating a method for adjusting a temperature of a receiver ring resonator of a receiver module in an optical communication system according to one example embodiment.

[0010] Figure 4 FIG. 4 is a flowchart illustrating a method for providing crosstalk data of a transmitter ring resonator to a receiver module in an optical communication system according to one example embodiment.

[0011] Figure 5 FIG. 5 is a flowchart illustrating a method for mitigating crosstalk in a data signal received at a receiver module in an optical communication system according to one example embodiment.

[0012] The drawings are not exhaustive and do not limit the disclosure to the precise forms disclosed. DETAILED DESCRIPTION

[0013] Silicon photonics are typically affected by temperature variations. Various solutions have been proposed to address the many thermal effects on silicon photonics. For example, integrated thermal controllers can be used to control the temperature of individual components in silicon photonic devices. A goal is to achieve wavelength tracking and locking at the modulator. For instance, existing techniques attempt to measure the bit error rate (BER) in an optical link and adjust the temperature of the transmitter ring modulator and / or receiver ring modulator based on the BER count. The aim is to adjust the temperature of the transmitter ring modulator and / or receiver ring modulator in a communication network so that the BER count is reduced below a threshold.

[0014] An optical communication system is disclosed, which provides a technique for reducing network communication errors. Silicon photonics technology is employed in the optical communication system to provide cost-effective, high-bandwidth, and low-latency connectivity.

[0015] Ring resonators based on silicon photonics technology typically heat up during operation. This can affect link quality and cause a thermal shift in the resonant wavelength of the transmitter ring relative to the receiver ring. The techniques disclosed in this paper provide a temperature synchronization algorithm for optical communication systems, enabling precise temperature control of the ring resonators at both the transmitter and receiver ends, which may typically be physically far apart and located in different temperature environments.

[0016] Silicon photonics technology integrates optical transceivers and / or optical paths on a semiconductor substrate. Silicon photonics technology can provide hybrid devices that include both electrical domains (e.g., controllers) and optical domains (e.g., optical transceivers). The techniques disclosed herein also provide methods for utilizing silicon photonics technology to reduce communication errors caused by temperature variations and optical crosstalk, thereby improving the overall performance of optical communication systems.

[0017] Now for reference Figure 1 . Figure 1 An optical communication system 100 according to an example embodiment is illustrated. The optical communication system 100 includes a first transceiver module 102 and a second transceiver module 104. It should be understood that, although in Figure 1 The diagram shows two transceiver modules, but the optical communication system 100 may include more transceiver modules. The first transceiver module 102 and the second transceiver module 104 are connected to each other via an optical fiber 106.

[0018] The first transceiver module 102 includes a transmitter (Tx) ring resonator 110 and a receiver (Rx) ring resonator 112. The Tx ring resonator 110 includes an optical input port (Opt In) 110a, an optical output port (Drop Out) 110b, and a through port (Thru Out) 110c. The optical input port 110a is coupled to a light source 114 and is configured to receive an input optical signal for the Tx ring resonator 110. The optical output port 110b is coupled to a Tx photodetector 116. An optical signal designated for the Tx ring resonator 110 is filtered at the optical output port 110b and can be detected by the Tx photodetector 116. The Tx photodetector 116 is configured to detect the optical signal at the optical output port 110b and convert the optical signal to an electrical signal. In some embodiments, the Tx photodetector 116 can be a photodiode. An optical signal designated for output is filtered at the through port 110c for transmission to a destination (e.g., the Rx ring resonator 152 at the second transceiver module 104).

[0019] The Rx ring resonator 112 includes an optical input port (Opt In) 112a and an optical output port (Drop Out) 112b. The optical input port 112a is configured to receive an optical signal from an external source (e.g., the Tx ring resonator 150 of the second transceiver module 104). The Rx ring resonator 112 is configured to modulate the received optical signal and output at the optical output port 112b. An Rx photodetector 120 is coupled to the optical output port 112b and is configured to detect the optical signal at the optical output port 112b. In some embodiments, the Rx photodetector 120 can be a photodiode.

[0020] The first transceiver module 102 further includes a controller circuit 118 configured to control the operation of the Tx ring resonator 110 and the Rx ring resonator 112. The first transceiver module 102 also includes a Tx heater 122, a diode 124, and a Tx temperature sensor 126 arranged at or near the Tx ring resonator 110, and an Rx heater 128 and an Rx temperature sensor 130 arranged at or near the Rx ring resonator 112. The controller circuit 118 is coupled to the light source 114, the Tx photodetector 116, the Rx photodetector 120, the Tx heater 122, the diode 124, the Tx temperature sensor 126, the Rx heater 128, and the Rx temperature sensor 130. The controller circuit 118 is configured to provide control signals to these components to perform the various functions described herein. In some embodiments, the controller circuit 118 can be an application specific integrated circuit (ASIC).

[0021] The light source 114 can be a laser diode configured to emit optical signals of various wavelengths. The optical signals from the light source 114 are received at the Tx input port 110a, modulated by the Tx ring resonator 110, and then transmitted at the Tx through port 110c. The Tx heater 122 is configured to provide thermal energy to adjust the temperature of the Tx ring resonator 110. The diode 124 is configured to modulate the optical signal based on a control signal provided by the controller circuit 118. In some embodiments, the diode 124 is configured to modulate the optical signal at a speed on the order of nanoseconds or faster. The Tx temperature sensor 126 is configured to detect the temperature of the Tx ring resonator 110. The temperature reading is sent to the controller circuit 118 to implement the temperature synchronization techniques disclosed herein. The Tx photodetector 116 is configured to detect the optical signal at the optical output port 110b, convert the detected optical signal to an electrical signal, and send the electrical signal to the controller circuit 118 to implement the various control techniques disclosed herein. The controller circuit 118 can be referred to as a Tx controller circuit when performing control functions related to the Tx ring resonator 110.

[0022] The Rx heater 128 is configured to provide thermal energy to adjust the temperature of the Rx ring resonator 112. The Rx temperature sensor 130 is configured to detect the temperature of the Rx ring resonator 112. The temperature reading is sent to the controller circuit 118 to implement the temperature synchronization techniques disclosed herein. The Rx photodetector 120 is configured to detect the optical signal at the optical output port 112b, convert the detected optical signal to an electrical signal, and send the electrical signal to the controller circuit 118 to implement the various control techniques disclosed herein. The controller circuit 118 can be referred to as an Rx controller circuit when performing control functions related to the Rx ring resonator 112.

[0023] The second transceiver module 104 includes a Tx ring resonator 150 and an Rx ring resonator 152. The Tx ring resonator 150 includes an optical input port (Opt In) 150a, an optical output port (Drop Out) 150b, and a through port (Thru Out) 150c. The optical input port 150a is coupled to a light source 154 and is configured to receive an input optical signal for the Tx ring resonator 150. The optical output port 150b is coupled to a Tx photodetector 156. The optical signal designated for the Tx ring resonator 150 is filtered at the optical output port 150b and can be detected by the Tx photodetector 156. In some embodiments, the Tx photodetector 156 can be a photodiode. The optical signal designated for output is filtered at the through port 150c for transmission to a destination (e.g., the Rx ring resonator 112 at the first transceiver module 102). In some embodiments, the Tx ring resonator 150 is configured to modulate the optical signal based on a control signal provided by the controller circuit 118. In some embodiments, the Tx ring resonator 150 is configured to modulate the optical signal at a speed on the order of nanoseconds or faster. The Tx temperature sensor 158 is configured to detect the temperature of the Tx ring resonator 150. The temperature reading is sent to the controller circuit 118 to implement the temperature synchronization techniques disclosed herein. Figure 1In the illustrated example, the pass-through port 150c at the second transceiver module 104 is connected to the optical input port 112a at the first transceiver module 102 via the optical cable 106.

[0024] The Rx ring resonator 152 includes an optical input port (Opt In) 152a and an optical output port (Drop Out) 152b. The optical input port 152a is configured to receive an optical signal from an external source (e.g., the Tx ring resonator 110 of the first transceiver module 102). In Figure 1 In the illustrated example, the optical input port 152a at the second transceiver module 104 is connected to the pass-through port 110c at the first transceiver module 102 via the optical cable 106. The Rx ring resonator 152 is configured to modulate the received optical signal and output at the optical output port 152b. The Rx photodetector 160 is coupled to the optical output port 152b and is configured to detect the optical signal at the optical output port 152b.

[0025] The second transceiver module 104 further includes a controller circuit 158 configured to control the operation of the Tx ring resonator 150 and the Rx ring resonator 152. The second transceiver module 104 also includes a Tx heater 162, a diode 164, and a Tx temperature sensor 166 arranged at or near the Tx ring resonator 150, and a Rx heater 168 and a Rx temperature sensor 170 arranged at or near the Rx ring resonator 152. The controller circuit 158 is coupled to the light source 154, the Tx photodetector 156, the Rx photodetector 160, the Tx heater 162, the diode 164, the Tx temperature sensor 166, the Rx heater 168, and the Rx temperature sensor 170. The controller circuit 158 is configured to provide control signals to these components to perform the various functions described herein. In some embodiments, the controller circuit 158 can be an application-specific integrated circuit (ASIC). The functions of the components of the second transceiver module 104 are similar to the corresponding components of the first transceiver module 102, and can be referred to the above description.

[0026] The optical signals transmitted in the optical cable 106 can be based on dense wavelength-division multiplexing (DWDM) technology or other suitable optical communication protocols currently existing or developed hereinafter.

[0027] The techniques described herein are primarily from the perspective of the first transceiver module 102, but it should be understood that the above techniques can be applied to any transceiver module in the optical communication system 100, including the second transceiver module 104. Similarly, when the techniques described herein are from the perspective of the second transceiver module 104, the above techniques can be equally applied to the first transceiver module 102.

[0028] At the start-up phase of the first transceiver module 102, the controller circuit 118 is configured to provide a control signal to the Tx heater 122 to cause the Tx ring resonator 110 to prepare for operation at an operating temperature. Once the Tx ring resonator 110 is at the operating temperature, the controller circuit 118 controls the light source 114 to emit light and controls the diode 124 to start modulating the Tx ring resonator 110. The controller circuit 118 instructs the Tx temperature sensor 126 to report a temperature reading of the Tx ring resonator 110. The Tx temperature sensor 124 can be configured to periodically (e.g., at one second intervals) detect a temperature reading of the Tx ring resonator 110 and report the temperature reading to the controller circuit 118. Based on the temperature reading, the controller circuit 118 can calculate a temperature change value. For example, the controller circuit 118 can compare a current temperature reading with a previous temperature reading to obtain the temperature change value. As a non-limiting example, the temperature change value can be 1 °C, 5 °C, -1 °C, -5 °C, etc. In some instances, the temperature change value can be zero to indicate that there is no temperature change of the Tx ring resonator 110 within the detection interval.

[0029] When the temperature change value is a non-zero value, the controller circuit 118 is configured to encode the temperature change value in the outgoing data stream via the Tx ring resonator 110. For example, the controller circuit 118 can control the diode 124 to write the temperature change value on a designated portion of the outgoing data stream. As a non-limiting example, the designated portion can be a header of a data packet or a data segment that is specifically reserved for the temperature change value. This technique allows the actual temperature change at the Tx ring resonator 110 to be communicated to a receiver module (e.g., the Rx ring resonator 152 of the second transceiver module 104) so that the second transceiver module 104 can adjust the temperature of the Rx ring resonator 152 based on the received temperature change value. For example, after the data stream is received at the Rx ring resonator 152 of the second transceiver module 104, the photodetector 160 converts the received optical signal into an electrical signal and forwards the electrical signal to the controller circuit 158. The controller circuit 158 extracts the temperature change value from the electrical signal and controls the Rx heater 168 to adjust the temperature of the Rx ring resonator 152 based on the temperature change value. The above technique enables the Tx ring resonator and the Rx ring resonator to synchronize their temperature drifts, thereby reducing data communication errors.

[0030] The temperature change value, even if zero, can be periodically encoded in the data stream from the Tx loop resonator 110 of the first transceiver module 102 to the Rx loop resonator 152 of the second transceiver module 104. If the temperature change value is zero, the controller circuit 158 does not adjust the temperature of the Rx loop resonator 152. In some implementations, after the controller circuit 118 of the first transceiver module 102 obtains the temperature change value based on the detected temperature of the Tx loop resonator 110, the controller circuit 118 can be configured to determine whether the temperature change value is greater than a threshold value. If the temperature change value is greater than the threshold value, the controller circuit 118 is configured to encode the temperature change value in the outgoing data stream via the Tx loop resonator 110. If the temperature change value is equal to or less than the threshold value, the controller circuit 118 does not encode the temperature change value in the outgoing data stream, even if the temperature change value is a non-zero value. This technique can prevent the controller circuit 158 of the second transceiver module 152 from adjusting the temperature of the Rx loop resonator 152 based on minor temperature changes at the Tx loop resonator 110.

[0031] In some embodiments, the controller circuit 118 can categorize the temperature change value of the Tx loop resonator 110 into a plurality of levels, each level represented by a temperature code. As a non-limiting example, level 1 can represent a change of 1 °C. For example, temperature change values of 2.1 °C and 2.9 °C can be categorized into the same level, while temperature change values of 1.9 °C and 2.1 °C are categorized into different levels. The controller circuit 118 can then encode the temperature code in the outgoing data stream via the Tx loop resonator 110. Based on the temperature code, the controller circuit 158 controls the heater 168 to adjust the temperature of the Rx loop resonator 152. In some embodiments, the level distance can be progressive. As a non-limiting example, lower levels can have a larger level distance than higher levels. In one implementation, for example, level 1 can be 0 °C to 3 °C, level 2 can be 3 °C to 4.5 °C, and level 3 can be 4.5 °C to 5.5 °C. The progressive level categorization can reflect that smaller temperature change values can not significantly disrupt the data communication between the Tx loop resonator 110 and the Rx loop resonator 152, while larger temperature change values tend to negatively impact the integrity of the data communication.

[0032] Alternatively or additionally, the controller circuit 118 of the first transceiver module 102 can encode the raw temperature reading from the Tx temperature sensor 126 into the data stream. The controller circuit 158 of the second transceiver module 104 can extract the temperature reading from the data stream and control the Rx heater 168 to adjust the temperature of the Rx loop resonator 152.

[0033] These techniques enable the Tx ring resonator 110 and the Rx ring resonator 152 to synchronize their temperatures, thereby providing stable data communication therebetween. In contrast to conventional schemes in which temperature is indirectly measured using link quality parameters (e.g., BER counts), the techniques disclosed herein employ actual temperature parameters (e.g., temperature change values and / or temperature readings). Since actual temperature parameters are encoded into the data stream, the receiving end can adjust the temperature of its Rx ring resonator with higher precision and lower complexity.

[0034] In some embodiments, similar techniques can be employed to communicate temperature changes at the Rx ring resonator 112 of the first transceiver module 102 to the second transceiver module 104, enabling the controller circuit 158 to adjust the temperature of the Tx ring resonator 150. To this end, each of the Rx ring resonators 112 and 152 is provided with an Rx temperature sensor 130 or 170 to obtain temperature readings of the Rx ring resonators 112 and 152. As explained above, the temperature readings from the Rx temperature sensors 130 or 170 can be converted into temperature change values by the controller circuit 118 or 158. The controller circuit 118 or 158 then encodes the temperature change values in the data stream to the opposite transceiver module via the Tx ring resonator 110 or 150.

[0035] The Tx ring resonator 110 can be used to encode other system parameters in the data stream. For example, when the Tx ring resonator 110 is encoding data in the data stream, crosstalk can be induced at the Tx ring resonator 110 between the optical channels. Based on DWDM technology, the Tx ring resonator 110 can be configured to output signals in multiple optical channels, where each of the aforementioned optical channels operates at a different wavelength. When the Tx ring resonator 110 encodes data in the data stream into one of the optical channels at the pass-through port 110c, it can induce crosstalk or noise that is exhibited in another optical channel. The crosstalk can be observed when the compliment of the data stream encoded at the pass-through port 110c can be optically present at the output port 110b. One major cause of crosstalk comes from the carrier injection modulator (e.g., the Tx ring resonator 110), which when turned on, produces a "blue shift" or spectral shift to higher frequencies.

[0036] To obtain the crosstalk data, the controller circuit 118 is configured to analyze the optical signal at the output port 110b. Specifically, the optical signal at the output port 110b is captured by the Tx photodetector 116 and converted into an electrical signal. The controller circuit 118 obtains the electrical signal from the Tx photodetector 116. Then, the controller circuit 118 is configured to compare the signal from a first optical channel in the optical channel operating at the longest wavelength with the signal in a second optical channel adjacent to the first optical channel. Based on the above comparison, the controller circuit 118 is configured to extract the crosstalk data imposed on the second optical channel by the signal from the first optical channel. Once the crosstalk data is obtained, the controller circuit 118 is configured to encode the crosstalk data in a subsequent signal in the second optical channel via the Tx ring resonator 110. The above signal and the subsequent signal from the second optical channel are outputted at the pass-through port 110c in the form of a data stream and transmitted to the input port 152a of the Rx ring resonator 152 of the second transceiver module 104 via the optical cable 106.

[0037] After the data stream is received at the Rx ring resonator 152, the Rx photodetector 160 is configured to detect the above signal and the subsequent signal from the second optical channel. Then, the controller circuit 158 is configured to extract the crosstalk data encoded in the subsequent signal from the second optical channel and subtract the crosstalk data from the signal received before the subsequent signal. These techniques allow the receiving side to cancel the crosstalk generated at the transmitting side (e.g., at the Tx ring resonator 110 or 150), so that a clearer form of data signal can be obtained.

[0038] These techniques can be applied to each optical channel operated by the Tx ring resonator 110 (or 150) except for the first optical channel operating at the longest wavelength at the Tx ring resonator 110 (or 150). The controller circuit 118 (or 158) is configured to encode the crosstalk-free data in the output signal in the first optical channel. This is because the first optical channel does not experience crosstalk when it operates at the lowest carrier frequency. A general description of the techniques is provided herein. In some embodiments, the controller circuit (e.g., the controller circuit 118 or 158) is configured to compare a signal from an nth optical channel with a signal from an (n + 1)th optical channel adjacent to the nth optical channel, extract an nth crosstalk data imposed on the (n + 1)th optical channel by the signal from the nth optical channel, and encode the nth crosstalk data in a subsequent output signal in the (n + 1)th optical channel via the transmitter resonator.

[0039] Reference is now made to Figure 2 . Figure 2is a flowchart illustrating a method 200 for providing a temperature parameter of a Tx ring resonator to a receiver module in an optical communication system, according to one example embodiment. The method 200 can be performed by a controller circuit (e.g., the controller circuit 118 or 158 in the transmitter module 102 or 104, respectively) in the optical communication system. At 202, the controller circuit obtains a temperature change value based on a detected temperature of the Tx ring resonator. To detect the temperature of the Tx ring resonator, a temperature sensor (e.g., the Tx temperature sensor 126 or 166 in the transmitter module 102 or 104, respectively) is employed. The temperature sensor is configured to detect the temperature of the Tx ring resonator periodically or upon request. Temperature readings from the temperature sensor are provided to the controller circuit to compute at least one temperature change value for indicating a change in temperature at the Tx ring resonator over a period of time. Figure 1 Figure 1 To detect the temperature of the Tx ring resonator, a temperature sensor (e.g., the Tx temperature sensor 126 or 166 in the transmitter module 102 or 104, respectively) is employed. The temperature sensor is configured to detect the temperature of the Tx ring resonator periodically or upon request. Temperature readings from the temperature sensor are provided to the controller circuit to compute at least one temperature change value for indicating a change in temperature at the Tx ring resonator over a period of time.

[0040] At 204, the controller circuit determines whether the temperature change value is a non-zero value. If the temperature change value is a zero value (NO at 204), the method 200 returns to 202. When the temperature change value is a zero value, it indicates that no temperature change is detected on the Tx ring resonator and, therefore, there is no need to inform the receiver module of any temperature change. If the temperature change value is a non-zero value (YES at 204), at 206, the controller circuit determines whether the non-zero value is greater than a temperature change threshold. If the non-zero value is equal to or less than the temperature change threshold (NO at 206), the method 200 returns to 202. When the non-zero value is equal to or less than the temperature change threshold, it indicates that the temperature change of the Tx ring resonator is not large enough and, therefore, there is no need to inform the receiver module. If the non-zero value is greater than the temperature change threshold (YES at 206), at 208, the controller circuit encodes the temperature change value in an outgoing data stream to the receiver module via the Tx ring resonator. The temperature change value enables the receiver module to make a corresponding temperature adjustment to its Rx ring resonator that is coupled to the Tx ring resonator of the transmitter module.

[0041] In some implementations, one or both of the operations 204 and 206 can be omitted. Depending on the operational protocol defined for the transmitter module and the receiver module, when the operations 204 and 206 are omitted at the transmitter module, the operations can be performed by the receiver module to determine whether to adjust the temperature of its Rx ring resonator. Figure 3 An example is shown in FIG. 3.

[0042] Figure 3 is a flowchart illustrating a method 300 for adjusting a temperature of an Rx ring resonator of a receiver module in an optical communication system, according to one example embodiment. The method 300 can be performed by a controller circuit (e.g., the controller circuit 118 or 158 in the transmitter module 102 or 104, respectively) in the optical communication system. At 302, the controller circuit receives a temperature change value from a transmitter module in the optical communication system. The temperature change value is encoded in an incoming data stream from the transmitter module via a Tx ring resonator of the transmitter module. The temperature change value enables the controller circuit to make a corresponding temperature adjustment to an Rx ring resonator of the receiver module that is coupled to the Tx ring resonator of the transmitter module. At 304, the controller circuit adjusts the temperature of the Rx ring resonator based on the temperature change value.​Figure 1 The controller circuit extracts the temperature change value from the incoming data stream at 302. The controller circuit obtains the incoming data stream from a photodetector coupled to the receiver module's Rx ring resonator.

[0043] At 304, the controller circuit determines whether the temperature change value is a non-zero value. If the temperature change value is a zero value (NO at 304), the method 300 returns to 302. When the temperature change value is a zero value, it indicates that no temperature change is detected on the transmitter module's Tx ring resonator, and thus there is no need to adjust the temperature of the Rx ring resonator. If the temperature change value is a non-zero value (YES at 304), at 306, the controller circuit determines whether the non-zero value is greater than a temperature change threshold. If the non-zero value is equal to or less than the temperature change threshold (NO at 306), the method 300 returns to 302. When the non-zero value is equal to or less than the temperature change threshold, it indicates that the temperature change of the Tx ring resonator is not large enough, and thus there is no need to adjust the temperature of the Rx ring resonator. If the non-zero value is greater than the temperature change threshold (YES at 306), at 308, the controller circuit controls a heater for the Rx ring resonator to adjust the temperature of the Rx ring resonator based on the temperature change value. In some embodiments, one or both of operations 304 and 306 can be omitted.

[0044] Figure 4 is a flowchart illustrating a method 400 for providing transmitter module's Tx ring resonator's crosstalk data to a receiver module in an optical communication system, according to one example embodiment. The method 400 can be performed by a controller circuit (e.g., the controller circuit 118 or 158 in the transceiver module 102 or 104 in the optical communication system 100 of Figure 1 is a flowchart illustrating a method 400 for providing transmitter module's Tx ring resonator's crosstalk data to a receiver module in an optical communication system, according to one example embodiment. The method 400 can be performed by a controller circuit (e.g., the controller circuit 118 or 158 in the transceiver module 102 or 104 in the optical communication system 100 of Figure 1 At 402, the controller circuit sets m optical channels for communication at the Tx ring resonator. Each of the m optical channels operates at a different wavelength. At 404, the controller circuit compares a signal from an nth optical channel with a signal from an (n + 1)th optical channel adjacent to the nth optical channel, where the nth optical channel operates at a longer wavelength than the (n + 1)th optical channel. The controller circuit can obtain the signal from the nth optical channel and the signal from the (n + 1)th optical channel from a feedback loop of the transmitter module. For example, with reference to Figure 1The controller circuit 118 instructs the diode 124 to modulate the Tx ring resonator to encode the data signal in the optical channel. When the Tx ring resonator 110 encodes the data signal in the optical channel to be transmitted from the through port 110c, a complement of the data signal is applied at the output port 110b and can be detected by the Tx photodetector 116, which then transmits the data signal to the controller circuit 118. As a result, the data signal from the optical channel can be obtained by the controller circuit 118. The feedback loop is formed by the controller circuit 118, the diode 124, the Tx ring resonator 102, and the Tx photodetector 116.

[0045] Based on the comparison at 404, at 406, the controller circuit extracts the nth crosstalk data applied on the (n + 1)th optical channel by the signal from the nth optical channel. At 408, the controller circuit encodes the nth crosstalk data in the subsequent output signal in the (n + 1)th optical channel via the Tx ring resonator. Since the crosstalk data observed at the (n + 1)th optical channel is encoded in the same optical channel, the receiver module can extract the crosstalk data from the optical channel that just transmitted the data signal that needs to be corrected. Other encoding techniques can be considered. For example, all the crosstalk data of the multiple optical channels can be transmitted by any one of the optical channels. In this implementation, each crosstalk data can be assigned an identifier to indicate the respective optical channel that is affected by the crosstalk data, so that the receiver module can correctly subtract the crosstalk data from the respective data signal. As a non-limiting example, all the crosstalk data of the multiple optical channels can be transmitted by the optical channel that operates at the longest wavelength. As explained above, the optical channel that operates at the longest wavelength does not experience crosstalk caused by adjacent channels. This allows the crosstalk data to be encoded as a clean carrier.

[0046] At 410, the controller circuit continues to process the crosstalk of the next optical channel, i.e., the (n + 1)th optical channel. At 412, the controller circuit determines whether the crosstalk data encoding process has been performed for all m optical channels. That is, the controller circuit determines whether N is greater than M. If there is one or more optical channels that have not yet undergone the crosstalk data encoding process (NO at 412), the method 400 returns to 404 to iterate the operations 404-412 to encode the crosstalk data of another optical channel. If the crosstalk data encoding process has been performed for all m optical channels (YES at 412), the method 400 ends at 414.

[0047] Figure 5is a flowchart illustrating a method 500 for mitigating crosstalk in data signals received at a receiver module in an optical communication system, according to one example embodiment. The method 500 can be performed by a controller circuit (e.g., the controller circuit 118 or 158 in Figure 1 the receiver module (e.g., the transceiver module 102 or 104) in an optical communication system. At 502, the controller circuit (e.g., the controller circuit 158 in Figure 1 extracts crosstalk data encoded in respective data signals in respective optical channels. Rx ring resonators (e.g., the Rx ring resonators 152 in Figure 1 the receiver module receive respective data signals in the optical domain, which are then detected by Rx photodetectors (e.g., the Rx photodetectors 160). The Rx photodetectors convert the optical data signals into electrical data signals and send the electrical data signals to the controller circuit. The controller circuit extracts the crosstalk data encoded in the respective data signals. At 504, the controller circuit subtracts the crosstalk data from data signals received prior to the respective data signals. These techniques allow the receiver module to mitigate crosstalk in data signals generated at Tx ring resonators of a transmitter module when the Tx ring resonators encode data signals for the optical channels.

[0048] In summary, the techniques disclosed herein provide solutions for communicating temperature parameters and crosstalk data from a transmitter module to a receiver module to enable the receiver module to adjust its temperature parameters and mitigate crosstalk in received data signals. These techniques enable forward error correction to be implemented in the physical layer to improve stability and accuracy of data communication.

[0049] As used herein, a circuit can be implemented with any form of hardware, software, or combinations thereof. For example, one or more processors, controllers, ASICs, PLAs, PALs, CPLDs, FPGAs, logical components, software routines, or other mechanisms can be implemented to make up a circuit. In implementation, various circuits described herein can be implemented as discrete circuits or the described functions and features can be shared among one or more circuits. Even though various features or functions of embodiments can be described as being carried out by separate circuits, these features and functions can be shared among one or more common circuits, and such description shall not require or imply that separate circuits are required to implement such features or functionality.

[0050] Generally, the words "component," "engine," "system," "database," "data store," and the like can refer to logic embodied in hardware or firmware, or to a software module being written in a programming language that can be executed on a hardware device. The software component can be compiled into an executable program or installed as a dynamic link library, or can be written in an interpreted programming language such as BASIC, Perl, or Python. It will be appreciated that software components can be callable from other components or from themselves, and / or can be invoked in response to detected events or interrupts. Software components configured for execution on computing devices can be provided on computer readable media, such as compact discs, digital video discs, flash drives, magnetic disks, and any other tangible, media, or as a digital download (and can be originally stored in a compressed, encrypted, uncompressed, or uncompressed form, and can be installed prior to execution, decompressed, decrypted, or decrypted). Such software code can be stored in a memory device, such as a memory on a computing device, for execution by a processor. Software code can be embedded in firmware such as an EPROM. It will further be appreciated that hardware components can include connected logic units, such as gates and flip-flops, and / or can include programmable units, such as programmable gate arrays or processors.

[0051] In common usage, the term "or" should be interpreted in the inclusive sense unless otherwise indicated or logically apparent from the context. For example, when the term "or" is paired with another term, such as "A or B," the exclusive sense of "or" is specifically indicated. As another example, the exclusive sense can also be specifically indicated by the addition of "exclusive" or "but not both" after a listing of items, such as "A or B, exclusive or A and B, but not both." Also, descriptions of resources, operations, or structures in the singular shall not be construed as excluding the plural. Unless specifically stated otherwise, or as is logically apparent from the context, conditional language, such as, among others, "can," "could," "might," or "may," generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and / or steps.

[0052] Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. Adjectives such as “conventional,” “traditional,” “normal,” “standard,” “known,” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that can be available or known now or at any time in the future. In certain instances, the use of varying language or phraseology throughout the specification may not be a indication of an intention to limit the scope of what the inventor(s) could consider a disclosure of the disclosure.

Claims

1. An optical transceiver module, comprising: A light source, configured to emit light; A transmitter resonator configured to emit an optical signal from the light source; A temperature sensor configured to detect the temperature of the transmitter resonator; The controller circuit is configured to: The first temperature change value is obtained based on the detected temperature; as well as The first temperature change value is encoded in the outgoing data stream via the transmitter resonator; A receiver resonator configured to receive an incoming data stream; as well as A heater, coupled to the receiver resonator, is used to adjust the temperature of the receiver resonator. The controller circuit is further configured as follows: Extract the second temperature change value from the incoming data stream; and The heater is controlled to adjust the temperature of the receiver resonator based on the second temperature change value.

2. The optical transceiver module as described in claim 1, wherein, The transmitter resonator includes a ring resonator.

3. The optical transceiver module as described in claim 1, wherein, The controller circuit is further configured to: The first temperature change value is extracted periodically based on the detected temperature.

4. The optical transceiver module as described in claim 1, wherein, The receiver resonator includes a ring resonator.

5. The optical transceiver module as described in claim 1, wherein: The transmitter resonator is configured to output signals in multiple optical channels, each of which operates at a different wavelength; as well as The controller circuit is further configured to: The signal from the first optical channel operating at the longest wavelength in the optical channels is compared with the signal from the second optical channel adjacent to the first optical channel; Based on the comparison, crosstalk data applied to the second optical channel by the signal from the first optical channel is extracted; as well as The crosstalk data is encoded in the subsequent output signal in the second optical channel via the transmitter resonator.

6. The optical transceiver module as described in claim 5, wherein, The controller circuit is further configured to: The signal from the nth optical channel is compared with the signal from the (n+1)th optical channel adjacent to the nth optical channel; Extract the nth crosstalk data applied to the (n+1)th optical channel by the signal from the nth optical channel; as well as The nth crosstalk data is encoded into the subsequent output signal in the (n+1)th optical channel via the transmitter resonator.

7. The optical transceiver module as described in claim 5, wherein, The controller circuit is configured to encode crosstalk-free data in the output signal of the first optical channel.

8. An optical transceiver module, comprising: A receiver resonator configured to receive an incoming data stream; A heater, coupled to the receiver resonator, to adjust the temperature of the receiver resonator; as well as The controller circuit is configured to: Extract the first temperature change value from the incoming data stream; as well as Based on the first temperature change value, the heater is controlled to adjust the temperature of the receiver resonator. in: The receiver resonator is configured to receive incoming data signals in a plurality of input optical channels, each of which operates at a different wavelength; as well as The controller circuit is further configured to: Extract the crosstalk data encoded in the corresponding data signal in the corresponding optical channel; and Subtract the crosstalk data from the data signal received before the corresponding data signal.

9. The optical transceiver module as claimed in claim 8, wherein, The receiver resonator includes a ring resonator.

10. The optical transceiver module as claimed in claim 8, wherein, The controller circuit is further configured to: The first temperature change value is periodically extracted from the incoming data stream; and In response to detecting that a subsequent first temperature change value is different from a previous first temperature change value, the heater is controlled to adjust the temperature of the receiver resonator based on the subsequent first temperature change value.

11. The optical transceiver module of claim 8, further comprising: A light source, configured to emit light; A transmitter resonator configured to emit an optical signal from the light source; as well as A temperature sensor, configured to detect the temperature of the transmitter resonator, The controller circuit is further configured as follows: A second temperature change value is obtained based on the detected temperature; and The second temperature change value is encoded in the outgoing data stream via the transmitter resonator.

12. The optical transceiver module as claimed in claim 11, wherein, The transmitter resonator includes a ring resonator.

13. The optical transceiver module of claim 11, wherein: The transmitter resonator is configured to output signals in multiple optical channels, each of which operates at a different wavelength. as well as The controller circuit is further configured to: The signal from the first optical channel operating at the longest wavelength in the optical channels is compared with the signal from the second optical channel adjacent to the first optical channel; Based on the comparison, crosstalk data applied to the second optical channel by the signal from the first optical channel is extracted; as well as The crosstalk data is encoded in the subsequent output signal in the second optical channel via the transmitter resonator.

14. The optical transceiver module as claimed in claim 13, wherein, The controller circuit is further configured to: The signal from the nth optical channel is compared with the signal from the (n+1)th optical channel adjacent to the nth optical channel; Extract the nth crosstalk data applied to the (n+1)th optical channel by the signal from the nth optical channel; as well as The nth crosstalk data is encoded into the subsequent output signal in the (n+1)th optical channel via the transmitter resonator.

15. The optical transceiver module as claimed in claim 13, wherein, The controller circuit is configured to encode crosstalk-free data in the output signal of the first optical channel.

16. An optical communication system comprising a transmitter module and a receiver module coupled to each other via one or more optical fibers. in, The transmitter module includes: A light source, configured to emit light; A transmitter resonator configured to emit an optical signal from the light source; A temperature sensor, configured to detect the temperature of the transmitter resonator; and Transmitter controller circuit, the transmitter controller circuit being configured to: A first temperature change value is obtained based on the detected temperature; and The first temperature change value is encoded in the data stream via the transmitter resonator; and The receiver module includes: A receiver resonator configured to receive the data stream; A heater, coupled to the receiver resonator, is used to adjust the temperature of the receiver resonator; and Receiver controller circuit, the receiver controller circuit being configured to: Extract the first temperature change value from the data stream; and The heater is controlled to adjust the temperature of the receiver resonator based on the first temperature change value.

17. The optical communication system of claim 16, wherein: The transmitter resonator is configured to output signals in multiple optical channels, each of which operates at a different wavelength; and The transmitter controller circuit is further configured to: The signal from the first optical channel operating at the longest wavelength in the optical channels is compared with the signal from the second optical channel adjacent to the first optical channel; Based on the comparison, crosstalk data applied to the second optical channel by the signal from the first optical channel is extracted; as well as The crosstalk data is encoded into a subsequent signal in the second optical channel via the transmitter resonator.

18. The optical communication system of claim 17, wherein: The receiver resonator is configured to receive signals in the second optical channel and subsequent signals; and The receiver controller circuit is further configured to: Extract the crosstalk data from the subsequent signal; and Subtract the crosstalk data from the signal.

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