Patent Publication Number: US-11664983-B2

Title: Hybrid quantum key distribution link for an optical transceiver

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Greek Application No. 20200100576, filed Sep. 22, 2020, the content of which is hereby incorporated by reference herein in its entirety. 
     TECHNOLOGICAL FIELD 
     Embodiments of the present invention relate generally to quantum key distribution for optical transceivers. 
     BACKGROUND 
     Traditional security protocols for network devices generally employ software that introduces latency to computational processes and/or communications associated with the network devices. For example, traditional security protocols for network devices include traditional key exchange protocols such as a Diffie-Hellman key exchange protocol, a Rivest-Shamir-Adleman (RSA) key exchange protocol, etc. 
     BRIEF SUMMARY 
     Example embodiments of the present invention relate generally to system(s), method and apparatus to facilitate quantum key distribution for optical transceivers. The details of some embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims. 
     In an embodiment, a system comprises a first vertical cavity surface emitting laser (VCSEL), a second VCSEL, and a network interface controller. The first VCSEL is configured to emit a first optical signal associated with data. The second VCSEL is configured to emit a second optical signal associated with quantum key distribution (QKD). The network interface controller is configured to manage transmission of the first optical signal associated with the first VCSEL and the second optical signal associated with the second VCSEL via an optical communication channel coupled to a network interface module. 
     In some embodiments, the network interface controller is configured to manage transmission of the first optical signal and the second optical signal based on a filter configured to filter the second optical signal. In some embodiments, the network interface controller is configured to select the first optical signal or the second optical signal for transmission as an output optical signal via the optical communication channel. 
     In some embodiments, the network interface controller is configured to measure an electrical characteristic of a photodiode of the second VCSEL. Furthermore, in some embodiments, the network interface controller is configured to manage the transmission of the first optical signal and the second optical signal based on the electrical characteristic measured. 
     In some embodiments, the network interface controller is configured to compare measurement of states of qubits associated with the second optical signal to facilitate the transmission of the first optical signal and the second optical signal. In some embodiments, the network interface controller is configured to perform error correction with respect to the first optical signal to facilitate the transmission of the first optical signal and the second optical signal. In some embodiments, the network interface controller is configured to manage the transmission of the first optical signal and the second optical signal based on a BB84 QKD protocol, a T12 QKD protocol, or a coherent one way (COW) QKD protocol. 
     In some embodiments, the network interface controller is configured to perform a first QKD communication process associated with the second VCSEL. Furthermore, in some embodiments, the system further comprises a graphics processing unit configured to perform a second QKD communication process associated with the second VCSEL. 
     In some embodiments, the system further comprises a QSFP device that comprises the first VCSEL and the second VCSEL. In some embodiments, the system is a transceiver device. 
     In another embodiment, a system comprises a first network interface module and a network interface controller. The first network interface module comprises a first VCSEL and a second VCSEL. The first VCSEL is configured to emit a first optical signal associated with data. The second VCSEL is configured to emit a second optical signal associated with QKD. The network interface controller is configured to manage transmission of the first optical signal associated with the first VCSEL and the second optical signal associated with the second VCSEL via an optical communication channel coupled to a second network interface module. 
     In some embodiments, the first network interface module is a quad small form-factor pluggable (QSFP) network interface module. In some embodiments, the first network interface module further comprises a filter configured to filter configured to filter the second optical signal to facilitate the transmission of the first optical signal or the second optical signal via the optical communication channel. In some embodiments, the network interface controller is configured to select the first optical signal or the second optical signal for transmission as an output optical signal via the optical communication channel. 
     In some embodiments, the network interface controller is configured to measure an electrical characteristic of a photodiode of the second VCSEL. Furthermore, in some embodiments, the network interface controller is configured to manage the transmission of the first optical signal and the second optical signal based on the electrical characteristic measured. 
     In some embodiments, the network interface controller is configured to compare measurement of states of qubits associated with the second optical signal to facilitate the transmission of the first optical signal and the second optical signal. In some embodiments, the network interface controller is configured to perform error correction with respect to the first optical signal to facilitate the transmission of the first optical signal and the second optical signal. In some embodiments, the network interface controller is configured to manage the transmission of the first optical signal and the second optical signal based on a BB84 QKD protocol, a T12 QKD protocol, or a COW QKD protocol. 
     In some embodiments, the network interface controller is configured to perform a first QKD communication process associated with the second VCSEL. Furthermore, in some embodiments, the system further comprises a graphics processing unit configured to perform a second QKD communication process associated with the second VCSEL. In some embodiments, the system is a transceiver device. 
     In yet another embodiment, a method is provided. The method includes controlling emission of a first optical signal associated with data via a first VCSEL of a network interface module. The method also includes controlling emission of a second optical signal associated with QKD via a second VCSEL of the network interface module. The method also includes managing transmission of the first optical signal and the second optical signal via an optical communication channel coupled to the network interface module. 
     The above summary is provided merely for purposes of summarizing some example embodiments to provide a basic understanding of some aspects of the present invention. Accordingly, it will be appreciated that the above-described embodiments are merely examples and should not be construed to narrow the scope or spirit of the present invention in any way. It will be appreciated that the scope of the present invention encompasses many potential embodiments in addition to those here summarized, some of which will be further described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Having thus described the disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIG.  1    illustrates an exemplary system that facilitates a hybrid quantum key distribution (QKD) link, in accordance with one or more embodiments of the present disclosure; 
         FIG.  2    illustrates another exemplary system that facilitates a hybrid QKD link, in accordance with one or more embodiments of the present disclosure; 
         FIG.  3    illustrates yet another exemplary system that facilitates a hybrid QKD link, in accordance with one or more embodiments of the present disclosure; 
         FIG.  4    illustrates yet another exemplary system that facilitates a hybrid QKD link, in accordance with one or more embodiments of the present disclosure; 
         FIG.  5    illustrates a module pad layout that facilitates a hybrid QKD link, in accordance with one or more embodiments of the present disclosure; 
         FIG.  6    illustrates another module pad layout that facilitates a hybrid QKD link, in accordance with one or more embodiments of the present disclosure; 
         FIG.  7    is a flowchart illustrating an example method for facilitating a hybrid QKD link, in accordance with one or more embodiments of the present disclosure; and 
         FIG.  8    illustrates an example computing system that may be embedded in the communication system, in accordance with one or more embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, the embodiments may take many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. The terms “exemplary” and “example” as may be used herein are not provided to convey any qualitative assessment, but instead merely to convey an illustration of an example. Thus, use of any such terms should not be taken to limit the spirit and scope of embodiments of the present invention. 
     Embodiments of the present disclosure are described below with reference to block diagrams and flowchart illustrations. Thus, it should be understood that each block of the block diagrams and flowchart illustrations may be implemented in the form of a computer program product, an entirely hardware embodiment, a combination of hardware and computer program products, and/or apparatus, systems, computing devices/entities, computing entities, and/or the like carrying out instructions, operations, steps, and similar words used interchangeably (e.g., the executable instructions, instructions for execution, program code, and/or the like) on a computer-readable storage medium for execution. For example, retrieval, loading, and execution of code may be performed sequentially such that one instruction is retrieved, loaded, and executed at a time. In some example embodiments, retrieval, loading, and/or execution may be performed in parallel such that multiple instructions are retrieved, loaded, and/or executed together. Thus, such embodiments can produce specifically-configured machines performing the steps or operations specified in the block diagrams and flowchart illustrations. Accordingly, the block diagrams and flowchart illustrations support various combinations of embodiments for performing the specified instructions, operations, or steps. 
     Traditional security protocols for network devices generally employ software that introduces latency to computational processes and/or communications associated with the network devices. For example, traditional security protocols for network devices include traditional key exchange protocols such as a Diffie-Hellman key exchange protocol, a Rivest-Shamir-Adleman (RSA) key exchange protocol, etc. that introduce latency to computational processes and/or communications associated with the network devices. Furthermore, with traditional security protocols, security vulnerabilities for data transmitted via a communication channel still exist. For example, with traditional key exchange protocols, it is possible to obtain unauthorized access to data transmitted via a communication channel (e.g., data transmitted using classical computing techniques) since it is generally difficult to detect when the communication channel is being monitored and/or accessed by an unauthorized entity. Moreover, traditional security protocols are generally based on mathematical encryption with computational complexity (e.g., prime number factorization) that can be solved with quantum computing in a shorter amount of time as compared to classical computing. 
     Thus, to address these and/or other issues, a hybrid quantum key distribution link for an optical transceiver is disclosed herein. Quantum Key Distribution (QKD) is a technology that provides security to an optical communication channel via quantum mechanics. In an aspect, QKD employs photons to exchange one or more keys (e.g., one or more cryptographic keys) via an optical communication channel. A vertical cavity surface emitting laser (VCSEL) is a semiconductor laser diode that emits an optical signal (e.g., an optical beam) vertically with respect to a top surface of the VCSEL. According to one or more embodiments, a network interface module can include a redundant VCSEL to facilitate improved security associated with QKD for an optical communication channel. For example, in one or more embodiments, a network interface module can include a first VCSEL (e.g., a first VCSEL hardware device) that emits an optical signal associated with data to be transmitted via an optical communication channel and a second VCSEL (e.g., a second VCSEL hardware device) that emits another optical signal associated with QKD to facilitate encryption of the data associated with the first VCSEL. In one or more embodiments, the second VCSEL can be configured for quantum encryption based on quantum dot gain media. As such, the second VCSEL can be a source for QKD. In an embodiment, the network interface module can be a quad small form-factor pluggable (QSFP) network interface module. 
     According to one or more embodiments, a network interface controller (NIC) can perform analysis (e.g., real-time analysis) with respect to the second VCSEL to facilitate managing transmission of the optical signal associated with the first VCSEL and/or the other optical signal associated with the second VCSEL. For example, in one or more embodiments, the NIC can measure one or more characteristics associated with a photodiode of the second VCSEL to facilitate managing transmission of the optical signal associated with the first VCSEL and/or the other optical signal associated with the second VCSEL. According to one or more embodiments, a graphics processing unit (GPU) and/or another accelerator hardware unit can perform one or more computational tasks associated with analysis (e.g., real-time analysis) of the second VCSEL. In one or more embodiments, one or more pins of the network interface module can be employed for transferring information related to one or more QKD keys via the optical communication channel. 
     As such, a low cost QKD device can be provided for improved security for an optical communication channel. In an embodiment, the network interface module that includes the redundant VCSEL can be employed for an intra-datacenter connection. In another embodiment, the network interface module that includes the redundant VCSEL can be employed for high performance computing connection. However, it is to be appreciated that, in certain embodiments, the network interface module that includes the redundant VCSEL can be employed in another type of networking environment and/or another type of communications network. Moreover, according to one or more embodiments, hardware and/or intelligence to facilitate QKD technology can be implemented via a network interface module. For instance, according to one or more embodiments, QKD optics and classical optics can be implemented in a compact pluggable network interface module. According to one or more embodiments, the network interface module can be backwards compatible with classical network device technologies and/or can provide QKD capability for a network device (e.g., a NIC). Furthermore, as compared to conventional security protocols (e.g., conventional key exchange protocols), embodiments disclosed herein provide for improved security for a network interface, improved performance for a network interface module, and/or improved efficiency for a network interface module. 
       FIG.  1    illustrates a system  100  that facilitates a hybrid QKD link according to one or more embodiments of the present disclosure. For instance, in one or more embodiments, the system  100  implements a hybrid QKD link for a transceiver device (e.g., an optical transceiver). The system  100  includes a QSFP network interface module  102 . The QSFP network interface module  102  can be, for example, a transceiver device (e.g., an optical transceiver) that facilitates fiber optic communication. In one or more embodiments, the QSFP network interface module  102  can be a pluggable optical transceiver with a set of pins to facilitate connection with an optical communication channel  104 . The optical communication channel  104  can be, for example, a fiber optic communication channel (e.g., a transparent fiber optic connection, a fiber optic wire, etc.) that transmits pulses of infrared light. In an embodiment, the optical communication channel  104  includes a single optical communication channel (e.g., a single fiber optic wire). In another embodiment, the optical communication channel  104  includes two or more optical communication channels (e.g., two or more fiber optic wires). For example, in an embodiment, the optical communication channel  104  can include one or more fiber optic wires (e.g., four parallel fiber optic wires) for transmission of an optical signal (e.g., the optical signal  110 ), one or more fiber optic wires (e.g., four parallel fiber optic wires) for reception of an optical signal, and a fiber optic wire for transmission of a QKD signal (e.g., the QKD optical signal  112 ). In another embodiment, the optical communication channel  104  can include a single fiber optic wire where respective signals for classical channels with respective wavelengths (e.g., four classical channels with respective wavelengths are multiplexed) and a quantum channel (e.g., a fifth channel with a respective wavelength) are multiplexed and transmitted via the single fiber optic wire. In another embodiment, the optical communication channel  104  can include two or more fiber optic wires (e.g., four parallel fiber optic wires) where a quantum channel is implemented in a fiber optic wire from the two or more fiber optic wires. In another embodiment, the optical communication channel  104  can include a first fiber optic wire where respective signals for classical channels with respective wavelengths (e.g., four classical channels with respective wavelengths are multiplexed) are multiplexed and transmitted via the first fiber optic wire, and a second fiber optic wire where signals for a quantum channel (e.g., a fifth channel with a respective wavelength) are transmitted via the second fiber optic wire. In another embodiment, the optical communication channel  104  can include additionally or alternatively include a fiber bundle. However, it is to be appreciated that, in certain embodiments, the optical communication channel  104  can be implemented in a different manner to facilitate communication of the optical signal  110  and/or the QKD optical signal  112 . 
     In an embodiment, the QSFP network interface module  102  includes at least a VCSEL  106  (e.g., a first VCSEL) and a VCSEL  108  (e.g., a second VCSEL). In one or more embodiments, the VCSEL  106  can be configured to emit an optical signal  110 . The optical signal  110  can be, for example, a first optical signal associated with data for transmission via the optical communication channel  104 . For example, in one or more embodiments, the optical signal  110  can be an electromagnetic signal that transmits data at 10G, 25G, 40G, 50G, 100G, 200G, 400G or another data speed via the optical communication channel  104 . In one or more embodiments, the VCSEL  106  can emit the optical signal  110  at a particular wavelength (e.g., 850 nm or another wavelength). In an embodiment, the VCSEL  106  is a semiconductor laser diode that emits the optical signal  110  vertically with respect to a top surface of the VCSEL  106 . For example, in one or more embodiments, the VCSEL  106  can include a photodiode, a set of mirrors (e.g., a set of distributed Bragg reflector mirrors) parallel to a wafer surface, one or more oxide layers, a gain region, and/or a laser cavity (e.g., an active region) to facilitate generation of a laser light for the optical signal  110 . In one or more embodiments, the set of mirrors (e.g., the set of distributed Bragg reflector mirrors) of the VCSEL  106  can include a set of layers with alternating high refractive indices and low refractive indices to facilitate generation of a laser light for the optical signal  110 . In a non-limiting example, the VCSEL  106  can be associated with 4× fiber channel data links. In one or more embodiments, an optical path of the optical signal  110  can include a mirror  114  to facilitate transmission of the optical signal  110  via the optical communication channel  104 . For example, the mirror  114  can be an optical path component (e.g., a reflective surface) that redirects and/or guides the optical signal  110  to the optical communication channel  104 . 
     Additionally, in one or more embodiments, the VCSEL  108  can be configured to emit a QKD optical signal  112 . The QKD optical signal  112  can be, for example, a second optical signal associated with QKD to facilitate encryption of the data associated with the optical signal  110 . In an aspect, the VCSEL  108  can be a redundant VCSEL in the QSFP network interface module  102  to provide security for the optical communication channel  104  via one or more QKD protocols. For instance, in one or more embodiments, the VCSEL  108  can be a redundant VCSEL in the QSFP network interface module  102  to provide a source for one or more quantum keys (e.g., one or more quantum keys associated with entangled photons) for transmission via the optical communication channel  104 . In one or more embodiments, the VCSEL  108  can provide quantum encryption based on a set of quantum dots employed as a gain laser media (e.g., a source of optical gain) for the VCSEL  108 . In one or more embodiments, the VCSEL  108  can emit the QKD optical signal  112  at a greater wavelength than the optical signal  110 . For example, in a non-limiting embodiment, the VCSEL  108  can emit the QKD optical signal  112  at a wavelength (e.g., wavelength λ2) that is twice as long as a wavelength (e.g., wavelength λ1) of the optical signal  110 . In an embodiment, the VCSEL  108  is a semiconductor laser diode that emits the QKD optical signal  112  vertically with respect to a top surface of the VCSEL  108 . For example, in one or more embodiments, the VCSEL  108  can include a photodiode and set of mirrors (e.g., a set of distributed Bragg reflector mirrors) parallel to a wafer surface, one or more oxide layers, a gain region, and/or a laser cavity (e.g., an active region) to facilitate generation of a laser light for the QKD optical signal  112 . In one or more embodiments, the set of mirrors (e.g., the set of distributed Bragg reflector mirrors) of the VCSEL  108  can include a set of layers with alternating high refractive indices and low refractive indices to facilitate generation of a laser light for the QKD optical signal  112 . In an embodiment, the VCSEL  106  can be a single mode VCSEL configured for classical optical communication and the VCSEL  108  can be a single model VCSEL configured for QKD optical communication. For example, in an embodiment associated with a BB84 QKD protocol, two single mode VCSELs transmitting at non-orthogonal polarizations can be employed. In another embodiment associated with a BB84 QKD protocol, one single mode VCSEL and a polarization scrambler can be employed. In one or more embodiments, an optical path of the QKD optical signal  112  can include a mirror  116  to facilitate transmission of the QKD optical signal  112  via the optical communication channel  104 . For example, the mirror  116  can be an optical path component (e.g., a reflective surface) that redirects and/or guides the QKD optical signal  112  to the optical communication channel  104 . In one or more embodiments, by employing the VCSEL  106  and the VCSEL  108 , the optical communication channel  104  can be a hybrid QKD link that facilitates transmission of the optical signal  110  and the QKD optical signal  112 . It is to be appreciated that, in certain embodiments, the QSFP network interface module  102  can include more than two VCSELs. For example, in certain embodiments, the QSFP network interface module  102  can additionally include one or more additional VCSELs associated with classical optical communication and/or one or more additional VCSELs associated with QKD. Moreover, in certain embodiments, both the VCSEL  106  and the VCSEL  108  can be employed for QKD. 
     In one or more embodiments, the system  100  additionally includes a NIC  118 . In an embodiment, the NIC  118  can be coupled (e.g., physically coupled and/or communicatively coupled) to the QSFP network interface module  102 . In another embodiment, the QSFP network interface module  102  can include the NIC  118 . The NIC  118  can be configured to manage transmission of the optical signal  110  and/or the QKD optical signal  112  via the optical communication channel  104 . In an embodiment, the NIC  118  can be configured to select the optical signal  110  or the QKD optical signal  112  for transmission via the optical communication channel  104 . For example, in an embodiment, the NIC  118  can be configured to manage timing of transmission of the optical signal  110  and/or the QKD optical signal  112  over a single optical communication channel (e.g., a single fiber optic wire) of the optical communication channel  104 . In another embodiment, the NIC  118  can be configured to select the optical signal  110  for transmission via a first optical communication channel (e.g., a first fiber optic wire) of the optical communication channel  104  and the QKD optical signal  112  for transmission via a second optical communication channel (e.g., a second fiber optic wire) of the optical communication channel  104 . 
     In one or more embodiments, the NIC  118  can be configured to manage emission of the QKD optical signal  112  to facilitate transmission of one or more quantum keys (e.g., one or more QKD keys) via the optical communication channel  104 . For example, in one or more embodiments, the NIC  118  can be configured to manage one or more inputs provided to the VCSEL  108  and/or one or more settings for the VCSEL  108  to transmission of one or more quantum keys (e.g., one or more QKD keys) via the optical communication channel  104 . In an embodiment associated with a BB84 QKD protocol, the NIC  118  can select which VCSEL to transmit (or the NIC  118  can control a state of the polarization scrambler) to facilitate emission of an optical signal at an appropriate polarization. In one or more embodiments, control from the NIC  118  to the QSFP network interface module  102  can be realized based on an electrical lane control signal and/or by sending one or more different data streams to each VCSEL of the QSFP network interface module  102 . In an embodiment associated with a protocol that employs time-bin encoding (e.g., a COW QKD protocol), the NIC  118  can drive the VCSEL  106  and/or the VCSEL  108  with the appropriate data. In one or more embodiments, the NIC  118  can be configured to perform one or more quantum processes (e.g., quantum processing) and/or quantum programming associated with the VCSEL  108 . In one or more embodiments, the NIC  118  can be configured to select either the VCSEL  106  or the VCSEL  108  for transmission of a respective optical signal (e.g., the optical signal  110  or the QKD optical signal  112 ). Additionally or alternatively, in one or more embodiments, the NIC  118  can determine a polarization state (e.g., control a state of a polarization scrambler) for the VCSEL  106  and/or the VCSEL  108 . In one or more embodiments, the NIC  118  can transmit one or more control signal (e.g., one or more electrical control signals) to the VCSEL  106  and/or the VCSEL  108  to facilitate transmission of the optical signal  110  and/or the QKD optical signal  112 . In one or more embodiments, the NIC  118  can additionally or alternatively configure the VCSEL  106  and/or the VCSEL  108  with certain data to facilitate transmission of the optical signal  110  and/or the QKD optical signal  112 . In one or more embodiments, the NIC  118  can additionally or alternatively configure the VCSEL  108  based on time-bin encoding to facilitate encoding of qubit information associated with the QKD optical signal  112 . 
     In one or more embodiments, the NIC  118  can be configured to measure an electrical characteristic of a photodiode of the VCSEL  108 . Furthermore, in one or more embodiments, the NIC  118  can be configured to manage the transmission of the optical signal  110  and/or the QKD optical signal  112  based on the electrical characteristic measured. In one or more embodiments, the NIC  118  can be configured to compare measurement of states of qubits associated with the QKD optical signal  112  to facilitate the transmission of the optical signal  110  and/or the QKD optical signal  112 . In one or more embodiments, the NIC  118  can be configured to perform error correction, sifting and/or privacy amplification with respect to the optical signal  110  to facilitate the transmission of the optical signal  110  and/or the QKD optical signal  112 . In one or more embodiments, the NIC  118  can be configured to manage the transmission of the optical signal and/or the QKD optical signal  112  based on a BB84 QKD protocol, a T12 QKD protocol, a coherent one way (COW) QKD protocol, and/or another QKD protocol. For example, in one or more embodiments, the NIC  118  can configure the VCSEL  108  for transmission of the QKD optical signal  112  based on a BB84 QKD protocol, a T12 QKD protocol, a COW QKD protocol, and/or another QKD protocol. 
       FIG.  2    illustrates a system  100 ′ that facilitates a hybrid QKD link according to one or more embodiments of the present disclosure. The system  100 ′ illustrates an exemplary embodiment associated with the system  100 . The system  100 ′ includes the QSFP network interface module  102 , the optical communication channel  104 , and/or the NIC  118 . In an embodiment, the QSFP network interface module  102  includes the VCSEL  106 , the VCSEL  108 , the mirror  114 , the mirror  116  and/or a filter  202 . In one or more embodiments, the NIC  118  can be configured manage transmission of the optical signal  110  and/or the QKD optical signal  112  based on the filter  202 . In an embodiment, the filter  202  can be configured to filter the QKD optical signal  112 . For instance, in one or more embodiments, the filter  202  can be configured to filter an optical signal with a wavelength (e.g., wavelength λ2) that corresponds to a wavelength (e.g., wavelength λ2) of the QKD optical signal  112 . In an example, the filter  202  can be configured to filter optical signals with a wavelength λ2 that corresponds to the QKD optical signal  112 . In one or more embodiments, the filter  202  can be an optical filter that selectively transmits and/or filters different wavelengths. In one or more embodiments, the NIC  118  can control filtering by the filter  202 . For example, in one or more embodiments, the NIC  118  can be configured to control the filter  202  to selectively filter the wavelength (e.g., wavelength λ2) of the QKD optical signal  112  or not. In one or more embodiments, the filter  202  can be located in an optical path of the optical signal  110  and/or the QKD optical signal  112 . In one or more embodiments, the filter  202  can be coupled to the mirror  114  that provides an output optical signal (e.g., the optical signal  110  and/or the QKD optical signal  112 ) to the optical communication channel  104 . In an embodiment, the filter  202  can be a thin film filter. In another embodiment, the filter  202  can be configured based on a prism or grating. In one or more embodiments, the filter  202  can be combined with a beamforming element (e.g., a microelectromechanical systems (MEMS) mirror or a liquid crystal on silicon (LCOS) display) to, for example, facilitate dynamic alteration of one or more portions of the filter  202 . 
       FIG.  3    illustrates a system  100 ″ that facilitates a hybrid QKD link according to one or more embodiments of the present disclosure. The system  100 ″ illustrates an exemplary embodiment associated with the system  100 . The system  100 ″ includes the QSFP network interface module  102 , the optical communication channel  104 , the NIC  118 , and/or a GPU  302 . In an embodiment, the QSFP network interface module  102  includes the VCSEL  106 , the VCSEL  108 , the mirror  114 , and/or the mirror  116 . In certain embodiments, the QSFP network interface module  102  additionally includes the filter  202 . In an embodiment, the GPU  302  can be coupled (e.g., physically coupled and/or communicatively coupled) to the QSFP network interface module  102 . In another embodiment, the QSFP network interface module  102  can include the GPU  302 . In one or more embodiments, the GPU  302  can be employed in combination with the NIC  118  to manage transmission of the optical signal  110  and/or the QKD optical signal  112  via the optical communication channel  104 . For example, in an embodiment, the NIC  118  can be configured to perform a first QKD communication process associated with the VCSEL  108  and the GPU  302  can be configured to perform a second QKD communication process associated with the VCSEL  108 . Additionally or alternatively, in an embodiment, the NIC  118  can be configured to perform a first communication process associated with the VCSEL  106  and the GPU  302  can be configured to perform a second communication process associated with the VCSEL  106 . Additionally or alternatively, in an embodiment, the NIC  118  can be configured to perform a first error correction process associated with the optical signal  110  and the GPU  302  can be configured to perform a second error correction process associated with the optical signal  110 . In certain embodiments, the GPU  302  can be configured to perform error correction, sifting and/or privacy amplification (e.g., rather than the NIC  118  performing error correction, sifting and/or privacy amplification) with respect to the optical signal  110  to facilitate the transmission of the optical signal  110  and/or the QKD optical signal  112 . In certain embodiments, the GPU  302  can be configured to perform at least a portion of one or more quantum processes (e.g., quantum processing) and/or quantum programming associated with the VCSEL  108 . In certain embodiments, the GPU  302  can be configured to perform one or more other computational tasks associated with the VCSEL  106  and/or the VCSEL  108 . In certain embodiments, the GPU  302  can be configured as another type of accelerator hardware unit that performs one or more computational tasks associated with the VCSEL  106  and/or the VCSEL  108 . 
       FIG.  4    illustrates a system  400  that facilitates a hybrid QKD link according to one or more embodiments of the present disclosure. The system  400  includes the QSFP network interface module  102 , the optical communication channel  104 , the NIC  118 , and/or a QSFP network interface module  402 . For instance, the QSFP network interface module  102  can be a first QSFP network interface module and the QSFP network interface module  402  can be a second QSFP network interface module. Furthermore, the QSFP network interface module  102  and the QSFP network interface module  402  can be coupled via the optical communication channel  104 . In an embodiment, the QSFP network interface module  102  includes the VCSEL  106 , the VCSEL  108 , the mirror  114 , and/or the mirror  116 . In certain embodiments, the QSFP network interface module  102  additionally includes the filter  202 . In certain embodiments, the GPU  302  is additionally coupled to the QSFP network interface module  102 . In one or more embodiments, the QSFP network interface module  102  is coupled to the optical communication channel  104 . Additionally, in one or more embodiments, the QSFP network interface module  402  is coupled to the optical communication channel  104 . In an embodiment, the QSFP network interface module  102  can be a first transceiver device (e.g., a first optical transceiver) coupled to the optical communication channel  104  and the QSFP network interface module  402  can be a second transceiver device (e.g., a second optical transceiver) coupled to the optical communication channel  104 . In certain embodiments, the QSFP network interface module  102  can be employed as a transmitter device that transmits data (e.g., communication data) and/or one or more quantum keys (e.g., one or more QKD keys) to the QSFP network interface module  402  (e.g., a receiver device) via the optical communication channel  104 . For example, in one or more embodiments, the QSFP network interface module  402  can receive the optical signal  110  and/or the QKD optical signal  112  (e.g., the optical signal  110  and/or the QKD optical signal  112  transmitted by the QSFP network interface module  102 ) via the optical communication channel  104 . In one or more embodiments, the QSFP network interface module  402  can be configured similar to the QSFP network interface module  102 . For example, in an embodiment, the QSFP network interface module  402  can include a second set of the VCSEL  106 , the VCSEL  108 , the mirror  114 , and/or the mirror  116 . In certain embodiments, the QSFP network interface module  102  can additionally include a second version of the filter  202 . In certain embodiments, second version of the NIC  118  and/or the GPU  302  can be coupled to the QSFP network interface module  402 . In one or more embodiments, the QSFP network interface module  402  can be configured based on a QKD protocol associated with the QSFP network interface module  102 . 
       FIG.  5    illustrates a module pad layout  500  that facilitates a hybrid QKD link according to one or more embodiments of the present disclosure. For example, the module pad layout  500  can illustrate a top side viewed from the top for a module pad employed by the QSFP network interface module  102 . In an embodiment, the module pad layout  500  can correspond to a module pad (e.g., a serial communication interface) of the QSFP network interface module  102  that is connected to the optical communication channel  104 . In an aspect, the module pad layout  500  can be a module-host electrical interface. In another aspect, the module pad layout  500  can be configured to provide QKD key transfer functionality (e.g., without altering legacy communication functionality for a QSFP-DD network interface module). In one or more embodiments, the module pad layout  500  includes Legacy QSFP28 pads  502  and additional QSFP-DD pads  504 . In one or more embodiments, the Legacy QSFP28 pads  502  can be contact pads (e.g., to facilitate electrical interconnections) associated with classical network communication and the additional QSFP-DD pads  504  can be contact pads (e.g., to facilitate electrical interconnections) associated with quantum communication. In an embodiment, the Legacy QSFP28 pads  502  can facilitate transmission of the optical signal  110  via the optical communication channel  104 . Furthermore, the additional QSFP-DD pads  504  can facilitate transmission of the QKD optical signal  112  via the optical communication channel  104 . In a non-limiting embodiment, the Legacy QSFP28 pads  502  can be legacy QSFP28 pads and the additional QSFP-DD pads  504  can be QSFP-DD pads. However, it is to be appreciated that, in certain embodiments, the Legacy QSFP28 pads  502  and/or the additional QSFP-DD pads  504  can be different type of module pads. As such, with the module pad layout  500 , the QSFP network interface module  102  can provide transmission of both the optical signal  110  and the QKD optical signal  112  via the optical communication channel  104 . For example, with the module pad layout  500 , the QSFP network interface module  102  can provide transmission of both data related to one or more communications and one or more quantum keys (e.g., one or more QKD keys) via the optical communication channel  104 . In one or more embodiments, the QKD optical signal  112  (e.g., the one or more quantum keys) can be transmitted via a management interface associated with the additional QSFP-DD pads  504 . In one or more embodiments, with the module pad layout  500 , a network device can detect that a pluggable transceiver with QKD capability has been attached to the network device and the network device can enable a communication interface according to the module pad layout  500  (e.g. according to a configuration of the Legacy QSFP28 pads  502  and/or the additional QSFP-DD pads  504 ). As such, a network device can be backwards compatible with one or more QSFP network interface modules by employing the additional QSFP-DD pads  504 . In one or more embodiments, the additional QSFP-DD pads  504  can leverage one or more previously unused module pads such as, for example, module pads #66 and #69 in QSFP-DD form factor. In one or more embodiments, the additional QSFP-DD pads  504  can additionally or alternatively leverage one or more vendor specific module pads. In one or more embodiments, the additional QSFP-DD pads  504  can transmit QKD key information through a management interface. For example, in one or more embodiments, the additional QSFP-DD pads  504  can transmit QKD key information via a serial communication interface (e.g., a two-wire serial communication interface) such as, for example, pins SDA and SCL for QSFP, OSFP and/or QSFP-DD form factors. In one or more embodiments related to a host system implementation compatible with the QSFP network interface module  102 , the host system can detect that a pluggable network interface module with QKD capability has been attached to the host system and/or can enable the communication interface according to the module pad layout  500 . Therefore, the host system can be backwards compatible with other vendors (e.g., multi-source agreement (MSA)-compatible) and/or can be QKD compatible when a compliant module (e.g., the QSFP network interface module  102 ) is connected. 
       FIG.  6    illustrates a module pad layout  600  that facilitates a hybrid QKD link according to one or more embodiments of the present disclosure. The module pad layout  600  can illustrate a bottom side viewed from the bottom for a module pad employed by the QSFP network interface module  102 . For example, in an embodiment, the module pad layout  600  can illustrate a bottom side viewed from the bottom for a module pad employed by the QSFP network interface module  102  and the module pad layout  500  can illustrate a top side viewed from the top for the module pad employed by the QSFP network interface module  102 . In an embodiment, the module pad layout  600  can correspond to a module pad (e.g., a serial communication interface) of the QSFP network interface module  102  that is connected to the optical communication channel  104 . In one or more embodiments, the module pad layout  600  can be employed in combination with the module pad layout  500 . In an aspect, the module pad layout  600  can be a module-host electrical interface. In another aspect, the module pad layout  600  can be configured to provide QKD key transfer functionality (e.g., without altering legacy communication functionality for a QSFP network interface module). In one or more embodiments, the module pad layout  600  includes additional QSFP-DD pads  602  and Legacy QSFP28 pads  604 . In one or more embodiments, the Legacy QSFP28 pads  604  can be contact pads (e.g., to facilitate electrical interconnections) associated with classical network communication and the additional QSFP-DD pads  602  can be contact pads (e.g., to facilitate electrical interconnections) associated with quantum communication. In an embodiment, the Legacy QSFP28 pads  604  can facilitate transmission of the optical signal  110  via the optical communication channel  104 . Furthermore, the additional QSFP-DD pads  602  can be configured to facilitate transmission of the QKD optical signal  112  via the optical communication channel  104 . In a non-limiting embodiment, the additional QSFP-DD pads  602  can be QSFP-DD pads and the Legacy QSFP28 pads  604  can be legacy QSFP28 pads. However, it is to be appreciated that, in certain embodiments, the additional QSFP-DD pads  602  and/or the Legacy QSFP28 pads  604  can be different type of module pads. As such, with the module pad layout  600 , the QSFP network interface module  102  can provide transmission of both the optical signal  110  and the QKD optical signal  112  via the optical communication channel  104 . For example, with the module pad layout  600 , the QSFP network interface module  102  can provide transmission of both data related to one or more communications and one or more quantum keys (e.g., one or more QKD keys) via the optical communication channel  104 . In one or more embodiments, the QKD optical signal  112  (e.g., the one or more quantum keys) can be transmitted via a management interface associated with the additional QSFP-DD pads  602 . In one or more embodiments, with the module pad layout  600 , a network device can detect that a pluggable transceiver with QKD capability has been attached to the network device and the network device can enable a communication interface according to the module pad layout  600  (e.g. according to a configuration of the Legacy QSFP28 pads  604  and/or the additional QSFP-DD pads  602 ). As such, a network device can be backwards compatible with one or more QSFP network interface modules by employing the additional QSFP-DD pads  602 . In one or more embodiments, the additional QSFP-DD pads  602  can leverage one or more previously unused module pads such as, for example, module pads #46 in QSFP-DD form factor. In one or more embodiments, the additional QSFP-DD pads  602  can additionally or alternatively leverage one or more vendor specific module pads such as, for example, VS1-3 pads #47, #49 and #50 in QSFP-DD form factor. In one or more embodiments, the additional QSFP-DD pads  602  can transmit QKD key information through a management interface. For example, in one or more embodiments, the additional QSFP-DD pads  602  can transmit QKD key information via a serial communication interface (e.g., a two-wire serial communication interface) such as, for example, pins SDA and SCL for QSFP, OSFP and/or QSFP-DD form factors. In one or more embodiments related to a host system implementation compatible with the QSFP network interface module  102 , the host system can detect that a pluggable network interface module with QKD capability has been attached to the host system and/or can enable the communication interface according to the module pad layout  600 . Therefore, the host system can be backwards compatible with other vendors (e.g., multi-source agreement (MSA)-compatible) and/or can be QKD compatible when a compliant module (e.g., the QSFP network interface module  102 ) is connected. 
       FIG.  7    is a flowchart illustrating an example method for facilitating quantum key distribution in accordance with one or more embodiments of the present disclosure. It will be understood that each block of the flowcharts, and combinations of blocks in the flowcharts, may be implemented by various means. In some example embodiments, certain ones of the operations herein may be modified or further amplified as described below. Moreover, in some embodiments additional optional operations may also be included. It should be appreciated that each of the modifications, optional additions, or amplifications described herein may be included with the operations herein either alone or in combination with any others among the features described herein. The operations illustrated in  FIG.  7    may, for example, be performed by an example computing system  800  (shown in  FIG.  8   ) that is embedded in a QSFP network interface module (e.g., the QSFP network interface module  102  and/or  402 ), a VCSEL (e.g., the VCSEL  106  and/or the VCSEL  108 ), and/or a NIC (e.g., the NIC  118 ). In some embodiments, the computing system  700  is a firmware computing system embedded in a QSFP network interface module (e.g., the QSFP network interface module  102  and/or  402 ), a VCSEL (e.g., the VCSEL  106  and/or the VCSEL  108 ), and/or a NIC (e.g., the NIC  118 ). In one or more embodiments, one or more of the operations illustrated in  FIG.  7    may, for example, be performed by a QSFP network interface module (e.g., the QSFP network interface module  102  and/or  402 ), a VCSEL (e.g., the VCSEL  106  and/or the VCSEL  108 ), and/or a NIC (e.g., the NIC  118 ). In one or more embodiments, at operation  702 , the computing system  800  controls emission of a first optical signal associated with data via a first vertical cavity surface emitting laser (VCSEL) of a network interface module. The network interface module can be, for example, a QSFP network interface module (e.g., the QSFP network interface module  102 ). In one or more embodiments, at operation  704 , the computing system  800  controls emission of a second optical signal associated with quantum key distribution (QKD) via a second VCSEL of the network interface module. In an embodiment, the second VCSCEL can be configured as a source for QKD. In one or more embodiments, at operation  706 , the computing system  800  manages transmission of the first optical signal and the second optical signal via an optical communication channel coupled to the network interface module. 
       FIG.  8    illustrates the computing system  800  that may be embedded in a datacenter network system. In some cases, the computing system  800  may be a firmware computing system communicatively coupled with, and configured to control, one or more circuit modules associated with a network interface module (e.g., a QSFP network interface module). For example, the computing system  800  may be a firmware computing system and/or a controller computing system communicatively coupled with one or more circuit modules, such as a QSFP network interface module (e.g., the QSFP network interface module  102  and/or  402 ), a VCSEL (e.g., the VCSEL  106  and/or the VCSEL  108 ), and/or a NIC (e.g., the NIC  118 ). The computing system  800  may include or otherwise be in communication with a processor  810 , a memory circuitry  820 , and communication circuitry  830 . In some embodiments, the processor  810  (which may include multiple or co-processors or any other processing circuitry associated with the processor) may be in communication with the memory circuitry  820 . The memory circuitry  820  may comprise non-transitory memory circuitry and may include one or more volatile and/or non-volatile memories. In some examples, the memory circuitry  820  may be an electronic storage device (e.g., a computer readable storage medium) configured to store data that may be retrievable by the processor  810 . In some examples, the data stored in the memory  820  may include classical communication protocol data and/or quantum communication protocol data, or the like for enabling the apparatus to carry out various functions or methods in accordance with embodiments of the present invention, described herein. 
     In some examples, the processor  810  may be embodied in a number of different ways. For example, the processor may be embodied as one or more of various hardware processing means such as a microprocessor, a coprocessor, a digital signal processor (DSP), a controller, or a processing element with or without an accompanying DSP. The processor  810  may also be embodied in various other processing circuitry including integrated circuits such as, for example, an FPGA (field programmable gate array), a microcontroller unit (MCU), an ASIC (application specific integrated circuit), a hardware accelerator, or a special-purpose electronic chip. Furthermore, in some embodiments, the processor may include one or more processing cores configured to perform independently. A multi-core processor may enable multiprocessing within a single physical package. Additionally or alternatively, the processor may include one or more processors configured in tandem via the bus to enable independent execution of instructions, pipelining, and/or multithreading. In some embodiments, the processor  810  is a microprocessor. 
     In an example embodiment, the processor  810  may be configured to execute instructions, such as computer program code or instructions, stored in the memory circuitry  820  or otherwise accessible to the processor  810 . Alternatively or additionally, the processor  810  may be configured to execute hard-coded functionality. As such, whether configured by hardware or software instructions, or by a combination thereof, the processor  810  may represent a computing entity (e.g., physically embodied in circuitry) configured to perform operations according to an embodiment of the present invention described herein. For example, when the processor  810  is embodied as an ASIC, FPGA, or similar, the processor may be configured as hardware for conducting the operations of an embodiment of the invention. Alternatively, when the processor  810  is embodied to execute software or computer program instructions, the instructions may specifically configure the processor  810  to perform the algorithms and/or operations described herein when the instructions are executed. However, in some cases, the processor  810  may be a processor of a device (e.g., a mobile terminal or a fixed computing device) specifically configured to employ an embodiment of the present invention by further configuration of the processor using instructions for performing the algorithms and/or operations described herein. The processor  810  may further include a clock, an arithmetic logic unit (ALU) and logic gates configured to support operation of the processor  810 , among other things. 
     The computing system  800  may optionally also include the communication circuitry  830 . The communication circuitry may be any means embodied in either hardware or a combination of hardware and software that is configured to receive and/or transmit data from/to a network and/or any other device or module in communication with the computing system  800 . In this regard, the communication interface may include, for example, supporting hardware and/or software for enabling communications. As such, for example, the communication circuitry  830  may include a communication modem and/or other hardware/software for supporting communication via cable, universal serial bus (USB), integrated circuit receiver, or other mechanisms. 
     Many modifications and other embodiments of the present inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the present inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.