Reconfigurable optical transceiver for multiple modulation techniques

Abstract

An optical module includes a plurality of lasers, each of at least some of the lasers configured to be selectively turned on and off according to a modulation type to be used. Each laser corresponds to a respective wavelength. The optical module also includes an optical modulation system having a plurality of optical modulators. A reconfigurable optical network of the optical module is configured to selectively direct light from the plurality of lasers to the optical modulation system according to a modulation type to be used.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 332,310, filed on April 19, 2022, entitled “Format Agnostic Receiver for Direct and Coherent Detection,” the entire contents of which are expressly incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to optical communications and, more particularly, to optical transceivers. Background Art

[0004] In a period of growth in Internet technology and usage, the need for high-speed data transmission has increased rapidly. For example, average Internet traffic in 2021 is estimated to exceed 700 megabytes per second. The technologies used to support this sustained level of usage will continue to proliferate. Optical transmission of data can support large amounts of data per channel, which is generally limited more by the rate at which the electronics can encode the signal onto the optical channel than by the bandwidth of the channel itself. Improvements in optical modulation performance will continue to drive the adoption of such technologies.

[0005] There are many different modulation techniques currently used for optical communications. Examples of such modulation techniques include: i) intensity modulation techniques, such as intensity modulation, direct detection (IMDD), dual polarization IMDD; and ii) coherent modulation techniques, such as quadrature phase shift keying (QPSK) modulation, dual polarization QPSK (DP-QPSK) modulation, differential QPSK (DQPSK) modulation, dual polarization DQPSK, M-ary quadrature amplitude modulation (M-QAM), dual polarization M-QAM, etc. Typical optical transceivers can only generate and receive one type of optical modulation (or a small part of the various optical modulation types available before). For example, a typical optical transceiver that can generate and receive IMDD modulated optical signals cannot generate or receive QPSK or M-QAM modulated optical signals. As another example, a typical optical transceiver that can generate and receive QPSK or M-QAM modulated optical signals cannot generate or receive IMDD modulated optical signals. Summary of the invention

[0006] In one embodiment, an optical module for multiple optical modulation techniques includes: a plurality of lasers, each of at least some of the lasers being configured to be selectively turned on and off according to a modulation type to be used, each laser corresponding to a corresponding wavelength; an optical modulation system including a plurality of optical modulators; and a reconfigurable optical network configured to selectively direct light from the plurality of lasers to the optical modulation system according to the modulation type to be used. In another embodiment, a method for controlling a reconfigurable optical module for transmitting information via an optical medium includes: determining at a controller a modulation type to be used for transmitting information via an optical medium, the modulation type being determined by a plurality of different types of optical modulation techniques, including at least a first type and a second type; controlling, by the controller, the plurality of lasers of the reconfigurable optical module to i) turn on or ii) turn off at least some of the lasers in the plurality of lasers according to the modulation type to be used, each laser corresponding to a corresponding wavelength; and controlling, by the controller, the reconfigurable optical network of the reconfigurable optical module to selectively direct light from the plurality of lasers to the optical modulation system of the reconfigurable optical module differently according to the modulation type to be used.

[0007] In another embodiment, an optical module for multiple optical modulation techniques includes: an optoelectronic conversion circuit system including multiple photodiodes coupled to multiple transimpedance amplifiers (TIAs), the multiple photodiodes including multi-input photodiodes, each multi-input photodiode including a first side and a second side opposite the first side; an optical processor configured to optically process one or more optical signals corresponding to coherent modulation, the optical processor coupled to the multiple photodiodes, including multiple outputs of the optical processor coupled to corresponding first sides of the multi-input photodiodes; and an optical network configured to i) in a first configuration corresponding to a first modulation technique, direct optical signals corresponding to light received via an optical medium to corresponding second sides of the multi-input photodiodes so that the light bypasses the optical processor, and ii) in a second configuration corresponding to a second modulation technique, direct one or more optical signals corresponding to light received via the optical medium to one or more inputs of the optical processor.

[0008] In another embodiment, a method for operating a reconfigurable optical module includes an optoelectronic conversion circuit system including a plurality of photodiodes coupled to a plurality of TIAs. The plurality of photodiodes include a multi-input photodiode, each multi-input photodiode having a first side and a second side opposite the first side. The optical module also includes an optical processor configured to optically process one or more optical signals corresponding to coherent modulation, the optical processor coupled to the plurality of photodiodes. A plurality of outputs of the optical processor are coupled to respective first sides of the multi-input photodiodes. The method includes: determining at a controller a modulation type of an optical signal received via an optical medium that a reconfigurable optical module will process, the modulation type being determined by a plurality of different types of optical modulation techniques, including at least a first type and a second type; and controlling, by the controller, a reconfigurable optical network of the reconfigurable optical module to selectively i) in a first configuration corresponding to a first modulation technique, direct an optical signal corresponding to light received via the optical medium to a corresponding first side of a multi-input photodiode so that the light bypasses an optical processor, and ii) in a second configuration corresponding to a second modulation technique, direct one or more optical signals corresponding to light received via the optical medium to one or more inputs of the optical processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a simplified block diagram of an example optical transmitter that can be reconfigured to generate amplitude modulated and coherently modulated signals in accordance with an embodiment.

[0010] Figure 2A According to the embodiment Figure 1 Simplified block diagram of a reconfigurable optical module used in an optical transmitter.

[0011] Figure 2B According to the embodiment Figure 2A Illustration of a reconfigurable optical module in a first configuration, in which the optical module is configured to generate a signal modulated according to a first modulation technique.

[0012] Figure 2C According to the embodiment Figure 2A An illustration of a reconfigurable optical module in a second configuration, wherein the optical module is configured to generate a signal modulated according to a second modulation technique.

[0013] Figure 3 is a simplified block diagram of an example optical receiver that can be reconfigured to process amplitude modulated and coherently modulated signals in accordance with an embodiment.

[0014] Figure 4A According to the embodiment Figure 3Simplified block diagram of a reconfigurable optical module used in an optical receiver.

[0015] Figure 4B According to the embodiment Figure 4A Illustration of a reconfigurable optical module in a first configuration, in which the optical module is configured to receive and process a signal modulated according to a first modulation technique.

[0016] Figure 4C According to the embodiment Figure 4A An illustration of a reconfigurable optical module in a second configuration, wherein the optical module is configured to generate a signal modulated according to a second modulation technique.

[0017] Figure 4D According to another embodiment Figure 4A An illustration of a reconfigurable optical module in a second configuration, wherein the optical module is configured to generate a signal modulated according to a second modulation technique.

[0018] Figure 5A According to the embodiment, Figure 3 Reconfigurable optical receiver and / or Figure 4A A simplified diagram of an example optoelectronic conversion circuit for a reconfigurable optical module.

[0019] Figure 5B According to an embodiment, an optical receiver is connected with Figure 4B The corresponding first configuration operation Figure 5A Schematic diagram of the operation of the photoelectric conversion circuit.

[0020] Figure 5C According to an embodiment, an optical receiver is connected with Figure 4C The corresponding second configuration operation Figure 5A Schematic diagram of the operation of the photoelectric conversion circuit.

[0021] Figure 5D According to an embodiment, when the optical receiver is operated in another configuration Figure 5A Schematic diagram of the operation of the photoelectric conversion circuit.

[0022] Figure 6 is a flow chart of an example method for operating a reconfigurable optical transmitter capable of modulating optical signals according to different optical modulation techniques, according to an embodiment.

[0023] Figure 7 is a flow chart of an example method for operating a reconfigurable optical receiver capable of demodulating optical signals modulated according to different optical modulation techniques, according to an embodiment. DETAILED DESCRIPTION

[0024] As described above, a typical optical transceiver is capable of generating and receiving optical signals according to only one type of optical modulation (or a small subset of the various types of optical modulation currently available). For example, a typical optical transceiver that is capable of generating and demodulating amplitude modulated optical signals cannot generate or demodulate coherent modulated optical signals. As another example, a typical optical transceiver that is capable of generating and receiving coherent modulated optical signals cannot generate and receive amplitude modulated optical signals.

[0025] In the embodiments described below, the reconfigurable optical transmitter is capable of generating optical signals modulated according to various optical modulation techniques. As an illustrative example, according to some embodiments, the optical transmitter is capable of generating amplitude modulated optical signals and may be reconfigured to generate coherent modulated optical signals.

[0026] In accordance with some embodiments, a reconfigurable optical transceiver utilizes an innovative optical network that is reconfigurable to i) provide light from multiple lasers to corresponding inputs of an optical modulation system in a first configuration for amplitude modulation, and ii) provide light from a single laser to multiple inputs of the optical modulation system in a second configuration for coherent modulation.

[0027] In other embodiments described below, the reconfigurable optical receiver is capable of demodulating optical signals modulated according to various optical modulation techniques. As an illustrative example, according to some embodiments, the optical receiver is capable of demodulating amplitude modulated optical signals and can be reconfigured to demodulate coherently modulated optical signals.

[0028] According to some embodiments, the reconfigurable optical receiver utilizes an innovative photoelectric conversion circuit that is capable of processing optical signals modulated according to various optical modulation techniques. For example, according to some embodiments, the photoelectric conversion circuit is capable of processing amplitude modulated signals as well as coherent modulated signals. On the other hand, a typical optical receiver uses a first photoelectric conversion circuit configured to process amplitude modulated signals or a second photoelectric conversion circuit configured to process coherent modulated signals, i.e., wherein the first photoelectric conversion circuit is different from the second photoelectric conversion circuit.

[0029] Figure 1 is a simplified diagram of an example optical transmitter 100 that can be reconfigured to generate amplitude modulation and coherent modulation signals according to an embodiment. The optical transmitter 100 includes a baseband processor and a modulation signal generator 104 (sometimes referred to herein as "baseband processor 104" for brevity) that is configured to i) receive data to be transmitted via an optical communication medium (not shown) (e.g., from a host processor (not shown)), and ii) generate a modulation signal using the received data.

[0030] The optical transmitter 100 also includes an optical module 108 coupled to the baseband processor 104. The optical module 108 is configured to use the modulated signal from the baseband processor 104 to generate an optical transmission signal for transmission via the optical communication medium.

[0031] The baseband processor 104 includes a digital signal processor (DSP, not shown) configured to perform various processing actions, such as one or more of the following: i) forward error correction (FEC) encoding, ii) signal pre-compensation, etc. In addition, the DSP is further configured to map the data to be transmitted to transmission symbols (e.g., mapped to intensity levels for intensity modulation, mapped to constellation points for M-QAM, etc.). The DSP is also configured to generate a digital modulation signal based on the transmission symbols.

[0032] The baseband processor 104 also includes an analog front end (AFE) circuit system (not shown) configured to generate an analog modulation signal based on the digital modulation signal output by the DSP. For example, the AFE includes one or more analog-to-digital converters (ADCs) configured to convert the digital modulation signal into an analog modulation signal.

[0033] The baseband processor 104 also includes a controller 112 configured to generate control signals for reconfiguring the optical module 108 to generate optical transmission signals according to different modulation techniques. In other embodiments, the controller 112 is located outside the baseband processor 104. According to one embodiment, the controller 112 includes a processor coupled to a memory, and the processor is configured to execute machine-readable instructions in the memory, which, when executed by the processor, cause the controller 112 to generate control signals. Additionally or alternatively, in another embodiment, the controller 112 includes a hardware circuit system (e.g., a hardware state machine) that additionally or alternatively causes the controller 112 to generate control signals.

[0034] The optical module 108 includes a plurality of lasers 120 optically coupled to a reconfigurable optical network 124. The reconfigurable optical network 124 is optically coupled to an optical modulation system 128. The optical module 108 also includes a driver circuitry 132 coupled to the optical modulation system 128.

[0035] In one embodiment, each of the plurality of lasers 120 is configured to generate light of a corresponding wavelength. Each of at least some of the plurality of lasers 120 is configured to be turned on and off based on a corresponding control signal from the controller 112. For example, in a first configuration of the optical module 108, the plurality of lasers 120 (e.g., all lasers 120) are turned on by a control signal from the controller 112; and in a second configuration of the optical module 108, only one of the lasers 120 is turned on by a control signal from the controller 112, while the remaining lasers 120 are turned off.

[0036] In one embodiment, the reconfigurable optical network 124 is configured to differently direct light from the plurality of lasers 120 to the optical modulation system 128 according to a control signal from the controller 112. For example, in a first configuration of the optical module 108, the control signal from the controller 112 controls the reconfigurable optical network 124 to direct light of a respective wavelength from a respective laser 120 to a respective optical input of the optical modulation system 128; and in a second configuration of the optical module 108, the control signal from the controller 112 controls the reconfigurable optical network 124 to direct light from one of the lasers 120 to a plurality of optical inputs of the optical modulation system 128.

[0037] In one embodiment, the controller 112 configures the optical modulation system 128 differently depending on the type of modulation to be used using a modulation control signal generated by the controller 112. For example, in a first configuration of the optical module 108, the modulation control signal from the controller 112 configures the optical modulation system 128 for a first modulation type, while in a second configuration of the optical module 108, the modulation control signal from the controller 112 configures the optical modulation system 128 for a second modulation type. As an illustrative example, the modulation control signal i) selects a first modulator operating point of an optical modulator of the optical modulation system 128 for the first modulation type, and ii) selects a second modulator operating point (different from the first modulator operating point) of the optical modulator for the second modulation type.

[0038] The driver circuitry is configured to condition the modulation signal received from the baseband processor 104 to generate a conditioned modulation signal, and provide the conditioned modulator signal to the optical modulation system 128. The optical modulation system 128 then modulates the light received from the reconfigurable optical network 124 based on the conditioned modulation signal. In some embodiments, the driver circuitry 132 is included in the baseband processor 104, for example as part of the AFE circuitry described above.

[0039] In operation, when transmitting data via multiple wavelengths using intensity modulation, the baseband processor 104 generates control signals to turn on the multiple lasers 120. In addition, the baseband processor 104 generates control signals to configure the reconfigurable optical network 124 to direct light of corresponding wavelengths from corresponding lasers 120 to corresponding optical inputs of the optical modulation system 128. In addition, the baseband processor 104 generates modulator control signals to configure the optical modulators of the optical modulation system 128 for intensity modulation. For example, the baseband processor 104 generates modulator control signals to select the operating point of the optical modulators of the optical modulation system 128 to be a first modulator operating point suitable for intensity modulation.

[0040] In addition, the baseband processor 104 generates a modulation signal corresponding to the intensity modulation using the received data (e.g., from the host computer) and provides the modulation signal to the driver 132. The driver 132 then provides the conditioned modulation signal to the optical modulation system 128, which causes the optical modulation system 128 to modulate the data onto multiple wavelengths using intensity modulation.

[0041] On the other hand, when data is transmitted via a single wavelength using coherent modulation, the baseband processor 104 generates control signals to turn on one laser 120 and turn off the other lasers 120. In addition, the baseband processor 104 generates control signals to configure the reconfigurable optical network 124 to direct light from one laser 120 to multiple optical inputs of the optical modulation system 128. In addition, the baseband processor 104 generates modulator control signals to configure the optical modulators of the optical modulation system 128 for coherent modulation. For example, the baseband processor 104 generates modulator control signals to select the operating point of the optical modulators of the optical modulation system 128 to be a second modulator operating point (different from the first operating point) suitable for coherent modulation.

[0042] In addition, the baseband processor 104 generates a modulation signal corresponding to coherent modulation using received data (e.g., from a host computer) and provides the modulation signal to the driver 132. The driver 132 then provides the conditioned modulation signal to the optical modulation system 128, which causes the optical modulation system 128 to modulate the data onto a wavelength using coherent modulation.

[0043] Figure 2A is a simplified block diagram of an example optical module 200 according to an embodiment that can be reconfigured to generate optical transmission signals according to different modulation techniques. The optical module 200 is used as Figure 1 The optical module 108, and for ease of explanation, reference is made to Figure 1 describe Figure 2A In other embodiments, the optical module 200 is used with Figure 1Similarly, in some embodiments, the transmitter 100 uses a suitable optical module different from the optical module 200.

[0044] Optical module 200 includes multiple lasers 204. In one embodiment, multiple lasers 204 are configured to generate light of corresponding different wavelengths. For example, in a communication system using fiber optic cables that comply with ITU standard G.652, lasers 204 are configured to generate light of 1271 nanometers (nm) (sometimes referred to as λ1); light of 1291 nm (sometimes referred to as λ2); light of 1311 nm (sometimes referred to as λ3); and light of 1331 nm (sometimes referred to as λ4). In other embodiments, lasers 204 are generated at other suitable wavelengths. In one embodiment, lasers 204 correspond to lasers 120 ( Figure 1 ).

[0045] The optical module 200 also includes an optical modulation system 208. The optical modulation system 208 includes a plurality of optical modulators 212. In one embodiment, the optical modulators 212 include Mach-Zehnder (MZ) modulators. In other embodiments, the optical modulation system 208 includes suitable optical modulators other than MZ modulators.

[0046] Each modulator 212 has i) an optical input for receiving light, and ii) a signal configured to receive light from, for example, a driver circuit system (not shown) (such as driver circuit system 132 ( Figure 1 )) Two modulation signal inputs receiving modulation signals. Each modulator 212 is configured to modulate light received via an optical input based on a modulation signal received via the modulation signal input to generate a modulated optical output signal.

[0047] In one embodiment, the modulator 212 is configured differently depending on the type of modulation to be used. For example, in a first configuration of the optical module 200, a modulation control signal (not shown) from the controller 112 configures the modulator 212 for a first modulation type; while in a second configuration of the optical module 200, the modulation control signal configures the modulator 212 for a second modulation type. As an illustrative example, the modulation control signal i) selects a first modulator operating point of the modulator 212 for the first modulation type, and ii) selects a second modulator operating point (different from the first modulator operating point) of the modulator 212 for the second modulation type.

[0048] The outputs of modulator 212-1 and modulator 212-2 are combined and provided to a first input of a polarization beam rotator combiner (PBRC) 220. Similarly, the outputs of modulator 212-3 and modulator 212-4 are combined and provided to a second input of PBRC 220. PBRC 220 is configured to combine light received via the two inputs of PBRC 220 while rotating the polarization of light corresponding to the light received by the first input of PBRC 220 by 90 degrees relative to the polarization of light corresponding to the light received by the second input of PBRC 220.

[0049] Laser 204 is optically coupled to optical modulation system 208 via reconfigurable optical network 232. Reconfigurable optical network 232 is configured to receive control signals (such as from controller 112, for example) and to receive the optical modulation system 208. Figure 1 ) or the like) to differently direct light from the plurality of lasers 204 to the optical modulation system 208. For example, in a first configuration of the optical module 200, a laser control signal from the controller controls the reconfigurable optical network 232 to direct light from each of the lasers 204 to a corresponding optical input of the optical modulation system 208; whereas in a second configuration of the optical module 200, the laser control signal controls the reconfigurable optical network 232 to direct light from one of the lasers 204 (e.g., the laser 204-2 or another suitable laser in the lasers 204) to a plurality of optical inputs of the optical modulation system 208.

[0050] The reconfigurable optical network 232 includes a plurality of variable optical couplers 236, 240, 244, which are arranged to i) direct light from each of the lasers 204 to a corresponding optical input of the optical modulation system 208, or ii) direct light from one of the lasers 204 (e.g., laser 204-2 or another suitable laser in the lasers 204) to a plurality of optical inputs of the optical modulation system 208, depending on the configuration of the reconfigurable optical network 232. Each variable optical coupler 236, 240, 244 includes a first optical input, a second optical input, a first optical output, a second optical output, and a control input. Each variable optical coupler 236, 240, 244 is configured to direct light from the first optical input to the first optical output, and to direct light from the second optical input to the second optical output. In addition, each variable optical coupler 236, 240, 244 is configured to selectively couple light from the first optical input cross to the second optical output, and selectively couple light from the second optical input cross to the first optical output. For example, when the laser control signal is in the first state, the variable optical coupler 236, 240, 244 does not couple light from the first optical input optical cross to the second optical output, nor does it couple light from the second optical input optical cross to the first optical output. On the other hand, when the laser control signal is in the second state, the variable optical coupler 236, 240, 244 couples light from the first optical input cross to the second optical output, and couples light from the second optical input cross to the first optical output.

[0051] The output of laser 204-2 is coupled to a first input of variable coupler 236, and the output of laser 204-3 is coupled to a second input of variable coupler 236. The output of laser 204-1 is coupled to a first input of variable coupler 240, and the first output of variable coupler 236 is coupled to a second input of variable coupler 240. The output of laser 204-4 is coupled to a second input of variable coupler 244, and the second output of variable coupler 236 is coupled to a first input of variable coupler 244. The first output of variable coupler 240 is coupled to an optical input of MZ modulator 212-1, and the second output of variable coupler 240 is coupled to an optical input of MZ modulator 212-2. The first output of variable coupler 244 is coupled to an optical input of MZ modulator 212-3, and the second output of variable coupler 244 is coupled to an optical input of MZ modulator 212-4.

[0052] In operation, when transmitting data via multiple wavelengths using intensity modulation, the laser control signal is set to turn on all lasers 204. In addition, the optical network control signal is set to configure the variable couplers 236, 240, 244 so that the variable couplers 236, 240, 244 do not provide cross-coupling between the corresponding first input and the corresponding second output and between the corresponding second input and the corresponding first output. As a result, the reconfigurable optical network 232 passes light from the laser 204-1 to the optical input of the MZ modulator 212-1; the reconfigurable optical network 232 passes light from the laser 204-2 to the optical input of the MZ modulator 212-2; the reconfigurable optical network 232 passes light from the laser 204-3 to the optical input of the MZ modulator 212-3; and the reconfigurable optical network 232 passes light from the laser 204-4 to the optical input of the MZ modulator 212-4.

[0053] In addition, the modulator control signal (not shown) configures the MZ modulator 212 for intensity modulation. For example, the modulator control signal selects the operating point of the MZ modulator 212 as a first modulator operating point suitable for intensity modulation.

[0054] In addition, the modulation signal controls the MZ modulator 212 to modulate corresponding data onto corresponding light received by the MZ modulator 212. In addition, the modulated light from the MZ modulator 212-1 and the modulated light from the MZ modulator 212-2 are combined and provided to a first input of the PBRC 220; and the modulated light from the MZ modulator 212-3 and the modulated light from the MZ modulator 212-4 are combined and provided to a second input of the PBRC 220. The PBRC 220 combines the modulated light from the MZ modulators 212-1 and 212-2 with the modulated light from the MZ modulators 212-3 and 212-4 to generate an optical transmission signal.

[0055] On the other hand, when data is transmitted via a single wavelength using coherent modulation, the laser control signal is set to turn on the laser 204-2 and turn off the other lasers 204. In addition, the optical network control signal is set to configure the variable couplers 236, 240, 244 so that the variable couplers 236, 240, 244 cross-couple light between the corresponding first input and the corresponding second output and between the corresponding second input and the corresponding first output. As a result, the reconfigurable optical network 232 passes light from the laser 204-3 to the optical inputs of all MZ modulators 212.

[0056] In addition, the modulator control signal (not shown) configures the MZ modulator 212 for coherent modulation. For example, the modulator control signal selects the operating point of the MZ modulator 212 to be a second modulator operating point (different from the first operating point) suitable for coherent modulation.

[0057] In addition, the modulation signal applied to the MZ modulator 212-1 causes the MZ modulator 212-1 to generate a first in-phase (I) signal, and the modulation signal applied to the MZ modulator 212-2 causes the MZ modulator 212-2 to generate a first quadrature (Q) signal. Similarly, the modulation signal applied to the MZ modulator 212-3 causes the MZ modulator 212-3 to generate a second I signal, and the modulation signal applied to the MZ modulator 212-4 causes the MZ modulator 212-4 to generate a second Q signal. In addition, the first I signal and the first Q signal are combined and provided to the first input of the PBRC 220; and the second I signal and the second Q signal are combined and provided to the second input of the PBRC 220. The PBRC 220 combines the first I signal and the first Q signal with the second I signal and the second Q signal to generate an optical transmission signal. The optical transmission signal includes: i) a first I signal and a first Q signal in a first polarization direction, and ii) a second I signal and a second Q signal in a second polarization direction.

[0058] Figure 2B According to the embodiment Figure 2A Schematic diagram of an optical module 200 configured to transmit data via multiple wavelengths using intensity modulation. The laser control signal is set to turn on all lasers 204. In addition, the optical network control signal is set to configure the variable couplers 236, 240, 244 so that the variable couplers 236, 240, 244 do not provide cross-coupling between the corresponding first input and the corresponding second output and between the corresponding second input and the corresponding first output. As a result, the reconfigurable optical network 232 passes light from the laser 204-1 to the optical input of the MZ modulator 212-1; the reconfigurable optical network 232 passes light from the laser 204-2 to the optical input of the MZ modulator 212-2; the reconfigurable optical network 232 passes light from the laser 204-3 to the optical input of the MZ modulator 212-3; and the reconfigurable optical network 232 passes light from the laser 204-4 to the optical input of the MZ modulator 212-4.

[0059] In addition, the modulator control signal (not shown) configures the MZ modulator 212 for intensity modulation. For example, the modulator control signal selects the operating point of the MZ modulator 212 as a first modulator operating point suitable for intensity modulation.

[0060] In addition, the modulation signal controls the MZ modulator 212 to modulate corresponding data onto corresponding light received by the MZ modulator 212. In addition, the modulated light from the MZ modulator 212-1 and the modulated light from the MZ modulator 212-2 are combined and provided to a first input of the PBRC 220; and the modulated light from the MZ modulator 212-3 and the modulated light from the MZ modulator 212-4 are combined and provided to a second input of the PBRC 220. The PBRC 220 combines the modulated light from the MZ modulators 212-1 and 212-2 with the modulated light from the MZ modulators 212-3 and 212-4 to generate an optical transmission signal.

[0061] Figure 2C According to the embodiment Figure 2A Schematic diagram of an optical module 200 configured to transmit data via a single wavelength (e.g., λ3) using coherent modulation. The laser control signal is set to turn on laser 204-2 and turn off other lasers 204. In addition, the optical network control signal is set to configure the variable couplers 236, 240, 244 so that the variable couplers 236, 240, 244 cross-couple light between the corresponding first input and the corresponding second output and between the corresponding second input and the corresponding first output. As a result, the reconfigurable optical network 232 passes light from the laser 204-3 to the optical inputs of all MZ modulators 212.

[0062] In addition, the modulator control signal (not shown) configures the MZ modulator 212 for coherent modulation. For example, the modulator control signal selects the operating point of the MZ modulator 212 to be a second modulator operating point (different from the first operating point) suitable for coherent modulation.

[0063] The MZ modulators 212-1 and 212-2 are used as the first IQ modulator 260 in the X polarization direction; and the MZ modulators 212-3 and 212-4 are used as the second IQ modulator 264 in the Y polarization direction. In addition, the first IQ modulated signal from the first IQ modulator 260 is combined by the PBRC 220 with the second IQ modulated signal from the second IQ modulator 264. The optical transmission signal includes: i) a first IQ signal in the first polarization direction, and ii) a second IQ signal in the second polarization direction.

[0064] Figure 3 is a simplified diagram of an example optical receiver 300 that can be reconfigured to process amplitude modulated and coherently modulated signals according to an embodiment. In one embodiment, the optical transmitter 100 ( Figure 1) and the optical receiver 300 are included in a transceiver that is reconfigurable to generate and process amplitude modulated and coherently modulated signals. In other embodiments, the optical receiver 300 is included in a Figure 1 The optical transmitter 100 is a transceiver of a different suitable reconfigurable optical transceiver. Similarly, in other embodiments, Figure 1 The optical transmitter 100 is included in a transceiver having another suitable reconfigurable receiver different from the optical receiver 300 .

[0065] The optical receiver 300 includes an optical module 304 configured to i) receive an optical signal via an optical communication medium (not shown), ii) optically process the optical signal to generate a plurality of processed optical signals, and iii) generate a plurality of electrical signals based on the processed optical signals.

[0066] The optical receiver 300 also includes a baseband processor 308 coupled to the optical module 304. The baseband processor 308 is configured to i) receive a plurality of electrical signals from the optical module 304, ii) convert the plurality of electrical signals to digital domain signals, iii) process the digital domain signals to recover received data from the digital domain signals, and iv) output the received data (e.g., to a host processor (not shown)).

[0067] The baseband processor 308 includes an AFE circuit system (not shown) configured to convert multiple electrical signals from the optical module 304 into digital domain signals. For example, the AFE includes one or more digital-to-analog converters (DACs) configured to convert the electrical signals from the optical module 304 into digital domain signals.

[0068] The baseband processor 308 also includes a DSP (not shown) configured to perform various processing actions, such as one or more of the following: i) filtering (e.g., equalization) of digital domain signals, ii) recovering information bits from digital domain signals, iii) performing FEC decoding, and the like.

[0069] The baseband processor 308 also includes a controller 312 configured to generate one or more control signals for reconfiguring the optical module 304 to process the optical receive signal according to different demodulation techniques. In other embodiments, the controller 312 is external to the baseband processor 308. According to one embodiment, the controller 312 includes a processor coupled to a memory, and the processor is configured to execute machine-readable instructions in the memory, which, when executed by the processor, cause the controller 312 to generate one or more control signals. Additionally or alternatively, in another embodiment, the controller 312 includes a hardware circuit system (e.g., a hardware state machine) that additionally or alternatively causes the controller 112 to generate one or more control signals.

[0070] The optical module 304 includes a reconfigurable optical network 320 optically coupled to an optical-to-electrical conversion circuitry 324. The reconfigurable optical network 320 is also optically coupled to an optical processor 328. The optical processor 328 is also optically coupled to the optical-to-electrical conversion circuitry 324.

[0071] In one embodiment, the reconfigurable optical network 320 is configured to selectively direct light corresponding to the optical receive signal i) to the optical processor 328, or ii) to the optoelectronic conversion circuit system 324 in a manner that bypasses the optical processor 328, based on one or more control signals from the controller 312. For example, in a first configuration of the optical module 304, one or more control signals from the controller 312 control the reconfigurable optical network 320 to demultiplex a plurality of wavelengths of light in the optical receive signal, and direct the demultiplexed light to the optoelectronic conversion circuit system 324 in a manner that bypasses the optical processor 328; and in a second configuration of the optical module 304, one or more control signals from the controller 312 control the reconfigurable optical network 320 to split the optical receive signal into i) a first polarized optical signal polarized in a first direction and ii) a second polarized optical signal polarized in a second direction, and direct the first polarized optical signal and the second polarized optical signal to the optical processor 328.

[0072] In operation, when the optical signal includes data multiplexed on multiple wavelengths using intensity modulation, one or more control signals from the baseband processor 308 control the reconfigurable optical network 320 to demultiplex the multiple wavelengths of light in the optical receive signal and direct the demultiplexed light to the optical-to-electrical conversion circuit system 324 in a manner that bypasses the optical processor 328. The optical-to-electrical conversion circuit system 324 generates multiple electrical signals based on the demultiplexed light, and the baseband processor 308 processes the electrical signals based on the intensity demodulation technique to recover the information bits.

[0073] On the other hand, when the optical signal corresponds to dual-polarization coherent modulation, one or more control signals from the baseband processor 308 control the reconfigurable optical network 320 to split the optical reception signal into i) a first polarization optical signal polarized in a first direction and ii) a second polarization optical signal polarized in a second direction, and guide the first polarization optical signal and the second polarization optical signal to the optical processor 328. The optical processor 328 performs optical processing on the first polarization optical signal and the second polarization optical signal to generate a plurality of processed optical signals. The optoelectronic conversion circuit system 324 generates a plurality of electrical signals based on the processed optical signals, and the baseband processor 308 processes the electrical signals based on the coherent demodulation technology to recover the information bits.

[0074] Figure 4A is a simplified block diagram of an example optical module 400 that can be reconfigured to process optical receive signals according to different demodulation techniques according to an embodiment. The optical module 400 is used as Figure 3 The optical module 304, and for ease of explanation, refer to Figure 3 describe Figure 4A In other embodiments, the optical module 400 is used with Figure 3 Similarly, in some embodiments, receiver 300 uses a suitable optical module different from optical module 400.

[0075] Optical module 400 includes a reconfigurable optical network 404 optically coupled to optical-to-electrical conversion circuitry 408. Reconfigurable optical network 404 is also optically coupled to an optical processor 412. Optical processor 412 is also optically coupled to optical-to-electrical conversion circuitry 408.

[0076] In one embodiment, the reconfigurable optical network 404 is configured based on the information from (e.g., the controller 312) Figure 3 )) selectively directs light corresponding to the optical receive signal i) to the optical processor 412, or ii) to the optoelectronic conversion circuit system 408 in a manner bypassing the optical processor 412. For example, in a first configuration of the optical module 404, the control signal controls the reconfigurable optical network 404 to demultiplex lights of multiple wavelengths in the optical receive signal, and direct the demultiplexed light to the optoelectronic conversion circuit system 408 in a manner bypassing the optical processor 412; and in a second configuration of the optical module 404, the control signal controls the reconfigurable optical network 404 to split the optical receive signal into i) a first polarized optical signal polarized in a first direction and ii) a second polarized optical signal polarized in a second direction, and directs the first polarized optical signal and the second polarized optical signal to the optical processor 412.

[0077] The reconfigurable optical network 404 includes an optical demultiplexer 420 configured to demultiplex a plurality of optical signals of corresponding wavelengths from light received at an input of the optical demultiplexer 420, which optical signals have been multiplexed at a transmitter. The demultiplexed optical signals are output via corresponding outputs of the optical demultiplexer 420. One output of the output of the optical demultiplexer 420 is optically coupled to an input of an optical switch 424, and the remaining outputs of the optical demultiplexer 420 are optically coupled to the optical-to-electrical conversion circuit system 408.

[0078] One of the outputs of optical switch 424 is coupled to optical-to-electrical conversion circuitry 408, and the other output of optical switch 424 is coupled to the input of polarization beam splitter (PBS) 428. Depending on the state of the control signal, optical switch 424 selectively provides one output of optical multiplexer 420 to i) optical-to-electrical conversion circuitry 408 or ii) PBS 438.

[0079] PBS 428 is configured to split an optical signal received at an input of PBS 428 into a first output optical signal and a second output optical signal. The first output optical signal corresponds to light in the input signal that is polarized in a first direction, and the second output signal corresponds to light in the input optical signal that is polarized in a second direction that is different from the first direction. The output of PBS 428 is coupled to an input of optical processor 412.

[0080] The optical processor 412 is configured to generate four pairs of outputs based on the optical signal received from the PBS 428. The optical processor 412 includes a plurality of optical couplers (e.g., 3 decibel (3db) optical couplers) and one or more optical phase shifters. In some embodiments, the optical processor 412 includes one or more optical delay lines. In some embodiments, the optical processor 412 is configured to optically mix the received optical signal with a delayed version of the optical signal.

[0081] Generally, the type of optical processor 412 depends on the type of optical modulation to be used and / or the amount of optical demodulation processing to be performed by the optical processor 412 versus the baseband processor (e.g., baseband processor 308 ( Figure 3 )) The amount of demodulation processing to be performed. In some embodiments, each optical processor 120 includes a coherent internal dual polarization (2-Pol) 90 degree hybrid device. In other embodiments, each optical processor 120 includes one or more delay line interferometers (DLI). In some embodiments, each optical processor 120 includes one or more Mach-Zehnder interferometers (MZI).

[0082] In some embodiments, the optical processor 412 corresponds to a coherent extension dual polarization (2-Pol) 90 degree hybrid device, and the coherent extension 2-Pol 90 degree hybrid device 412 is configured to optically mix the optical signal received from the PBS 428 with a local optical oscillator (not shown), and generate four pairs of outputs based on the optical signal received from the PBS 428. For example, the coherent extension 2-Pol 90 degree hybrid device 412 is configured to generate a pair of in-phase (I) signals and a pair of quadrature (Q) signals based on each output of the PBS 428. For example, in some embodiments involving M-QAM or DQPSK demodulation, the power of the signal output by the coherent extension 2-Pol 90 degree hybrid device 412 can be expressed as:

[0083] P I，1 (t) = 1 / 4 | A (t) | | A LO |cos(ω if t+θ if ) (Equation 1)

[0084] P I，2 (t) = -1 / 4|A(t)||A LO |cos(ω if t+θ if ) (Equation 2)

[0085] P Q，1 (t) = 1 / 4 | A (t) | | A LO |sin(ω if t+θ if ) (Equation 3)

[0086] P Q，2 (t)=-1 / 4|A(t)|IA LO |sin(ω if t+θ if ) (Equation 4)

[0087] Where P I，1 (t) is the optical power of the first I signal, P I，2 (t) is the optical power of the second I signal, P Q,1 (t) is the optical energy of the first Q signal, P Q，2 (t) is the optical energy of the second Q signal, A(t) is the signal electric field from PBS 428, and A LO (t) is the local oscillator laser electric field. ω if and θ if A and A respectively LO The frequency and phase difference between them.

[0088] In some embodiments where each optical processor 412 corresponds to one or more DLIs, the output of each PBS 428 is coupled to a corresponding set of one or more DLIs 428. The set of one or more DLIs 428 is configured to generate four pairs of outputs based on the optical signals received from the PBSs 428. For example, the DLIs 412 are configured to generate a pair of I signals and a pair of Q signals based on each output of the PBSs 428. In embodiments involving DQPSK demodulation, the power of the signal output by the DLI 412 can be expressed as:

[0089] P I，1 (t)=1 / 4|A(t)+A(tT s )| 2 (Equation 5)

[0090] P I，2 (t) = 1 / 4 | A(t) - A(tT s )| 2 (Equation 6)

[0091] P Q，1 (t)=1 / 4|A(t)+A(tT s )| 2 (Equation 7)

[0092] P Q,2 (t)=1 / 4|A(t)+A(tT s )| 2 (Equation 8)

[0093] Where P I，1 (t) is the optical power of the first I signal, P I，2 (t) is the optical power of the second I signal, P Q，1 (t) is the optical energy of the first Q signal, P Q,2 (t) is the optical energy of the second Q signal, A(t) is the signal from PBS 428, T s is the symbol delay.

[0094] The optical-to-electrical conversion circuit 408 includes multiple instances of corresponding photodiode circuits 440 coupled to corresponding transimpedance amplifiers (TIAs) 444. As will be further described below, according to one embodiment, each photodiode circuit 440 is configured to convert one or more optical signals into a current signal, and the corresponding TIA 444 is configured to convert the current signal into a voltage signal.

[0095] The optical-to-electrical conversion circuit 408 is configured to process optical signals modulated according to a variety of different optical modulation techniques. Figure 4AAs shown, each of the photodiode circuits 440 is optically coupled to both i) a corresponding output of the optical demultiplexer 420 and ii) a corresponding output of the optical processor 412. As will be further described below, each of the photodiode circuits 440 includes a multi-input photodiode that is configured to each receive i) a corresponding output of the optical demultiplexer 420 and ii) a corresponding output of the optical processor 412.

[0096] As will be further described below, when the optical module 400 is in the first configuration, each of the photodiode circuits 440 receives a corresponding intensity modulated signal from the optical demultiplexer 420; and when the optical module 400 is in the second configuration, each of the photodiode circuits 440 receives a set of optical signals from the optical processor 412.

[0097] When the optical module 400 is in the first configuration, each of the photodiode circuits 440 is configured to generate a current signal corresponding to the intensity modulated signal from the optical demultiplexer 420. According to one embodiment, when the optical module 400 is in the second configuration, each pair of the photodiode circuits 440 and the TIA 444 is configured to generate a voltage signal corresponding to the subtraction of a pair of I signals corresponding to i) (e.g., equations 1 and 2, or equations 5 and 6) or a pair of Q signals corresponding to ii) (e.g., equations 3 and 4, or equations 7 and 8).

[0098] Figure 4B is an illustration of an optical module 400 in a first configuration according to an embodiment, wherein the optical module 400 is configured to receive an intensity modulated signal multiplexed on multiple wavelengths.

[0099] The optical demultiplexer 420 demultiplexes the input optical receive signal into four outputs. One of these outputs is provided to the optical switch 424, while the remaining three outputs of the demultiplexer are provided to the corresponding photodiode circuit 440. In the first configuration, the control signal provided to the optical switch 424 controls the optical switch 424 to direct one output of the demultiplexer to the photodiode circuit 440-2. Therefore, the PBS 428 ( Figure 4A ) does not receive an optical signal. Therefore, PBS 428 does not provide any optical signal to optical processor 412 ( Figure 4A ), and the optical processor 412 does not provide any optical signal to the photodiode circuit 440. Therefore, the PBS 428 and the optical processor 412 are Figure 4B 4 is not shown to help illustrate the path of the optical signal through the optical module 400 in the first configuration.

[0100] Each of the photodiode circuits 440 generates a respective current signal corresponding to the intensity modulated signal from a respective output of the optical demultiplexer 420. The TIA 444 generates a respective voltage signal based on the current signal from the photodiode circuits 440.

[0101] Figure 4C is an illustration of an optical module 400 in a second configuration according to an embodiment, wherein the optical module 400 is configured to receive and demodulate a bipolar DQPSK signal or an M-QAM signal. Figure 4C In the embodiment of FIG. 4 , the optical processor 412 corresponds to a coherent in-line 2-Pol 90 degree hybrid device 412. The DQPSK modulated or M-QAM signal is modulated at the λ3 wavelength.

[0102] Since the optical receive signal includes only the λ3 wavelength, the three outputs of the optical demultiplexer 420 have no signal, and the output of the optical demultiplexer 420 corresponding to the λ3 wavelength is provided to the optical switch 424. In the second configuration, the control signal provided to the optical switch 424 controls the optical switch 424 to direct the λ3 wavelength output of the demultiplexer to the PBS 428.

[0103] The PBS 428 splits the input optical signal into a first output optical signal (corresponding to light polarized in a first direction) and a second output optical signal (corresponding to light polarized in a second direction), and the first optical signal and the second optical signal are received by the coherent extension 2-Pol 90 degree hybrid 412. As described above, the coherent extension 2-Pol 90 degree hybrid 412 generates a pair of I signals and a pair of Q signals based on each output of the PBS 428.

[0104] Each photodiode circuit 440 receives a corresponding pair of I signals (e.g., equations 1 and 2) or ii) a corresponding pair of Q signals (e.g., equations 3 and 4), and each photodiode circuit 440 / TIA 444 pair generates a voltage signal corresponding to the subtraction of the corresponding pair of I signals i) or the corresponding pair of Q signals ii).

[0105] Figure 4D is an illustration of an optical module 400 in a second configuration according to another embodiment, wherein the optical receiver 100 is configured to receive and demodulate multiple DQPSK signals. Figure 1 In the embodiment of D, each optical processor 412 corresponds to a group of one or more DLIs.

[0106] and Figure 4C Compared with the embodiment of Figure 4DIn an embodiment, more demodulation processing is performed in the DLI 412 (optical processor 412), and therefore the baseband processor needs to perform less demodulation processing. In one embodiment, a polarization controller (PC) is coupled between the optical switch 424 and the input of the PBS 428.

[0107] Figure 5A is a method for reconfigurable optical receivers (such as Figure 3 An optical receiver 300) and a reconfigurable optical module (such as Figure 4A A simplified diagram of an example photoelectric conversion circuit 500 of a reconfigurable optical module 400 of FIG. 4 is shown in FIG. Figure 4A The photoelectric conversion circuit 500 is described. In some embodiments, the photoelectric conversion circuit 500 is used with Figure 4A Similarly, the optical module 400 uses a different suitable reconfigurable optical module than the reconfigurable optical module 400 of FIG. Figure 5A The photoelectric conversion circuit 500 is a different suitable photoelectric conversion circuit.

[0108] In one embodiment, photoelectric conversion circuit 500 is used for each of: i) photodiode circuitry 444-1 and TIA 444-1, ii) photodiode circuitry 440-2 and TIA 444-2, iii) photodiode circuitry 440-3 and TIA 444-3, and iv) photodiode circuitry 440-4 and TIA 444-4.

[0109] The photoelectric conversion circuit 500 includes a photodiode circuit 504 coupled to a TIA 508. The photodiode circuit 504 includes a photodiode 512 and a multi-input photodiode 516. The photodiode 512 includes an anode 520 and a cathode 524, and the multi-input photodiode 516 includes an anode 528 and a cathode 532. The multi-input photodiode 516 is coupled in series with the photodiode 512. For example, the cathode 532 of the multi-input photodiode 516 is coupled to the anode 520 of the photodiode 512. In one embodiment, the anode 528 is coupled to ground.

[0110] Photodiode circuit 504 also includes bias circuitry 540 configured to apply a reverse bias across photodiode 512 and multi-input photodiode 516 .

[0111] TIA 508 includes an operational amplifier 544 and an impedance 548 coupled between an input of the operational amplifier 544 and an output of the operational amplifier 544. In one embodiment, impedance 548 is a suitable resistor. In one embodiment, operational amplifier 544 includes an additional input (not shown) coupled to ground.

[0112] In other embodiments, the TIA 508 includes other suitable circuitry configured to convert a current signal into a voltage signal (e.g., it does not include an operational amplifier and / or does not include an impedance coupled between an input of the operational amplifier and an output of the operational amplifier). As an illustrative example only, the TIA 508 includes a common gate / common base amplifier.

[0113] In other embodiments, the photodiode circuit 504 includes another suitable arrangement of the photodiode 512 and the multi-input photodiode 516. For example, in some embodiments, the cathode 532 of the multi-input photodiode 516 is not coupled to the anode 520 of the photodiode 512. In some such embodiments, each of the photodiode 512 and the multi-input photodiode 516 is coupled to a respective input of another suitable TIA and / or a respective input of a respective TIA.

[0114] Photodiode circuit 504 includes node 560, which is coupled between photodiode 512 and multi-input photodiode 516 and is also coupled to the input of operational amplifier 544. Node 560 outputs a current to operational amplifier 544 that is the sum of i) the current flowing from anode 520 and ii) the current flowing from cathode 532. In other words, node 560 outputs a current to operational amplifier 544 that is the difference between i) the current flowing from anode 520 and ii) the current flowing into cathode 532.

[0115] In one embodiment, node 560 includes a connection between anode 520 and cathode 532. In other embodiments, node 560 includes one or more passive components (not shown). For example, node 560 includes a first resistor (not shown) connected in series with photodiode 512 and a second resistor (not shown) connected in series with multi-input photodiode 516. In other embodiments, the node includes one or more active components (not shown). For example, node 560 includes one or more transistors (not shown) arranged to act as amplifiers and / or buffers between i) photodiode 512 and multi-input photodiode 516 and ii) TIA 508.

[0116] In operation, when an optical signal illuminates the photodiode 512, the current flowing out of the anode 520 increases with the intensity of the light illuminating the photodiode 512. Similarly, when an optical signal illuminates the multi-input photodiode 516, the current flowing into the cathode 532 increases with the intensity of the light illuminating the multi-input photodiode 516. In addition, as described above, the current output by the node 560 corresponds to the difference between i) the current flowing out of the anode 520 and ii) the current flowing into the cathode 532. The TIA 508 is used to convert the current signal output by the node 560 into a voltage signal.

[0117] exist Figure 5A In the example of , the multi-input photodiode 516 is configured to receive three optical signals. In other embodiments, the multi-input photodiode 516 is configured to receive two optical signals. For example, in an embodiment where the optoelectronic conversion circuit 500 is used for the photodiode circuit system 440-1 and the TIA 444-1, the multi-input photodiode 516 receives the first optical signal from the optical demultiplexer 420 and receives the second optical signal from the optical processor 412.

[0118] In one embodiment, the multi-input photodiode 516 includes a front side and a back side opposite to the front side; and the multi-input photodiode 516 is configured so that when light irradiates the front side, the current flowing into the cathode 532 increases with the intensity of the light irradiating the front side, and when light irradiates the back side, the current flowing into the cathode 532 increases with the intensity of the light irradiating the back side. In such an embodiment, the photoelectric conversion circuit 500 (and / or an optical module including the photoelectric conversion circuit 500) is configured to direct the light from the first light source to the front side and direct the light from the second light source to the back side. For example, the photoelectric conversion circuit 500 (and / or an optical module including the photoelectric conversion circuit 500) is configured to direct the light from one of the optical demultiplexer 420 and the optical processor 412 to the front side and direct the light from the other of the optical demultiplexer 420 and the optical processor 412 to the back side.

[0119] In another embodiment, the multi-input photodiode 516 additionally or alternatively includes an active region on one side of the multi-input photodiode 516, the size of the active region being configured to accommodate receiving optical signals from multiple sources. For example, the size of the active region is configured to accommodate receiving optical signals from at least the optical demultiplexer 420 and the optical processor 412. In one embodiment, the size of the active region of the multi-input photodiode 516 is substantially larger (i.e., at least 20% larger) than the size of the active region of the photodiode 512. In other embodiments, the size of the active region of the multi-input photodiode 516 is not substantially larger than the size of the active region of the photodiode 512.

[0120] Reference now Figure 4A and Figure 5A In one embodiment, optical processor 412 is optically coupled to photodiode 512 via a waveguide that directs light from the output of optical processor 412 to multi-input photodiode 516. In another embodiment, optical processor 412 is optically coupled to photodiode 512 via a fiber optic cable that directs light from the output of optical processor 412 to photodiode 512. In another embodiment, photodiode 512 receives light from the output of optical processor 412 via free space.

[0121] In one embodiment, the optical demultiplexer 420 is optically coupled to the multi-input photodiode 516 via a first waveguide that directs light from the output of the optical demultiplexer 420 to the multi-input photodiode 516; and the output of the optical processor 412 is optically coupled to the multi-input photodiode 516 via a second waveguide that directs light from the output of the optical processor 412 to the multi-input photodiode 516. In some such embodiments, the first waveguide directs light from the output of the optical demultiplexer 420 to one of a front side of the multi-input photodiode 516 and a back side of the multi-input photodiode 516; and the second waveguide directs light from the output of the optical processor 412 to the other of a front side of the multi-input photodiode 516 and a back side of the multi-input photodiode 516. In other such embodiments, an active region on one side of the multi-input photodiode 516 has a size configured to accommodate receiving light from the first waveguide and receiving light from the second waveguide.

[0122] In another embodiment, the optical demultiplexer 420 is optically coupled to the multi-input photodiode 516 via a first fiber optic cable that directs light from the output of the optical demultiplexer 420 to the multi-input photodiode 516; and the optical processor 412 is optically coupled to the multi-input photodiode 516 via a second fiber optic cable that directs light from the output of the optical processor 412 to the multi-input photodiode 516. In some such embodiments, the first fiber optic cable directs light from the output of the optical demultiplexer 420 to one of a front side of the multi-input photodiode 516 and a back side of the multi-input photodiode 516; and the second fiber optic cable directs light from the output of the optical processor 412 to the other of a front side of the multi-input photodiode 516 and a back side of the multi-input photodiode 516. In other such embodiments, an active region on one side of the multi-input photodiode 516 has a size configured to accommodate light from the first fiber optic cable and light from the second fiber optic cable.

[0123] In another embodiment, the multi-input photodiode 516 receives light from the output of the optical demultiplexer 420 via free space and receives light from the output of the optical processor 412 via free space. In some such embodiments, the optical-to-electrical conversion circuit system 500 and / or the optical module (e.g., the optical module 304, the optical module 400, etc.) is configured to: i) direct light from the output of the optical demultiplexer 420 to one of the front side of the multi-input photodiode 516 and the back side of the multi-input photodiode 516 via free space; and ii) direct light from the output of the optical processor 412 to the other of the front side of the multi-input photodiode 516 and the back side of the multi-input photodiode 516 via free space. In other such embodiments, the active area on one side of the multi-input photodiode 516 has a size configured to accommodate receiving light from the optical demultiplexer 420 via free space and receiving light from the output of the optical processor 412 via free space.

[0124] In other embodiments, the multi-input photodiode 516 receives light from the output of the optical demultiplexer 420 via one of a waveguide, a fiber optic cable, free space, etc., and receives light from the output of the optical processor 412 via another of a waveguide, a fiber optic cable, free space, etc. In some such embodiments, light from the optical demultiplexer 420 is directed to one of the front side of the multi-input photodiode 516 or the back side of the multi-input photodiode 516, and light from the optical processor 412 is directed to the other of the front side of the multi-input photodiode 516 or the back side of the multi-input photodiode 516. In some other such embodiments, the size of the active area on one side of the multi-input photodiode 516 is configured to accommodate receiving light from the optical demultiplexer 420 via one of a waveguide, a fiber optic cable, free space, etc. and receiving light from the output of the optical processor 412 via another of a waveguide, a fiber optic cable, free space, etc.

[0125] The multi-input photodiode 516 is configured to receive different optical signals corresponding to different modulation techniques. For example, in the optical receiver 300, the multi-input photodiode 516 is configured to receive one of the optical signals corresponding to an intensity modulated optical signal, and the multi-input photodiode 516 is configured to receive another of the optical signals corresponding to a coherent modulated signal.

[0126] Figure 5B According to an embodiment, the optical receiver 300 operates in a first configuration (such as the above reference Figure 3 , Figure 4A and Figure 4B When Figure 5ASchematic diagram of the operation of the optoelectronic conversion circuit 500. For example, when the optoelectronic conversion circuit 500 is used as the photodiode circuit 440-1 and the TIA 444-1, the multi-input photodiode 516 does not receive an optical signal from the optical processor 412. Instead, the multi-input photodiode 516 receives an optical signal (e.g., an IMDD signal) from the optical demultiplexer 420. In addition, the photodiode 512 does not receive an optical signal from the optical processor 412. Therefore, the current signal output from the node 560 reflects the change in light intensity in the IMDD signal from the optical demultiplexer 420. The TIA 508 converts the current signal into a voltage signal.

[0127] Figure 5C According to an embodiment, when the optical receiver 300 operates in a second configuration (such as the above reference Figure 3 , Figure 4A , Figure 4C and Figure 4D When Figure 5A FIG. 5 is a diagram of the operation of the photoelectric conversion circuit 500. For example, when the photoelectric conversion circuit 500 is used as Figure 4C When the photodiode circuit 440-1 and the TIA 444-1 are connected, the photodiode 512 receives a first optical signal (e.g., a first DQSPK signal) from the optical processor 412, such as an optical signal corresponding to Equation 1. In addition, the multi-input photodiode 516 does not receive an optical signal from the optical demultiplexer 420. Instead, the multi-input photodiode 516 receives a second optical signal (e.g., a second DQSPK signal) from the optical processor 412, such as an optical signal corresponding to Equation 2. Therefore, the current signal output from the node 560 corresponds to the difference between i) the current flowing out of the anode 520 due to the first optical signal and ii) the current flowing into the cathode 532 due to the second optical signal.

[0128] When the first optical signal corresponds to Equation 1 and the second optical signal corresponds to Equation 2, the current signal output from the node 560 is proportional to the following equation:

[0129] P I，1 (t)-P I，2 (t)=1 / 2|A(t)||A LO |cos(ω if t+θ if ) (Equation 9)

[0130] TIA 444 converts the current signal output by node 560 into a voltage signal.

[0131] As another example, in the case where the photoelectric conversion circuit 500 is used as Figure 4DWhen the photodiode circuit 440-1 and the TIA 444-1 are connected, the photodiode 512 receives a first optical signal (e.g., a first DQSPK signal) from a set of DLIs 412, such as an optical signal corresponding to Equation 5. In addition, the multi-input photodiode 516 does not receive an optical signal from the optical demultiplexer 420. Instead, the multi-input photodiode 516 receives a second optical signal (e.g., a second DQSPK signal) from a set of DLIs 412, such as an optical signal corresponding to Equation 6. Therefore, the current signal output from the node 560 corresponds to the difference between i) the current flowing out of the anode 520 due to the first optical signal and ii) the current flowing into the cathode 532 due to the second optical signal.

[0132] When the first optical signal corresponds to Equation 5 and the second optical signal corresponds to Equation 6, the current signal output from the node 560 is proportional to the following equation:

[0133] P I,1 (t)-P I,2 (t) = A(t)A(tT s ) (Equation 10)

[0134] Where A(t) is equal to:

[0135]

[0136] Where P0 is a constant, is the phase of the optical signal. Then, the current signal output from node 560 is proportional to the following equation:

[0137]

[0138] in and is either 0 or π depending on the bit transmitted.

[0139] TIA 444 converts the current signal output by node 560 into a voltage signal. In DQPSK, or π, depending on the bits transmitted, and the DSP of the baseband processor 308 can reconstruct the original bit stream from the output of the TIA 444.

[0140] Figure 5D is according to an embodiment when the optical receiver 100 operates in a configuration corresponding to in-line M-QAM demodulation Figure 5A Schematic diagram of the operation of the photoelectric conversion circuit 500. Referring again to Figure 3 and Figure 4AIn the case of extended M-QAM demodulation, the optical processor 412 includes a coherent extended 2-pol 90 degree mixer 412 that mixes the optical signal from the PBS 428 with a local oscillator signal (not shown) as part of the generation of the output signal. When the optoelectronic conversion circuit 500 is used as the photodiode circuit 440-1 and the TIA 444-1, the photodiode 512 receives a first optical signal (e.g., a first extended M-QAM signal) from the coherent extended 2-pol 90 degree mixer 412, such as the optical signal corresponding to Equation 1. In addition, the multi-input photodiode 516 does not receive an optical signal from the optical demultiplexer 420. Instead, the multi-input photodiode 516 receives a second optical signal (e.g., a second extended M-QAM signal) from the coherent extended 2-pol 90 degree mixer 412, such as the optical signal corresponding to Equation 2. Therefore, the current signal output from the node 560 corresponds to the difference between i) the current flowing out of the anode 520 due to the first optical signal and ii) the current flowing into the cathode 532 due to the second optical signal.

[0141] When the first optical signal corresponds to Equation 1 and the second optical signal corresponds to Equation 2, the current signal output from the node 560 is proportional to Equation 9. The TIA 508 converts the current signal output by the node 560 into a voltage signal.

[0142] Figure 6 is a flow chart of an example method 600 for operating a reconfigurable optical transmitter capable of modulating an optical signal according to different optical modulation techniques according to an embodiment. In some embodiments, the method 600 is performed by Figure 1 Reconfigurable optical transmitter and / or use Figure 2A For ease of explanation, refer to Figure 1 and Figure 2A describe Figure 6 In other embodiments, method 600 uses Figure 1 Another suitable reconfigurable optical receiver different from the reconfigurable optical receiver and / or using the Figure 2A The optical module 200 may be implemented by another suitable optical module.

[0143] At block 604, a modulation type to be used by the reconfigurable optical transmitter is determined. The reconfigurable optical transmitter is capable of modulating optical signals according to a plurality of different types of optical modulation techniques, including at least a first type and a second type. In one embodiment, the first type corresponds to intensity modulation, in which multiple signals are modulated on different wavelengths, and in one embodiment, the second type involves coherent modulation on a single wavelength. For example, in an illustrative embodiment, the first type corresponds to IMDD modulation, and the second type corresponds to DQPSK or M-QAM.

[0144] In one embodiment, the controller of the optical receiver 100 determines the modulation type at block 704. In another embodiment, the controller 112 of the optical transmitter 100 determines the modulation type at block 604.

[0145] In response to determining at block 604 that the reconfigurable optical transmitter is to use the first modulation type, the flow proceeds to block 608. At block 608, the controller of the optical transmitter controls the plurality of lasers of the optical transmitter so that the plurality of lasers are turned on. In one embodiment, the plurality of lasers correspond to respective wavelengths. For example, the controller 112 controls the lasers 120 / 204 so that all lasers 120 / 204 are turned on.

[0146] At block 610, the controller configures the optical modulator of the optical transmitter for a first modulation type. For example, the controller 112 sets the modulator operating point of the MZ modulator 212 to a first modulator operation suitable for the first type of modulation.

[0147] At block 612, the controller of the optical transmitter controls the reconfigurable optical network of the optical transmitter such that light from the plurality of lasers is provided to corresponding modulators of the optical transmitter. For example, the controller 112 controls the reconfigurable optical network 124 / 232 such that light from the plurality of lasers 120 / 204 is provided to corresponding modulators 128 / 212 of the optical transmitter.

[0148] At block 616, the plurality of modulators modulate the respective data onto the plurality of wavelengths according to the first modulation type. In one embodiment, the baseband processor 104 generates a modulation signal that is used to control the plurality of modulators 128 / 212 to modulate the respective data onto the plurality of wavelengths according to the first modulation type. In one embodiment, modulating the respective data onto the plurality of wavelengths at block 616 includes receiving the modulation signal from the baseband processor 104 at the driver circuitry 132, and controlling the plurality of modulators using the driver circuitry 132 based on the modulation signal from the baseband processor 104.

[0149] On the other hand, in response to determining at block 604 that the reconfigurable optical transmitter is to use a second modulation type, the flow proceeds to block 620. At block 620, the controller of the optical transmitter controls the plurality of lasers of the optical transmitter such that one laser is turned on and the other lasers are turned off. In embodiments where the plurality of lasers correspond to respective wavelengths, the controller of the optical transmitter controls the plurality of lasers of the optical transmitter such that one laser at one wavelength is turned on and the other lasers at the other respective wavelengths are turned off. For example, the controller 112 controls the lasers 120 / 204 such that one of the lasers 120 / 204 (e.g., laser 204-2) is turned on and the remaining lasers 120 / 204 (e.g., lasers 204-1, 204-3, and 204-4) are turned off.

[0150] At block 622, the controller configures the optical modulator of the optical transmitter for the second modulation type. For example, the controller 112 sets the modulator operating point of the MZ modulator 212 to a second modulator operating point (different from the first modulator operating point) suitable for the second type of modulation.

[0151] At block 624, the controller of the optical transmitter controls the reconfigurable optical network of the optical transmitter such that light from one laser is provided to multiple modulators of the optical transmitter. For example, the controller 112 controls the reconfigurable optical network 124 / 232 such that light from one laser 120 / 204 (e.g., laser 204-2) is provided to all modulators 128 / 212 of the optical transmitter.

[0152] At block 628, the plurality of modulators modulate the corresponding data onto a wavelength according to the second modulation type. In one embodiment, the baseband processor 104 generates a modulation signal that is used to control the plurality of modulators 128 / 212 to modulate the data onto a wavelength according to the first modulation type. In one embodiment, modulating the data onto a wavelength at block 628 includes receiving the modulation signal from the baseband processor 104 at the driver circuitry 132, and controlling the plurality of modulators using the driver circuitry 132 based on the modulation signal from the baseband processor 104.

[0153] Figure 7 is a flow chart of an example method 700 for operating a reconfigurable optical receiver capable of demodulating optical signals modulated according to different optical modulation techniques, according to an embodiment. In one embodiment, the method 700 uses Figure 3 Reconfigurable optical receiver and / or Figure 4A For ease of explanation, refer to Figure 3 and Figure 4A describe Figure 7 In other embodiments, method 700 uses Figure 3 Another suitable reconfigurable optical receiver different from the reconfigurable optical receiver and / or using the same Figure 4A The reconfigurable optical module may be implemented by another suitable reconfigurable optical module.

[0154] At block 704, a modulation type to be processed by the reconfigurable optical receiver is determined. The reconfigurable optical receiver is capable of demodulating optical signals modulated according to a plurality of different types of optical modulation techniques, including at least a first type and a second type. In one embodiment, the first type does not involve the use of an optical processor of the reconfigurable optical receiver, and the second type involves the use of an optical processor. For example, in one embodiment, the first type corresponds to intensity modulation (e.g., IMDD modulation), and the second type corresponds to coherent modulation (e.g., DQPSK or M-QAM modulation).

[0155] In one embodiment, the controller 312 of the optical receiver 300 determines the modulation type at block 704 .

[0156] In response to determining at block 704 that the modulation type to be processed by the reconfigurable optical receiver is the first type, flow continues to block 708. At block 708, the reconfigurable optical network of the reconfigurable optical receiver is controlled such that an optical signal corresponding to a signal received by the reconfigurable optical receiver bypasses an optical processor of the reconfigurable optical receiver. For example, the reconfigurable optical network 328 / 404 is controlled such that an output of the optical demultiplexer 420 bypasses the optical processor 412. For example, the controller 312 of the optical receiver 300 generates a control signal to control the optical switch 424 such that the output of the optical demultiplexer 420 bypasses the optical processor 412. In another embodiment in which the reconfigurable optical network includes an optical switch coupled to an input of the optical demultiplexer, the control signal controls the optical switch such that the optical signal bypasses the optical processor and is provided to an input of the optical demultiplexer 420.

[0157] At block 712, the optical signal bypassing the optical signal at block 708 is provided to a multi-input photodiode of a photodiode circuit of a reconfigurable optical receiver. For example, the output of optical demultiplexer 420 bypasses optical processor 412 and is received at a first side of a multi-input photodiode of photodiode circuit 440-2.

[0158] On the other hand, in response to determining at block 704 that the modulation type to be processed by the reconfigurable optical receiver is the second type, the process continues to block 716. At block 716, the reconfigurable optical network of the reconfigurable optical receiver is controlled so that an optical signal corresponding to the signal received by the reconfigurable optical receiver is provided to an optical processor of the reconfigurable optical receiver. For example, the reconfigurable optical network 328 / 404 is controlled so that the output of the optical demultiplexer 420 is provided to the PBS 428, which is coupled to the optical processor 412. For example, the controller 312 of the optical receiver 300 generates a control signal to control the optical switch 424 so that the output of the optical demultiplexer 420 is provided to the PBS 428. In another embodiment in which the reconfigurable optical network includes an optical switch coupled to an input of the optical demultiplexer, the control signal controls the optical switch so that the optical signal bypasses the optical demultiplexer 420 and is provided to the input of the PBS 428.

[0159] At block 720, the plurality of outputs of the optical processor are provided to a photodiode circuit of the reconfigurable optical receiver, including providing a first output of the optical processor 120 to a multi-input photodiode. For example, providing an output of the optical processor 412 to the photodiode circuit 440 includes providing the first output of the optical processor 412 to a second side of the multi-input photodiode of the photodiode circuit 124, the second side being opposite to the first side of the multi-input photodiode. In another embodiment, the first output of the optical processor 412 is provided to an active region on the first side of the multi-input photodiode.

[0160] At block 724, the current signal output of the photodiode circuit is converted to a voltage signal using a TIA. For example, the current signal output by the photodiode circuit 124-1 is converted to a voltage signal by the TIA 128-1.

[0161] At block 728, the voltage signal generated at block 724 is sampled by the ADC to generate a digital domain signal. For example, the ADC of the baseband processor 308 samples the voltage signal output by the TIA 128-1.

[0162] At block 732, the DSP processes the digital domain signal generated at block 732 to recover information bits from the digital domain signal. For example, the baseband processor 308 processes the digital domain signal generated by the ADC.

[0163] Embodiment 1: An optical module for multiple optical modulation technologies, the optical module comprising:

[0164] a plurality of lasers, each of at least some of the lasers being configured to be selectively turned on and off depending on the type of modulation to be used, each laser corresponding to a respective wavelength;

[0165] An optical modulation system comprising a plurality of optical modulators; and

[0166] A reconfigurable optical network is configured to selectively direct light from the plurality of lasers to the optical modulation system based on the type of modulation to be used.

[0167] Embodiment 2: The optical module of embodiment 1, wherein: the plurality of lasers are configurable such that a plurality of lasers of the plurality of lasers i) are turned on in a first configuration of the optical module, and ii) are turned off in a second configuration of the optical module; and

[0168] The reconfigurable optical network is configurable such that i) light from corresponding lasers of the plurality of lasers is directed to corresponding modulators in the first configuration, and ii) light from a first laser turned on in the second configuration is directed to a plurality of modulators in the second configuration.

[0169] Embodiment 3: The optical module according to embodiment 2, wherein the reconfigurable optical network comprises:

[0170] a first variable optical coupler having i) a first input coupled to the first laser, ii) a first output, and iii) a second output;

[0171] a second variable optical coupler having i) a first input coupled to the first output of the first variable optical coupler, ii) a first output coupled to an input of a first optical modulator of the plurality of optical modulators, and iii) a second output coupled to an input of a second optical modulator of the plurality of optical modulators; and

[0172] a third variable optical coupler having i) a first input coupled to the second output of the first variable optical coupler, ii) a first output coupled to an input of a third optical modulator among the plurality of optical modulators, and iii) a second output coupled to an input of a fourth optical modulator among the plurality of optical modulators.

[0173] Embodiment 4: The optical module according to embodiment 3, wherein:

[0174] the first variable optical coupler comprising a second input coupled to a second laser of the plurality of lasers;

[0175] the second variable optical coupler comprises a second input coupled to a third laser of the plurality of lasers; and

[0176] The third variable optical coupler includes a second input coupled to a fourth laser of the plurality of lasers.

[0177] Embodiment 5: An optical transceiver, comprising the optical module according to any one of Embodiments 1 to 4, the optical transceiver further comprising:

[0178] a controller configured to generate control signals to selectively turn on and off said at least some of said lasers according to said modulation type to be used; and

[0179] The baseband processor is configured as

[0180] receive data to be transmitted, and

[0181] A modulation signal for controlling the plurality of optical modulators is generated based on the data to be transmitted.

[0182] Embodiment 6: The optical transceiver according to Embodiment 5, wherein the baseband processor includes the controller.

[0183] Embodiment 7: A method of controlling a reconfigurable optical module for transmitting information via an optical medium, the method comprising:

[0184] determining, at a controller, a modulation type to be used to transmit the information via the optical medium, the modulation type being determined by a plurality of different types of optical modulation techniques, including at least a first type and a second type;

[0185] controlling, by the controller, a plurality of lasers of the reconfigurable optical module to i) turn on or ii) turn off at least some of the lasers of the plurality of lasers, each laser corresponding to a respective wavelength, according to the type of modulation to be used; and

[0186] A reconfigurable optical network of the reconfigurable optical module is controlled by the controller to selectively direct light from the plurality of lasers differently to an optical modulation system of the reconfigurable optical module according to the type of modulation to be used.

[0187] Embodiment 8: The control method of the reconfigurable optical module according to Embodiment 7, wherein:

[0188] Controlling the plurality of lasers comprises controlling the plurality of lasers such that a plurality of lasers of the plurality of lasers i) are turned on in a first configuration of the optical module and ii) are turned off in a second configuration of the optical module; and

[0189] Controlling the reconfigurable optical network includes controlling the reconfigurable optical network so that i) light from corresponding lasers of the plurality of lasers is directed to corresponding modulators in the first configuration, and ii) light from a first laser turned on in the second configuration is directed to a plurality of modulators in the second configuration.

[0190] Embodiment 9: The method for controlling the reconfigurable optical module according to embodiment 7 or 8, wherein controlling the reconfigurable optical network comprises:

[0191] controlling a first variable optical coupler having a first input coupled to the first laser so that light from the first laser is i) directed only to a first output of the first variable optical coupler in the first configuration, and iii) directed to the first output of the first variable optical coupler and a second output of the first variable optical coupler in the second configuration;

[0192] controlling a second variable optical coupler having a first input coupled to the first output of the first variable optical coupler so that light from the first laser is i) directed only to the first output of the second variable optical coupler coupled to a first modulator of the plurality of modulators in the first configuration, and iii) directed to the first output of the first variable optical coupler and the second output of the second variable optical coupler coupled to a second modulator of the plurality of modulators in the second configuration; and

[0193] controlling a third variable optical coupler having a first input coupled to the second output of the first variable optical coupler so that light received via the first input of the third variable optical coupler is i) guided only to the first output of the third variable optical coupler coupled to a third modulator of the plurality of modulators in the first configuration, and iii) guided to the first output of the first variable optical coupler and the second output of the second variable optical coupler coupled to a fourth modulator of the plurality of modulators in the second configuration.

[0194] Embodiment 10: According to the control method of the reconfigurable optical module according to Embodiment 9, controlling the reconfigurable optical network further comprises:

[0195] controlling the first variable optical coupler so that light from a second laser coupled to a second input of the first variable optical coupler is directed only to the second output of the first variable optical coupler in the first configuration;

[0196] controlling the second variable optical coupler so that light from a third laser coupled to a second input of the second variable optical coupler is directed only to the second output of the second variable optical coupler in the first configuration; and

[0197] The third variable optical coupler is controlled such that light from a fourth laser coupled to the second input of the third variable optical coupler is directed only to the second output of the third variable optical coupler in the first configuration.

[0198] Embodiment 11: A method for controlling an optical transceiver, comprising the method according to any one of Embodiments 7 to 11, wherein the method for controlling the optical transceiver further comprises:

[0199] receiving, at a baseband processor of the transceiver, data to be transmitted via an optical medium;

[0200] generating, at the baseband processor, modulation signals for controlling the plurality of optical modulators based on the data received at the baseband processor; and

[0201] The modulation signal is provided to the optical module to control the plurality of optical modulators.

[0202] Embodiment 12: An optical module for multiple optical modulation technologies, the optical module comprising:

[0203] Opto-electrical conversion circuitry including a plurality of photodiodes coupled to a plurality of transimpedance amplifiers (TIAs), the plurality of photodiodes including multi-input photodiodes, each multi-input photodiode including a first side and a second side opposite the first side;

[0204] an optical processor configured to optically process one or more optical signals corresponding to the coherent modulation, the optical processor coupled to the plurality of photodiodes, including a plurality of outputs of the optical processor coupled to respective first sides of the multi-input photodiodes; and

[0205] An optical network is configured to i) direct optical signals corresponding to light received via an optical medium to respective second sides of the multi-input photodiodes in a first configuration corresponding to a first modulation technique such that the light bypasses the optical processor, and ii) direct one or more optical signals corresponding to light received via the optical medium to one or more inputs of the optical processor in a second configuration corresponding to a second modulation technique.

[0206] Embodiment 13: The optical module according to embodiment 12, wherein the optical network comprises:

[0207] An optical demultiplexer has a plurality of outputs optically coupled to respective second sides of the multi-input photodiodes.

[0208] Embodiment 14: The optical module according to embodiment 13, wherein the optical network further comprises:

[0209] an optical switch having i) an input coupled to one of the outputs of the optical demultiplexer, ii) a first output coupled to a second side of one of the multiple-input photodiodes, and iii) a second output coupled to one or more inputs of the optical processor, wherein i) in the first configuration corresponding to the first modulation technique, the optical switch directs the optical signal from the one output of the optical demultiplexer to the second side of the one multiple-input photodiode, and ii) in the second configuration corresponding to the second modulation technique, the optical switch directs the optical signal from the one output of the optical demultiplexer to the one or more inputs of the optical processor.

[0210] Embodiment 15: The optical module according to embodiment 14, wherein the optical network further comprises:

[0211] A polarization beam splitter is coupled between the second output of the optical switch and the optical processor.

[0212] Embodiment 16: An optical receiver, comprising the optical module according to any one of Embodiments 12 to 15, further comprising:

[0213] A plurality of analog-to-digital converters (ADCs) are coupled to the plurality of TIAs, and the plurality of ADCs convert analog outputs of the TIAs into corresponding digital domain signals.

[0214] Embodiment 17: The optical receiver according to Embodiment 16, further comprising:

[0215] A baseband processor is coupled to the plurality of ADCs, the baseband processor being configured to recover information bits from the digital domain signal.

[0216] Embodiment 18: A method of operating a reconfigurable optical module, the optical module comprising an optoelectronic conversion circuit system, the optoelectronic conversion circuit system comprising a plurality of photodiodes coupled to a plurality of transimpedance amplifiers (TIAs), the plurality of photodiodes comprising multi-input photodiodes, each multi-input photodiode comprising a first side and a second side opposite the first side, the optical module further comprising an optical processor configured to optically process one or more optical signals corresponding to coherent modulation, the optical processor coupled to the plurality of photodiodes, comprising a plurality of outputs of the optical processor coupled to respective first sides of the multi-input photodiodes, the method comprising:

[0217] determining, at a controller, a modulation type of an optical signal received via an optical medium to be processed by the reconfigurable optical module, the modulation type being determined by a plurality of different types of optical modulation techniques, including at least a first type and a second type; and

[0218] A reconfigurable optical network of the reconfigurable optical module is controlled by a controller to selectively i) direct optical signals corresponding to light received via the optical medium to respective first sides of the multi-input photodiodes in a first configuration corresponding to a first modulation technique such that the light bypasses the optical processor, and ii) direct one or more optical signals corresponding to light received via the optical medium to one or more inputs of the optical processor in a second configuration corresponding to a second modulation technique.

[0219] Embodiment 19: The method for operating the reconfigurable optical module according to Embodiment 18, further comprising, in the first configuration:

[0220] demultiplexing light of corresponding wavelengths from an optical signal corresponding to light received via the optical medium using an optical demultiplexer; and

[0221] Respective optical signals output by the optical demultiplexer are provided to respective second sides of the multi-input photodiodes.

[0222] Embodiment 20: A method for operating a reconfigurable optical module according to Embodiment 19, wherein the reconfigurable optical network comprises an optical switch having i) an input coupled to one of the outputs of the optical demultiplexer, ii) a first output coupled to a second side of one of the multi-input photodiodes, and iii) a second output coupled to one or more inputs of the optical processor, and wherein controlling the reconfigurable optical network comprises:

[0223] The optical switch is controlled by the controller such that i) in the first configuration corresponding to the first modulation technique, the optical switch directs the optical signal from the one output of the optical demultiplexer to the second side of the one multi-input photodiode, and ii) in the second configuration corresponding to the second modulation technique, the optical switch directs the optical signal from the one output of the optical demultiplexer to the one or more inputs of the optical processor.

[0224] Embodiment 21: The method for operating the reconfigurable optical module according to Embodiment 20, further comprising the second configuration:

[0225] splitting an output signal from the second output of the optical switch into a first polarization signal and a second polarization signal by a polarization beam splitter; and

[0226] The first polarization signal and the second polarization signal are provided to an input of the optical processor.

[0227] Embodiment 22: A method of operating an optical receiver, comprising the method according to any one of Embodiments 18 to 21, the method further comprising:

[0228] The analog outputs of the TIA are converted into corresponding digital domain signals by a plurality of analog-to-digital converters (ADCs).

[0229] Embodiment 23: The operating method of the optical receiver according to Embodiment 22, further comprising:

[0230] The information bits are recovered from the digital domain signal by a baseband processor.

[0231] Embodiment 24: An optical module according to any one of Embodiments 1 to 6, wherein:

[0232] The optical modulation system is configurable such that the plurality of modulators are i) configured to modulate according to a first modulation technique when the optical modulation system is in a first configuration and ii) configured to modulate according to a second modulation technique when the optical modulation system is in a second configuration.

[0233] Embodiment 25: The method for controlling the reconfigurable optical module according to any one of Embodiments 7 to 11, further comprising:

[0234] The optical modulation system is configured such that a plurality of modulators of the optical modulation system are i) configured to modulate according to a first modulation technique when the optical modulation system is in a first configuration, and ii) configured to modulate according to a second modulation technique when the optical modulation system is in a second configuration.

[0235] Embodiment 24: An optical transceiver comprising i) any one of embodiments 1 to 6 or 24, and ii) any one of embodiments 12 to 17.

[0236] Embodiment 25: A method of operating an optical transceiver, comprising i) any one of embodiments 7 to 11 or 25, and ii) any one of embodiments 18 to 23.

[0237] Some of the various blocks, operations, and techniques described above may be implemented using hardware, a processor executing firmware instructions, a processor executing software instructions, or any suitable combination thereof. When implemented using a processor executing software or firmware instructions, the software or firmware instructions may be stored in any suitable computer-readable memory. The software or firmware instructions may include machine-readable instructions that, when executed by one or more processors, cause the one or more processors to perform various actions.

[0238] When implemented in hardware, the hardware may include one or more of discrete components, integrated circuits, application specific integrated circuits (ASICs), programmable logic devices (PLDs), and the like.

[0239] Although the present invention has been described with reference to specific examples, these examples are only intended to illustrate and not to limit the present invention, and changes, additions and / or deletions may be made to the disclosed embodiments without departing from the scope of the present invention.

Claims

1. An optical module for multiple optical modulation technologies, the optical module comprising: a plurality of lasers, each of at least some of the lasers being configured to be selectively turned on and off depending on the type of modulation to be used, each laser corresponding to a respective wavelength; An optical modulation system comprising a plurality of optical modulators; as well as A reconfigurable optical network is configured to selectively direct light from the plurality of lasers to the optical modulation system based on the type of modulation to be used.

2. The optical module according to claim 1, wherein: The plurality of lasers are configurable such that a plurality of lasers of the plurality of lasers are i) turned on in a first configuration of the optical module and ii) turned off in a second configuration of the optical module; and The reconfigurable optical network is configurable such that i) light from corresponding lasers of the plurality of lasers is directed to corresponding modulators in the first configuration, and ii) light from a first laser turned on in the second configuration is directed to a plurality of modulators in the second configuration.

3. The optical module of claim 2, wherein the reconfigurable optical network comprises: a first variable optical coupler having i) a first input coupled to the first laser, ii) a first output, and iii) a second output; a second variable optical coupler having i) a first input coupled to the first output of the first variable optical coupler, ii) a first output coupled to an input of a first optical modulator of the plurality of optical modulators, and iii) a second output coupled to an input of a second optical modulator of the plurality of optical modulators; as well as a third variable optical coupler having i) a first input coupled to the second output of the first variable optical coupler, ii) a first output coupled to an input of a third optical modulator among the plurality of optical modulators, and iii) a second output coupled to an input of a fourth optical modulator among the plurality of optical modulators.

4. The optical module according to claim 3, wherein: the first variable optical coupler comprising a second input coupled to a second laser of the plurality of lasers; the second variable optical coupler comprises a second input coupled to a third laser of the plurality of lasers; and The third variable optical coupler includes a second input coupled to a fourth laser of the plurality of lasers.

5. The optical module according to claim 1, wherein: The optical modulation system is configurable such that the plurality of modulators are i) configured to modulate according to a first modulation technique when the optical modulation system is in a first configuration and ii) configured to modulate according to a second modulation technique when the optical modulation system is in a second configuration.

6. An optical transceiver, comprising the optical module according to claim 1, the optical transceiver further comprising: a controller configured to generate control signals to selectively turn on and off said at least some of said lasers according to said modulation type to be used; as well as The baseband processor is configured as receive data to be transmitted, and A modulation signal for controlling the plurality of optical modulators is generated based on the data to be transmitted.

7. The optical transceiver of claim 6, wherein a baseband processor comprises the controller.

8. A method of controlling a reconfigurable optical module for transmitting information via an optical medium, the method comprising: determining, at a controller, a modulation type to be used to transmit the information via the optical medium, the modulation type being determined by a plurality of different types of optical modulation techniques, including at least a first type and a second type; controlling, by the controller, a plurality of lasers of the reconfigurable optical module to i) turn on or ii) turn off at least some of the lasers of the plurality of lasers, each laser corresponding to a respective wavelength, according to the type of modulation to be used; as well as A reconfigurable optical network of the reconfigurable optical module is controlled by the controller to selectively direct light from the plurality of lasers differently to an optical modulation system of the reconfigurable optical module according to the type of modulation to be used.

9. The method for controlling the reconfigurable optical module according to claim 8, wherein: Controlling the plurality of lasers comprises: controlling the plurality of lasers such that a plurality of lasers of the plurality of lasers i) are turned on in a first configuration of the optical module, and ii) are turned off in a second configuration of the optical module; and Controlling the reconfigurable optical network comprises controlling the reconfigurable optical network so that i) light from corresponding lasers among the plurality of lasers is directed to corresponding modulators in the first configuration, and ii) light from a first laser turned on in the second configuration is directed to a plurality of modulators in the second configuration.

10. The method of controlling the reconfigurable optical module according to claim 8, wherein controlling the reconfigurable optical network comprises: controlling a first variable optical coupler having a first input coupled to the first laser such that light from the first laser is i) directed only to a first output of the first variable optical coupler in the first configuration and iii) directed to the first output of the first variable optical coupler and a second output of the first variable optical coupler in the second configuration; controlling a second variable optical coupler having a first input coupled to the first output of the first variable optical coupler such that light from the first laser i) is directed only to the first output coupled to the second variable optical coupler, which is coupled to a first modulator of the plurality of modulators, in the first configuration, and iii) is directed to the first output of the first variable optical coupler and to the second output of the second variable optical coupler, which is coupled to a second modulator of the plurality of modulators, in the second configuration; as well as controlling a third variable optical coupler having a first input coupled to the second output of the first variable optical coupler such that light received via the first input of the third variable optical coupler is i) directed only to the first output of the third variable optical coupler, which is coupled to a third modulator of the plurality of modulators, in the first configuration, and iii) directed to the first output of the first variable optical coupler and the second output of the second variable optical coupler, which is coupled to a fourth modulator of the plurality of modulators, in the second configuration.

11. The method for controlling the reconfigurable optical module according to claim 10, wherein controlling the reconfigurable optical network further comprises: controlling the first variable optical coupler so that light from a second laser coupled to a second input of the first variable optical coupler is directed only to the second output of the first variable optical coupler in the first configuration; controlling the second variable optical coupler so that light from a third laser coupled to a second input of the second variable optical coupler is directed only to the second output of the second variable optical coupler in the first configuration; as well as The third variable optical coupler is controlled such that light from a fourth laser coupled to the second input of the third variable optical coupler is directed only to the second output of the third variable optical coupler in the first configuration.

12. The method of controlling the reconfigurable optical module according to claim 8, further comprising: The optical modulation system is configured such that a plurality of modulators of the optical modulation system are i) configured to modulate according to a first modulation technique when the optical modulation system is in a first configuration, and ii) configured to modulate according to a second modulation technique when the optical modulation system is in a second configuration.

13. A method of controlling an optical transceiver, comprising the method according to claim 8, the method of controlling the optical transceiver further comprising: receiving, at a baseband processor of the transceiver, data to be transmitted via an optical medium; generating, at the baseband processor, modulation signals for controlling the plurality of optical modulators based on the data received at the baseband processor; as well as The modulation signal is provided to the optical module to control the plurality of optical modulators.

14. An optical module for multiple optical modulation technologies, the optical module comprising: an optoelectronic conversion circuit system including a plurality of photodiodes coupled to a plurality of transimpedance amplifiers (TIA), the plurality of photodiodes including a multi-input photodiode, each of the multi-input photodiodes including a first side and a second side opposite the first side; an optical processor configured to optically process one or more optical signals corresponding to the coherent modulation, the optical processor coupled to the plurality of photodiodes, including a plurality of outputs of the optical processor coupled to respective first sides of the multi-input photodiodes; as well as An optical network is configured to i) direct optical signals corresponding to light received via an optical medium to respective second sides of the multi-input photodiodes in a first configuration corresponding to a first modulation technique such that the light bypasses the optical processor, and ii) direct one or more optical signals corresponding to light received via the optical medium to one or more inputs of the optical processor in a second configuration corresponding to a second modulation technique.

15. The optical module of claim 14, wherein the optical network comprises: An optical demultiplexer has a plurality of outputs optically coupled to respective second sides of the multi-input photodiodes.

16. The optical module of claim 15, wherein the optical network further comprises: an optical switch having i) an input coupled to one of the outputs of the optical demultiplexer, ii) a first output coupled to a second side of one of the multiple-input photodiodes, and iii) a second output coupled to one or more inputs of the optical processor, wherein i) in the first configuration corresponding to the first modulation technique, the optical switch directs the optical signal from the one output of the optical demultiplexer to the second side of the one multiple-input photodiode, and ii) in the second configuration corresponding to the second modulation technique, the optical switch directs the optical signal from the one output of the optical demultiplexer to the one or more inputs of the optical processor.

17. The optical module of claim 15, wherein the optical network further comprises: A polarization beam splitter is coupled between the second output of the optical switch and the optical processor.

18. An optical receiver, comprising the optical module according to claim 14, further comprising: A plurality of analog-to-digital converters ADCs are coupled to the plurality of TIAs, and the plurality of ADCs convert analog outputs of the TIAs into corresponding digital domain signals.

19. The optical receiver of claim 18, further comprising: A baseband processor is coupled to the plurality of ADCs, the baseband processor being configured to recover information bits from the digital domain signal.

20. A method of operating a reconfigurable optical module, the optical module comprising an optoelectronic conversion circuit system, the optoelectronic conversion circuit system comprising a plurality of photodiodes coupled to a plurality of transimpedance amplifiers (TIA), the plurality of photodiodes comprising a multi-input photodiode, each multi-input photodiode comprising a first side and a second side opposite the first side, the optical module further comprising an optical processor configured to optically process one or more optical signals corresponding to coherent modulation, the optical processor coupled to the plurality of photodiodes, comprising a plurality of outputs of the optical processor coupled to respective first sides of the multi-input photodiodes, the method comprising: determining, at a controller, a modulation type of an optical signal received via an optical medium to be processed by the reconfigurable optical module, the modulation type being determined by a plurality of different types of optical modulation techniques, including at least a first type and a second type; as well as A reconfigurable optical network of the reconfigurable optical module is controlled by a controller to selectively i) direct optical signals corresponding to light received via the optical medium to respective first sides of the multi-input photodiodes in a first configuration corresponding to a first modulation technique such that the light bypasses the optical processor, and ii) direct one or more optical signals corresponding to light received via the optical medium to one or more inputs of the optical processor in a second configuration corresponding to a second modulation technique.

21. The method of operating the reconfigurable optical module according to claim 20, further comprising, in the first configuration: demultiplexing light of corresponding wavelengths from an optical signal corresponding to light received via the optical medium using an optical demultiplexer; and Respective optical signals output by the optical demultiplexer are provided to respective second sides of the multi-input photodiodes.

22. The method of operating the reconfigurable optical module of claim 21, wherein the reconfigurable optical network comprises an optical switch having i) an input coupled to one of the outputs of the optical demultiplexer, ii) a first output coupled to a second side of one of the multi-input photodiodes, and iii) a second output coupled to one or more inputs of the optical processor, and wherein controlling the reconfigurable optical network comprises: The optical switch is controlled by the controller such that i) in the first configuration corresponding to the first modulation technique, the optical switch directs the optical signal from the one output of the optical demultiplexer to the second side of the one multi-input photodiode, and ii) in the second configuration corresponding to the second modulation technique, the optical switch directs the optical signal from the one output of the optical demultiplexer to the one or more inputs of the optical processor.

23. The method of operating the reconfigurable optical module according to claim 22, further comprising the second configuration: splitting an output signal from the second output of the optical switch into a first polarization signal and a second polarization signal by a polarization beam splitter; and The first polarization signal and the second polarization signal are provided to an input of the optical processor.

24. A method of operating an optical receiver, comprising the method of claim 20, the method further comprising: The analog output of the TIA is converted into corresponding digital domain signals by a plurality of analog-to-digital converters ADC.

25. The method of operating the optical receiver according to claim 24, further comprising: The information bits are recovered from the digital domain signal by a baseband processor.

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