Coherent optical receiver and method for coherent optical reception

Abstract

Embodiments of the present disclosure may include a coherent optical receiver and a method for coherent optical reception, where the coherent optical receiver includes a PCSEL that generates a first optical beam and a second optical beam. According to various embodiments, the physical emission direction of the first light beam may be at an angle of 180 degrees to the physical emission direction of the second light beam, or in some cases 180 degrees plus / minus 10 degrees. Embodiments may also include a first hybrid receiver that receives the first portion of the input optical signal to the coherent optical receiver and the first optical beam as local oscillator signals, generating one or more first optical hybrid receiver output signals. Embodiments may also include a second hybrid receiver that receives a second portion of the input optical signal to the coherent optical receiver and the second optical beam as local oscillator signals, generating one or more second optical hybrid receiver output signals.

Description

Technical Field

[0001] The present disclosure generally relates to a coherent optical receiver having a PCSEL that transmits in two directions. Background Art

[0002] Various aspects of the present disclosure relate to a coherent optical receiver having a PCSEL that transmits in two directions. Conventional solutions for coherent optical receivers can suffer from various problems. To this end, conventional systems and methods for coherent optical receivers can be costly, cumbersome, and / or inefficient.

[0003] By comparing such methods with some aspects of the present methods and systems set forth in the remainder of this disclosure, with reference to the accompanying figures, the limitations and shortcomings of conventional systems and methods will become apparent to those skilled in the art. Summary of the Invention

[0004] Shown in at least one of these figures and / or described in connection therewith, and more completely set forth in the claims, is a coherent optical receiver having a PCSEL that transmits in two directions.

[0005] These and other advantages, aspects and novel features of the present disclosure, as well as details of illustrated embodiments thereof, will be more fully understood from the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The various features and advantages of the present disclosure may be more readily understood by reference to the following detailed description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like structural elements.

[0007] Figure 1 is a block diagram illustrating a coherent optical receiver according to some embodiments of the present disclosure.

[0008] Figure 2 It is further illustrated that according to some embodiments of the present disclosure Figure 1 Block diagram of a coherent optical receiver.

[0009] Figure 3 is a flowchart illustrating a method according to some embodiments of the present disclosure.

[0010] Figure 4 An exemplary coherent optical receiver is shown.

[0011] Figure 5 An exemplary coherent optical receiver according to various embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0012] The following discussion provides various examples of semiconductor devices and methods of manufacturing semiconductor devices. These examples are non-limiting, and the scope of the appended claims should not be limited to the specific examples disclosed. In the following discussion, the terms "example" and "for example" are non-limiting.

[0013] The accompanying drawings illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present disclosure. In addition, the elements in the accompanying drawings are not necessarily drawn to scale. For example, the dimensions of some elements in the accompanying drawings may be exaggerated relative to other elements to help improve understanding of the examples discussed in this disclosure. The same reference numerals in different drawings represent the same elements.

[0014] The term "or" means any one or more items in a list connected by "or". As an example, "x or y" means any element of the three-element set {(x), (y), (x, y)}. As another example, "x, y, or z" means any element of the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}.

[0015] The terms “including,” “comprising,” “containing,” and / or “comprising” are “open” terms and specify the presence of described features, but do not preclude the presence or addition of one or more other features.

[0016] The terms "first," "second," etc., may be used herein to describe various elements, and these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, for example, a first element discussed in this disclosure could be referred to as a second element without departing from the teachings of this disclosure.

[0017] Unless otherwise specified, the term "coupled" can be used to describe two elements that are in direct contact with each other or to describe two elements that are indirectly connected through one or more other elements. For example, if element A is coupled to element B, element A can be directly in contact with element B or indirectly connected to element B through an intermediate element C. Similarly, the terms "over" or "on" can be used to describe two elements that are in direct contact with each other or to describe two elements that are indirectly connected through one or more other elements.

[0018] Embodiments of the present disclosure may include a coherent optical receiver including a PCSEL that generates a first light beam and a second light beam. According to various embodiments, the physical emission direction of the first light beam may be at an angle of 180 degrees to the physical emission direction of the second light beam, or in some cases, 180 degrees plus / minus 10 degrees.

[0019] Embodiments may further include a first hybrid receiver that receives a first portion of the input optical signal of the coherent optical receiver and a first optical beam as a local oscillator signal and generates one or more first optical hybrid receiver output signals. Embodiments may further include a second hybrid receiver that receives a second portion of the input optical signal of the coherent optical receiver and a second optical beam as a local oscillator signal and generates one or more second optical hybrid receiver output signals. Embodiments may further include a signal processing unit operable to convert the first optical hybrid receiver output signal and / or the second optical hybrid receiver output signal into an electrical signal.

[0020] According to various embodiments, the received first light beam may be rotated and / or polarized relative to the input light signal. According to various embodiments, the received second light beam may be rotated and / or polarized relative to the input light signal. According to various embodiments, the angle between the first light beam and the second light beam may be substantially 180 degrees.

[0021] According to various embodiments, the coherent optical receiver may include one or more polarizers and / or rotators. Embodiments may also include that either or both of the first portion of the received input optical signal or the second portion of the received input optical signal may be rotated and / or polarized relative to the first or second optical beam generated at the PCSEL.

[0022] Throughout this specification, the terms "polarizer" and "rotator" will be used interchangeably, similar to the verbs "polarize" and "rotate." These two terms refer to modifying or adjusting the polarization state of some optical signal, aligning or matching the polarization of two light beams, and / or changing the orientation of the polarization state of some optical signal.

[0023] According to various embodiments, the signal processing unit may include one or more analog-to-digital converters. According to various embodiments, the signal processing unit may include a digital signal processor. According to various embodiments, the electrical signal may be digitized. According to various embodiments, the electrical signal represents information extracted from the input light.

[0024] Embodiments of the present disclosure may also include a method for coherent optical reception, the method comprising generating a first light beam and a second light beam using a PCSEL. According to various embodiments, the physical emission direction of the first light beam may be at an angle of 180 degrees to the physical emission direction of the second light beam, or in some cases, 180 degrees plus / minus 10 degrees.

[0025] Embodiments may further include receiving, at a first hybrid receiver, a first portion of an input optical signal and a first optical beam as local oscillator signals, and generating one or more first optical hybrid receiver output signals. Embodiments may further include receiving, at a second hybrid receiver, a second portion of the input optical signal and a second optical beam as local oscillator signals, and generating one or more second optical hybrid receiver output signals. Embodiments may further include converting, at a signal processing unit, the first optical hybrid receiver output signal and / or the second optical hybrid receiver output signal into an electrical signal.

[0026] According to various embodiments, the method may include rotating and / or polarizing the received first light beam relative to the input light signal. According to various embodiments, the method may include rotating and / or polarizing the received second light beam relative to the input light signal.

[0027] According to various embodiments, the angle between the first and second light beams generated at the PCSEL can be substantially 180 degrees, or in some cases 180 degrees plus or minus 10 degrees. According to various embodiments, the method can include polarizing and / or rotating one or more light beams. According to various embodiments, the method can include rotating and / or polarizing a first portion of a received input optical signal and / or a second portion of a received input optical signal relative to the first or second light beams generated at the PCSEL.

[0028] According to various embodiments, the method may include analog-to-digital conversion in the signal processing unit. According to various embodiments, the method may include digital signal processing in the signal processing unit. According to various embodiments, the method may include digitizing the electrical signal. According to various embodiments, the method may include extracting information from the input light and representing the information in the electrical signal.

[0029] Reference Figure 1 , Figure 1is a block diagram illustrating a coherent optical receiver 1A according to some embodiments of the present disclosure. In some embodiments, the coherent optical receiver 1A may include a PCSEL 17 that generates a first optical beam and a second optical beam, and a signal processing unit 60 operable to convert an output signal of the first hybrid receiver 20 and / or an output signal of the second hybrid receiver 30 into an electrical signal. The coherent optical receiver 1A may also include a first hybrid receiver 20 that receives a first portion of an input optical signal at the coherent optical receiver 1A and the first optical beam as a local oscillator signal and generates one or more first optical hybrid receiver output signals. The coherent optical receiver 1A may also include a second hybrid receiver 30 that receives a second portion of the input optical signal at the coherent optical receiver 1A and the second optical beam as a local oscillator signal and generates one or more second optical hybrid receiver output signals. The physical emission direction of the first optical beam may be 180 degrees from the physical emission direction of the second optical beam, or in some cases, 180 degrees plus / minus 10 degrees.

[0030] In some embodiments, the received first light beam can be rotated and / or polarized relative to the input light signal. In some embodiments, the received second light beam can be rotated and / or polarized relative to the input light signal. In some embodiments, the angle can be substantially 180 degrees. In some embodiments, either or both of the first portion of the received input light signal or the second portion of the received input light signal can be rotated and / or polarized relative to the first light beam or the second light beam generated at the PCSEL 17. In some embodiments, the signal processing unit 60 includes one or more analog-to-digital converters. In some embodiments, the signal processing unit 60 can include a digital signal processor. In some embodiments, the electrical signal can be digitized. In some embodiments, the electrical signal can represent information extracted from the input light.

[0031] Figure 2 It is further illustrated that according to some embodiments of the present disclosure Figure 1 In some embodiments, the coherent optical receiver 1A may include one or more polarizers 11 and / or rotators 11.

[0032] Figure 3is a flow chart illustrating a method according to some embodiments of the present disclosure. In some embodiments, at 310, the method may include generating a first optical beam and a second optical beam using a PCSEL. At 320, the method may include receiving a first portion of an input optical signal and a first optical beam as a local oscillator signal at a first hybrid receiver, and generating one or more first optical hybrid receiver output signals. At 330, the method may include receiving a second portion of the input optical signal and a second optical beam as a local oscillator signal at a second hybrid receiver, and generating one or more second optical hybrid receiver output signals. At 340, the method may include converting the first optical hybrid receiver output signal and / or the second optical hybrid receiver output signal into an electrical signal in a signal processing unit. The physical emission direction of the first optical beam may be at an angle of 180 degrees to the physical emission direction of the second optical beam, or in some cases, 180 degrees plus / minus 10 degrees.

[0033] In some embodiments, the method may include rotating and / or polarizing a received first light beam relative to an input light signal. In some embodiments, the method may include rotating and / or polarizing a received second light beam relative to the input light signal. In some embodiments, the angle may be substantially 180 degrees. In some embodiments, the method may include polarizing and / or rotating one or more light beams.

[0034] In some embodiments, the method may include rotating and / or polarizing a first portion of a received input optical signal and / or a second portion of a received input optical signal relative to a first optical beam or a second optical beam generated at a PCSEL. In some embodiments, analog-to-digital conversion may be performed in a signal processing unit. In some embodiments, digital signal processing may be performed in a signal processing unit. In some embodiments, the method may include digitizing an electrical signal. In some embodiments, the method may include extracting information from the input light and representing the information in the electrical signal.

[0035] Reference Figure 4 , shows a coherent optical receiver 1 that receives an input signal x(t) and generates an output signal y[n]. The coherent optical receiver 1 may include a polarization beam splitter (PBS) 50, a local oscillator 10, a beam splitter (BS) 40, an X-hybrid receiver 20, a Y-hybrid receiver 30, and a signal processing unit 60. The input signal x(t) may be an information-bearing signal.

[0036] For example, x(t) can be amplitude modulated, frequency modulated, or phase modulated. For example, x(t) can be a quadrature amplitude modulated signal (QAM) or a phase shift keyed modulated signal (PSK). The output signal y[n] can be the output signal of a coherent optical receiver 1. The coherent optical receiver 1 can be used in a fiber-optic communication system to detect an information signal from modulated light. The main function of the coherent optical receiver can be to convert the phase and amplitude information of the input signal x(t) into an electrical form y[n] that can be processed by electronic equipment. For example, the coherent optical receiver 1 can be used for high-speed data transmission.

[0037] PBS 50 is operable to split an input signal x(t) into an X optical signal component 2 and a Y optical signal component 4. For example, the X optical signal component 2 can also be referred to as a horizontally polarized component. For example, the Y optical signal component 4 can also be referred to as a vertically polarized component. The X optical signal component 2 can be orthogonal to the Y optical signal component 4, meaning that the X optical signal component 2 and the Y optical signal component 4 are polarized differently. Generally, the X optical signal component 2 and the Y optical signal component 4 can be orthogonal, but the actual orientation of these polarizations can vary. Therefore, the terms horizontal and vertical are used relative to each other. PBS 50 is operable to manage the polarization of the input signal x(t) so that its output signals 2 and 4 match the polarization of the local oscillator signals 6 and 8 for mixing in the X hybrid receiver 20 and / or the Y hybrid receiver 30. PBS 50 can generate an output signal that may include a rotated portion of the input signal to match the polarization of the signal from the local oscillator in the mixing mixer.

[0038] The LO 10 can be operated to generate a light beam of a specific frequency that can be used to mix with the input signal x(t). The frequency of the local oscillator 10 can be close to or the same as the frequency of the input signal x(t). The LO 10 can be a laser.

[0039] A beam splitter (BS) 40 is operable to receive the optical signal 18 and generate a plurality of output signals 6, 8, each of which includes a portion of the power of the received optical signal. According to various embodiments of the present disclosure, the BS 40 can receive the local oscillator signal 18 and split it into the plurality of output signals 6, 8 that provide LO signals to the X-hybrid receiver 20, the Y-hybrid receiver 30.

[0040] The X-hybrid receiver 20 and the Y-hybrid receiver 30 can operate to mix the X-signal optical component 2 and the Y-signal optical component 4 with light from the local oscillator laser 6 and the local oscillator laser 8. This process can generate interference between the X-signal optical component 2 and the Y-signal optical component 4 and the local oscillator light 6 and the local oscillator light 8, which can be used to decode the phase and amplitude information of the X-signal optical component 2 and the Y-signal optical component 4. For example, the X-hybrid receiver 20 can receive the X-signal optical component 2 and the local oscillator signal 6 and generate / detect the in-phase component 10 of the X-signal optical component 2 and the quadrature component 12 of the X-signal optical component 2. Similarly, the Y-hybrid receiver 30 can receive the Y-signal optical component 4 and the local oscillator signal 8 and generate / detect the in-phase component 14 of the X-signal optical component 2 and the quadrature component 16 of the X-signal optical component 4.

[0041] The signal processing unit 60 is operable to receive the optical light signals 10, 12, 14, and 16 and convert them into electrical signals. The signal processing unit 60 may include photodetectors. These may be used to convert the mixed optical signals into electrical signals. The output electrical signals of the signal processing unit 60 may be discrete and / or analog. For example, y[n] may be digital and processed. Accordingly, for example, the signal processing unit 60 may include an analog-to-digital converter and a digital signal processor. The signal processing unit 60 may typically include a digital signal processor, which may be used to compensate for impairments such as chromatic dispersion and polarization mode dispersion.

[0042] Figure 5 An exemplary coherent optical receiver 1A according to various embodiments of the present disclosure is shown. Figure 5 A coherent optical receiver 1A is shown with an input signal x(t) and an output signal y[n]. Figure 5 Also shown are PBS 50, as well as X-hybrid receiver 20, Y-hybrid receiver 30, signal processing unit 60, PCSEL / PCSEL-based local oscillator 17, and polarizer / rotator 11. The functionality of coherent optical receiver 1A may be similar to that of coherent optical receiver 1. However, LO 10 and BS 40 may be replaced by PCSEL-based local oscillator 17 and polarizer / rotator 11.

[0043] The PCSEL 17 may be a photonic crystal surface emitting laser (PCSEL) capable of operating as a local oscillator. A PCSEL is a type of semiconductor laser that combines the features of a photonic crystal laser (PCL) and a vertical cavity surface emitting laser (VCSEL). The PCSEL combines many of the advantages of both PCLs and VCSELs, achieving high efficiency, high power output, good beam quality, and a compact form factor. The PCSEL 17 may be specifically designed to emit the same light from both the top and bottom surfaces of the semiconductor. Accordingly, the PCSEL 17 can emit in two physical directions. For this reason, various embodiments of the present disclosure may eliminate the need for a beam splitter (e.g., BS 40) to generate two beams. The PCSEL 17 can thus generate a local oscillator optical signal and transmit it in two physical directions 6 and 8, which can be coupled to the X-hybrid receiver 20 and the Y-hybrid receiver 30. In some cases, as shown in exemplary polarizer / rotator 11, it may be desirable to polarize or rotate one or more outputs of PCSEL 17 to match the polarization of X signal light component 2 and / or Y signal light component 4. One advantage of this configuration is that it can be implemented in a smaller form factor than a conventional beam splitter (e.g., BS 40). Conventional beam splitters (e.g., BS 40) operate to split a light beam into two separate beams. In many cases, the beam splitter can include a partially reflective glass substrate with a desired reflection to transmission ratio, i.e., it can partially act as a mirror. When a light beam strikes the surface of the beam splitter, a portion of the light can be reflected at a typically 90° angle, while the remaining portion can be transmitted through the glass. Because embodiments can include one or more mirrors in addition to the light source, a conventional beam splitter can be physically larger than a light source that directly generates multiple light beams.

[0044] The present disclosure includes reference to certain examples, however, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present disclosure. In addition, modifications may be made to the disclosed examples without departing from the scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the disclosed examples, and the present disclosure will include all examples that fall within the scope of the appended claims.

Claims

1. A coherent optical receiver, comprising: A PCSEL generates a first light beam and a second light beam, wherein a physical emission direction of the first light beam forms an angle of 180 degrees plus / minus 10 degrees with a physical emission direction of the second light beam; a first hybrid receiver that receives a first portion of an input optical signal to the coherent optical receiver and the first optical beam as a local oscillator signal and generates one or more first optical hybrid receiver output signals; a second hybrid receiver receiving a second portion of the input optical signal to the coherent optical receiver and the second optical beam as a local oscillator signal, and generating one or more second optical hybrid receiver output signals; and A signal processing unit is operable to convert the first optical hybrid receiver output signal and / or the second optical hybrid receiver output signal into an electrical signal.

2. The coherent optical receiver according to claim 1, wherein: The received first light beam is rotated and / or polarized relative to the input light signal.

3. The coherent optical receiver according to claim 1, wherein: The received second light beam is rotated and / or polarized relative to the input light signal.

4. The coherent optical receiver according to claim 1, wherein: The angle is 180 degrees.

5. The coherent optical receiver according to claim 1, wherein: The coherent optical receiver includes one or more polarizers and / or rotators. The coherent optical receiver according to claim 1 , wherein: Either or both of the first portion of the received input optical signal and the second portion of the received input optical signal are rotated and / or polarized relative to the first light beam or the second light beam generated at the PCSEL.

7. The coherent optical receiver according to claim 1, wherein: The signal processing unit includes one or more analog-to-digital converters.

8. The coherent optical receiver according to claim 1, wherein: The signal processing unit includes a digital signal processor.

9. The coherent optical receiver according to claim 1, wherein: The electrical signal is digitized.

10. The coherent optical receiver according to claim 1, wherein: The electrical signal represents information extracted from the input light.

11. A method for coherent optical reception, the method comprising: generating a first light beam and a second light beam using a PCSEL, wherein a physical emission direction of the first light beam is at an angle of 180 degrees plus / minus 10 degrees to a physical emission direction of the second light beam; receiving, at a first hybrid receiver, a first portion of an input optical signal and the first optical beam as a local oscillator signal, and generating one or more first optical hybrid receiver output signals; receiving, at a second hybrid receiver, a second portion of the input optical signal and the second optical beam as a local oscillator signal, and generating one or more second optical hybrid receiver output signals; and The first optical hybrid receiver output signal and / or the second optical hybrid receiver output signal are converted into electrical signals in a signal processing unit.

12. The method according to claim 11, comprising: The received first light beam is rotated and / or polarized relative to the input light signal.

13. The method according to claim 11, comprising: The received second light beam is rotated and / or polarized relative to the input light signal.

14. The method according to claim 11, wherein The angle is 180 degrees.

15. The method according to claim 11, comprising: Polarize and / or rotate one or more light beams.

16. The method according to claim 11, comprising: A first portion of the received input optical signal and / or a second portion of the received input optical signal is rotated and / or polarized relative to the first optical beam or the second optical beam generated at the PCSEL.

17. The method according to claim 11, comprising: Analog-to-digital conversion in the signal processing unit.

18. The method according to claim 11, comprising: Digital signal processing in the signal processing unit.

19. The method according to claim 11, comprising: The electrical signal is digitized.

20. The method according to claim 11, comprising: Information is extracted from the input light and represented in the electrical signal.

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