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R I Killey - One of the best experts on this subject based on the ideXlab platform.
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comparison of low complexity coherent receivers for udwdm pons lambda to the user
Journal of Lightwave Technology, 2018Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, E C Thomse, P AyvelAbstract:It is predicted that demand in future optical access networks will reach multigigabit/s per user. However, the limited performance of the direct detection receiver technology currently used in the optical network units at the customers’ premises restricts data rates per user. Therefore, the concept of coherent-enabled access networks has attracted attention in recent years, as this technology offers high receiver sensitivity, Inherent Frequency selectivity, and linear field detection enabling the full compensation of linear channel impairments. However, the complexity of conventional (dual-polarization digital) coherent receivers has so far prevented their introduction into access networks. Thus, to exploit the benefits of coherent technology in access networks, low complexity coherent receivers, suitable for implementation in ONUs, are needed. In this paper, the recently proposed low complexity coherent (i.e., polarization-independent Alamouti-coding heterodyne) receiver is, for the first time, compared in terms of its minimum receiver sensitivity with five previously reported receiver designs, including a detailed discussion on their advantages and limitations. It is shown that, of all the configurations considered, the Alamouti-coding based receiver approach allows the lowest number of photons per bit (PPB) transmitted (with a lower bound of 15.5 PPB in an ideal implementation of the system), while requiring the lowest optical receiver hardware complexity (in terms of the optical component count). It also exhibits comparable complexity to the currently deployed direct-detection receivers, which typically require over 1000 PPB. Finally, a comparison of experimentally achieved receiver sensitivities and transmission distances using these receivers is presented. The highest spectral efficiency and longest transmission distance at the highest bit rate (10 Gb/s) was reported using the Alamouti-coding receiver, which is also the only one, to date, to have been demonstrated in a full system bidirectional transmission.
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comparison of low complexity coherent receivers for udwdm pons lambda to the user
arXiv: Signal Processing, 2017Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, E C Thomse, P AyvelAbstract:It is predicted that demand in optical access networks will reach multi-Gb/s per user. However, the limited performance of the direct detection receiver technology currently used in the optical network units at the customers' premises restricts data rates/user. Therefore, the concept of coherent-enabled access networks has attracted attention in recent years, as this technology offers high receiver sensitivity, Inherent Frequency selectivity, and linear field detection enabling the full compensation of linear channel impairments. However, the complexity of conventional (dual-polarisation digital) coherent receivers has so far prevented their introduction into access networks. Thus, to exploit the benefits of coherent technology in the ONUs, low complexity coherent receivers, suitable for implementation in ONUs, are needed. In this paper, the recently proposed low complexity coherent (i.e., polarisation-independent Alamouti-coding heterodyne) receiver is, for the first time, compared in terms of its minimum receiver sensitivity with five previously reported receiver designs, including a detailed discussion on their advantages and limitations. It is shown that the Alamouti-coding based receiver approach allows the lowest number of photons per bit (PPB) transmitted (with a lower bound of 15.5 PPB in an ideal system simulations) whilst requiring the lowest optical receiver hardware complexity. It also exhibits comparable complexity to the currently deployed direct-detection receivers, which typically require >1000 PPB. Finally, a comparison of experimentally achieved receiver sensitivities and transmission distances using these receivers is presented. The highest spectral efficiency and longest transmission distance at the highest bit rate reported using the Alamouti-coding receiver, which is also the only one, to date, to have been demonstrated in a full system bidirectional transmission.
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Polarization-insensitive single-balanced photodiode coherent receiver for long-reach WDM-PONs
2016Co-Authors: Erkilinç Ms, R I Killey, Lavery D, Shi K, Bc Thomsen, Bayvel P, Sj SavoryAbstract:In an access network based on a passive optical network architecture, coherent detection is attractive since it allows for high receiver sensitivity coupled with Inherent Frequency selectivity. Nevertheless, solutions employed in core networks are prohibitively complex and costly, requiring the optical complexity of the coherent receivers to be reduced to make them feasible for access networks. For monolithic integration, a key challenge is posed by the polarization beam splitter (PBS). If, however, the PBS is removed, the receiver needs to be redesigned to be insensitive to the incoming polarization state of the received signal. In this paper, we experimentally demonstrate a polarization-insensitive (i.e., polarization-independent) coherent receiver for the optical network unit in passive optical networks (PONs). The receiver consists of only a 3-dB coupler and a single-balanced photodiode such that the complexity is comparable to a direct detection receiver. The proposed cost-effective coherent receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection. To verify the technique, the Alamouti-coded orthogonal Frequency division multiplexing (OFDM) signal is rotated over the full Poincaré sphere. Compared to the dual-polarization-OFDM signal operating at a net bit rate of 10 Gb/s per polarization (a gross bit rate of 10.7 Gb/s including a 7% FEC overhead), only a 0.6 dB sensitivity degradation is observed. The sensitivity at the FEC threshold, assumed to be 4 × 10-3, is measured to be -41.5 dBm (56 photons-per-bit) on a 25-GHz grid. Following this, different channel spacings are investigated and the signal is transmitted over 80 km of standard single-mode fiber in a long-reach wavelength division multiplexed PON system. The loss budgets are found to be 43.0 and 42.8 dB for 50- and 25-GHz grids, respectively
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polarization insensitive single balanced photodiode coherent receiver for long reach wdm pon s
Journal of Lightwave Technology, 2016Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, Benn C Thomsen, P Bayvel, Seb J. SavoryAbstract:In an access network based on a passive optical network architecture, coherent detection is attractive since it allows for high receiver sensitivity coupled with Inherent Frequency selectivity. Nevertheless, solutions employed in core networks are prohibitively complex and costly, requiring the optical complexity of the coherent receivers to be reduced to make them feasible for access networks. For monolithic integration, a key challenge is posed by the polarization beam splitter (PBS). If, however, the PBS is removed, the receiver needs to be redesigned to be insensitive to the incoming polarization state of the received signal. In this paper, we experimentally demonstrate a polarization-insensitive (i.e., polarization-independent) coherent receiver for the optical network unit in passive optical networks (PONs). The receiver consists of only a 3-dB coupler and a single-balanced photodiode such that the complexity is comparable to a direct detection receiver. The proposed cost-effective coherent receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection. To verify the technique, the Alamouti-coded orthogonal Frequency division multiplexing (OFDM) signal is rotated over the full Poincare sphere. Compared to the dual-polarization-OFDM signal operating at a net bit rate of 10 Gb/s per polarization (a gross bit rate of 10.7 Gb/s including a 7% FEC overhead), only a 0.6 dB sensitivity degradation is observed. The sensitivity at the FEC threshold, assumed to be $4\times 10^{-3}$ , is measured to be $-$ 41.5 dBm (56 photons-per-bit) on a 25-GHz grid. Following this, different channel spacings are investigated and the signal is transmitted over 80 km of standard single-mode fiber in a long-reach wavelength division multiplexed PON system. The loss budgets are found to be 43.0 and 42.8 dB for 50- and 25-GHz grids, respectively.
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Polarization-insensitive single-balanced photodiode coherent receiver for long-reach WDM-PONs
2016Co-Authors: Erkilinç Ms, R I Killey, Lavery D, Shi K, Bc Thomsen, Bayvel P, Sj SavoryAbstract:© 2015 IEEE. In an access network based on a passive optical network architecture, coherent detection is attractive since it allows for high receiver sensitivity coupled with Inherent Frequency selectivity. Nevertheless, solutions employed in core networks are prohibitively complex and costly, requiring the optical complexity of the coherent receivers to be reduced to make them feasible for access networks. For monolithic integration, a key challenge is posed by the polarization beam splitter (PBS). If, however, the PBS is removed, the receiver needs to be redesigned to be insensitive to the incoming polarization state of the received signal. In this paper, we experimentally demonstrate a polarization-insensitive (i.e., polarization-independent) coherent receiver for the optical network unit in passive optical networks (PONs). The receiver consists of only a 3-dB coupler and a single-balanced photodiode such that the complexity is comparable to a direct detection receiver. The proposed cost-effective coherent receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection. To verify the technique, the Alamouti-coded orthogonal Frequency division multiplexing (OFDM) signal is rotated over the full Poincaré sphere. Compared to the dual-polarization-OFDM signal operating at a net bit rate of 10 Gb/s per polarization (a gross bit rate of 10.7 Gb/s including a 7% FEC overhead), only a 0.6 dB sensitivity degradation is observed. The sensitivity at the FEC threshold, assumed to be 4 × 10-3, is measured to be -41.5 dBm (56 photons-per-bit) on a 25-GHz grid. Following this, different channel spacings are investigated and the signal is transmitted over 80 km of standard single-mode fiber in a long-reach wavelength division multiplexed PON system. The loss budgets are found to be 43.0 and 42.8 dB for 50- and 25-GHz grids, respectively
Seze M Erkilinc - One of the best experts on this subject based on the ideXlab platform.
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comparison of low complexity coherent receivers for udwdm pons lambda to the user
Journal of Lightwave Technology, 2018Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, E C Thomse, P AyvelAbstract:It is predicted that demand in future optical access networks will reach multigigabit/s per user. However, the limited performance of the direct detection receiver technology currently used in the optical network units at the customers’ premises restricts data rates per user. Therefore, the concept of coherent-enabled access networks has attracted attention in recent years, as this technology offers high receiver sensitivity, Inherent Frequency selectivity, and linear field detection enabling the full compensation of linear channel impairments. However, the complexity of conventional (dual-polarization digital) coherent receivers has so far prevented their introduction into access networks. Thus, to exploit the benefits of coherent technology in access networks, low complexity coherent receivers, suitable for implementation in ONUs, are needed. In this paper, the recently proposed low complexity coherent (i.e., polarization-independent Alamouti-coding heterodyne) receiver is, for the first time, compared in terms of its minimum receiver sensitivity with five previously reported receiver designs, including a detailed discussion on their advantages and limitations. It is shown that, of all the configurations considered, the Alamouti-coding based receiver approach allows the lowest number of photons per bit (PPB) transmitted (with a lower bound of 15.5 PPB in an ideal implementation of the system), while requiring the lowest optical receiver hardware complexity (in terms of the optical component count). It also exhibits comparable complexity to the currently deployed direct-detection receivers, which typically require over 1000 PPB. Finally, a comparison of experimentally achieved receiver sensitivities and transmission distances using these receivers is presented. The highest spectral efficiency and longest transmission distance at the highest bit rate (10 Gb/s) was reported using the Alamouti-coding receiver, which is also the only one, to date, to have been demonstrated in a full system bidirectional transmission.
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comparison of low complexity coherent receivers for udwdm pons lambda to the user
arXiv: Signal Processing, 2017Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, E C Thomse, P AyvelAbstract:It is predicted that demand in optical access networks will reach multi-Gb/s per user. However, the limited performance of the direct detection receiver technology currently used in the optical network units at the customers' premises restricts data rates/user. Therefore, the concept of coherent-enabled access networks has attracted attention in recent years, as this technology offers high receiver sensitivity, Inherent Frequency selectivity, and linear field detection enabling the full compensation of linear channel impairments. However, the complexity of conventional (dual-polarisation digital) coherent receivers has so far prevented their introduction into access networks. Thus, to exploit the benefits of coherent technology in the ONUs, low complexity coherent receivers, suitable for implementation in ONUs, are needed. In this paper, the recently proposed low complexity coherent (i.e., polarisation-independent Alamouti-coding heterodyne) receiver is, for the first time, compared in terms of its minimum receiver sensitivity with five previously reported receiver designs, including a detailed discussion on their advantages and limitations. It is shown that the Alamouti-coding based receiver approach allows the lowest number of photons per bit (PPB) transmitted (with a lower bound of 15.5 PPB in an ideal system simulations) whilst requiring the lowest optical receiver hardware complexity. It also exhibits comparable complexity to the currently deployed direct-detection receivers, which typically require >1000 PPB. Finally, a comparison of experimentally achieved receiver sensitivities and transmission distances using these receivers is presented. The highest spectral efficiency and longest transmission distance at the highest bit rate reported using the Alamouti-coding receiver, which is also the only one, to date, to have been demonstrated in a full system bidirectional transmission.
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polarization insensitive single balanced photodiode coherent receiver for long reach wdm pon s
Journal of Lightwave Technology, 2016Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, Benn C Thomsen, P Bayvel, Seb J. SavoryAbstract:In an access network based on a passive optical network architecture, coherent detection is attractive since it allows for high receiver sensitivity coupled with Inherent Frequency selectivity. Nevertheless, solutions employed in core networks are prohibitively complex and costly, requiring the optical complexity of the coherent receivers to be reduced to make them feasible for access networks. For monolithic integration, a key challenge is posed by the polarization beam splitter (PBS). If, however, the PBS is removed, the receiver needs to be redesigned to be insensitive to the incoming polarization state of the received signal. In this paper, we experimentally demonstrate a polarization-insensitive (i.e., polarization-independent) coherent receiver for the optical network unit in passive optical networks (PONs). The receiver consists of only a 3-dB coupler and a single-balanced photodiode such that the complexity is comparable to a direct detection receiver. The proposed cost-effective coherent receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection. To verify the technique, the Alamouti-coded orthogonal Frequency division multiplexing (OFDM) signal is rotated over the full Poincare sphere. Compared to the dual-polarization-OFDM signal operating at a net bit rate of 10 Gb/s per polarization (a gross bit rate of 10.7 Gb/s including a 7% FEC overhead), only a 0.6 dB sensitivity degradation is observed. The sensitivity at the FEC threshold, assumed to be $4\times 10^{-3}$ , is measured to be $-$ 41.5 dBm (56 photons-per-bit) on a 25-GHz grid. Following this, different channel spacings are investigated and the signal is transmitted over 80 km of standard single-mode fiber in a long-reach wavelength division multiplexed PON system. The loss budgets are found to be 43.0 and 42.8 dB for 50- and 25-GHz grids, respectively.
Seb J. Savory - One of the best experts on this subject based on the ideXlab platform.
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polarization insensitive single balanced photodiode coherent receiver for long reach wdm pon s
Journal of Lightwave Technology, 2016Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, Benn C Thomsen, P Bayvel, Seb J. SavoryAbstract:In an access network based on a passive optical network architecture, coherent detection is attractive since it allows for high receiver sensitivity coupled with Inherent Frequency selectivity. Nevertheless, solutions employed in core networks are prohibitively complex and costly, requiring the optical complexity of the coherent receivers to be reduced to make them feasible for access networks. For monolithic integration, a key challenge is posed by the polarization beam splitter (PBS). If, however, the PBS is removed, the receiver needs to be redesigned to be insensitive to the incoming polarization state of the received signal. In this paper, we experimentally demonstrate a polarization-insensitive (i.e., polarization-independent) coherent receiver for the optical network unit in passive optical networks (PONs). The receiver consists of only a 3-dB coupler and a single-balanced photodiode such that the complexity is comparable to a direct detection receiver. The proposed cost-effective coherent receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection. To verify the technique, the Alamouti-coded orthogonal Frequency division multiplexing (OFDM) signal is rotated over the full Poincare sphere. Compared to the dual-polarization-OFDM signal operating at a net bit rate of 10 Gb/s per polarization (a gross bit rate of 10.7 Gb/s including a 7% FEC overhead), only a 0.6 dB sensitivity degradation is observed. The sensitivity at the FEC threshold, assumed to be $4\times 10^{-3}$ , is measured to be $-$ 41.5 dBm (56 photons-per-bit) on a 25-GHz grid. Following this, different channel spacings are investigated and the signal is transmitted over 80 km of standard single-mode fiber in a long-reach wavelength division multiplexed PON system. The loss budgets are found to be 43.0 and 42.8 dB for 50- and 25-GHz grids, respectively.
Domanic Lavery - One of the best experts on this subject based on the ideXlab platform.
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comparison of low complexity coherent receivers for udwdm pons lambda to the user
Journal of Lightwave Technology, 2018Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, E C Thomse, P AyvelAbstract:It is predicted that demand in future optical access networks will reach multigigabit/s per user. However, the limited performance of the direct detection receiver technology currently used in the optical network units at the customers’ premises restricts data rates per user. Therefore, the concept of coherent-enabled access networks has attracted attention in recent years, as this technology offers high receiver sensitivity, Inherent Frequency selectivity, and linear field detection enabling the full compensation of linear channel impairments. However, the complexity of conventional (dual-polarization digital) coherent receivers has so far prevented their introduction into access networks. Thus, to exploit the benefits of coherent technology in access networks, low complexity coherent receivers, suitable for implementation in ONUs, are needed. In this paper, the recently proposed low complexity coherent (i.e., polarization-independent Alamouti-coding heterodyne) receiver is, for the first time, compared in terms of its minimum receiver sensitivity with five previously reported receiver designs, including a detailed discussion on their advantages and limitations. It is shown that, of all the configurations considered, the Alamouti-coding based receiver approach allows the lowest number of photons per bit (PPB) transmitted (with a lower bound of 15.5 PPB in an ideal implementation of the system), while requiring the lowest optical receiver hardware complexity (in terms of the optical component count). It also exhibits comparable complexity to the currently deployed direct-detection receivers, which typically require over 1000 PPB. Finally, a comparison of experimentally achieved receiver sensitivities and transmission distances using these receivers is presented. The highest spectral efficiency and longest transmission distance at the highest bit rate (10 Gb/s) was reported using the Alamouti-coding receiver, which is also the only one, to date, to have been demonstrated in a full system bidirectional transmission.
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comparison of low complexity coherent receivers for udwdm pons lambda to the user
arXiv: Signal Processing, 2017Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, E C Thomse, P AyvelAbstract:It is predicted that demand in optical access networks will reach multi-Gb/s per user. However, the limited performance of the direct detection receiver technology currently used in the optical network units at the customers' premises restricts data rates/user. Therefore, the concept of coherent-enabled access networks has attracted attention in recent years, as this technology offers high receiver sensitivity, Inherent Frequency selectivity, and linear field detection enabling the full compensation of linear channel impairments. However, the complexity of conventional (dual-polarisation digital) coherent receivers has so far prevented their introduction into access networks. Thus, to exploit the benefits of coherent technology in the ONUs, low complexity coherent receivers, suitable for implementation in ONUs, are needed. In this paper, the recently proposed low complexity coherent (i.e., polarisation-independent Alamouti-coding heterodyne) receiver is, for the first time, compared in terms of its minimum receiver sensitivity with five previously reported receiver designs, including a detailed discussion on their advantages and limitations. It is shown that the Alamouti-coding based receiver approach allows the lowest number of photons per bit (PPB) transmitted (with a lower bound of 15.5 PPB in an ideal system simulations) whilst requiring the lowest optical receiver hardware complexity. It also exhibits comparable complexity to the currently deployed direct-detection receivers, which typically require >1000 PPB. Finally, a comparison of experimentally achieved receiver sensitivities and transmission distances using these receivers is presented. The highest spectral efficiency and longest transmission distance at the highest bit rate reported using the Alamouti-coding receiver, which is also the only one, to date, to have been demonstrated in a full system bidirectional transmission.
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polarization insensitive single balanced photodiode coherent receiver for long reach wdm pon s
Journal of Lightwave Technology, 2016Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, Benn C Thomsen, P Bayvel, Seb J. SavoryAbstract:In an access network based on a passive optical network architecture, coherent detection is attractive since it allows for high receiver sensitivity coupled with Inherent Frequency selectivity. Nevertheless, solutions employed in core networks are prohibitively complex and costly, requiring the optical complexity of the coherent receivers to be reduced to make them feasible for access networks. For monolithic integration, a key challenge is posed by the polarization beam splitter (PBS). If, however, the PBS is removed, the receiver needs to be redesigned to be insensitive to the incoming polarization state of the received signal. In this paper, we experimentally demonstrate a polarization-insensitive (i.e., polarization-independent) coherent receiver for the optical network unit in passive optical networks (PONs). The receiver consists of only a 3-dB coupler and a single-balanced photodiode such that the complexity is comparable to a direct detection receiver. The proposed cost-effective coherent receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection. To verify the technique, the Alamouti-coded orthogonal Frequency division multiplexing (OFDM) signal is rotated over the full Poincare sphere. Compared to the dual-polarization-OFDM signal operating at a net bit rate of 10 Gb/s per polarization (a gross bit rate of 10.7 Gb/s including a 7% FEC overhead), only a 0.6 dB sensitivity degradation is observed. The sensitivity at the FEC threshold, assumed to be $4\times 10^{-3}$ , is measured to be $-$ 41.5 dBm (56 photons-per-bit) on a 25-GHz grid. Following this, different channel spacings are investigated and the signal is transmitted over 80 km of standard single-mode fiber in a long-reach wavelength division multiplexed PON system. The loss budgets are found to be 43.0 and 42.8 dB for 50- and 25-GHz grids, respectively.
Kai Shi - One of the best experts on this subject based on the ideXlab platform.
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comparison of low complexity coherent receivers for udwdm pons lambda to the user
Journal of Lightwave Technology, 2018Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, E C Thomse, P AyvelAbstract:It is predicted that demand in future optical access networks will reach multigigabit/s per user. However, the limited performance of the direct detection receiver technology currently used in the optical network units at the customers’ premises restricts data rates per user. Therefore, the concept of coherent-enabled access networks has attracted attention in recent years, as this technology offers high receiver sensitivity, Inherent Frequency selectivity, and linear field detection enabling the full compensation of linear channel impairments. However, the complexity of conventional (dual-polarization digital) coherent receivers has so far prevented their introduction into access networks. Thus, to exploit the benefits of coherent technology in access networks, low complexity coherent receivers, suitable for implementation in ONUs, are needed. In this paper, the recently proposed low complexity coherent (i.e., polarization-independent Alamouti-coding heterodyne) receiver is, for the first time, compared in terms of its minimum receiver sensitivity with five previously reported receiver designs, including a detailed discussion on their advantages and limitations. It is shown that, of all the configurations considered, the Alamouti-coding based receiver approach allows the lowest number of photons per bit (PPB) transmitted (with a lower bound of 15.5 PPB in an ideal implementation of the system), while requiring the lowest optical receiver hardware complexity (in terms of the optical component count). It also exhibits comparable complexity to the currently deployed direct-detection receivers, which typically require over 1000 PPB. Finally, a comparison of experimentally achieved receiver sensitivities and transmission distances using these receivers is presented. The highest spectral efficiency and longest transmission distance at the highest bit rate (10 Gb/s) was reported using the Alamouti-coding receiver, which is also the only one, to date, to have been demonstrated in a full system bidirectional transmission.
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comparison of low complexity coherent receivers for udwdm pons lambda to the user
arXiv: Signal Processing, 2017Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, E C Thomse, P AyvelAbstract:It is predicted that demand in optical access networks will reach multi-Gb/s per user. However, the limited performance of the direct detection receiver technology currently used in the optical network units at the customers' premises restricts data rates/user. Therefore, the concept of coherent-enabled access networks has attracted attention in recent years, as this technology offers high receiver sensitivity, Inherent Frequency selectivity, and linear field detection enabling the full compensation of linear channel impairments. However, the complexity of conventional (dual-polarisation digital) coherent receivers has so far prevented their introduction into access networks. Thus, to exploit the benefits of coherent technology in the ONUs, low complexity coherent receivers, suitable for implementation in ONUs, are needed. In this paper, the recently proposed low complexity coherent (i.e., polarisation-independent Alamouti-coding heterodyne) receiver is, for the first time, compared in terms of its minimum receiver sensitivity with five previously reported receiver designs, including a detailed discussion on their advantages and limitations. It is shown that the Alamouti-coding based receiver approach allows the lowest number of photons per bit (PPB) transmitted (with a lower bound of 15.5 PPB in an ideal system simulations) whilst requiring the lowest optical receiver hardware complexity. It also exhibits comparable complexity to the currently deployed direct-detection receivers, which typically require >1000 PPB. Finally, a comparison of experimentally achieved receiver sensitivities and transmission distances using these receivers is presented. The highest spectral efficiency and longest transmission distance at the highest bit rate reported using the Alamouti-coding receiver, which is also the only one, to date, to have been demonstrated in a full system bidirectional transmission.
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polarization insensitive single balanced photodiode coherent receiver for long reach wdm pon s
Journal of Lightwave Technology, 2016Co-Authors: Seze M Erkilinc, Domanic Lavery, R I Killey, Kai Shi, Benn C Thomsen, P Bayvel, Seb J. SavoryAbstract:In an access network based on a passive optical network architecture, coherent detection is attractive since it allows for high receiver sensitivity coupled with Inherent Frequency selectivity. Nevertheless, solutions employed in core networks are prohibitively complex and costly, requiring the optical complexity of the coherent receivers to be reduced to make them feasible for access networks. For monolithic integration, a key challenge is posed by the polarization beam splitter (PBS). If, however, the PBS is removed, the receiver needs to be redesigned to be insensitive to the incoming polarization state of the received signal. In this paper, we experimentally demonstrate a polarization-insensitive (i.e., polarization-independent) coherent receiver for the optical network unit in passive optical networks (PONs). The receiver consists of only a 3-dB coupler and a single-balanced photodiode such that the complexity is comparable to a direct detection receiver. The proposed cost-effective coherent receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection. To verify the technique, the Alamouti-coded orthogonal Frequency division multiplexing (OFDM) signal is rotated over the full Poincare sphere. Compared to the dual-polarization-OFDM signal operating at a net bit rate of 10 Gb/s per polarization (a gross bit rate of 10.7 Gb/s including a 7% FEC overhead), only a 0.6 dB sensitivity degradation is observed. The sensitivity at the FEC threshold, assumed to be $4\times 10^{-3}$ , is measured to be $-$ 41.5 dBm (56 photons-per-bit) on a 25-GHz grid. Following this, different channel spacings are investigated and the signal is transmitted over 80 km of standard single-mode fiber in a long-reach wavelength division multiplexed PON system. The loss budgets are found to be 43.0 and 42.8 dB for 50- and 25-GHz grids, respectively.