Km Of Standard Single-mode Fiber Research Articles

Analysis of a photonic integrated circuit for passive optical network for 5G NR.

This work presents the performance analysis of a passive optical network (PON) proposal with photonic integrated circuits (PIC). The PON architecture was simulated on MATLAB, focusing on the main functionalities of the optical line terminal, distribution network, and network unity regarded its effects on the physical layer. We show a simulated PIC, implemented on MATLAB through its analytic transfer function equation, used to implement orthogonal frequency division multiplexing in the optical domain to enhance the current optical networks for the 5G New-Radio (NR) scenario. We analyzed the OOK and optical PAM4 compared with phase modulation formats such as the DPSK and DQPSK. All modulation formats can be directly detected for the case in the study, simplifying the reception. Consequently, this work achieved a maximum symmetric transmission capacity of 1.2Tbps over 90km of standard single-mode fiber with 128 carriers, 64 carriers for downstream and 64 for upstream, obtained from an optical frequency comb with 0.3dB flatness. We concluded that phase modulation formats associated with PIC could increase PON capability and push further our current scenario to the 5G new era.

Impact of the input OSNR on data-driven optical fiber channel modeling

The data-driven approach is promising for computationally efficient modeling of optical fiber channels. Here, for the first time to our knowledge, we investigate the impact of the input optical signal-to-noise ratio (OSNR) on the accuracy of data-driven modeling for optical fiber channels, based on a conditional generative adversarial network (cGAN). Initially, considering a single span of 80 km of standard single mode fiber (SSMF), we vary the launched optical power for the ease of emulating both linear and nonlinear transmission scenarios. When the input OSNR of a root raised cosine (RRC)-shaped 16 quadrature amplitude modulation signal with a roll-off factor of 0.1 varies, we identify that there occurs an OSNR threshold for accurately modeling a single span of 80 km of SSMF in order to reach the normalized mean square error of less than 0.02 in relevance to the traditional split-step Fourier method. The OSNR thresholds are 19 dB and 21 dB, respectively, under scenarios of linear and nonlinear transmissions. Moreover, we verify that the OSNR threshold of accurate modeling is insensitive to both the modulation format and the RRC shaping of the input signal. Furthermore, we find that the cascaded use of cGAN well-trained for the single SSMF span is capable of modeling the multiple-span SSMF transmission in the case that the input OSNR threshold of 22.6 dB is satisfied. We believe that the identification of the OSNR threshold for data-driven optical fiber channel modeling is useful for the accurate and efficient emulation of long-haul fiber optical transmission.

Nonlinearity aware bisection-based sphere shaping for optical digital subcarrier multiplexing systems.

In this paper, a nonlinearity-tolerant sphere shaping is proposed based on the parallel bisection structure. Compared to enumerative sphere shaping (ESS), the bisection-based sphere shaping (BS-SS) can achieve a lower average energy and rate loss at the same blocklength by selecting all preferential sequences. The nonlinearity-tolerant BS-SS (BS-SS-NLI) can mitigate the fiber nonlinearity by reducing the energy variation, which is demonstrated in the simulations with probabilistically shaped, single channel, dual-polarization 64-ary quadrature amplitude modulation (DP-64QAM) for a multi-span long-haul transmission over 2500 km of standard single-mode fiber (SSMF) applying digital subcarrier multiplexing (SCM), comparing with recent literature kurtosis-limited ESS (K-ESS) and list-encoding constant composition distribution matching (L-CCDM). The BS-SS-NLI can provide 0.25 dB effective signal-to-noise ratio (SNR) gain over ESS and 0.39 dB gain over L-CCDM. The achievable information rate (AIR) can be improved ∼0.1 bits/4D-symbol by BS-SS-NLI over ESS.

Design and Analysis of an O+E-Band Hybrid Optical Amplifier for CWDM Systems.

Broadband amplification in the O+E-band is very desirable nowadays as a way of coping with increasing bandwidth demands. The main issue with doped fiber amplifiers working in this band such as the bismuth-doped fiber amplifier is that they are costly and not widely available. Therefore, a wideband and flat-gain hybrid optical amplifier (HOA) covering the O+E-band based on a parallel combination of a praseodymium-doped fiber amplifier (PDFA) and a semiconductor optical amplifier (SOA) is proposed and demonstrated through numerical simulations. The praseodymium-doped fiber (PDF) core is pumped using a laser diode with a power of 500 mW that is centered at a wavelength of 1030 nm. The SOA is driven by an injection current of 60 mA. The performance of the HOA is analyzed by the optimization of various parameters such as the PDF length, Pr3+ concentration, pump wavelength, and injection current. A flat average gain of 24 dB with a flatness of 1 dB and an output power of 9.6 dBm is observed over a wavelength range of 1270-1450 nm. The noise figure (NF) varies from a minimum of 4 dB to a maximum of 5.9 dB for a signal power of 0 dBm. A gain reduction of around 4 dB is observed for an O-band signal at a wavelength of 1290 nm by considering the up-conversion effect. The transmission performance of the designed HOA as a pre-amplifier is evaluated based on the bit-error rate (BER) analysis for a coarse wavelength-division multiplexing (CWDM) system of eight on-off keying (OOK)-modulated channels, each having a data rate of 10 Gbps. An error-free transmission over 60 km of standard single-mode fiber (SMF) is achieved for different data rates of 5 Gbps, 7.5 Gbps, and 10 Gbps.

Silicon photonic modulators for net 300 Gbps/λ IM/DD and Net 1 Tbps/λ coherent transmission using All-Electronic equalization

In this manuscript we describe the design and transmission system performance of two traveling wave Silicon Photonic (SiP) modulators: i) an O-band, single phase shifter based Mach-Zehnder Modulator (MZM); and ii) a C-band, two phase shifter based Inphase/Quadrature Modulator (IQM). For the O-band device, we demonstrate the transmission of 134 Gbaud PAM-4 (net 250 Gbps) at a BER below the 6.7 % overhead (OH) hard-decision forward error correction (HD-FEC) threshold of 3.8 × 10−3 over 2 km of standard single-mode fiber (SSMF), and we transmit 115 Gbaud PAM-8 (net 288 Gbps) and net 305 Gbps probabilistically shaped (PS)-PAM-8 assuming the 19.02 % overhead soft-decision (SD) FEC. For the C-band device and employing dual-polarization (DP) emulation, we transmit 105 Gbaud DP-64QAM over 80 km below the 25 % overhead SD- FEC BER threshold of 5 × 10−2; featuring the first demonstration of net 1 Tbps transmission using an all-silicon IQM.

Independent dual-single sideband lower-IF RF receiver based on a single photodetector.

The two sidebands of the independent dual-single-sideband (dual-SSB) signal can carry different information, which achieves higher spectral efficiency and system capacity. However, the receiver divides the signal into two channels, so a pair of optical bandpass filters (OBPFs) and photodetectors (PDs) are generally required to select and detect an independent dual-SSB signal. To reduce the complexity and cost of the receiver, we propose an independent dual-SSB lower intermediate frequency (IF) radio frequency (RF) signal detection scheme based on a single PD combined with conventional digital signal processing (DSP). A theoretical analysis is presented and validated by a simulation. The left sideband (LSB) and the right sideband (RSB) are quadrature phase-shift keying (QPSK) modulated. After 50-km standard single-mode fiber (SSMF) transmission, a 10-Gbps 16QAM signal is synthesized from 2 × 5-Gbps dual-SSB QPSK and the independent dual-SSB is extracted by DSP. The bit error rate (BER) of the dual-SSB (LSB and RSB) is below the hard-decision forward-error-correction (HD-FEC) threshold of 3.8 × 10-3.

Security enhancement of a W-band millimeter-wave signal based on 3D Hilbert scrambling and diffusion.

A physical layer enhancement scheme of the W-band millimeter-wave signal based on chaotic grouping and segmentation encryption, 3D Hilbert scrambling, and diffusion is proposed in this paper. Chaotic grouping and segmentation bit-level encryption can enhance the randomness of data and enlarge the key space. 3D Hilbert scrambling and chaotic diffusion are performed in symbol and subcarrier domains. The correlation of data can be effectively reduced after encryption. The analyses show that the key space of the proposed scheme can reach ∼10152. The encrypted W-band millimeter-wave signal can be successfully transmitted in the orthogonal frequency division multiplexing (OFDM) radio-over-fiber (RoF) system of 50-km standard single-mode fiber (SSMF) and 3-m wireless channel, and the experimental results demonstrate that the proposed scheme can enhance the security of the system without negatively affecting transmission performance.

Optical Generation and Transmission of mmWave Signals in 5G ERA: Experimental Evaluation Paradigm

We demonstrate the generation, of a mmWave signal via the injection of an optical frequency comb (OFC) into an integrated tunable dual distributed Bragg reflector (DBR) laser as well as the fiber transmission and the processing of this signal by an optical beamforming network (OBFN). The dual DBR laser is based on a hybrid indium phosphide (InP) – polymer photonic integrated circuit (PIC). Two different cases have been examined in which the microwave signal is centered around 39 GHz and 60 GHz respectively, carrying quadrature amplitude modulation (QAM) formats at 0.5 Gbaud. In this proof-of-concept scenario, the OBFN consists of two optical paths, where the relative true time delay is induced by an optical delay line (ODL). Extensive comparison between the back-to-back (B2B) case and scenarios with transmission over 25 km of standard single-mode fiber (SSMF) has been made using the error-vector magnitude (EVM) and the bit-error ratio (BER) as evaluation criteria. In all cases, error-free transmission was suggested for all QPSK signals, whereas a worst-case EVM of 11.8% was observed for 16-QAM transmission, successfully showcasing the concept’s potential. The generated microwave signal’s frequency can be set arbitrarily high, provided that high-speed photodetection equipment is available for the detection and down-conversion of the signal. Extension to higher antenna elements (AEs) numbers is straight-forward, relying only on the number of available photodetectors.

30-GBaud DP 16-QAM transmission in the E-band enabled by bismuth-doped fiber amplifiers.

We report the transmission of five 30-GBaud dual polarization 16-QAM signals over 160 km of standard single-mode fiber in the E-band (1410-1460 nm). The transmission line consists of two 80-km spans and three independent bismuth-doped fiber amplifiers. The developed amplifiers feature a maximum gain of 27.3 dB, 33.8 dB, and 28.3 dB with a minimum noise figure of 4.8 dB, 4.7 dB, and 5.3 dB, respectively. The maximum signal Q2 factor penalty is 4.5 dB, and the overall performance of the system is above the pre-forward-error-correction (FEC) threshold for a 10-15 post-FEC bit error rate. To the best of our knowledge, this is the record experimentally demonstrated transmission length for a coherent detection signal in the E-band.

Design, analysis, and characterization of a compact silicon photonic modulator with meandered phase shifters.

We present a C-band Mach-Zehnder modulator with meandered phase shifters and a compact footprint of 432 × 260 μm2 on the silicon-on-insulator platform. Electrode, p-n junction, and optical transit time are considered when performing the electro-optic bandwidth (EO BW) simulations. The simulation results prove that the dominant bandwidth limiting factor for this type of modulator is optical transit time. The insertion loss of the modulator without bias is 2.1 dB. The measured half-wave voltage (V π ) and 3-dB EO BW at -0.5 V bias are 6.4 V and 7.7 GHz, respectively. 53 Gbaud PAM-4 transmission over 2 km of standard single-mode fiber is achieved at a bit error rate (BER) below the 6.7% overhead hard-decision forward error correction BER threshold of 3.8×10 -3.

Experimental Demonstration of Constant-Envelope OFDM to Reduce Intermodulation Impairments and Increase Robustness Against Fiber Nonlinearities

Direct detection optical orthogonal frequency division multiplexing (DDO-OFDM) systems have been proposed as a well-suited solution for cost-sensitive applications, but also for metro/regional optical links. In this article, we experimentally demonstrate tolerance enhancements of constant-envelope OFDM (CE-OFDM) signals towards Mach–Zehnder modulator (MZM) intermodulation impairments and fiber nonlinear Kerr effects. The additional tolerance is achieved by the reduced peak-to-average power ratio (PAPR) of CE-OFDM signals, unlike conventional OFDM signals that inherently possess high PAPR values and therefore, are prone to distortions induced by the above-mentioned impairments. The experiments show that the transmission of CE-OFDM signals with PAPR <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$=3$</tex-math></inline-formula> dB over 1000 km of dispersion-uncompensated standard single-mode fiber (SSMF) is successfully accomplished. The proper choice of the MZM bias point, as well as the electrical phase modulation index, provides link length enlargements at the same bit error rate. An enlargement around 320 km of SSMF was achieved with an optical launch power of 10 dBm and with a guard-band of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\approx 16\%$</tex-math></inline-formula> of the signal bandwidth when compared to conventional DDO-OFDM systems.

Broadband Optical Heterodyne Millimeter-Wave-over-Fiber Wireless Links Based on a Quantum Dash Dual-Wavelength DFB Laser

We demonstrate real-time broadband multi-Gb/s electrical RF synthesizer-free millimeter-wave (MMW) signals generation and wireless transmission at the 5G new radio (NR) frequency band of 47 GHz based on analog radio-over-fiber (A-RoF) fronthaul. This is enabled by a low noise, highly correlated, monolithic C-band semiconductor InAs/InP quantum-dash (QDash) dual-wavelength distributed feedback (DW-DFB) laser. One laser mode is encoded using 4-/6-GBaud multilevel quadrature amplitude modulation (M-QAM) (16-/32-/64-QAM) baseband data signals, the other lasing mode is used as an optical local oscillator for optical-heterodyne remote up-conversion to a MMW carrier of 47.27 GHz. Consequently, optical baseband modulated data signals with data capacity up to 36 Gb/s (6-GBaud × 64-QAM) are transmitted through back-to-back (BtB) and 25-/50-km of standard single mode fiber (SSMF) before the MMW carrier is optically synthesized remotely for free space wireless data transmission and detection over up to 9-m. The end-to-end MMW-over-fiber (MMWoF) wireless link is thoroughly characterized exhibiting promising error-vector-magnitude (EVM) and bit-error-rate (BER) values. The 4-/6-GBaud 16-QAM MMWoF wireless links achieve EVMs down to 6.32%/7.33%, 6.71%/7.78%, and 7.35%/8.91% through BtB, 25-km, and 50-km SSMF, respectively. Similarly, the EVM for 32-QAM and 64-QAM links is observed to be 5.56%/6.56% and 6.05%/6.62%, respectively. Moreover, in each case, the calculated BER is below the forward error correction (FEC) limit of 3.8 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> . The results corroborate the potential and viability of the QDash DW-DFB laser as a simple, efficient and cost-effective alternative to individual laser sources for deployment in broadband photonic MMWoF fronthaul systems of 5G wireless networks.

C-band 120-Gb/s PAM-4 transmission over 50-km SSMF with improved weighted decision-feedback equalizer

An improved weighted decision-feedback equalizer (IWDFE) is adopted and experimentally demonstrated to mitigate chromatic dispersion (CD) induced power fading for C-band four-level pulse amplitude modulation (PAM-4) system. Based on a compressed sigmoid nonlinear function, the IWDFE is superior to the conventional DFE, rule-1 and rule-2 based WDFEs in reducing both the error propagation probability and percentage of errors. The IWDFE is combined with a feed-forward equalizer (FFE) to deal with both pre-cursor and post-cursor interference simultaneously. We also introduce 2nd-order polynomial nonlinear terms in both FFE and IWDFE at receiver side, constructing a nonlinear FFE-IWDFE (N-FFE-IWDFE) to simultaneously equalize both the CD-induced power fading and nonlinear distortions. Experimental results show that compared with nonlinear FFE-DFE (N-FFE-DFE), rule-1 and rule-2 based nonlinear FFE-WDFEs (N-FFE-WDFEs), the N-FFE-IWDFE can significantly reduce the bit error ratio (BER), which is close to that of the error-propagation-free N-FFE-DFE. By utilizing the N-FFE-IWDFE, 120-Gb/s PAM-4 transmission system over 50-km standard single-mode fiber (SSMF) is realized with the BER below 7% hard-decision forward error correction (HD-FEC) limit of 3.8 × 10−3, achieving around 1.1-dB improvement of the receiver sensitivity over the N-FFE-DFE. To the best of our knowledge, this is the first time that an IWDFE is employed for C-band IM/DD optical transmission system.

Parallel Bisection-based Distribution Matching for Nonlinearity-tolerant Probabilistic Shaping in Coherent Optical Communication Systems

A nonlinearity-tolerant constant composition distribution matching (CCDM) scheme based on a parallel bisection architecture is proposed. Compared with CCDM based on arithmetic coding (AC), the bisection-based CCDM (BS-CCDM) can achieve the same linear performance and an improved tolerance to fiber nonlinear impairments in unrepeated fiber transmissions. The same linear performance of AC-CCDM and BS-CCDM is evaluated both in simulations and experiments with various modulation formats and shaping rates. The improved fiber nonlinear performance is demonstrated in simulations with probabilistically shaped dual-polarization 16-ary quadrature amplitude modulation (DP-16QAM) signals for unrepeated transmission over 250 km of standard single-mode fiber (SSMF). BS-CCDM provides a ∼0.22 dB gain in effective signal-to-noise ratio (SNR) on average over AC-CCDM for a variety of spectral efficiencies with a block length of 64. And a gain in achievable information rate (AIR) of ∼0.11 bits/4D-symbol is obtained correspondingly. In addition, by further optimizing the look-up tables (LUTs) in BS-CCDM, a better trade-off between the linear performance and nonlinearity tolerance is achieved. Compared with AC-CCDM, the optimized BS-CCDM provides the gain of 0.48 dB and 0.7 dB in effective SNR for the block length of 64 and 128, respectively.

60 GHz Resonant Photoreceiver With an Integrated SiGe HBT Amplifier for Low Cost Analog Radio-Over-Fiber Links

An analog radio-over-fiber photoreceiver based on a resonant narrowband transimpedance low noise amplifier (TILNA) is proposed and demonstrated for use in low-cost and low-power remote radio heads for distributed antenna systems in the unlicensed 60 GHz band. The amplifier is designed to present a conjugate matched impedance to a wirebonded photodiode where the input impedance has a real part of 10Ω while the output impedance is matched towards 50 Ω. Fabricated in a 55 nm SiGe BiCMOS technology, the TILNA features a three stage common emitter low noise amplifier with 17 dB of gain, a 3.4 dB noise figure, an output 1-dB compression point of 8 dBm and low power consumption of 33.6 mW while occupying only 0.25 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of chip space including pads. The photoreceiver, formed by the TILNA and a wirebonded InP UTC photodiode, offers 29 dB higher gain than a 50 Ω terminated reference photodiode where 11 dB improvement is provided by resonant matching. Experimental results show that the proposed photoreceiver has achieved up to 20Gbps C-band transmission of complex modulated waveforms over 5km of standard single-mode fiber using 4 Gbaud QAM32 with an RMS EVM of 11.5%.

Simultaneous transmission of clock and data signals in photonic-assisted WDM passive optical networks

This work reports on the use of a gain-switched vertical cavity surface-emitting laser (VCSEL) optical frequency comb (OFC) to generate multiple optical carriers for applications in future wavelength-division multiplexing (WDM) passive optical network (PON) systems. The VCSEL-based OFC system was tested for its ability to simultaneously transmit error-free data signals up to 30 Gbps, and a 50 MHz clock signal proposed to be used for latency monitoring of the network. The system was demonstrated over a fiber distance beyond 20 km. Four optical carrier signals were filtered from the generated OFC. Three of the four optical carriers were combined and amplitude-modulated with 5 and 10 Gbps on–off keying (OOK) data signals. The fourth optical carrier was amplitude-modulated with a 50 MHz clock signal. These four modulated optical carriers were multiplexed and transmitted over 21 km of standard single-mode fiber. When the three data-carrying optical carriers were modulated with 5 Gbps OOK data and multiplexed with the clock-carrying carrier, a negligible transmission penalty was achieved after fiber transmission. When these three data-carrying optical carriers were modulated with 10 Gbps OOK data and multiplexed with a clock-carrying carrier, a maximum transmission penalty of 4.8 dB was achieved after fiber transmission. The system was investigated at a minim bit error rate (BER) of 10 − 9 . A receiver sensitivity of less than − 11 d B m was achieved at both bit rates. The clock signal suffered little effect when transmitted with the three optical carriers at both 5 and 10 Gbps data rate. A power penalty of 15.37 dB, mainly due to fiber attenuation, was experienced in the clock after fiber transmission. Due to the unavailability of the numerical system to quantify the clock performance in terms of phase noise, the phase-noise results could not be provided. Nevertheless, the provided qualitative results were able to show that the transmitted clock integrity was able to be retained after being multiplexed with transmission on the 21 km fiber channel. For the first time, to the best of our knowledge, we have simultaneously reported on data and clock transmission results using a low-power, VCSEL-based OFC to realize a WDM-PON system. These results are attractive as they demonstrate and motivate the possibility of using gain-switched VCSELs as OFC sources in future WDM-PON networks requiring enhanced channel capacity and stringent network latency monitoring to realize intelligent, simple, and power-efficient PON networks.

Huffman-Coded Sphere Shaping for Extended-Reach Single-Span Links

Huffman-coded sphere shaping (HCSS) is an algorithm for finite-length probabilistic constellation shaping, which provides nearly optimal energy efficiency at low implementation complexity. In this paper, we experimentally study the nonlinear performance of HCSS employing dual-polarization 64-ary quadrature amplitude modulation (DP-64QAM) in an extended-reach single-span link comprising 200 km of standard single-mode fiber (SSMF). We investigate the effects of shaping sequence length, dimensionality of symbol mapping, and shaping rate. We determine that the naive approach of Maxwell–Boltzmann distribution matching — which is optimal in the additive white Gaussian noise channel — provides a maximum achievable information rate (AIR) gain of 0.18 bits/4D-symbol with respect to uniform signaling at optimum launch power in the infinite length regime. Conversely, HCSS can achieve a gain of 0.37 bits/4D-symbol over uniform signaling using amplitude sequence length of 32, which may be implemented without multiplications, using integer comparison and addition operations only. Coded system performance, with a net data rate of approximately 425 Gb/s for both shaped and uniform inputs, is also analyzed.

Demonstration of 108 Gb/s Duo-Binary PAM-8 Transmission and the Probabilistic Modeling of DB-PAM-M BER

We report 108 Gb/s Duo-Binary PAM-8 (DB-PAM-8) transmission using direct-detection aided by Volterra equalizer. The bit-error-rate (BER) performance of the DB-PAM-8 signal has been evaluated through error counting by varying the bit rate, received optical power, and reach. The experimental results suggest that up to 108, 102, and 84 Gb/s signals can be propagated in back-to-back (B2B), and over 10, and 20 km of standard single-mode fiber (SMF), respectively, below the low-density parity-check forward error correction (LDPC-FEC) threshold. Furthermore, we derive a probabilistic model of the BER for multilevel DB-PAM-M signaling that is verified using our measurements. The model of this important performance metric turned out to be accurate enough, especially at low BER values, where its use is more convenient.

Physical Layer Encryption for WDM Optical Communication Systems Using Private Chaotic Phase Scrambling

Protecting the security of optical network is a major worldwide challenge. The conventional schemes for securing communications are based on cryptography at the MAC layer and its higher layers, which are facing a great threat with the development of quantum computers. Optical encryption is a promising way for building security on the physical layer of optical communications. In this work, we propose a novel optical encryption scheme for wavelength division multiplexing (WDM) fiber-optic communication systems, by utilizing the private chaotic phase scrambling. Secure transmission of 50 Gbps signal over 50-km standard single-mode fiber is experimentally and numerically demonstrated. The results show that the WDM signal is efficiently encrypted into a noise-like signal, due to the spectral broadening effect of chaotic phase scrambling. Since the processes of encryption and decryption are totally implemented in the optical domain, the proposed scheme can encrypt the entire network traffic with low latency and high speed. Moreover, the proposed encryption scheme is compatible with the existing WDM optical networks, and only one pair of encryption and decryption devices is sufficient to encrypt all WDM channels, thus the scheme can be easily implemented at low hardware cost.

100-GBd Waveguide Bragg Grating Modulator in Thin-Film Lithium Niobate

An integrated electro-optic modulator based on a waveguide Bragg grating in thin-film lithium niobate is introduced. The compact device with a footprint of 10 × 400 μm2 displays an optical extinction ratio of 53.8 dB at a wavelength of 1555.9 nm in the C-band. With a simple intensity modulation and direct detection scheme, data rates up to 100 Gbit/s are demonstrated with 2-, 4- and 8-level pulse-amplitude modulation formats. The optical filter characteristic of a waveguide Bragg grating modulator suppresses one optical sideband, resulting in inherent single sideband modulation. This enables transmission of a 100 Gbit/s on-off keying signal over 12 km of standard single-mode fiber at 1559.05 nm, without the need for chromatic dispersion compensation.