DC-1 Gb/s burst-mode compatible receiver for optical busapplications

The characteristics and performance of a high-speed, burst-mode compatible receiver for optical bus or packet communications are described. It employs an Si bipolar differential transimpedance amplifier, an auto-threshold tracking level control circuit, and a DC-coupled decision circuit (ECL compatible quantizer). To cope with intermittent data packets, the threshold control circuit can capture data amplitude and set the logic threshold in about 1 ns. Using an avalanche photodiode, the typical receiver sensitivity is -37.5 dBm (10 ^-9 BER) at bit rates up to 900 Mb/s, with a dynamic range of 23 dB for both pseudorandom and burst-mode signals. At 1 Gb/s, the sensitivity is -35 dBm. With a worst-case reset time <100 ns for the threshold control circuit, this receiver can be used for optical bus applications where data signals with varying optical power are employed     

Physical Media Dependent Prototype for 10‐Gigabit‐Capable PON OLT

In this work, we study the physical layer solutions for 10‐gigabit‐capable passive optical networks (PONs), particularly for an optical link terminal (OLT) including a 10‐Gbit/s electroabsorption modulated laser (EML) and a 2.5‐Gbit/s burst mode receiver (BM‐Rx) in a novel bidirectional optical subassembly (BOSA). As unique features, a bidirectional mini‐flat package and a 9‐pin TO package are developed for a 10‐gigabit‐capable PON OLT BOSA composed of a 1,577‐nm EML and a 1,270‐nm avalanche photodiode BM‐Rx, including a single‐chip burst mode integrated circuit that is integrated with a transimpedance and limiting amplifier. In the developed prototype, the 10‐Gbit/s transmitter and 2.5‐Gbit/s receiver characteristics are evaluated and compared with the physical media dependent (PMD) specifications in ITU‐T G.987.2 for XG‐PON1. By conducting the 10‐Gbit/s downstream and 2.5‐Gbit/s upstream transmission experiments, we verify that the developed 10‐gigabit‐capable PON PMD prototype can operate for extended network coverage of up to a 40‐km fiber reach.     

A high-resolution burst-mode laser transmitter with fast and accurate level monitoring for 1.25 Gb/s upstream GPONs

An innovative burst-mode laser transmitter (BM-TX) is presented for gigabit-capable passive optical network (GPON) upstream transmission at 1.25 Gb/s. The laser bias and modulation current each can reach 80 mA with a resolution of 0.1 mA providing a total drive current up to 160 mA. Both currents are generated by 10-bit current steering digital-to-analog converters (DACs), the architecture of which is specially adapted to yield a monotonic current setting at settling times below 12.8 ns. Tests show that fast automatic power control (APC) can stabilize and track the launched optical power with a tolerance of less than 1 dB over a wide temperature range for outdoor operation. The APC only requires a straightforward calibration of the "0" and the "1" level at room temperature. Optical level monitoring on strings of four consecutive "0" bytes and two consecutive "1" bytes at 1.25 Gb/s is demonstrated. APC based on such short strings of data has not been shown before. The circuits have been designed in a 0.35 /spl mu/m SiGe BiCMOS process. Experimental results show that this dc-coupled BM-TX meets the specifications of the recently approved ITU-T Recommendation G.984.2 supporting an intelligent power leveling mechanism (PLM).     

High-speed, burst-mode, packet-capable optical receiver andinstantaneous clock recovery for optical bus operation

This paper describes an enhanced performance version of a high-speed burst-mode compatible optical receiver and its application to 622-Mb/s optical bus operation in conjunction with an instantaneous clock recovery scheme. The receiver is fabricated in a 12 GHz f_t silicon bipolar technology and consists of a differential transimpedance amplifier with an auto-threshold level controller and a high-speed quantizer. Using an InGaAs avalanche photodiode, the typical burst mode sensitivity is around -34 dBm (10^-9 BER) at bit rates up to 1.5 Gb/s with a dynamic range of 26 db for both pseudorandom and burst signals. The results using a laser beam modulated by a high-speed external modulator indicate that the receiver can be operated at bit rates higher than 2 Gb/s. With a worst-case self-resetting time <50 ns for the threshold control circuit, the receiver is usable for optical packet communication where data signals with varying optical power are employed. This receiver was demonstrated in a 622-Mb/s optical bus application where the clock signal was recovered from the packet data signal using a novel high-speed CMOS instantaneous clock recovery IC     

A Burst-Mode 3R Receiver for 10-Gbit/s PON Systems With High Sensitivity, Wide Dynamic Range, and Fast Response

The burst-mode 3R receiver using monolithic ICs for 10-Gbit/s-class optical access networks is reported. In a point-to-multipoint access system like a passive optical network (PON), the receiver at the optical line terminal (OLT) must be able to handle burst-mode optical packets with significantly different powers and phases. An OLT receiver with high sensitivity with instantaneous response to burst inputs is desired for widening the accommodation area and for high efficiency in PON uplinks. Currently, the diffusion of high-speed Internet connection services represented by fiber to the home services at 1.25 Gbit/s is remarkable and the standardization of the next-generation system operating at 10 Gbit/s has started in IEEE. We first discuss the issues in the implementation of 10-Gbit/s-class PON systems, focusing on securing the accommodation area and the quality of the service comparable with those of the deployed system. Against that background, we propose target specifications for sensitivity, a dynamic range and response speed of the 10-Gbit/s-class burst-mode receiver so as to secure the power budget and the upstream efficiency comparable with those of the already-installed systems. Our burst-mode 3R receiver was designed to meet the above requirements and developed using monolithic ICs of transimpedance amplifier, limiting amplifier, and clock and data recovery circuit fabricated by using SiGe BiCMOS technologies along with a p-i-n photodiode. High sensitivity of , a wide dynamic range of over 16.5 dB, and quick response time of 75 ns were confirmed for burst inputs with extremely different powers.     

Burst-mode optical transmitter with DC-coupled burst-enable signal for 2.5-Gb/s GPON system

In this paper, first burst-mode transmitter for 2.5-Gb/s gigabit-capable passive optical networks (GPON) system is evaluated. Small form factor (SFF) type optical network unit (ONU) generates 2.5-Gb/s optical eyes with commercial distributed feedback-laser diode (DFB-LD). For the fast burst signal access, burst enable (BEN) connection on the evaluation board utilizes DC-coupling configuration. Resultant optical output waveform shows 16.30 dB extinction ratio with wide eye opening for GPON mask test. No significant eye degradation is detected in high temperature operation and after 10 km distance transmission. Proposed GPON ONU successfully shows fast timing characteristics of 2.17 nsec for Tx enable stage and 1.17 ns for Tx disable stage.     

An optical surveillance technique based on cavity mode analysis of SL-RSOA for GPON

An optical in-service surveillance technique based on cavity mode analysis of self-injection locked reflective semiconductor optical amplifier (SL-RSOA) for gigabit-capable passive optical network (GPON) is proposed. At each optical network unit (ONU), an upstream transmitter utilizing SL-RSOA can generate both upstream data signal and surveillance signal due to presence of external cavity. We can able to detect both upstream data and surveillance signals from all ONUs simultaneously at the optical line terminal (OLT) by assigning a distinct cavity mode frequency to each upstream transmitter. We also estimate the power penalty induced by the surveillance signals on the upstream data channel during simultaneous detection mechanism. Further, we propose an alternative method to detect the surveillance signals by allocating a separate monitoring time slot in upstream GPON transmission convergence (GTC) frame so as to reduce the influence of surveillance signals on the upstream data channel.     

Simulations and Experiments on the Effective Optical Gain of FEC in a GPON Uplink

This letter studies the effective optical gain of Reed-Solomon (RS) forward-error correction (FEC) in a burst-mode gigabit passive optical network (GPON) uplink. Numerical simulations are made of the performance of an RS (255, 239) FEC code. For the first time, FEC performance is measured in a 1.25-Gb/s burst-mode GPON uplink in the presence of mode partition noise (MPN). Measurements show that the effective optical gain of RS (255, 239) can be considerably higher than 2.7 dB when MPN dominates     

Sensitivity penalty calculation for burst-mode receivers using avalanche photodiodes

This paper presents the sensitivity penalty for burst-mode receivers using avalanche photodiodes. The analysis takes into account detailed avalanche photodiode statistics, additive Gaussian noise, intersymbol interference and dc offsets in the receiver channel. The penalty has been calculated via comparison of bit-error rates (BERs), obtained using numerical integration, both in continuous- and burst-mode operation. Sensitivity penalties for burst-mode operation as a function of the mean avalanche gain are presented. The Gaussian approximation systematically underestimates the burst-mode penalty. It is shown that the penalty depends upon both the type of avalanche photodiode (APD) and the required BER. Optimum avalanche gains maximizing the sensitivity of the receiver are given. The influence of dc-offsets upon the sensitivity is studied. Furthermore, it is shown that the impulse response of the filters used to extract the decision threshold profoundly impacts the receiver performance. Finally, some important guidelines for the design of high sensitivity and wide dynamic range burst-mode receivers are given.     

Performance analysis of burst-mode receivers with clock phase alignment and forward error correction for GPON

We experimentally demonstrate the performance analysis of burst-mode receivers (BMRx) in a 622 Mb/s 20-km gigabit-capable passive optical network (GPON) uplink. Our receiver features automatic phase acquisition using a clock phase aligner (CPA), and forward-error correction using (255, 239) Reed-Solomon (RS) codes. The BMRx provides instantaneous (0 preamble bit) phase acquisition and a packet-loss ratio (PLR) < 10^?6 for any phase step (±2π rads) between consecutive packets, while also supporting more than 600 consecutive identical digits (CIDs). The receiver also accomplishes a 3-dB coding gain at a bit-error rate (BER) of 10^?10. The CPA makes use of a phase picking algorithm and an oversampling clock-and-data recovery circuit operated at 2× the bit rate. The receiver meets the GPON physical media dependent layer specifications defined in the ITU-T recommendation G.984.2 standard. We investigate the PLR performance of the system and quantify it as a function of the phase step between consecutive packets, received signal power, CID immunity, and BER, while also assessing the tradeoffs in preamble length, power penalty, and pattern correlator error resistance. We also study the impact of mode-partition noise in the GPON uplink in terms of the effective PLR and BER coding gain performance of the system. In addition, we demonstrate how the CPA and the RS(255, 239) codes can be used in tandem for dynamic burst-error correction giving reliable BERs in bursty channels.     

Hybrid WDM/TDM-PON with wavelength-selection-free transmitters

A hybrid wavelength-division-multiplexed/time-division-multiplexed passive optical network serving 128 subscribers with wavelength-selection-free transmitters is presented by cascading 1/spl times/16 arrayed-waveguide gratings (AWGs) and 1/spl times/8 splitters. The wavelength-selection-free transmitter is an uncooled Fabry-Pe/spl acute/rot laser diode (FP-LD) wavelength-locked to an externally injected narrow-band amplified spontaneous emission (ASE). Bit-error rates better than 10/sup -9/ over temperature ranging from 0 to 60/spl deg/C are achieved in all 16 wavelength channels using a single FP-LD with an ASE injection of about -15 and -2 dBm in 622-Mb/s upstream and 1.25-Gb/s downstream transmissions over a 10-km feeder fiber, respectively. It is also reported that the ASE injection does not exert penalty upon burst-mode operations of the FP-LDs in the upstream.     

Performance Analysis of AC-Coupled Burst-Mode Receiver for Fiber-Optic Burst-Switching Networks

Performance Analysis of AC-Coupled Burst-Mode Receiver for Fiber-Optic Burst-Switching Networks A generalized theoretical analysis of an AC-coupled burst-mode receiver is presented. This receiver is designed to operate in optical burst-switching networks using DC-balanced data coding such as 8B10B. Analytic expressions for the recovery time are derived as a function of the system dynamic range, power penalty, and data-coding format. The theoretical calculations are verified with a detailed simulation. It is shown that locking time of the order of nanoseconds can be achieved with commercially available AC-coupled receivers. The burst-mode receiver can adapt to large ($≫ 10$dB) amplitude variations in 30 ns with a power penalty of 2 dB at 12.5 Gb/s. An overall optimization of the transmitter-receiver link-setup time is performed for an optical burst-switching network based on tunable laser transmitters. The dark interval during laser tuning ($sim 50$ns) is shown to have a beneficial impact on the receiver's response time, effectively reducing its locking time to a few nanoseconds, thus resulting in an overall link setup time of about 50 ns, limited by the laser's tuning time.     

An Experimental 50 Mb/s Fiber Optic PCM Repeater

An experimental repeater for amplification and regeneration of 50 Mb/s fiber-optical pulses has been built and tested. For the receiver either Si p-i-n or avalanche photodiodes are used in conjunction with a high impedance FET input amplifier. The high voltage for the avalanche photodiode is generated internally and controlled by the received signal. This AGC circuit is capable of compensating for temperature changes of the avalanche gain over the range of-40 - +60degC. The optical transmitter consists of either a GaAs light emitting diode or a GaA1As laser diode coupled to optical fibers and directly modulated by a current driver with 30 percent electrical efficiency. For 10^-9error rate, the required average optical signal power for a pseudorandom signal is p-i-n diode: -41.5 dBm; avalanche diode: -56.6 dBm. The optical output power into a fiber with 1 percent index difference is LED: -17 dBm; GaAlAs laser: 0 dBm. The repeater power requirement is about 2 W.     

Three-stage burst-mode transimpedance amplifier in deep-sub-/spl mu/m CMOS technology

A transimpedance amplifier, designed in a digital 120-nm CMOS technology, used as preamplifier for optical burst-mode receivers in passive optical networks is presented. A wide optical input power range of 27 dB can be handled with a variable transimpedance without stability problems by varying the open-loop gain by a factor of 115. Noise and stability analysis of the optical receiver are presented. Sensitivities of - 31.3 dBm at 622 Mb/s and - 28.6 dBm at 1.25 Gb/s with a bit error ratio of 10/sup -10/ and a pseudorandom bit stream of 2/sup 31/-1 are achieved with a power consumption of 88.5 mW.     

10-Gb/s strained MQW DFB-LD transmitter module and superlattice APDreceiver module using GaAs MESFET IC's

This paper describes the design and performance of a 10-Gb/s laser diode (LD) transmitter and avalanche photodiode (APD) receiver, both of which are based on GaAs MESFET IC's. The LD transmitter consists of a strained MQW distributed-feedback LD and one chip LD driver IC. The module output power is +4.6 dBm at 10 Gb/s. The APD receiver consists of an InGaAsP/InAl/As superlattice-APD and an IC-preamplifier with the 10-Gb/s receiver sensitivity of -27.4 dBm. As for the LD transmitter, we discuss the optimum impedance-matching design from the viewpoint of high-speed interconnection between LD and driver IC's. As for the APD receiver, the key issue is input impedance design of preamplifier IC, considering noise and bandwidth characteristics. Total performance of the transmitter and receiver is verified by a 10-Gb/s transmission experiment and a penalty-free 10-Gb/s fiber-optic link over 80 km of conventional single-mode fiber is successfully achieved     

A CMOS burst-mode optical transmitter for 1.25-Gb/s ethernet PON applications

This brief presents a CMOS burst-mode optical transmitter suitable for use in 1.25-Gb/s Ethernet passive optical network applications. Based on feedback from the monitoring photodiode, in order to control consecutive burst data the proposed transmitter in this brief uses a reset mechanism, which allows fast responses from the beginning of a high-speed input burst. The chip is fabricated in mixed-mode 0.18-/spl mu/m CMOS technology and measurements are implemented in a chip-on-board configuration using a pig-tailed type Fabry-Perot laser. Under burst-mode operation of 1.25-Gb/s pseudorandom binary sequences, measurements show about 1-dBm averaged transmitted optical power with an over 12-dB extinction ratio over a wide temperature range.     

Demonstration of a WDM/TDM hybrid PON based on a colorless frame-level reach extender

We propose a hybrid passive optical network (PON) consisting of a 2.5 Gb/s reflective semiconductor optical amplifier (RSOA)-based 32 channel loopback wavelength division multiplexing-passive optical network (WDM–PON) and a colorless OEO-based frame-level reach extender (RE). This hybrid PON is designed to support a 128-way split over a 50 km transmission distance per single wavelength channel. We experimentally demonstrate the feasibility of this design through downstream and upstream packet transmission with a commercial gigabit-capable PON (GPON) product. Even if the colorless frame-level RE uses active devices at the remote node, it is still possible to increase the optical link budget through backward compatibility with existing GPON products. This design also provides wavelength conversion and an upstream burst-to-continuous mode conversion between the WDM–PON and GPON. The proposed hybrid PON can satisfy a packet loss ratio (PLR) of 10^?10 at the downstream and upstream transmission including the use of forward error correction (FEC).     

10 Gb/s-Based PON Over OCDMA Uplink Burst Transmission Using SSFBG Encoder/Multi-Port Decoder and Burst-Mode Receiver

In this paper, we propose a novel 10 Gb/s-based passive optical network (PON) over optical code division multiple access (OCDMA) system to realize the new generation full capacity optical access network which is easily upgraded from existing time division multiplexing PON (TDM-PON) without sacrificing the currently uplink bandwidth assigned to the individual user. 16-ONU (4-OCDMA x 4-packet) uplink burst transmission, an upgrade scenario by a factor of four of conventional 10 Gb/s-based PON, is experimentally demonstrated by using multi-level phase-shift-keying (PSK) super-structured fiber Bragg grating (SSFBG) encoder/multi-port decoder and burst-mode receiver. In the discussions, it will be shown that 32 users can be accommodated in 10 Gb/s-based PON over OCDMA system, and a key is newly introduced multi-level phase-shifted en/decoding, of which auto-correlation waveform can be preferably adopted in the burst-mode reception at 10 Gb/s.      

An instantaneous response CMOS optical receiver IC with widedynamic range and extremely high sensitivity using feed-forwardauto-bias adjustment

An instantaneous response CMOS optical-receiver IC is described with wide input dynamic range and high sensitivity. In a TCM (time compression multiplexing)-TDMA (time division multiple access) fiber-optic subscriber system, a receiver should be able to handle burst-data packets with different amplitude. This requires quick response and a wide dynamic range. Instantaneous response is achieved with a new feed-forward auto-bias adjustment technique. In addition, multistaged offset compensation provides a wide dynamic range without any external elements and adjustments. Using these design techniques, an optical receiver IC was fabricated in a standard 0.8-μm CMOS technology. The receiver has a wide dynamic range of more than 25 dB for burst-mode optical input at 29 Mb/s. It has high transimpedance gain of 150 dBΩ and high sensitivity of -42 dBm with stable operation for FET threshold voltage and power supply voltage fluctuation