All-optical Timing Extraction Research Articles

Simultaneous four-wave mixing and cross-absorption modulation inside a single EAM for high-speed optical demultiplexing and clock recovery

We report a novel technique that utilizes a single electroabsorption modulator (EAM) to perform simultaneous four-wave mixing (FWM) demultiplexing and all-optical timing extraction. The extracted timing, using fast cross-absorption saturation, is used to recover the subharmonic optical clock from 80-Gb/s data. Investigations of the single-pump FWM process in EAM shows a wide wavelength detuning range with almost flat FWM efficiency at large detuning. Enhancement of FWM efficiency with reverse bias of the EAM was observed.

Subharmonic optical clock recovery from 160 Gb/s using time-dependent loss saturation inside a single electroabsorption modulator

A single electroabsorption modulator (EAM) is utilized to perform subharmonic all-optical timing extraction from 160 Gb/s. The extraction technique is based on fast time-dependent loss saturation inside the EAM. The extracted timing is used for optical clock recovery with /spl les/340 fs of timing jitter. The clock recovery technique is bit-rate flexible, and the bit-error-ratio measurements reveal an error-free operation with no receiver sensitivity penalty.

All-optical timing extraction with simultaneous optical demultiplexing from 40 Gb/s using a single electroabsorption modulator

We demonstrate a technique for performing optical time-division demultiplexing with simultaneous all-optical timing extraction using a single electroabsorption modulator (EAM). The technique is based on time-dependent transmission of the all-optically controlled EAM using a counterpropagation scheme between the data and clock optical pulses. The extracted timing is used in a feedback configuration to recover the optical clock. The bit error ratio measurement for demultiplexing from 40 Gb/s (4/spl times/10 Gb/s, 2/sup 31/-1 pseudorandom bit sequence) to 10 Gb/s showed an error-free operation with a 3.2-dB power penalty. The recovered clock-timing jitter is less than 200 fs.

Optical 3R regeneration using a single EAM for all-optical timing extraction with simultaneous reshaping and wavelength conversion

The authors demonstrate a technique that utilizes a single electro-absorption modulator (EAM) to perform simultaneous all-optical timing extraction, reshaping, and wavelength conversion. The extracted timing is used to generate an error signal that is used to recover the optical clock. The same EAM is used to encode the incoming data onto the retimed clock pulses in order to perform 3R regeneration and wavelength conversion. The system performance was tested using a 2/sup 31/-1 pseudorandom binary sequence (PRBS) data running at 10 Gb/s with a 3.3-ps pulsewidth. The input data was degraded by adding a 500-kHz timing jitter and reducing the optical signal-to-noise ratio (SNR) to 18 dB. The 3R regenerated data showed a 4.7-dB improvement in power penalty and 20-dB improvement in optical SNR. The calculated timing jitter of the recovered clock is less than 230 fs.

All-optical timing extraction at 40 GHz using amode-locked figure-eight laser with an SLA

All-optical timing extraction using a figure-eight laser with a semiconductor nonlinearity generates a synchronised 40 GHz output pulse stream which displays lower timing jitter than the input stream. A high contrast ratio recovered clock is observed over a ~200 kHz locking range.

All-optical timing extraction with frequency division using a twin-section laser diode

All-optical timing extraction from a coded line signal with division of the extracted clock frequency is demonstrated using a single twin-section self-pulsating laser diode. Either the bit-rate clock or a submultiple of the bit-rate clock can be extracted, depending only on the DC biases applied to the self-pulsating laser diode. Timing extraction is carried out for the first time without optical injection locking of the self-pulsating laser diode by the optical data source. >

All-optical timing extraction using an optical tank circuit

An ultrafast all-optical timing extraction method using an optical tank circuit is described, and experimental results at 2 Gb/s are reported. A Fabry-Perot resonator, whose free spectral range is equal to the clock frequency of the incoming optical data stream, is utilized as the optical tank circuit. Its fully passive structure and ultra-high-bit-rate operation ( approximately Tb/s) is possible through decreasing resonator length. >

All-optical timing extraction using a 1.5μm self pulsating multielectrode DFB LD

All-optical timing extraction from an intensity modulated 196 Mbit/s return to zero optical data stream by the injection locking technique, using a 1.5μm self-pulsating multielectrode DFB LD is demonstrated. A frequency lock-in range, which depends upon both the injection signal level and the length of space continuation is investigated.