We demonstrate a tunable chromatic dispersion (CD) compensation technique using a semiconductor optical amplifier
(SOA) and a coil of dispersion compensation fiber (DCF). Based on cross-phase modulation (XPM) in the SOA, the
transient chirp of the received signal can be adjusted by tuning the drive current of the SOA and the power of clock
pulse. In this way, a 10-Gbit/s tunable CD compensation setup, ranging from -40ps/nm to 60ps/nm, is realized without
changing the length of the DCF.
A time- and wavelength-interleaved optical pulse source, which is based on spectral slicing and dispersion management,
is proposed and experimentally demonstrated. The pulse source has a simple configuration, and both the repetition rate
and the wavelength channels can be tuned easily.
Short locking and unlocking time is essepecially important in the packet clock recovery, as it determines the network
resource utilization. This paper presents a novel 10-GHz all-optical packet clock extractor with ultrafast locking and
unlocking time via self-phase modulation (SPM) effect of the semiconductor optical amplifier (SOA). Low finesse
Fabry-Perot (F-P) filter and a saturated SOA, in cascade, are used to directly extract the packet clock from the data
stream. An optical bandpass filter(OBPF) is used to filter out the red-shifted parts of the packet clock in order to reduce
the locking and unlocking time. We analytically investigate the impact of the locking and unlocking time thanks to the
self-gain modulation (SGM) effect and self-phase modulation(SPM) effect induced by the SOA, and demonstrate 10GHz
clock extraction with the establishing time of 200ps and vanishing time of 600ps experimentally.
We demonstrate a novel 40-Gb/s all-optical serial to parallel converter (AOSPC), which can convert 40-Gb/s serial
optical signals to 4-channel 10-Gb/s parallel optical signals. Moreover, based on the sequential multi-wavelength
conversion the AOSPC shows the regeneration ability.
We present a compact short pulses source, in which the pulses generated by large-signal directly modulated laser diode
are phase-modulated, and it can compress the pulse from 30ps to 5.3ps with 184fs timing jitter.
We experimentally demonstrate a 4×10-Gb/s optical multicast scheme using a semiconductor optical amplifier (SOA)
and a single optical source, which produce a 10-GHz multi-wavelength pulse-trains used as the probe light of the SOA.
The multicast principle is based on the multi-wavelength conversion (MWC) by means of the interaction of both cross
gain modulation (XGM) and transient cross phase modulation (T-XPM) of the SOA. Because of the nonlinear
amplification of SOA, the 4 output copies are regenerated with respect to the input degraded signal. This scheme is very
simple and allows photonic integration.
A novel 10Gbit/s all-optical packet clock extractor, which comprises a Fabry-Perot (F-P) filter and a semiconductor
optical amplifier (SOA), is proposed in this paper. Low Finesse Fabry-Perot (F-P) filter was used to directly extract the
packet clock from the data packet stream, which ensures that the clock locks fast and vanishes quickly. The clock,
amplitude modulated as a result of low-Q filter, then goes into SOA to reduce the low-frequency amplitude noise. The
impact of F-P filter and SOA on the locking and unlocking time of the packet clock is theoretically analyzed. The result
shows that the locking time is reduced while the unlocking time is increased, due to the self-gain modulation (SGM)
effect. We demonstrate instantaneous 10.075GHz clock extraction experimentally with the establishing time of about 8
code-periods and vanishing time of about 22 code-periods.
To improve the all-optical clock recovery, a novel device termed as code mixer was designed to preprocess the injected data signals. In the time domain, the code mixer can change the probability distribution of the amplitude of the data pulses and reduce the amount of codes "0". In the power spectrum, the code mixer can reduce the continuous spectral component. It was demonstrated experimentally that the code mixer could concentrate the probability distribution of the amplitude of the pulses to half of the maximum amplitude. It was also demonstrated theoretically and experimentally that using a code mixer of more ways or several cascade code mixers the clock signal recovered can be further improved. In the experiment of 40GHz all-optical clock recovery using an injection mode-locked fibre ring laser based on a semiconductor optical amplifier, the amplitude fluctuation and timing jitter of the clock pulses recovered caused by the pattern effect were reduced obviously.
40Gbit/s all-optical 3R regeneration was demonstrated. The wavelength of the data signal was converted with an SOA by cross-gain modulation (XGM). The clock recovery was based on Fabry-Perot (F-P) filter of high finesse (F=1000). The actual bit rate of the data signal was 40.04796Gbit/s, matching the free spectral range (FSR) of the F-P filter. Two SOAs were used in series as the decision gate to make full use of the nonlinearity. Taking advantage of the chirp, one narrowband OBF was used to reshape the waveforms in the clock recovery, so as to reduce the pattern effect. Another narrowband OBF was used after the decision gate to diminish the tails of the pulses. The clock signal had a root mean square (RMS) timing jitter of around 843fs. The output data signal of the regenerator had an optical signal-to-noise ratio (OSNR) of more than 40dB/0.1nm. The maximum timing jitter was 1.439ps.