C.S. Wong

All-optical NRZ to RZ format and wavelength converter by dual-wavelength injection locking

We propose and demonstrate nonreturn-to-zero (NRZ) to return-to-zero (RZ) data format and wavelength conversion using dual-wavelength injection locking of a Fabry–Perot (FP) laser diode. A negative power penalty of )9.5 dB was achieved at 10 � 9 bit-error-rate. The device operated over a 45 nm wavelength range with over 10 dB extinction ratio. We also describe the experimental conditions necessary for negative power penalty of dual-wavelength injection locking. 2002 Elsevier Science B.V. All rights reserved.

All-optical modulation format conversion and multicasting using injection-locked laser diodes

The functionality of optical modulation format conversion and wavelength conversion will be needed in next-generation wavelength routers. This paper describes a new approach for return-to-zero to nonreturn-to-zero format conversion using a birefringent fiber and an injection-locked Fabry-Pe/spl acute/rot laser diode. This paper also describes the demonstration of an all-optical multicaster based on a similar technique. Error-free operations were confirmed in the format converted and in every channel of the 8 /spl times/ 10-Gb/s multicast outputs.

Optical Differential-Phase-Shift-Keying Demodulation Using a Silicon Microring Resonator

We have for the first time experimentally demonstrated an ultrasmall, low power penalty, and robust 10 - Gb/s differential-phase-shift-keying demodulator using a silicon-based microring resonator. The microring resonator is compatible with a wide range of signal bit rates. In optical transmission measurements with 11.6-km nonzero dispersion-shifted fiber, the microring resonator demodulator had comparative power penalty compared with a Mach-Zehnder delay interferometer both in single ended detection. Error-free detection was achieved.

All-optical ASK/DPSK label-swapping and buffering using Fabry-Perot laser diodes

We describe an approach for optical label encoding that allows the realization of all-optical label-swapping in optical packet-switched networks. The proposed method is based on a combination of the amplitude-shift-keying (ASK) modulated payload with the differential phase-shift keying (DPSK) modulated label on the same optical carrier. We demonstrate an implementation using dual-wavelength injection locking (DWIL) of a Fabry-Perot laser diode. Bit-error-rate measurements were performed for the 10-Gb/s payload, and the 2.5-Gb/s label showed the feasibility of the proposed method. An all-optical buffer for the two-level ASK/DPSK optically labeled packets is also described. The buffer is implemented by routing the packet via a delay line if potential contention is predicted. Error-free operation was also achieved.

Optical packet labeling based on simultaneous polarization shift keying and amplitude shift keying.

We propose and demonstrate label encoding-swapping and transmission for an orthogonally labeled packet by use of a 10-Gbit/s amplitude shift keying payload and a 2.5-Gbit/s polarization shift keying (PolSK) label. A simple scheme for demodulating and demultiplexing the PolSK label based on an injection-locked Fabry-Perot laser diode is described. The extinction ratio of the newly added PolSK label can be precisely controlled and maintained after the intermediate node.

8/spl times/10 Gb/s multiwavelength injection locking of a FP laser diode for WDM multicast

8/spl times/10 Gb/s multiwavelength injection-locked FP-LD multiple-wavelength converter, having a potential application in WDM multicast switching networks is demonstrated. The average power penalty of the 8 channels was about 3 dB at 10/sup -9/ bit-error rate.

Polarization-independent time-division demultiplexing using orthogonal-pumps four-wave mixing

In this letter, we demonstrate a 40-Gb/s time-division demultiplexer (TDM) with simultaneous wavelength shift of 8.2 nm using polarization-diversity orthogonal-pumps four-wave mixing (FWM) in a single semiconductor optical amplifier (SOA). Bit error rate (BER) of less than 10/sup -9/ has been achieved. The power penalty for a BER of 10/sup -9/ was 4 dB. Demultiplexing of a 10-Gb/s signal to 2.5 Gb/s with wavelength shift over 20 nm was also demonstrated successfully.

A 110 GHz passive mode-locked fiber laser based on a nonlinear silicon-micro-ring-resonator

Mode-locked fiber lasers have many important applications in science and engineering. In this work, we demonstrate for the first time a 110 GHz high repetition rate mode-locked fiber laser using a silicon-based micro-ring resonator (SMRR) to act as an intra-cavity optical comb filter, as well as an optical nonlinear element. No electrical bias for the SMRR is required to reduce free carrier absorption. The SMRR has a free spectral range of 0.88 nm, enforcing laser mode-locking at the 110 GHz high rate. The optical nonlinearity of the SMRR also supports the dissipative four-wave mixing effect for generating the mode-locked optical pulse trains. The mode-locked pulse-width, optical 3 dB spectral bandwidth and the time–bandwidth product (TBP) are experimentally measured under different pump currents to the erbium-doped fiber-amplifier module inside the laser cavity. The relative intensity noise and the line-width of the proposed laser are also evaluated. Furthermore, a long-term monitoring is performed. The experimental results show that the optical pulse train generated by the SMRR-based mode-locked fiber laser has a 2.6 ps pulse-width (pump current at 400 mA) at a 110 GHz high repetition rate, narrow line-width (1 kHz), high stability (under observation of an hour), and nearly Gaussian transform-limited (TBP is 0.455).

250-GHz Passive Harmonic Mode-Locked Er-Doped Fiber Laser by Dissipative Four-Wave Mixing With Silicon-Based Micro-Ring

We propose and demonstrate a 250-GHz high-repetition-rate mode-locked Er-doped fiber laser, which utilizes a silicon micro-ring resonator (SMRR). The SMRR acts as an optical comb filter to help achieve passive mode-locking through the dissipative four-wave-mixing effect induced by a piece of high nonlinear fiber. A short section of polarization-maintaining fiber is inserted in the cavity to induce birefringence filtering to significantly enhance the stability of the proposed laser through the combined effects of optical filtering and nonlinear spectral broadening. The laser can operate about 2 and 6 nm in the case of 1.48-ps and 875-fs output pulsewidth, with 3-dB bandwidth, respectively. The laser can remain mode locked, during our measurement time, without any cavity length or temperature feedback control.

Reduction of amplitude transients and BER of direct Modulation laser using birefringent fiber loop

A birefringent fiber loop (BFL) is proposed to improve the signal from a directly modulated distributed feedback laser. The BFL is a simple and passive fiber device. The BFL reduces amplitude transients, frequency chirp, and pattern dependence. It also improves the extinction ratio of the directly modulated optical signal. We show that the BFL effectively extends the 10-Gb/s transmission range to 25 km at 1550-nm wavelength over conventional single-mode fiber.