A wavelength-tunable small form-factor pluggable (SFP) optical module is proposed and implemented, which is based on a self-designed 4-channel DFB laser array. The module adopts the widely used SFP packaging standard so that it is convenient to connect with other devices. It has an I2C interface for receiving wavelength tuning commands and downloading digital diagnostics monitoring information to the host processor. Three parts are included: the receiver, the transmitter and the microcontroller unit, to complete the conversion of optical-electro, electro-optical. A large range and high precision wavelength tuning is realized through innovative tuning methods. Two wavelength tuning methods are utilized: channel switching of 4-channel for coarse tuning and temperature tuning combined with current tuning for fine tuning to actualize the tunable output of the DFB laser array. This wavelength-tunable SFP optical module can replace several fixed wavelength optical modules in a traditional WDM system, thus greatly reducing costs and improving the utilization ratio of resources. Experimental results show the SFP optical module can achieve the continuity of wavelength tuning covering 1539.0 nm to 1551.0 nm. It can switch over 16 channels in a 100G-DWDM system or 31 channels in a 50G-DWDM system. The side mode suppression ratios (SMSRs) of most channels are above 40dB over the wavelength tuning range of 12 nm. The optical signal transmission rate is up to 1.25Gbps.
We propose a new method to investigate fast wavelength switching, which consists of control circuit, driving circuit and 8-channel DFB laser array using reconstruction-equivalent-chirp technique. The control circuit is in charge of selecting required lasers to switch wavelength, the driving circuit supply adjustable and stable direct current to the DFB laser arrays. Experimental results show that wavelength switching time of 8 channels is about 500ns and stability of laser output is promised.
An innovative approach to realise high chip rate in OCDMA transmission system is proposed and experimentally investigation, the high chip rate is achieved through a 2-D wavelength-hopping time-spreading en/decoder based on the supercontinuum light source. The source used in the experiment is generated by high nonlinear optical fiber (HNLF), Erbium-doped fiber amplifier (EDFA) which output power is 26 dBm, and distributed feed-back laser diode which works in the gain switch state. The span and the flatness of the light source are 20 nm and 3 dB, respectively, after equalization of wavelength selective switch (WSS). The wavelength-hopping time-spreading coder can be changed 20 nm in the wavelength and 400 ps in the time, is consist of WSS and delay lines. Therefore, the experimental results show that the chip rate can achieve 500 Gchip/s, in the case of 2.5 Gbit/s, while keeping a bit error rate below forward error correction limit after 40 km transmission.