We demonstrate a ridge waveguide sampled-grating distributed-feedback laser with quasi-continuous wavelength coverage over a 35nm range. The design is based on a 320nm-thick butt jointed passive waveguide optimized for carrier injection tuning. The butt-joint technology enable optimize the passive waveguide as well as active section. By tuning mirror sections,the laser provides 35nm tuning while maintaining 〉30dB sidemode suppression ratio.
A high-precision wavelength controller is presented in this paper. It is necessary to find out the difference between the central wavelength of a tunable fiber Fabry-Perot (FFP) filter and that of the input laser, while the wavelength control-ler operates at the states of wavelength-scanning and wavelength-locking modes. Firstly, a dynamic simulation model of tunable FFP filter is established, and the dynamic characteristic of tunable FFP filter modulated by an alternating current (AC) signal is simulated. Then the measuring time at wavelength-scanning mode compared with the theory time is discussed, and this time difference shows the difference between the central wavelength of a tunable FFP filter and that of the input laser. At last, the effects on wavelength-locking precision of time delays, including the time delay of opened-loop circuit, the time constant of the closed-loop circuit and the intrinsic hysteresis of piezoelectric (PZT) element, are analyzed. A wavelength controller of tunable FFP filter is designed and prepared. The experimental results at wavelength-locking mode show that a high locking precision is obtained.
