Best Paper Award 2014

Best Paper Award

High-Accuracy, High-Speed Wavelength Switching with Tunable Distributed Amplification (TDA-) DFB Laser Array

Takuya Kanai, Nobuhiro Nunoya, Takayuki Yamanaka, Ryuzo Iga, Makoto Shimokozono, Hiroyuki Ishii

[Trans. Electron. (JPN Edition), Vol. J97-C No.3, Mar. 2014]

Takuya Kanai	Nobuhiro Nunoya	Takayuki Yamanaka	Ryuzo Iga
Makoto Shimokozono	Hiroyuki Ishii

  The optical routers and optical packet switching systems based on wavelength division multiplexing have been studied for future optical networks. The high-speed, high-accuracy wavelength switching of tunable wavelength lasers is a key function of optical switches in wavelength routing systems. High-speed wavelength tuning can be accomplished by injecting current into a semiconductor since this provides a large and fast change in the refractive index as a result of carrier effects.
  The authors already demonstrated a tunable distributed amplification (TDA) DFB laser diode (LD) whose wavelength can be changed by a single tuning current without mode hopping. The TDA-DFB-LD consists of active-region and tuning region units. Wavelength tuning can be achieved by injecting current into the tuning region. The lasing frequency is rapidly increased by increasing the tuning current. However, increasing the tuning current induces gradual thermal frequency drift to a lower frequency as a result of the thermal effect. Therefore, thermal frequency drift must be suppressed to achieve high-speed, high-accuracy wavelength switching with a TDA-DFB-LD.
  In this paper, the authors demonstrated a thermal drift suppression technique of using tuning regions adjacent to the operating LD as thermal compensators in a TDA-DFB-LD array, and a narrow-interval TDA-DFB-LD array has been developed to increase the effect of the technique. As a result, high-speed (< 1 ㎲) and high-accuracy (< 1 GHz) wavelength switching was achieved.
  As stated above, the results described in this paper are highly original, and are based on the authors’ high-speed and high-accuracy wavelength switching with a TDA-DFB-LD array. The device will be a key function for optical switches in future optical network systems.