1.8 µm band broadband hybrid light source employing a combination of a super luminescent diode and thulium-doped fiber amplifier.

We have proposed a broadband hybrid light source that combines a super luminescent diode (SLD) and thulium-doped fiber amplifier (TDFA) and operates in the 1.8 µm band. This light source can improve the characteristics of the output spectrum by amplifying the output light of the SLD with TDFA. In this study, we investigate the dependence of the output spectral characteristics of the hybrid broadband light source on the thulium-doped fiber (TDF) length used in the TDFA as well as the output spectra of three newly developed SLDs of 1660, 1690, and 1730 nm bands. In the evaluation of the output bandwidth, there are various definitions of output bandwidth, but we adopted the bandwidth with power density of over -40dBm/0.1nm. This is because it is possible to evaluate in this band with a dynamic range of "30 dB/0.1 nm" by using a general optical spectrum analyzer. The hybrid light source achieves the bandwidth of 332 nm, from 1579 to 1911 nm, and a high total output power of over 15 dBm. The maximum ripple was less than ∼0.1dB, which is similar to the maximum value of that of the SLD, without any deterioration in the ripple characteristics owing to the hybrid configuration of the SLD and TDFA.

Sub-millisecond timing-jitter-free tuning of parametric dispersion compensator.

We demonstrate sub-millisecond tuning of a prototype parametric tunable dispersion compensator (P-TDC) based on cascaded polarization-diverse four-wave mixing (FWM) process with a fast tunable and highly wavelength-stable pump light source. The pump light source is developed using a tunable distributed amplification chirped sampled grating distributed reflector laser that is fully wavelength tunable by on-chip heaters with a 3-dB frequency response of 45 kHz, resulting in fast dispersion tuning of less than 50 µs without additional timing jitter. The P-TDC is developed as the first prototype to satisfy essential requirements for practical network uses: stable input-polarization diversity, input-wavelength preservation, and seamless dispersion tunability for entire C-band input wavelengths are simultaneously achieved.