We successfully demonstrate 10-Gbbaud quadrature phase-shift keying signal transmission over a 4-km-long endlessly single-mode holey fiber using a wavelength-tunable semiconductor quantum dot (QD) laser. The transmission is carried out in the waveband of 1040.72–1070.02 nm with a bandwidth of 7.89 THz, which is broader than conventional wavebands such as the C and L bands. In the study, a QD laser notable for its wavelength stability and tunability is employed for its broad bandwidth availability on the transmission. Observed bit error rates are within a forward error correction limit of 2×10–3 under homodyne coherent detection configuration with offline digital signal processing. The abundant frequency resources in this T band (1000–1260 nm) help increase the capacity of a transmission link using a large number of wavelength channels by the QD laser.
We successfully demonstrate 20-Gb/s quadrature phase-shift keying (QPSK) signal transmission. The transmission was carried out over endlessly single-mode holey fiber in the waveband of 1276.02–1304.26 nm, whose bandwidth of 5.09- THz is broader than the traditional C-band. A wavelength-tunable quantum dot (QD) laser with broad wavelength tunability helps realize bandwidth availability. A single InAs/InGaAs QD optical gainchip was grown using a sandwiched sub-nanometer separator technique in the wavelength of 1.3-μm band. Using this gain chip, the QD light source has good wavelength stability, compactness and wavelength tunablility. The measured transmission results show bit error rates within a forward error correction limit of 2×10–3 using intradyne coherent detection with offline digital signal processing. In this study, it is expected that abundant frequency resources such as the O-band are coherently enhanced by the use of a large number of wavelength channels by effectively using the QD- laser.