| Research Abstract |
An optical wavelength converter plays an important role in constructing highly-functional photonic networks. In this research, we conducted the exploratory study on the all-optical wavelength converter that operates in a wide range of input signal wavelength.
A novel all-optical wavelength conversion element is proposed. The wavelength converter is based on a nonlinear Bragg reflector (NBR-WC), and it works as a wavelength converter by switching an input CW probe light with a signal light applied as a pump. The refractive index change induced by the pump light is used to modulate the CW probe light. The signal gating power, the wavelength dependence on the grating coupling coefficient, the conversion efficiency, and the signal tuning range are estimated based on numerical calculations. Also, the proposed wavelength converter is fabricated, and its characterization is clarified. The NBR-WC exhibits a wide tuning range of input signal wavelength, which potentially extends over the C-band and L-band of Erbium doped fiber amplifier. We fabricated NBR-WC using a GaInAsP/InP waveguide. The core layer was composed of GaInAsP with a band gap wavelength of 1430nm. The fabricated device provided almost constant conversion efficiency of -9dB for 10dBm input signal peak power in the signal wavelength range of 1530-1565 nm. Also, the polarization dependence of NBR-WC could be removed by using high-mesa waveguide structure with a vertical grating Brass reflector.
Further issues such as improvement of an extinction ratio and conversion efficiency are discussed. Also, using the NBR-WC as a wavelength conversion element, we investigated the tunability of the converted wavelength, i.e., the probe wavelength.
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