New wideband and temperature-stabilized optical isolator for wavelength division multiplexing fiber transmission system

Abstract

In recent years, growing attention is being focused on wavelength disvision multiplexing optical communication system as a promising means of mass-scale communication. To realize these systems, wideband & temperature-stabilized optical isolators are essential, which in turn require Faraday rotators capable of ensuring a Faraday rotation stable against wavelength and temperature variation. A new wideband & temperature-stabilized optical isolator for 1.5 5 ?m wavelength has been developed using Bi-substituted holmium-ytterbium iron garnet (HoYbBilG) single crystal as a Faraday rotator. The optical isolator features 0.34?m bandwidth, less 0.6 dB insertion loss and over 37 dB backward loss at a wavelength of 1.55?m throughout the temperature range from -10 to 60°C. The Faraday rotation (FR) and optical absorption loss of HoYbBilG have been investigated in the near-infrared wavelength region (?=0.9—1.7?m). The specific Faraday rotation of Ho0.85Yb1.02Bi1.13Fe5O12 is about -767deg/cm at ?=1.55?m. The Faraday rotation wavelength and temperature characteristics of HoYbBilG crystals are also discussed. These results indicate that the Bi-substituted holmium-ytterbium iron garnet single crystals realize a high Faraday rotation stability against temperature and wavelength in the near infrared region