Erbium/thulium doped optical filter for optical fibres or waveguides.
摘要
An object of this invention is to provide an optical filter which has higher mass-producibility and economy. This feature can be realized by doping a rare earth element into the region (10) made of a glass material which can transmit light (e.g. optical fiber or waveguide). In a case that Er and Tm are doped as the rare earth element into the region (10), a ratio alpha Er/ alpha Tm between a contribution alpha Er of Er to attenuation and a contribution alpha Tm of Tm to attenuation is set in a range from about 1 to 1/25 for a 1.5 mu m band range, whereby attenuation in this wavelength range is retained above 50 dB/m to realize required cutoff function. <IMAGE>
申请公布号
EP0600490(A1)
申请公布日期
1994.06.08
申请号
EP19930119455
申请日期
1993.12.02
申请人
SUMITOMO ELECTRIC INDUSTRIES, LIMITED;NIPPON TELEGRAPH AND TELEPHONE CORPORATION