摘要： Lasing regimes of ring erbium ?ber lasers passively Q-switched by means of ?ber tapers coated with thin crystalline ?lms of either Bi2Te3 or Bi as saturable absorbers (SAs) are investigated. 10–15 μm in diameter and 5–10 mm long ?ber tapers are prepared by local chemical etching out of a silica light re?ecting cladding of the standard SMF-28 optical ?ber. Nanometer thick island ?lms of pure Bi and Bi2Te3 are synthesized on the surface of the ?ber tapers by applying the metalorganic chemical vapor deposition (MOCVD). The deposited ?lms are then covered with two di?erent polymers: either polyvinyl acetate (PVA) or polydimethylsiloxane elastomer (PDMSE). The ?ber section with polymer-coated SA ?ber is installed into the ring laser cavity in tandem with the section of an active ?ber. For all the samples a stable generation of microsecond pulses in the Q-switch mode at a wavelength of about 1560 nm is observed. To the best of our knowledge, a passively Q-switched ?ber laser with nanometer Bi ?lms as a saturable absorber is implemented for the ?rst time. It is established that even a small increase in the temperature of the surrounding medium leads to a signi?cant increase in the transmission coe?cient of polymer-coated tapers with deposited SA ?lms, which may be attributed to a decrease in the refractive index of the polymers. The most signi?cant increase in the transmission coe?cient with increasing temperature is observed in tapers coated with PVA, which has a refractive index larger than fused silica.