Optical performance of <inline-formula><math display="inline" overflow="scroll"><mrow><msup><mi mathvariant="normal">Er</mi><mrow><mn>3</mn><mo>+</mo></mrow></msup><mo>∕</mo><msup><mi mathvariant="normal">Yb</mi><mrow><mn>3</mn><mo>+</mo></mrow></msup></mrow></math></inline-formula> codoped core-cladding heterogeneous single-mode fiber amplifier

Abstract

A high-concentration Er3+/Yb3+ codoped core-cladding heterogeneous single-mode phosphate fiber amplifier with a similar numerical aperture to the Corning SMF-28 standard single-mode optical fiber is described. Measurements and calculations are given for the device's optical absorption, strong infrared fluorescence, absorption, and emission cross-sections of Er3+, Judd-Ofelt parameters, and spontaneous transition probabilities of Er3+ in the core glasses. The relative gain (the signal enhancement) of a 5.8-cm-long fiber amplifier was measured to be 32.3 dB, and after compensating for both the propagation loss and the absorption loss, a maximum internal gain of 2.6 dB/cm at 1.535 µm was obtained, which reveals an available core-cladding heterogeneous design strategy in developing high-gain amplifier devices.