R.J. Mears

High-gain rare-earth-doped fibre amplifier at 1.54µm

Optical amplifiers are of interest as wideband in-line repeaters for telecommunications and as signal regenerators for a variety of sensor applications. Much current research has concentrated on semiconductor laser amplifiers which are difficult to splice to fiber systems. It is clear that an amplifier consisting of a special optical fiber which is compatible with telecommunication fiber would overcome this problem. This paper describes the first results of an optical fiber amplifier based on an Er3+-doped fiber which has a maximum gain at a wavelength of 1.536 µm. A single-pass gain of 26 dB and a maximum output of 13 dBm at 140 MHz has been demonstrated

Single-mode neodymium fibre lasers

Rare-earth doped single-mode optical fibres have been grown in the Department of Electronic and Information Engineering at Southampton using a modified chemical vapour deposition technique. The technique involves the introduction of the core material and dopants as volatile compounds. A prototype resonator has been constructed using a Nd3+ doped fibre as the active medium and microscope objectives to couple in and out of the fibre. The resonator can then be longitudinally pumped by appropriate optical sources. Initial tests have involved a c.w. Rhodamine GG dyelaser as the pump source. When the dye laser is tuned to a Nd3+ absorption band at around 595 nm, lasing action at 1.08µm can be observed, with a threshold corresponding to a few milliwatts of absorbed dye laser power.