Narrow-band double-pass superluminescent diodes emitting at 1060 nm

Experimental data are presented which show that double-pass superluminescent diodes (SLDs) with fibre Bragg grating (FBG) based spectrally selective external reflectors offer emission linewidths in the range 0.1 — 1.0 nm, i.e., one to two orders of magnitude narrower in comparison with conventional SLDs and considerably broader in comparison with single-frequency semiconductor lasers. Their optical power at the single-mode fibre output reaches 5.0 — 8.0 mW, and can be raised to 50 mW using a semiconductor optical amplifier.