What is ASE of laser diodes?
(From: David Schaafsma (drdave@jnpcs.com).) ASE usually stands for Amplified Spontaneous Emission. It is part of any lasing process, and is just what it sounds like – spontaneous emission (not in the lasing mode) that gets amplified by the gain medium in the cavity. I find it easiest to think of this in terms of phase: The lasing mode will have one well-defined phase, while all the noise (ASE) modes will have some phase shift relative to the lasing mode. ASE is mostly a concern when you are trying to send modulated signals (e.g. bits) with your laser diode. In that case, ASE is essentially a noise source which degrades the signal (or S/N). In most electrically-pumped diodes, ASE is not so much a problem as RIN (Relative Intensity Noise), which can raise the bit error rate by changing the relative levels of the “on” bits. L-I characteristic for ASE is going to follow the lasing mode for the low part of the current range, but at some point (depending on cavity Q and carrier lifetime), yo
(From: David Schaafsma (drdave@jnpcs.com).) ASE usually stands for Amplified Spontaneous Emission. It is part of any lasing process, and is just what it sounds like – spontaneous emission (not in the lasing mode) that gets amplified by the gain medium in the cavity. I find it easiest to think of this in terms of phase: The lasing mode will have one well-defined phase, while all the noise (ASE) modes will have some phase shift relative to the lasing mode. ASE is mostly a concern when you are trying to send modulated signals (e.g. bits) with your laser diode. In that case, ASE is essentially a noise source which degrades the signal (or SNR). In most electrically-pumped diodes, ASE is not so much a problem as RIN (Relative Intensity Noise), which can raise the bit error rate by changing the relative levels of the “on” bits. L-I characteristic for ASE is going to follow the lasing mode for the low part of the current range, but at some point (depending on cavity Q and carrier lifetime), yo
