Technique for measurement of the gain spectra of semiconductor diode lasers

Abstract

A simple technique for determining the gain spectra of semiconductor lasers from measurements of the emission spectra of the laser is presented. The technique is insensitive to the response function of the device used to determine the emission spectra of the laser. Accurate estimates of the gain can be obtained from data which have been convolved with an instrument response function of ≲0.5 Å FWHM for a cavity free spectral range of 2.5 Å. Two applications of the gain data obtained by the technique are presented.

Advances in Measurements of Physical Parameters of Semiconductor Lasers

“…Cassidy [9] and later L. Lam Sin Cho [10] have shown theoretically and experimentally that the mode-sum method is less sensitive to the spectral bandwidth of the measurement system than the Hakki-Paoli technique.…”

“…Cassidy [9] proposed another way to analyze ASE in order to determine the material gain values. This technique, also called the mode-sum method, is based on a slightly different analysis of the same basic Eq.…”

Measurement of semiconductor laser gain and dispersion curves utilizing Fourier transforms of the emission spectra

“…In agreement with earlier publications on this topic [10], we understand that this transmission spectrum is a periodic function and equivalent to an infinite sum of equally displaced Lorentzshaped peaks. Instead of an infinite sum of Lorentz peaks, it is also possible to write (2) in the wavenumber domain as an infinite series of cosine functions, according to (3) This different representation of (2) in the wavenumber domain is advantageous for the understanding of the following steps. We remark at this point, that the Fourier transform of (2) would be a series of exponentially decaying delta-peaks with a constant harmonic amplitude ratio .…”

“…A number of different methods for the determination of the net gain spectrum have been proposed in the literature. The Hakki-Paoli method [1], [2] uses the ratio between the peaks and valleys of individual Fabry-Pérot resonances, while with Cassidy's method [3], one estimates the area under each Fabry-Pérot resonance and compares it with the corresponding area of a smooth, i.e., unstructured spectrum. Finally, Henry's method [4] utilizes the unamplified spontaneous emission spectrum and the relation between the stimulated and spontaneous emission coefficients to obtain the gain spectrum.…”

Signal-induced birefringence and dichroism in a tensile-strained bulk semiconductor optical amplifier and its application to wavelength conversion

“…However, a practical challenge of this practice is that the resolution of the spectrum analyzer, typically 0.1 nm, will not be sufficient to fully resolve the peaks and the valleys of the studied modes. Another practical problem is, in the spectrum, the periodicities in the ripple for TE and TM polarizations cannot be obtained precisely enough for one particular mode due to the high sensitivity to the instrument response function and low signal-to-noise ratio (SNR) [11], [12], and no exact dispersion relations are known yet. Therefore, Fig.…”