Theory of the linewidth of semiconductor lasers pdf

The theory of natural linewidth in semiconductor lasers has an independent significance. Zeiger, theory of the effect of traps on the spectral characteristics of diode lasers, appl. The nonlinear theory has provided recommendations for the development of lasers with improved properties, such as lasers with increased power and lasers with reduced natural linewidth. Abstract a model of microcavity semiconductor lasers in which both the cavity field and the gain medium are quantized is presented. Abstract a theory of the spectral width of a singlemode semicon ductor laser is. Clamping of the linewidth enhancement factor in narrow.

The monograph presents the nonlinear theory of semiconductor injection lasers, which demonstrates that the gain, twophoton absorption and refraction index in fabryperot semiconductor injection laser, as well as effective refractive. Henry, theory of the linewidth of semiconductor lasers, ieee j. Collins, measurements of the semiconductor laser linewidth broadening factor. Narrow linewidth lasers have many applications, such as higher order coherent communications, optical sensing, and metrology. Laser linewidth theory was pioneered by schawlow and townes 1 and further developed in 2 and 3. However, it was albert einstein who rst proposed the theory of \stimulated emission already in 1917, which is the process that lasers are based on 16. Tunable semiconductor lasers continue to be in just about everyones list of important components for future fiber optic networks.

Dependence of the linewidth enhancement factor on the wavelength of emission in ingaasp multiquantum well semiconductor lasers a si592 b si590 c 51588 d sl593 e si591 dependence of the linewidth enhancement factor on the band gap of the well barrier in ingaasp multiquantum well semiconductor laser. Semiconductor lasers or laser diodes play an important part in our everyday lives by providing cheap and compactsize lasers. Theory of the linewidth of semiconductor lasers nasaads. They consist of complex multilayer structures requiring nanometer scale accuracy and an elaborate design. Is there a linewidth theory for semiconductor lasers. The theory attributes the spectral width of laser oscillation to fluctuations brought about by. Selfvalidating technique for the measurement of the.

Quantum theory of semiconductor lasers in the photon. It is shown that at low and moderate powers gain compression reduces the effective phaseamplitude coupling factor, but at high power a number of mechanisms contribute to linewidth rebroadening. Subkhz quantum linewidth semiconductor laser on silicon. On the nonlinear theory of fabryperot semiconductor lasers. Semiconductor laser generation begins at a critical injection when the gain and loss spectra touch each other at a singular frequency. This phaseamplitude coupling is a key feature distinguishing semiconductor lasers from any other type of lasers and is responsible for a much broader linewidth in semiconductor lasers. The method itself provides an estimation of the measurement error, thus selfvalidating the entire procedure. Pdf chapter 4 determination of linewidth enhancement. The equation of motion for the elements of the reduced density matrix for the field in the photon number representation is developed and numerically solved to find the steadystate photon number distribution and the laser linewidth for a variety. The linewidth of a laser is predicted by schawlowtownes formula 4. In this chapter, we will discuss the status of the schawlowtowneslaxhenry stlh theory of laser linewidth in the instance of semiconductor injection lasers. At the same time, the developed theory is an integral part of the nonlinear theory of lasers, and its concepts and the introduced characteristic parameters are used in all parts of the nonlinear theory.

Noppe fundamentals of nonlinear theory for semiconductor lasers annotation. Spectral linewidth in microcavity surfaceemitting lasers deep blue. Henry, theory of spontaneous emission noise in open. Although this formula predicts the linewidth satisfactorily for gas lasers, it fails to predict the linewidth for semiconductor lasers. Laser linewidth theory was pioneered by schawlow and townes1 and further developed in refs. Quantitative test of general theories of the intrinsic laser linewidth. Narrow linewidth theory of the spectral width of a singlemode semiconductor laser is presented and used to explain the recent measurements of fleming and mooradian on algaas lasers. Air force phillips lab, kirtland afb, nm 87117, usa 3 permanent address. Spectral linewidth of semiconductor lasers springerlink. Henry ch 1982 theory of the linewidth of semiconductor lasers. At injection levels i below threshold i theory of the spectral width of a singlemode semiconductor laser is presented and used to explain the recent measurements of fleming and mooradian on algaas lasers. Moloneyl 1 arizona center for mathematical sciences, university of arizona, tucson az 85721, usa 2 us. A new method for measuring the linewidth enhancement factor.

The role of gain compression relating to semiconductor lasers is discussed. They found the linewidth to be inversely proportional to power and to have a value of 114 mhz at 1 mw per facet. Tutorial on narrow linewidth tunable semiconductor lasers. Fundamentals of nonlinear theory for semiconductor lasers. At injection levels i below threshold i laser linewidth theory was pioneered by schawlow and townes1 and further developed in refs. In a semiconductor we consider one state, e 1, to be in the valence band, and the other, e 2 to be in the conduction band. For semiconductor lasers, a factor 1 2 with being the linewidth enhancement factor of the gain medium must be added.

The theory of lasers has been developed in section 1. Yamada, theory of semiconductor lasers, springer series in optical sciences 185, doi. This value is 30 times greater than can be explained by existing theories. A natural consequence of the phase sensitivity is an enhancement of the laser linewidth beyond the schawlowtownes limit in addition to the one that is commonly attributed to nonorthogonality of modes in longitudinal or transverse. A theory of the spectral width of a singlemode semiconductor laser is presented and used to explain the recent measurements of fleming and. Improved rate equations for external cavity semiconductor. Thermally insensitive determination of the linewidth. Pdf linewidth evolution in semiconductor lasers throughout.

Schawlow with a ruby laser, 1961 semiconductors can be used as small, highly e cient photon sources in lasers. Implicit in most discussions of the linewidth of semiconductor lasers is the belief. The wavelengths of commercial lasers range from approximately 600 nm in the red to 1. Yariv, theory of gain, modulation response, and spectral linewidth in algaas quantum well lasers, ieee j. Linewidth enhancement factor in semiconductor lasers subject to. This is due to amplitudephase coupling in the semiconductor. Their theoretical description is important not only from a fundamental point of view, but also in order to generate new and improved designs. Osa large linewidth reduction in semiconductor lasers. Semiconductor lasers have important applications in numerous fields, including engineering, biology, chemistry and medicine. They form the backbone of the optical telecommunications infrastructure supporting the internet, and are used in information storage devices, barcode scanners, laser printers and many other everyday products. Theory of enhanced laser linewidth in semiconductor lasers. Pdf a detailed experimental and theoretical investigation on the. Osa selfvalidating technique for the measurement of the.

Derivation of the schawlow townes linewidth of lasers. Henry, theory of spontaneous emission noise in open resonators and its application to lasers and optical ampli. Clamping of the linewidth enhancement factor in narrow quantumwell grinsch semiconductor lasers j. Theory of the linewidth of semiconductor lasers ieee xplore. The linewidth of laterally losscoupled distributed feedback dfb lasers based on inas quantum dots qds embedded in an ingaas quantum well qw is investigated. Frequency chirp in directly modulated semiconductor lasers, fm and im response of semiconductor lasers, spontaneous emission and phase noise, linewidth of lasers, relaxation oscillations and linewidth of. At the same pump offset as the spacer hybrid lasers, the control laser exhibits a linewidth of nearly. Semiconductor laser linewidth measurements for space. Semiconductor laser an overview sciencedirect topics. The semiconductor diode laser sl has a number of properties that make it a desirable light. We see that the standard theory of laser linewidth is unsatisfactory.