Gain competition often inhibits the simultaneous lasing of multiple longitudinal modes in homogeneously broadened laser systems. A stability analysis is developed to demonstrate that the two lowest order degenerate longitudinal modes in an indexcoupled distributed feedback (DFB) laser will lase simultaneously when the index grating is chirped asymmetrically along the axis of the device. This ch...

A Yb fiber laser pumped cw narrow-linewidth tunable mid-IR source based on a difference frequency generation (DFG) in a periodically poled LiNbO3 (PPLN) crystal for trace gas detection was demonstrated. A high power Yb fiber laser and a distributed feedback (DFB) laser diode were used as DFG pump sources. This source generated mid-IR at 3 microns with a powers of ~2.5 microW and a spectral line...

High-linearity, low-noise DFB lasers are necessary for analog optical communications, including subcarrier multiplexed systems, wireless personal communication systems (PCS) service and phased array radar. In this thesis, we examine the dynamic range and distortion for a Fujitsu DFB laser. We extract parameters from the device and use these parameters to simulate the distortion characteristics....

There is an increasing need in many chemical sensing applications ranging from environmental science to industrial process control as well as medical diagnostics for fast, sensitive, and selective trace gas detection based on laser spectroscopy. The recent availability of novel pulsed and continuous wave (cw) quantum and interband cascade distributed feedback (QC and IC DFB) lasers as mid-infra...

The effects of optical injection locking on the nonlinear distortions of directly modulated semiconductor distributed feedback (DFB) lasers are investigated experimentally. The second harmonic distortion (SHD) and third harmonic distortion (THD), as well as the third-order intermodulation distortion (IMD3), are measured as functions of modulation frequency for both the free-running and injectio...

Calculation of the small-signal modulation characteristics of tunable DFB and DBR lasers requires rate equations for the photon number, the phase of the electric field, and the carrier densities. In this paper, we derive the rate equation for the photon number and phase from an optical transmission line model and present examples of the frequency and intensity modulation characteristics of a ph...

In this work, the techno-economic and exergy analyses of two gasification technologies with integration into heat power combined cycles are presented: i). Circulating fluidized bed (CFB) ii). Dual (DFB) systems. As feedstock, lignocellulosic biomass (sugarcane bagasse, SCB) was considered . The process fluidized-bed systems (circulating dual bed) syngas conversion were performed using Aspen Plu...

In this paper, we theoretically and experimentally analyze the influence of round-trip phase distributed feedback (DFB) lasers on harmonic-phase photocurrent, caused by external injection current. The results indicate that photocurrent introduced (HPIRP) reduces with increase modulation depth at a fixed frequency. Then, based HPIRP DFB laser, simple photonic generation method optical microwave ...

795 nm oxide-confined distributed feedback (DFB) lasers have been developed. The structure is used to realize lateral optical and current confinement, the first order surface gratings offer frequency selectivity for single longitudinal mode operation. fabricated 200-um-long devices exhibited a low-threshold of ∼4.8 mA, 3-dB modulation bandwidth ∼5.8 GHz maintained stable operation around with s...

A novel optical millimeter-wave generation using sideband injection locking is demonstrated using monolithic two-section DFB lasers. The tunable millimeter-wave is generated by adjusting the RF-modulation frequency and bias currents. Summary The optical generation of millimeter-wave has been demonstrated and attracted much attention because of its flexibility and applicability in broadband mobi...