Distributed-Feedback Semiconductor Lasers

Agrawal, Govind P.; Dutta, Niloy K.

doi:10.1007/978-1-4613-0481-4_7

Cited by 10 publications

(11 citation statements)

References 206 publications

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“…This effect can be seen in Figure Compressive strain increases gain, reduces threshold current densities, and slightly shifts lasing wavelength (due to band deformation potentials) [2], all of which improve operation of high power lasers. There are added benefits to modulated lasers in cluding reduction of frequency chirp, resulting from a decreased "antiguiding" factor, …”

Section: Electrically Pumped Semiconductor Lasersmentioning

confidence: 92%

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Finite aperture tapered unstable resonator lasers

Bedford¹

2003

Frontiers in Optics

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Section: Electrically Pumped Semiconductor Lasersmentioning

confidence: 92%

“…Auger Recombination Auger recombination, like non-radiative recombination, results in a reduction of carriers, but no increase in photons. Auger recombination is more significant in small band-gap materials because the hole probability is much larger for a given carrier density [2,19].…”

Section: Non-radiative Recombinationmentioning

confidence: 99%

Finite aperture tapered unstable resonator lasers

Bedford¹

2003

Frontiers in Optics

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“…The DFB spectral plots correspond to sample S.5, which has been detuned by +16 nm from the nominal wavelength of 1310 nm to the longer wavelength of 1326 nm (at 25°C). The spectral output shift to longer wavelengths observed at the high temperature of 85°C is typical of DFB laser sources which shift typically by a rate of ∼0.1 nm/°C due to the temperature dependence of refractive index . The side mode suppression ratio (SMSR) is maintained above 40 dB across the temperature range from 25°C to 85°C ( I = 50 mA).…”

Section: Grating Design and Spectral Performancementioning

confidence: 98%

Dynamic performance of detuned ridge waveguide AlInGaAs distributed feedback laser diodes

Cantú

McKee

Childs

et al. 2017

Microw. Opt. Technol. Lett.

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The dynamic behaviour of AlInGaAs ridge waveguide distributed feedback lasers is reported in this work covering five detuned wavelengths between 1291 nm and 1326 nm for a laser active layer optical peak gain design centred at 1310 nm at room temperature. The detuning is achieved by modifying the laser grating pitch that performs the mode selection within the laser cavity simultaneously across a single processed wafer. The dynamic behaviour is evaluated using the resonance frequencies of the detuned lasers measured at a range of injection currents for heatsink temperatures of 25 °C and 85 °C. The results confirm that a speed improvement can be achieved at 25 °C by detuning the laser to shorter wavelengths. However, the results also show that a lower direct modulation bandwidth at 85 °C makes the shorter wavelength design less attractive. For communications applications such as 10 Gbps uncooled operation, this trade-off between detuning and modulation bandwidth imply an optimum around -2 nm to +8 nm detuning (measured at 25 °C).Introduction: Distributed feedback (DFBs) lasers are essential components of uncooled fibre based optical communication applications where low chromatic dispersion is required over long transmission distances. In addition, single mode operation and intensity stability enable superior dynamic performance compared to that of the traditional Fabry-Pérot (FP) laser. The DFB lasers spectral purity is determined by an internal Bragg grating structure whose principles of operation are based on the coupled wave theory developed by Kögelnik and Shank in the 1970s [1]. The design of the grating itself is at the heart of the dynamic performance of the DFB laser, given the relationship between peak and differential optical gain, grating wavelength detuning, and the achievable value of the resonance (relaxation) frequency that limits the modulation bandwidth of the device. All these factors are also temperature dependent, adding to the design complexity.The authors in [2] proposed to improve the dynamic behaviour of DFB lasers by increasing their differential gain using wavelength detuning to shorter wavelengths. While the authors in [3] showed model and experiment results arguing that for a compressively strained 5 quantum well AlInGaAs system, the best way to preserve dynamic behaviour across temperature was to detune the lasing wavelength 25 nm longer than the peak optical gain wavelength.In this work the detuning technique and its effects on the dynamics of DFB lasers is explored for lasing wavelengths between ~20 nm below and ~16 nm above the peak optical gain (at 25 °C).A range of samples have been fabricated and tested in this work, where the pitch (Λ) of the grating layer has been varied gradually in order to detune the lasing wavelength from the peak optical gain of the multi-quantum wells (MQWs). All these lasers are designed on InP based ridge waveguide (RWG) technology, have a cavity length (L) of 250 µm, a room temperature threshold current (Ith) between 8 mA and 12 mA, and a slope efficien...

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“…The linear dependence observed between the laser temperature and wavelength operation observed in Fig. 4 b can be explained as a consequence of the linear variation of the laser effective mode index with temperature [12]. The rate of wavelength shift against temperature d λ /d T for each facet coatings (0.47 nm/°C for R 1 R 2 = 0.09, 0.51 nm/°C for R 1 R 2 = 0.14, 0.52 nm/°C for R 1 R 2 = 0.36 and 0.53 nm/°C for R 1 R 2 = 0.85) is commensurate with values reported in the literature (e.g.…”

Section: Spectral Characteristics In Temperaturementioning

confidence: 99%