Narrow spectral linewidth semiconductor lasers

Kunii, T.; Matsui, Yasuhiro

doi:10.1007/bf00620152

Cited by 12 publications

(2 citation statements)

References 45 publications

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“…Ehj(k) = -Ehj h2k2i(2mh*) (17) J'r = 1/i1/me* + l/mhl (18) in the small-signal analysis of Eq.s (6) and (7) we assume that the laser is driven by a dc voltage V and is modulated by a small ac voltage LV(t). The injected current density is J(t) = J0 + zJ(t), while the carrier and photon densities can be written in the form flt(t) = to nt(t) and S(t) = Sj0 + respectively, to and Snjo being the stationary values.…”

Section: Theorymentioning

confidence: 99%

<title>Small-signal response of a lamba/4-shifted MQW DFB laser as a three-level system</title>

Sarmento¹,

Ferreira

1996

SPIE Proceedings

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The small-signal response of a X/4-shifted multiple-quantum well (MQW) distributed feedback (DFB) laser is investigated. The gain spectrum shows two major peaks located at the lowest heavy-hole and light-hole transitions. Therefore, the MQW DFB laser is treated as a three-level system. In the low-power range the heavy-hole transition dominates, while in the high-power range there is a mixing of the heavy-hole and the light-hole transitions. It is shown that the dynamic response of the MQW DFB laser is significantly affected by the contribution due to the light-hole transition. Its dependence on the number of quantum wells and on the coupling coefficient of the grating (K) is also discussed.

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Section: Theorymentioning

confidence: 99%

<title>Small-signal response of a lamba/4-shifted MQW DFB laser as a three-level system</title>

Sarmento¹,

Ferreira

1996

SPIE Proceedings

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“…A common fabrication method that produces very homogeneous gratings inscribes a laser interference pattern either directly into a photosensitive guiding region [2] or into a photoresist followed by transfer of the obtained periodic pattern to the guiding region or a cladding, e.g., by an etch process [6], [7], [14]. Since laser interference does not allow one to produce a discrete phase shift, a distributed phase shift can instead be created, e.g., by a widening of the guiding region, which increases the effective refractive index by the desired amount [7], [15]- [17].…”

Section: Introductionmentioning

confidence: 99%

Accumulation of Distributed Phase Shift in Distributed-Feedback Resonators

et al. 2019

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Distributed-feedback waveguide lasers based on Bragg-grating resonators generate ultranarrow-linewidth emission. Oscillation at the center of the reflection band ensures maximum reflectivity, hence minimum linewidth. The required π/2 phase shift is often introduced by a distributed change in effective refractive index, e.g., by widening the waveguide. Despite careful design and fabrication, the experimentally observed resonance wavelength deviates from the designed wavelength. Even when thermally induced chirp or fabrication errors are negligible, this deviation is still present. Here, we show theoretically and experimentally that this deviation is of fundamental nature. The decay of light intensity during propagation from the phase-shift center into both sides of the Bragg grating due to reflection by the periodic grating and the refractive index change causes an incomplete accumulation of designed phase shift, thereby systematically shifting the resonance to a shorter wavelength. Considering the overlap integral between the distributed phase shift and light intensity in the design provides the desired performance.

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