Longitudinal spatial hole burning, its impact on laser operation, and suppression

Li, Xun

doi:10.1007/s11434-015-0812-1

Cited by 5 publications

(3 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is well known that the quarter-wavelength phase-shifted DFB laser provides a stable single mode operation with high SMSR, as it does not have the inherent dual mode degeneracy problem in uniform grating DFB lasers [22]. However, it suffers from the severe longitudinal spatial hole burning (LSHB) effect especially for high κL [23]. To mitigate the LSHB effect in quarter-wavelength phase-shifted DFB lasers, the corrugation pitch modulation (CPM) with the grating phase-shift distributed within a phase-arranging region (PAR) was proposed [24,25] to replace the conventional grating with an abrupt phase change.…”

Section: Effect Of Grating Dcr On Smsrmentioning

confidence: 99%

Impact of Grating Duty-Cycle Randomness on DFB Laser Performance

Yang,

Kong,

2024

Photonics

Self Cite

View full text Add to dashboard Cite

The duty-cycle randomness (DCR) of the Bragg grating of the distributed feedback (DFB) lasers introduced by the fabrication process is inevitable, even with state-of-the-art technologies such as electron beam lithography and dry or wet etching.This work investigates the impact of grating DCR on DFB laser performance through numerical simulations. The result reveals that such randomness causes a reduction in the side mode suppression ratio (SMSR), and deteriorates the noise characteristics, i.e., broadens the linewidth and increases the relative intensity noise (RIN). With the grating DCR, the effective grating coupling coefficient decreases as evidenced by the reduced Bragg stopband width. However, the longitudinal spatial hole burning (LSHB) effect in the DFB lasers can somewhat be diminished by the grating DCR. The seriousness of these effects depends on different grating structures and their coupling strengths. Our simulation shows that a degradation of 17 dB can be brought to the SMSR of the uniform grating DFB lasers with their duty cycles taking a deviation of ±25% in a uniformly distributed random fashion. It also broadens the linewidth of the quarter-wavelength phase-shifted DFB lasers by more than 2.5 folds. The impact of this effect on the RIN is moderate—less than 2%. All the performance deteriorations can partially be attributed to the effective reduction in the grating coupling coefficient of around 20% by such a DCR.

show abstract

Section: Effect Of Grating Dcr On Smsrmentioning

confidence: 99%

Impact of Grating Duty-Cycle Randomness on DFB Laser Performance

Yang,

Kong,

2024

Photonics

Self Cite

View full text Add to dashboard Cite

show abstract

“…A series of filters has been investigated for decades. [1,2] Filters have been applied to space communication, [3,4] gas detecting, [5] filtering the noises, [6] laser devices, [7,8] optical devices, [9,10] and some other areas. [11,12] Tunable filters have received much attention due to their increasing importance in improving the flexibilities of current and future wireless communication systems.…”

Section: Introductionmentioning

confidence: 99%

Superconducting tunable filter with constant bandwidth using coplanar waveguide resonators

Jiang¹,

Li²,

Wei³

et al. 2017

Chinese Phys. B

View full text Add to dashboard Cite

In this paper we propose a two-pole varactor-tuned superconducting filter using coplanar waveguide (CPW) spiralin-spiral-out (SISO) resonators. Novel internal and external coupling structures are introduced to meet the requirements for a tunable filter with a constant absolute bandwidth. The fabricated device has a frequency tuning range of 14.4% at frequencies ranging from 274.1 MHz to 317.7 MHz, a 3-dB bandwidth of 5.14 ± 0.06 MHz, and an insertion loss of 0.08 dB-0.70 dB. The simulated and measured results are in excellent agreement with each other.

show abstract

“…DFB (Distributed feedback) semiconductor lasers are the key elements in optical communications [1][2][3][4][5][6][7][8][9][10][11]. Reconstruction equivalent chirp (REC) technique based on sampled grating has been proposed and widely studied to reduce the fabrication cost and improve the laser performances [12][13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Transient mode competition in directly modulated DFB semiconductor laser

Xiao

Shi

Zheng

et al. 2015

Sci. China Phys. Mech. Astron.

View full text Add to dashboard Cite

A new effect of transient mode competition in directly modulated DFB laser based on equivalent phase-shift (EPS) technique is presented and studied. Since there are multi-order reflections in EPS structure and if the 0th order subgrating is properly designed, the transient lasing of 0th order will occur during the rising time of the injection current. As a result, transient mode competition between 1st order (main mode) and 0th order will occur accordingly. This can consume redundant carrier and suppress the transient relaxation oscillation, which may be applied in some areas like on-off switching modulation of DFB semiconductor lasers. As an example, an equivalent  phase shift (-EPS) is carefully designed to realize the effect. In such a laser the 0th order wavelength is in the margin of the material gain region and the 1st order wavelength is around the gain peak, while the stable single longitudinal mode (SLM) operation of the 1st order is guaranteed. The simulation investigation is performed. Good results with suppressed relaxation oscillation and 1.25 Gb/s directly on-off modulation (32 dB extinction ratio) are demonstrated. We believe it provides a new kind of method for on-off switching with high extinction ratio and weak relaxation oscillation. DFB semiconductor laser, mode competition, relaxation oscillation, sampled grating PACS number(s): 42.55.Px, 42.60.Mi, 42.60.Rn Citation: Xiao R L, Shi Y C, Zheng J L, et al. Transient mode competition in directly modulated DFB semiconductor laser.

show abstract

Longitudinal spatial hole burning, its impact on laser operation, and suppression

Cited by 5 publications

References 10 publications

Impact of Grating Duty-Cycle Randomness on DFB Laser Performance

Impact of Grating Duty-Cycle Randomness on DFB Laser Performance

Superconducting tunable filter with constant bandwidth using coplanar waveguide resonators

Transient mode competition in directly modulated DFB semiconductor laser

Contact Info

Product

Resources

About