A Novel Grating Coupling Coefficient Extraction Method for DFB Laser Diodes Based on Side Mode Spacing

Abstract

A novel method to extract the grating coupling coefficient of distributed feedback (DFB) lasers by comparing the theoretical and experimental values of the side mode spacing is demonstrated. Compared with the traditional method, the proposed method in this paper transforms the solution process of the lasing model with multiple unknown parameters into that with only the side mode spacing and coupling coefficient, which significantly reduces the computational workload. Furthermore, the bias current of the measured spectrum can be much higher than the threshold current, which makes the method less affected by noise. This paper theoretically analyzes the changing relationship between multiple parameters by calculating the lasing mode distribution, and the results show that the side mode spacing is only sensitive to the coupling coefficient. In addition, the grating coupling coefficients (57-61 cm −1 ) of the fabricated DFB laser diodes are experimentally extracted at 40-80 mA currents. The variation of the coupling coefficient with current is less than 2‰/mA, and the method exhibits pretty good stability. Meanwhile, the grating coupling coefficient extraction method for the complex grating types is also considered in this paper.

Brief Discussion on the Path of Promoting the Construction of Learning Style with "Six Rates"

“…We should strengthen classroom attendance management, classroom etiquette education, classroom civilization education, and classroom behavior education, guide students to develop correct learning habits, and teach them to consciously abide by and maintain classroom discipline: do not be late for class, leave early, do not leave without permission, and be absent from class, do not play mobile phones in class to improve attendance and class rate. [1] We should strive to establish a supervision group for the construction of academic style, establish a scientific and effective process supervision and evaluation mechanism, and regularly report on the construction of academic style, in order to strive to improve the honor incentive system, and support the realization of various goals.…”

A DFB Laser With Integrated Passive Region Suitable for PAM-4 Modulation Signal

“…The magnitudes of the electric fields on both sides of each segment are linked by the transmission matrix, as shown in the following equation, [3]…”

“…istributed feedback (DFB) lasers are a type of directly modulated lasers (DML) with a small footprint, lowcost fabrication, and low power consumption [1,2]. Compared with vertical cavity surface emitting lasers (VCSEL) or Fabry-Perot (FP) lasers, DFB lasers can also achieve stable single-mode output, and are widely used in medium and shortdistance optical communication systems, such as access networks and fronthaul systems [3][4][5][6]. DFB lasers play the role of breaking through the last barrier of information transmission between societies.…”

Design and characterisation of multi-mode interference reflector lasers for integrated photonics

“…Cleaved facets can only be used at the edge of the integrated circuit and etched facets are generally of slightly lower reflectivity due to imperfect side wall angle and roughness [7] that can be introduced during the etching process. DFBs [8], which can be of the sidewall or lateral type [9] to avoid localised or multiple regrowth steps, and photonic crystal or deep-etched DBRs, can be effective, the latter with only a few grating periods, to achieve high reflectivity. However, these generally require e-beam lithography for the feature size required, increasing cost and manufacturing time.…”