Fabrication And Research On The Key Properties Of 1.3 ?m Waveband Superluminescent Diodes

Since the 21st century, optical fiber sensing technology has gradually been an important factor of measuring the informatization level of a country. As the ideal light source of optical fiber sensor ?OFS? system, the performance of superluminescent diodes ?SLDs? directly determines the accuracy and stability of OFS system. In order to promote the development and application of domestic OFS system, and master high-precision sensor technology, we must develop high-performance SLDs, especially at 1.3 ?m range.In this thesis, the fabrication and key characteristics of 1.3 ?m SLDs are studied. The whole research process can be divided into four stages:the first stage, the preparation and optimization of the device process; the second stage, the fabrication of broad area lasers; the third stage, the fabrication of ridge waveguide lasers; the fourth stage, the fabrication of SLDs. Achievements of each stage are listed as follows:1. By using the existing equipments in the laboratory, we studied the whole process flow of the devices, including epitaxial wafer cleaning,photolithography, etching, deposition of SiO₂, sputtering metal electrodes,thinning, etc., and the wet etching technology of the ridge waveguide was optimized. The problem of undercut in the wet etching of InP waveguide was alleviated by using HBr:HCl?1.5:1? etching solution instead of the traditional H₃PO₄:HCl?3:1? etching solution.2. For the first time in our laboratory, we successfully fabricated the broad area 1.3 ?m lasers, with 100 ?m strip width and 500 ?m cavity length, which proved the feasibility of fabricating SLDs in our laboratory.The active region of the device consists of six cycles of unstrained quantum wells. At about 8 ? and continuous wave condition with thermal sink apparatus, the threshold current is 240 mA, the threshold current density is 480 A/cm2, and when the current is 350 mA, the peak wavelength is 1297.7 nm and the full width at half maximum ?FWHM? is 0.02 nm. At room temperature ?25 ?? and pulsed wave condition without thermal sink apparatus, the threshold current is 400 mA, the threshold current density is 800 A/cm², and when the current is 700 mA,the peak wavelength is 1304.6 nm and the FWHM is 0.16 nm.3. We designed a new SLD epitaxial wafer structure, the active region of which was tensile and compressive strained alternated MQWs,and then contacted other department to grow the epitaxial wafer by MOCVD technology. To evaluate the quality of the SLD epitaxial wafer,we successfully fabricated the ridge waveguide 1.3 ?m lasers, with 16 ?m2 strip width and 500 ?m cavity length. At about 10 ? and continuous wave condition without thermal sink apparatus, the threshold current is 165 mA, and the threshold current density of 2.06 kA/cm2 is achieved.When the current is 250 mA, the peak wavelength is 1319.3 nm, and the FWHM is 0.04 nm.4. Using the tensile and compressive strained alternated MQWs SLD epitaxial wafers above, we explored the fabrication of SLDs at 1.3 ?m.And the P-I-V curve of the sloped-waveguide SLDs was measured under the pulse condition, which did not have obvious infection point.Subsequently, we will measure the spectrum of these SLDs, and further improve the fabrication process.