CC BY
13PH-O-2
Photodiodes for detection of IR radiation from WGM lasers
E. Kunitsyna1,1. Andreev1, G. Konovalov1, Y. Yakovlev1, Y. Lebiadok2, M. Ahmetoglu (Afrailov)3, B. Kirezli3
1Ioffe Institute, Laboratory of Mid-Infrared Optoelectronics, St. Petersburg, Russian Federation 2SSPA "Optics- Optoelectronics & Laser Technology"- NAS of Belarus, Optoelectronics Laboratory, Minsk, Belarus
3Uludag University, Department of Physics, Bursa, Turkey
Semiconductor disk lasers operating on whispering gallery modes (WGM) in the IR range are of interest for laser-diode spectrometry, medicine, optical ultra-fast computing and switching systems. High Q factor of such lasers allows the use of the materials with low optical gain, thus resulting in a reduced threshold current and room temperature operation.
Detection of 2.0-2.3 p,m radiation from WGM lasers is an important task of mid-infrared photonics. For this purpose, cooled (77 K) InSb photodiodes are traditionally used. In this paper, we consider the possibility of applying the uncooled GalnAsSb/GaAlAsSb photodiodes for measuring the emission spectra of WGM-lasers.
The GalnAsSb/GaAlAsSb photodiodes exhibit a spectral sensitivity in the range of 0.9-2.4 p,m at room temperature. The monochromatic current sensitivity at the spectrum maximum is 1.1-1.2 A/W, which corresponds to a quantum efficiency of 0.6-0.7 without antireflection coatings. The operating speed of the photodiodes with 2 mm active area diameter at a load R = 50 Ohm does not exceed t = 120-250 ns. The radiation effect of 60Co (y)-ray source with 6 MeV photon energy and 1.5*10n gamma/cm2 fluency on the electrical and optical characteristics the photodiodes was investigated.
The emission spectra of the 400 p,m half-disk WGM lasers based on quantum-dimensional GalnAsSb/GaAlAsSb heterostructure were studied using a spectrometer with resolution 2 A. The lasers were exited with rectangular electrical pulses. The operating frequencies ranged from 2 to 16 kHz, the pulse duration could vary from 2 to 60 |is. The pump currents were 1=140-250 mA. As a result, equidistant laser modes were clear observed on the spectra. The intermode distance of 12 A indicates that the lasers work on the WGM modes of the first order.
The work was supported by the Russian Foundation for Basic Research (RFBR) under Grant No 18-52-00027 and the Belarusian Republican Foundation for Fundamental Research (BRFFR), project 018P-121.
