Types of Lasers for Optical Modules

‘Laser’ evolved from the abbreviation of LASER (Light Amplification by Stimulated Emission of Radiation). Laser is a kind of coherent light, with the characteristics of the same frequency, the same vibration direction and the same phase (or the phase difference remains constant). Optical communication system, to a large extent, depends on high quality laser light source.

Laser is the heart of an optical module, and its cost accounts for about 50% of the total cost of an optical module. This article mainly introduces the laser in an optical module. What are the types of lasers in optical modules? VCSEL, FP and DFB are all independent devices. If you want to transmit the light signal, it is driven with or without electric current, which is called Direct Modulated Laser (DML). EML is an integrated device. There are two modules on a chip, one is a laser (L), and the other is an EAM modulator, and these two formed together is called EML.

VCSEL

The full name of VCSEL is Vertical Cavity Surface Emitting Laser. It is a semiconductor laser of surface emitting type and a vertical cavity structure.

VCSEL can provide high quality laser beam and higher coupling efficiency. Compared with FP laser and DFB laser, VCSEL is easier to manufacture, making it possible to produce low-cost VCSEL based transceivers. VCSEL is mainly used for short-range optical modules. Read more on Types of Lasers for Optical Modules.