Narrow-ridge distributed feedback laser with mode field diffusion structure and application thereof

Abstract

The invention discloses a narrow-ridge distributed feedback laser with a mode field diffusion structure and application thereof. The distributed feedback laser comprises an N-surface electrode layer,a substrate layer, a buffer layer, a first waveguide layer, a multiple quantum well active layer, a second waveguide layer, a grating layer, an etching self-stop layer, a cladding layer, an ohmic contact layer, and a P-plane electrode layer; and the cladding layer and the ohmic contact layer are etched to form a ridge waveguide, and the ridge waveguide comprises a straight waveguide and a mode field diffusion structure. The ridge width in the horizontal direction is shrunk, disconnection of the end face ridges and deposition of a layer of low-refractive-index material film on the end face arerealized, the mode field area of output laser can be effectively increased, the power density of the end face of the laser is reduced, the damage threshold of the end face of the laser is improved, the maximum injection current is increased, the bandwidth is increased, the stray-free dynamic range is enlarged, the high-frequency response characteristic of the laser is improved, and the modulationrate is increased.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, in particular to a narrow ridge distributed feedback laser with a mode field diffusion structure and its application. Background technique [0002] High-speed semiconductor lasers are the core devices of high-speed communication systems. The high-performance transmitter uses a high-power, low-noise DFB (distributed feedback) laser as a light source, and realizes data loading through direct modulation or external modulation. The direct modulation format changes the optical amplitude by changing the magnitude of the laser injection current, and the external modulation technology uses an external optical modulator to modulate the continuous light emitted by the semiconductor laser. The external modulator can realize a wider modulation frequency range, but it has a large volume, high cost, high driving voltage, and 6-7dB greater insertion loss. Directly modulated semiconductor lasers have th...

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Problems solved by technology

Directly modulated DFB lasers increase the output power of the laser as the injection current increases. When the injection current is too large, the end face is prone to optical damage and the frequency response becomes poor.

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