Optical properties of the buried waveguide in a bistable InGaAsP semiconductor laser

Abstract

In this letter, we first examine the power reflection coefficient at the interface between InGaAsP active and passive waveguides in a bistable laser and the optical losses of the passive waveguide. An original method is used for carrier density investigations: the spontaneous emission from the uncleaved sides of the active region is analyzed. With the experimental results and from a simple model we then calculate the carrier density difference and the reflection coefficient at the interface. After that we examine the ratio of the output power from each uncoated cleaved facet and deduce the spectrally resolved modal attenuation.

Deriving Expression of Output Spectrum from Semiconductor Laser with Two Sub-cavities

“…It is noticed that the last term of U is varying at a period proportional to the reciprocal of the total optical length of the full cavity, namely, l/(n|L, + n 2 L 2 ), and the middle two terms are, respectively, proportional to X) 4 the reciprocals of n^i and n 2 L 2 . Where n, is the effective refractive index of the jth region.…”

“…For this type of lasers, the optical lengths of the two regions are comparable, and the reflection coefficient at the interface is smaller than 0.01 [4], After examining quantity U, it can be understood that the middle two terms can be neglected when the laser is biased well below its threshold. For this case, the ABLD behave like an ordinary diode laser of a length of L. When the laser is pumped above its threshold, the differece between the first and fourth terms becomes vanishingly small, and may be smaller and smaller following the further increase of the pump current.…”

Studying Semiconductor Lasers with Ray Trace Method

“…account that the peak wavelength λ& of the spontaneous emission is tens of nanometers shorter than λ §[7] from (16), it can be VR1 + VR2 )( J 0 -1)[VR1R2 (j. + 1) is a plot of the carrier deficit Δ Ν versus the injection current has been drawn.…”