|
High
frequency optoelectronics
Modulation
and detection of light at very high frequency has found many
applications, in the area of optical fibre or free space transmission.
With both telecom optical networks and microwave transport in mind,
several types of InP-based semiconductor devices are investigated
within the Alcatel Thales III-V Lab :
. Direct modulation
lasers, with emphasis on microwave linearity,
. Electro-absorption
Modulated Lasers (EMLs) intended for 10 and 40 Gbit/s data rates, and
companion tunable laser,
. Photodiodes
offering a high responsivity and good linearity over a bandwidth
exceeding 40 GHz.
The design, packaging
and testing
of these devices best illustrates the combined microwave and
optoelectronics competencies of the Lab.
1.5 µm
DFB laser diodes for Ku-Band analog microwave optical emitters with :
- wide bandwidht
(>18 GHz)
- low RIN
(<-150 dB/Hz)
- high linearity
(input IP3>26 dBm)
Top
view of a waveguide pin photodiode designed for 40 Gbit/s applications.
The anti-reflection coated dry-etched input facet (top center) is
offset from the cleaved facet, allowing collective on wafer processing.
Light is evanescently coupled from the multimode diluted quantum well
waveguide into the 5 x 25 µm 2 absorption region.
The
single active layer Electro-absorption modulated Laser is a versatile
source for 10 & 40 Gbit/s applications. It benefits from a
large
spectral and operating temperature range. This is due to the AlGaInAs
structure and the automatic thermal compensation with a positive Bragg
detuning, respectively.
|
