This document describes a dual laser fiber launch system using two lasers (405nm and 532nm) and off-the-shelf optical components. The compact and portable system achieves about 10% coupling efficiency to a single-mode fiber using mirrors for parallel alignment and a fiber port to control the fiber's position and tilt. The system is built within an optical cage for stability and uses standard parts, keeping the total cost around $1800 including the lasers.

1. Dual Laser Fiber Launch System
I have build this laser
fiber launch system
using two Actoprobe
lasers (405 and
532nm-20mW) and off
the shelf components
from ThorLabs. The
System is compact,
portable and easy to
align and use.

2. The coupling efficiency
to SM fiber of this
system is about 10%.
I am using two mirrors
for parallel alignment
(decenter) and a fiber
port PAF-X-18-A (to
launch fiber) to
control X-Y-Z offset
and tilt. No beam
expander is being
used to overfill the
back aperture of
the port.
Coupling Efficiency

3. Alignment and Parts
I first align the lasers by using upstream downstream mirrors along the
alignment arm (upstream and down stream IRIS). Then I replace the
alignment arm with port and adjust the X-Y-Z and tip on the fiber port.
I also Installed two ND filter wheels to adjust the intensity.
Upstream downstream
IRIS and mirrors
Lasers
ND filters

4. Stability and Cost
The system is built
within the cage system
so it has a good
stiffness, the system
does not get easily
misaligned when
moved from place to
place.
Right now it is blue and
green but it is easy to
add another channel to
make it RGB.
I am using off the shelf
components so the cost
of this system is around
$1800 including the
lasers.
Fiber ports

5. By: Pranav Rathi (PhD)
Confocal Raman Microscope