Discussion:
Focus quality of laser diodes with integrated lens
(too old to reply)
Mikko OH2HVJ
2019-06-20 13:03:50 UTC
Permalink
Hi,

We're using some 1.3-1.7um telco laser diodes for measurements and 5.6mm to-can
versions are becoming obsolete.

There are still suitable diodes with integrated fiber coupling lens,
which have focus at 7.5mm from the base. The coupled power may be
specified, but that's about it.

I'm a bit worried about stray light in the measurement and the focus
seems to have plenty of stray light when viewed with IR card.
I could put a pinhole at the focus, but that's again additional
mechanics and manufacturing steps.

Does anybody have experience in this kind of diodes and their focus
quality ?

--
mikko
g***@gmail.com
2019-06-20 13:52:09 UTC
Permalink
Post by Mikko OH2HVJ
Hi,
We're using some 1.3-1.7um telco laser diodes for measurements and 5.6mm to-can
versions are becoming obsolete.
There are still suitable diodes with integrated fiber coupling lens,
which have focus at 7.5mm from the base. The coupled power may be
specified, but that's about it.
I'm a bit worried about stray light in the measurement and the focus
seems to have plenty of stray light when viewed with IR card.
I could put a pinhole at the focus, but that's again additional
mechanics and manufacturing steps.
Does anybody have experience in this kind of diodes and their focus
quality ?
--
mikko
Hi Mikko, You mean a laser diode pigtailed into a fiber.
https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1489

Do you need a lot of them, or just a few for testing? Maybe
just buy a bunch before they go eol?

George H.
Mikko OH2HVJ
2019-06-20 14:12:17 UTC
Permalink
Post by g***@gmail.com
Hi Mikko, You mean a laser diode pigtailed into a fiber.
https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1489
Something like this, I guess these are used in the pigtailed versions:
http://www.lasermate.com/CWDM5AC2G.html
Post by g***@gmail.com
Do you need a lot of them, or just a few for testing? Maybe
just buy a bunch before they go eol?
Depends on what is a lot :-) Hundred pieces for starters and thousands
of pieces during the next few years. I'm afraid the current ones are
EOL, which is one of the reasons for updating design. We're buying all
we can get to buy some time.

--
mikko
g***@gmail.com
2019-06-20 15:13:17 UTC
Permalink
Post by Mikko OH2HVJ
Post by g***@gmail.com
Hi Mikko, You mean a laser diode pigtailed into a fiber.
https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1489
http://www.lasermate.com/CWDM5AC2G.html
OK. I've never used something like that.
(Hopefully Phil H. will have some ideas.)
Post by Mikko OH2HVJ
Post by g***@gmail.com
Do you need a lot of them, or just a few for testing? Maybe
just buy a bunch before they go eol?
Depends on what is a lot :-) Hundred pieces for starters and thousands
of pieces during the next few years. I'm afraid the current ones are
EOL, which is one of the reasons for updating design. We're buying all
we can get to buy some time.
OK that's harder. We have a lifetime supply of Sanyo 785 nm LD's.. but
for us that's about 500 pieces.

George H.
Post by Mikko OH2HVJ
--
mikko
Phil Hobbs
2019-06-23 13:28:32 UTC
Permalink
Post by g***@gmail.com
Post by Mikko OH2HVJ
Post by g***@gmail.com
Hi Mikko, You mean a laser diode pigtailed into a fiber.
https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1489
http://www.lasermate.com/CWDM5AC2G.html
OK. I've never used something like that.
(Hopefully Phil H. will have some ideas.)
Post by Mikko OH2HVJ
Post by g***@gmail.com
Do you need a lot of them, or just a few for testing? Maybe
just buy a bunch before they go eol?
Depends on what is a lot :-) Hundred pieces for starters and thousands
of pieces during the next few years. I'm afraid the current ones are
EOL, which is one of the reasons for updating design. We're buying all
we can get to buy some time.
OK that's harder. We have a lifetime supply of Sanyo 785 nm LD's.. but
for us that's about 500 pieces.
Yeah, something like that is going to have a lot of stray light--the
first surface reflections are going to rattle around inside the can and
come out in all directions. It has an aspheric singlet collimating
lens, which should be okay for a single object position and a single
focus. It isn't clear whether they correct the astigmatism that way.

Some DFB lasers have shallow waveguides, so that their divergence is
nearly the same in both axes.

Cheers

Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
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