• Focus quality of laser diodes with integrated lens

    From Mikko OH2HVJ@21:1/5 to All on Thu Jun 20 16:03:50 2019
    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

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  • From ggherold@gmail.com@21:1/5 to All on Thu Jun 20 06:52:09 2019
    On Thursday, June 20, 2019 at 9:03:51 AM UTC-4, Mikko OH2HVJ wrote:
    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.

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  • From Mikko OH2HVJ@21:1/5 to ggherold@gmail.com on Thu Jun 20 17:12:17 2019
    ggherold@gmail.com writes:

    On Thursday, June 20, 2019 at 9:03:51 AM UTC-4, Mikko OH2HVJ wrote:

    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

    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

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  • From ggherold@gmail.com@21:1/5 to All on Thu Jun 20 08:13:17 2019
    On Thursday, June 20, 2019 at 10:12:19 AM UTC-4, Mikko OH2HVJ wrote:
    ggherold@gmail.com writes:

    On Thursday, June 20, 2019 at 9:03:51 AM UTC-4, Mikko OH2HVJ wrote:

    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

    OK. I've never used something like that.
    (Hopefully Phil H. will have some ideas.)
    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.

    --
    mikko

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  • From Phil Hobbs@21:1/5 to ggherold@gmail.com on Sun Jun 23 09:28:32 2019
    On 6/20/19 11:13 AM, ggherold@gmail.com wrote:
    On Thursday, June 20, 2019 at 10:12:19 AM UTC-4, Mikko OH2HVJ wrote:
    ggherold@gmail.com writes:

    On Thursday, June 20, 2019 at 9:03:51 AM UTC-4, Mikko OH2HVJ wrote:

    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

    OK. I've never used something like that.
    (Hopefully Phil H. will have some ideas.)
    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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