Active surface of a laser diode?

[N_Cook]

For self-education I decided to take apart a presumably defunct DVD laser
unit to see the internal layout of splitters etc and what the laser diode
looks like. Googling in images I only find graphics or external views,
anyone know of a WWW view through the window of some good laser diodes ?.
Looking via x30 at what I assume to be the active surface is a uniform grey
colour and uniform crystalline appearance rectangular face (ie no obvious
hot spot/s) like a finer grained version of a fractured surface of cast
aluminium or monkey metal.
Is this the infamous Catastrophic Optical Damage ?
This one has a marking of RH on the body.

 

[N_Cook]

So if the active surface of this pic , (different internals to the one I
have looked at )
http://img98.imageshack.us/img98/7546/70756733678cc5bb59e9b.jpg
is the uppper part of the die then the same grey granular appearance

 

[Uffe Bćrentsen]

Den 01-04-2013 13:56, N_Cook skrev:

So if the active surface of this pic , (different internals to the one I
have looked at )
http://img98.imageshack.us/img98/7546/70756733678cc5bb59e9b.jpg
is the uppper part of the die then the same grey granular appearance

How about the small 'rod' that the 4 bonding wires from the right pin
goes on top of?


--
Uffe

 

[Ian Field]

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:kjbsja$fgv$1@dont-email.me...

So if the active surface of this pic , (different internals to the one I
have looked at )
http://img98.imageshack.us/img98/7546/70756733678cc5bb59e9b.jpg
is the uppper part of the die then the same grey granular appearance

The "active surface" is a channel through the die, there's a tiny aperture
in the middle of that "granular surface".

 

[N_Cook]

Ian Field <gangprobing.alien@ntlworld.com> wrote in message
news:Wqh6t.196813$zh5.151918@fx22.fr7...

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:kjbsja$fgv$1@dont-email.me...
So if the active surface of this pic , (different internals to the one I
have looked at )
http://img98.imageshack.us/img98/7546/70756733678cc5bb59e9b.jpg
is the uppper part of the die then the same grey granular appearance


The "active surface" is a channel through the die, there's a tiny aperture
in the middle of that "granular surface".

Smaller than the resolution of that photo or the small blackish rectangle on
the end of the "bar" that ends flush with the granular surface, on a line
between the centres of the end faces of the conductor pins.
Dimensions of that rectangle about one of those wires diameter x about 4
wire diameters

 

[George Herold]

On Apr 1, 7:56 am, "N_Cook" <dive...@tcp.co.uk> wrote:

So if the active surface of this pic , (different internals to the one I
have looked at )http://img98.imageshack.us/img98/7546/70756733678cc5bb59e9b.jpg
is the uppper part of the die then the same grey  granular appearance

I think the laser diode is the long gold bar with four wires going to
it.
I'm not sure what the silver cube next to it is.. a temerature
sensor?

The whole thing is on some substrate.. maybe Alumina or Silicon??

The emitting area of a laser diode is really tiny.

George H.

 

[Ian Field]

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:kjcb7l$kar$1@dont-email.me...

Ian Field <gangprobing.alien@ntlworld.com> wrote in message
news:Wqh6t.196813$zh5.151918@fx22.fr7...


"N_Cook" <diverse@tcp.co.uk> wrote in message
news:kjbsja$fgv$1@dont-email.me...
So if the active surface of this pic , (different internals to the one
I
have looked at )
http://img98.imageshack.us/img98/7546/70756733678cc5bb59e9b.jpg
is the uppper part of the die then the same grey granular appearance


The "active surface" is a channel through the die, there's a tiny
aperture
in the middle of that "granular surface".


Smaller than the resolution of that photo or the small blackish rectangle
on
the end of the "bar" that ends flush with the granular surface, on a line
between the centres of the end faces of the conductor pins.
Dimensions of that rectangle about one of those wires diameter x about 4
wire diameters

There are various laser tutorials online with exploded view representations
of the junction structure - that's where I got all I have.

 

[Sjouke Burry]

"N_Cook" <diverse@tcp.co.uk> wrote in news:kjbreu$8ds$1@dont-email.me:

For self-education I decided to take apart a presumably defunct DVD
laser unit to see the internal layout of splitters etc and what the
laser diode looks like. Googling in images I only find graphics or
external views, anyone know of a WWW view through the window of some
good laser diodes ?. Looking via x30 at what I assume to be the active
surface is a uniform grey colour and uniform crystalline appearance
rectangular face (ie no obvious hot spot/s) like a finer grained
version of a fractured surface of cast aluminium or monkey metal.
Is this the infamous Catastrophic Optical Damage ?
This one has a marking of RH on the body.

If it is a visible light laser diode, just use a lens to produce
an image of the chip on your wall.
That is safe to look at, and shows the light distribution.

 

[Wild_Bill]

Sam would likely know. Nice picture.

--
Cheers,
WB
..............


"N_Cook" <diverse@tcp.co.uk> wrote in message
news:kjbsja$fgv$1@dont-email.me...

So if the active surface of this pic , (different internals to the one I
have looked at )
http://img98.imageshack.us/img98/7546/70756733678cc5bb59e9b.jpg
is the uppper part of the die then the same grey granular appearance

 

[N_Cook]

Sjouke Burry <s@b> wrote in message
news:XnsA196225E0774Fsjoukeburrysoesterbe@213.75.12.10...

"N_Cook" <diverse@tcp.co.uk> wrote in news:kjbreu$8ds$1@dont-email.me:

For self-education I decided to take apart a presumably defunct DVD
laser unit to see the internal layout of splitters etc and what the
laser diode looks like. Googling in images I only find graphics or
external views, anyone know of a WWW view through the window of some
good laser diodes ?. Looking via x30 at what I assume to be the active
surface is a uniform grey colour and uniform crystalline appearance
rectangular face (ie no obvious hot spot/s) like a finer grained
version of a fractured surface of cast aluminium or monkey metal.
Is this the infamous Catastrophic Optical Damage ?
This one has a marking of RH on the body.






If it is a visible light laser diode, just use a lens to produce
an image of the chip on your wall.
That is safe to look at, and shows the light distribution.

I went the "unsafe " route and put 2.5V and 560R over the 1.6V DVM diode
test junction ( 1.3V of the other pair of pins of this recordable DVD
laser). The dim and dull-red light came from the junction between the grainy
block surface and the pillar . In my one the end of the pillar is a
"polished" surface with no metalisation over it unlike the one in that pic.