Optics
90° beam turn
EEL PACKAGING
Sub-millimetre Micro Turning Mirror
In-house product · Global inquiriesA silicon 45° precision optic that turns the horizontal beam of an edge-emitting laser (EEL) by 90°, so the laser can be packaged as SMD or COB and placed by automated SMT equipment instead of a hand-inserted TO-CAN.
Available with a gold or aluminium mirror surface, selected by wavelength and polarisation. Dimensional tolerance and surface cleanliness are graded by application and confirmed during engineering evaluation.
Assembly
SMT automation
Height on board
≈ 5 mm → ≈ 1 mm
THE BOTTLENECK
Why EELs are still stuck in TO-CAN
Edge-emitting lasers perform well but have long depended on the bulky, hand-inserted TO-CAN. Once mounted, the can still stands about 5 mm above the board, and the manual step keeps it off modern SMT lines and out of thin product designs.
A micro turning mirror converts horizontal emission into vertical emission, bringing module height down to about 1 mm and allowing placement roughly 5× faster than manual insertion.
DESIGN FOR MANUFACTURING
Three design layers, from optic to reliable volume assembly
01 · SILICON
Silicon substrate
The mirror absorbs part of the laser energy and heats up. Silicon conducts heat better than fused silica, limiting heat build-up at the reflective surface and the risk of coating delamination. The EEL itself is still cooled through its metal or ceramic SMD carrier.
02 · DFM
Designed for pick-and-place
The geometric centre and a dedicated pick-up platform are sized for standard nozzles, so a precision optic can run through high-throughput automated placement with stable results.
03 · ANTI-WICKING
Keeping the optical face clean
Edge geometry interrupts the capillary path of die-attach adhesive, so it cannot climb onto the reflective surface and degrade optical efficiency.
NOMINAL GEOMETRY
Nominal geometry and part numbering
The 45° optical design and the nominal geometry are common to every part we supply. Part numbers read series + material + MH + PW + SH + MW: series mR is the General grade and uR the Optical grade; material U0 is gold and L0 aluminium.
Scroll sideways to see the full drawing
Published nominal dimensions
- Mirror height H
- 460 µm
- Pick-up platform PW
- 250 µm
- Mirror step s
- 160 µm
- Mirror width W
- 250 µm
- 45° face projection L = H − s
- 300 µm
- Overall length
- 670 µm
These are the published nominal dimensions. The tolerance band and mirror-surface cleanliness criteria differ between the General and Optical grades and are confirmed during engineering evaluation. Typical COS submount height is 200–250 µm; an emitting distance below 100 µm is recommended.
ACCEPTANCE ANGLE
Will your laser fit? Two formulas
With submount height h and emitting distance d (facet to mirror), the upward and downward acceptance half-angles are
αup = atan((H − h) / (d + L))
αdown = atan((s − h) / d)
symmetric = 2 × min(αup, |αdown|)
| Use case | h (µm) | d (µm) | αup | αdown | Symmetric |
|---|---|---|---|---|---|
| 905 nm LiDAR | 200 | 80 | 34.4° | −26.6° | 53.1° |
| 808 nm LLLT | 250 | 100 | 27.7° | −42.0° | 55.4° |
| 1310 nm optical comms | 200 | 50 | 36.6° | −38.7° | 73.2° |
| Reference | 200 | 100 | 33.0° | −21.8° | 43.6° |
Nominal dimensions, tolerances not included. Compare against your laser’s full divergence angle using one definition consistently: 1/e² full angle = 1.699 × FWHM full angle. Results are for package evaluation, not a delivery guarantee.
INTERACTIVE TOOL
Run the numbers before requesting samples
Enter wavelength, fast/slow-axis divergence, submount height and emitting distance; the acceptance simulator returns the geometric acceptance and the mirror reflectance for gold or aluminium, and converts between FWHM and 1/e². Results are for package evaluation, not a delivery guarantee.
FAQ
Frequently asked questions
01What is a sub-millimetre micro turning mirror?
It is a silicon-based 45° precision optical component that redirects the horizontal beam of an edge-emitting laser (EEL) by 90° into a vertical emission, so the laser can be packaged in SMD or COB form and assembled on automated pick-and-place lines.
02What is the difference between the General grade (mR) and the Optical grade (uR)?
Both grades share the same 45° optical design and nominal geometry. They differ in the dimensional tolerance band and the visual cleanliness criteria of the mirror surface. The Optical grade is intended for applications with tight alignment margins or where surface defects directly affect coupling; the specific limits are confirmed during engineering evaluation.
03Should I choose a gold or an aluminium mirror?
Below 500 nm gold reflectance drops to roughly 52 %, so aluminium is required. Between 600 and 1000 nm gold is the usual choice; above 1000 nm the two materials are close. Reflectance at 808 nm: gold 98.2 % (s-polarised) / 96.5 % (p-polarised), aluminium 90.6 % (s) / 82.0 % (p). The s values are measured; both p values are Fresnel estimates, not measurements.
04How do I estimate whether my laser divergence fits the mirror?
Use the acceptance-angle formulas: αup = atan((H − h) / (d + L)) and αdown = atan((s − h) / d), where h is the submount height and d the distance from the emitting facet to the mirror. The symmetric equivalent acceptance angle is 2 × min(αup, |αdown|). With h = 200 µm and d = 80 µm (a typical 905 nm LiDAR layout) this gives about 53°. Convert divergence consistently: 1/e² full angle = 1.699 × FWHM full angle.
05Why silicon rather than fused silica?
The mirror absorbs the fraction of laser energy it does not reflect. Silicon conducts heat better than fused silica, reducing heat build-up near the reflective surface, and it connects to mature semiconductor processing for volume production. The EEL itself still needs a metal or ceramic SMD carrier for its own heat path.
06What does the anti-wicking geometry do?
Die-attach adhesive can climb the edges of a component by capillary action and contaminate the reflective face. The mirror’s edge geometry breaks that wicking path, lowering the risk of optical-surface contamination and efficiency loss.
07Which applications are suitable, and how do I request samples?
Typical uses are LLLT low-level laser therapy, LiDAR, 3D sensing and high-speed optical communication — anywhere an EEL must emit vertically. Send us the laser wavelength, submount height, emitting distance and package constraints through the contact page; our engineers will recommend the mirror material, grade and sample quantity. Inquiries from any country are welcome.
Tell us about your laser and package
Send the wavelength, submount height, emitting distance and package constraints. We will confirm the mirror material, grade and sample needs. Inquiries from any country are welcome.