# US 10,374,384 B2 · Laser feedback control systems

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- Number: US 10,374,384 B2
- Document ID: US10374384B2
- Status: Granted
- Kind: B2
- Application number: 15/746,274
- Filed: 2016-07-19
- Published: 2018-07-26
- Granted: 2019-08-06
- Earliest claimed: 2015-07-20
- Assignees: AFL Telecommunications LLC
- Applicants: AFL Telecommunications LLC
- Inventors: Mohamed Amine Jebali; Ryo Hasehawa
- Web page: https://patentgrep.com/patent/US10374384B2

## CPC

- H01S 3/1305: {Feedback control systems}
- B23K 26/032: {using optical means}
- B23K 26/0626: {Energy control of the laser beam (B23K26/0622 takes precedence)}
- H01S 3/0071: {Beam steering, e.g. whereby a mirror outside the cavity is present to change the beam direction}
- H01S 3/134: in gas lasers
- H01S 3/2232: {Carbon dioxide (CO2) or monoxide [CO]}
- G02B 27/108: {for sampling a portion of a beam or combining a small beam in a larger one, e.g. wherein the area ratio or power ratio of the divided beams significantly differs from unity, without spectral selectivity}
- H01S 3/1306: {Stabilisation of the amplitude}
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A laser feedback control system includes a laser operable to emit a laser beam. The control system further includes a prism mirror which includes a first reflective surface. The first reflective surface is oriented to reflect the laser beam at a first angle to a first direction of travel of the laser beam. The control system further includes a sampling mirror, the sampling mirror partially reflective and oriented such that the laser beam reflected at the first angle by the first reflective surface encounters the sampling mirror at a polarization insensitive angle of incidence. The control system further includes a detector positioned to detect a portion of the laser beam transmitted through the sampling mirror.

## Claims

### Claim 1

A laser feedback control system, comprising:
a laser operable to emit a laser beam;
a prism mirror comprising a first reflective external surface, the first reflective external surface oriented to reflect the laser beam at a first angle to a first direction of travel of the laser beam;
a sampling mirror, the sampling mirror partially reflective and oriented such that the laser beam reflected at the first angle by the first reflective external surface encounters the sampling mirror at a polarization insensitive angle of incidence; and
a detector positioned to detect a portion of the laser beam transmitted through the sampling mirror.

### Claim 2 (depends on 1)

The control system of claim 1, further comprising a controller configured to adjust a pulse width modulation signal based on the detected portion of the laser beam and transmit the adjusted pulse width modulation signal to the laser.

### Claim 3 (depends on 1)

The control system of claim 1; wherein the laser is a CO2 laser.

### Claim 4 (depends on 1)

The control system of claim 1, wherein the polarization insensitive angle of incidence is less than or equal to 6 degrees.

### Claim 5 (depends on 1)

The control system of claim 1, wherein the first reflective external surface is a polished; planar surface.

### Claim 6 (depends on 1)

The control system of claim 1, wherein the sampling mirror is less than or equal to 1% transmissive at a 10.6 micrometer wavelength.

### Claim 7 (depends on 1)

The control system of claim 1, wherein the sampling mirror is formed from zinc selenide.

### Claim 8 (depends on 1)

The control system of claim 1, wherein the prism mirror further comprising an opposing second reflective surface.

### Claim 9 (depends on 8)

The control system of claim 8, wherein the second reflective surface is a polished, planar surface.

### Claim 10 (depends on 8)

The control system of claim 8, wherein the second reflective surface is oriented to reflect a portion of the laser beam reflected by the sampling mirror.

### Claim 11 (depends on 10)

The control system of claim 10, wherein the portion of the laser beam reflected by the second reflective surface is reflected to the first direction.

### Claim 12

A laser feedback control system, comprising:
a laser operable to emit a laser beam;
a prism mirror comprising a first reflective external surface and an opposing second reflective external surface, the first reflective external surface oriented to reflect the laser beam at a first angle to a first direction of travel of the laser beam;
a sampling mirror, the sampling mirror partially reflective and oriented such that the laser beam reflected at the first angle by the first reflective external surface encounters the sampling mirror at a polarization insensitive angle of incidence; and
a detector positioned to detect a portion of the laser beam transmitted through the sampling mirror,
wherein the second reflective external surface is oriented to reflect a portion of the laser beam reflected by the sampling mirror to the first direction.

### Claim 13 (depends on 12)

The control system of claim 12, further comprising a controller configured to adjust a pulse width modulation signal based on the detected portion of the laser beam and transmit the adjusted pulse width modulation signal to the laser.

### Claim 14 (depends on 12)

The control system of claim 12, wherein the laser is a CO2 laser.

### Claim 15 (depends on 12)

The control system of claim 12, wherein the polarization insensitive angle of incidence is less than or equal to 6 degrees.

### Claim 16 (depends on 12)

The control system claim 12, wherein the first reflective external surface is a polished, planar surface.

### Claim 17 (depends on 12)

The control system of claim 12, wherein the sampling mirror is less than or equal to 1% transmissive at a 10.6 micrometer wavelength.

### Claim 18 (depends on 12)

The control system of claim 12, wherein the sampling mirror is formed from zinc selenide.

### Claim 19 (depends on 12)

The control system of claim 12, wherein thy: second reflective external surface is a polished, planar surface.