planar external cavity low noise narrow linewidth lasers...performance of planar-waveguide external...

1 PDV workshop SNL October 2012 RIO Inc.

Planar External Cavity Low Noise Narrow

Linewidth Lasers

Lew Stolpner

Redfern Integrated Optics Inc. Santa Clara, CA 95054, USA


Outline

1550 nm narrow linewidth lasers for fiber optic sensing

Planar External Cavity PLANEX Laser Design

Phase noise and linewidth reduction in the external cavity

PLANEX phase noise and linewidth

Wavelength and power stability

Wavelength tunability

Direct frequency modulation

Direct power modulation/pulsing

Phase locking

RIO laser products


Optical Sensing and Metrology

Wind Metrology

Wind energy

Air traffic control

Interferometric

Coherent Rayleigh

C-OTDR

Brillouin

DTSS

BOTDA/R

Coherent

Doppler LIDAR

Photonic Doppler

Velocimetry /Vibrometery

Oil and Gas

Seismic Reservoir Monitoring

Down well and SAGD

Pipeline Intrusion and Leakage Detection

Structural Monitoring

Static strain detection

Dynamic strain/vibration detection

Avionics/Space

LIDAR

RFOG

R&D/ Industrial/ Military,

metrology and process control

Military/security

Perimeter intrusion detection

Navy acoustic detection

Lasers

Low Noise

Narrow

Linewidth

Sensing

Technologies

Applications


Laser for Sensing: Key Requirements

Optical sensing market challenges for laser business

Market size it relatively small

Requirements vary significantly for various sensing technologies

Critical to make laser source suitable for multiple applications

Performance

1550 nm wavelength range to utilize availability of other Telco solutions

Low Phase/ Frequency Noise, Narrow linewidth, low RIN

Features

Small size, suitable for large multi-laser system integration

Frequency modulation and wavelength tunability

Field deployable

Stability in harsh environmental conditions

Reliability qualification to industry standards (Telcordia, MIL, Space)


PLC with Bragg grating on silicon wafers

Gain: optimized InP MQW chip

Packaging: 14-pin butterfly package, proven processes and materials

Planar External Cavity Laser PLANEXTM

TEC

Bragg Grating

PLC

Gain Chip

PLANEX ORION


PLANEXTM Laser Phase Noise

0.10

1.00

10.00

100.00

1 10 100 1000 10000 100000

Ph

as

e N

ois

e (

ura

d/s

qrt

(Hz)-

m)

Frequency (Hz)

Phase Noise Comparison

RIO PLANEX

FL-O

FL-K


Linewidth Measurement vs. Spectral Integration

1

10

100

1000

10000

1 10 100 1000 10000 100000 1000000

Fre

qu

ency

No

ise

(Hz/

sqrt

(Hz)

)

Frequency (Hz)

-40

-35

-30

-25

-20

-15

-10

-5

0

5

-250 -200 -150 -100 -50 0 50 100 150 200 250

SD

H B

eat

Sp

ectr

um

(d

B)

Frequency (kHz)

SDHmeasurement

Spectralintegration

Spectralintegration: whitenoise only

Integration

Both measurement and spectral integration match well down to -40 dB level on

Linewidth (LW) spectrum. (LW ~ 2.7 kHz @ -20 dB)

When only white noise level is integrated, SI provides pure Lorentzian LW ~ 1.2 kHz.

ORION Laser Frequency Noise

Laser Linewidth SDH Beat Spectrum

• Observation time on SI: 30 msec.

• SI for white noise only is done with fiber delay 400 km.

White noise level


-180

-170

-160

-150

-140

-130

-120

-110

-100

100 1,000 10,000 100,000

RIN

(d

B/H

z)

Frequency (Hz)

PLANEX RIN – Shot noise limited up to 5GHz

High frequencies of relaxation oscillations

Electron – Photon resonance

Photon-photon resonance (cavity round-trip)

RIN <– 140 dB/Hz at frequency > 2 kHz.

Shot noise limited up to 5 GHz

-180

-170

-160

-150

-140

-130

-120

-110

-100

0 5,000 10,000 15,000 20,000

RIN

(d

B/H

z)

Frequency (MHz)

RIN 100 kHz - 20 GHz RIN 100 Hz – 100 kHz


Excess Noise

RIO ORION laser

61.3 dB

Lorentzian linewidth as a parameter is not sufficient for

RIO developed special test to provide all information for Doppler metrology

applications

Excess noise < 0.2 dB for RIO laser with Lorentzian linewidth of 1.6 kHz


Power and Wavelength Stability

• Tested w. 10 mW ORION laser

• ORION laser is stabilized in

thermal chamber over 3 days

• ORION case reaches near

const. case temp. after 30 min.

of power-up

• Pk-Pk wavelength change over

3 days: 0.6 pm (NOTE: measured with Agilent 86122A

WM, WL differential accuracy: +/- 0.4 pm)

• Pk-Pk output power change

over 3 days: 0.19 mW (NOTE: measured with Agilent 86122A

WM, P calibration accuracy: +/- 0.5 dB)


Frequency Stability Test

ORION lasers modules (free running) frequency stability

measured with heterodyne mixing of two lasers

Laser stabilization time <1 s after turn on or re-tuning


ORION Laser Module Frequency Stability

Measurement Time Frequency stability

50 msec 150 kHz p-p

30 sec 1.5 MHz p-p

1 hour 4 MHz p-p

12 hours 20 MHz p-p


1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

0.1 1.0 10.0 100.0 1,000.0 10,000.0 100,000.0

All

an

Dev

iati

on

_N

ora

ma

lize

d

Observation Time (sec.)

ORION Laser Allan Deviation

Free-running. Case temperature stabilized : <0.2oC over 3 h

ORION (G3) – ORION (G4) beating ref.

Fiber Laser – ORION (G4) beating


Wavelength vs. TEC temperature: ~15 pm/ºC

Wavelength vs. bias current, CW: 0.4 -0.5 pm/mA (40-60 MHz/mA)

Wavelength Tunability

Phase continuous temperature tuning range ± 30 pm (± 4 GHz)

Fast wavelength tuning via bias current up to 4 pm (500 MHz)

Frequency tuning via bias current leads to simultaneous power

modulation

1550.800

1550.850

1550.900

1550.950

1551.000

18 19 20 21 22 23

Ts (C)

Wa

ve

len

gth

(n

m)

Wavelength vs. Bias Current

1543.570

1543.571

1543.572

1543.573

1543.574

1543.575

1543.576

1543.577

1543.578

1543.579

1543.580

90 95 100 105 110 115 120

Bias Current, mA

Wa

vele

ng

th,

nm


Wavelength Tuning and Direct FM

Tuning TEC Temperature and Bias Current

Slow thermal tuning up to +/- 30 pm (+/- 4 GHz)

Fast direct frequency modulation efficiency

CW : 0.9 MHz/mV (~ 50 MHz/mA)

10 kHz: 0.5MHz/mV

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

-35.00

-30.00

-25.00

-20.00

-15.00

-10.00

-5.00

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

-8 -3 2 7

DP

hase N

ois

e (

dB

)

WL

tu

nin

g (

pm

)

Set point

WL tuning_measured

Delta Phase Noise

24 C,123 mA

24.8 C,115 mA

25.6C,107 mA

26.8 C,95 mA

23.2 C,131 mA

22.4 C,139 mA

21.6 C,147 mA 0

20

40

60

80

100

120

140

160

180

200

0.01 0.1 1 10 100

FM

sen

sit

ivit

y M

Hz/V

,

fa/V

a

Frequency, MHz

DM Modulation

Electronic FM

Thermal FM


Low Frequency Noise with DM-FM

1

10

100

1000

10000

100000

1 10 100 1,000 10,000 100,000 1,000,000 10,000,000

Freq

uen

cy N

ois

e [H

z/sq

rt(H

z)]

Frequency (Hz)

Frequency Noise Measurements (MI at quadrature), Modulation: Sine-wave, Modulation frequency fm = 1 MHz, Input 100 mVpp


Reference Locking

Frequency noise spectrum of the PLANEX laser with (blue) and without

(red) frequency stabilization.

Within the control bandwidth of ~60 Hz, the noise was suppressed by a

factor up to ~1000.

Performance of planar-waveguide external cavity laser for precision measurements. Kenji Numata, Jordan Camp, Michael A. Krainak, and Lew Stolpner. October 2010 / Vol. 18, No.

22 / OPTICS EXPRESS

100

101

102

103

104

105

106

107

108

Fre

qu

en

cy

no

ise

[H

z/r

tHz]

10-4

10-3

10-2

10-1

100

101

102

103

104

105

Frequency [Hz]

Free-running Locked to acetylene


PLANEX- PLANEX FM

Parameter PLANEX PLANEX FM

Cavity 2 sections

GC + WBG PLC

3 sections

GC+ WBG PLC + LN FM

FM Modulation Direct bias current 1. Direct bias current

2. LN FM voltage

Residual AM Coupled with FM Practically decoupled with FM

FM frequency > 100 MHz

Not flat with phase reverse

>50 MHz bulk LN FM

>1 GHz with WG

Flat phase possible

H

R

Gain

Chip

PLC

AR

EOM

Chip

HR

Gain

Chip

Waveguide

Bragg

Grating

PLC

AR AR

AR

Waveguide

Lens


Direct Modulation/Pulsing of PLANEX laser

PLANEX laser modulation bandwidth > 1 GHz

25 Ohms impedance input

Unique direct modulation/pulsing while mountings

narrow linewidth performance

Minimal pulse shape distortion

Pulse Width > 5 nsec

Pulse Repetition

Frequency

up to 10 MHz

Extinction Ratio 25-32 dB

Linewidth < 15 kHz at pulse plateau

Pulse shape distortion Minimum or none

RMS Jitter 150 ps max


RIO Product Offering Wavelength

ITU DWDM or custom wavelength

4 Grades of linewidth/phase noise performance

PMF and SMF options

PLANEX™ and ORION™

> 10 mW

> 20 mW

RIO COLORADO

Wide tunable

RIO Grande

>1 W

> 2 W

Optical Phase Locked Loop (OPLL)

Typical Phase Noise

1

10

100

1000

1 10 100 1000Frequency, Hz

Ph

as

e N

ois

e, u

rad

/sq

rt(H

z)

1 m

OP

D

Gr 1

Gr 2

Gr 3

Gr4

Linewidth

, kHz

Grade 1 Grade 2 Grade 3 Grade 4 Optional

<15 <10 <5 <3 1


ORION Laser

Features Low noise current source and TEC controller

Input for direct modulation and wavelength tuning

OEM Module with SPI, RS-232 and RS-485 interface options, GUI

Benchtop OEM Source with USB interface options, GUI

Storage Temp, º C -40 to +85

Size, mm 100x56x13

Operational Temp Range, ºC 0-70

Power supply 5 V

Power Dissipation, < 6 W

@ 35 C case temperature <3 W

@ 50 C case temperature <4 W


ORION and Fiber Laser Comparison

Parameter

RIO008X

ORION

Koheras

Basik

NP Photonics

Rock

Orbits

Ethernal

Power >10 mW >10 mW >25mW >10 mW

RIN <-140 dB/Hz

(>1 kHz)

<-115 dB/Hz

(@1 MHz)

<-110 dB/Hz

(@1 MHz)

-120 dB/Hz

(@ 1MHz)

WL stability (FR), p-p 4 MHz 1 hour

20 MHz 12 h 20 MHz 1 h

20 MHz 1 h

50 MHz, 12 h

20 MHz 1 h

Storage Temp, º C -40 to +85 -20 to +50 -20 to +50 -20 to +50

Size, inches 4x2.25x0.5 8x4x1 8x5x1 7x3X1

Operational Temp Range, ºC 0-70 15-50 15-35 10-55

Power supply 5 V 12 V 5V 5V

Power Dissipation,

over specified case temp range < 6 W >10 W 20 W >10 W

@ 35 C case temperature <3 W 20 W

@ 50 C case temperature <4 W >10 W


RIO GRANDE: Amplified High Power Modules

Power 0.1 W up to 2 W, Low phase noise

Ultra low RIN

Narrow linewidth

High OSNR

0.1

1.0

10.0

100.0

1000.0

1 10 100 1000 10000 100000

Frequency (Hz)

Ph

as

e n

ois

e (m

rad

/sq

rt(H

z))

RIO GRANDE 9110515

ORION 800094

G1

G2

G3

G4

Fre

qu

en

cy n

ois

e (H

z/s

qrt(H

z))

100

1000

10000

10

-180.0

-170.0

-160.0

-150.0

-140.0

-130.0

-120.0

0 10,000 20,000 30,000 40,000 50,000

Frequency (kHz)

RIN

(d

B/H

z)


RIO COLORADO Wide Tunable Laser Performance Highlights

Low frequency noise

Low RIN

Available for C or L spectral bands

Cost effective solution

Convenience: GUI, integration

High Wavelength Stability (HWS) Mode Narrow linewidth <100 kHz

Optical Power Adjustment from 4 to 28 mW

Continuous Wavelength Sweep: 24 GHz peak-

peak or +/- 12 GHz) at any wavelength

Amplitude Modulation to 1MHz, M up to 10%

Ultra-Narrow Linewidth (UNL) Mode Ultra narrow linewidth ~ 25 kHz

Fixed wavelength and optical power

Frequency Modulation is available

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

-2,500 -1,500 -500 500 1,500 2,500

Norm

aliz

ed lin

ew

idth

spectr

um

(dB

)

Frequency (kHz)

Popt = 20 mW, Lorentzian Linewidth 22 kHz


OPLL - Dual Laser Source OPLL for distributed sensing and coherent metrology applications:

Distributed Brillouin Fiber Optic Sensing (BOTDA/BOTDR)

Heterodyne/ Coherent Metrology


OPLL Key Performance Specs and Features

Parameter Value Note

CW power > 5 mW average, two PM optical outputs

Laser frequency noise 103 Hz/Hz @ 100 Hz under locking conditions:

Linewidth <10 kHz

Phase noise -65 dB/Hz at 100 kHz offset

Frequency offset From 8 to 14 GHz step tuning

Tuning resolution 10 kHz

Continuous sweep tuning over 1GHz resolution 10 kHz @ 50msec speed

Locked step response time 5 msec at 10 MHz step


Exceptional Reliability for Space Applications Space qualification

Defined by NASA as “Game changing laser” for unique combination of high performance

and outstanding reliability for space applications

Selected by ESA and NASA for several space programs: PROBA-3, GRACE FO, LISA and

successfully completed Phase 1 of qualification testing

Reliability testing for space qualification

Environmental stress far exceeding Telcordia and MIL requirements

Tested production PLANEX units without special builds/selection/screening

Minimal changes after 1000 operating temperature cycles in vacuum and over 500

severe non-operational temperature cycles

0

5

10

15

20

25

30

35

40

0 100 200 300 400 500 600

Wa

ve

len

gth

Ch

an

ge

(p

m)

Cycles

Wavelength Change in Temp cycling (-40 C to 85 C)

100785

101033

101039

101132

101142

101163

101168

101248

101285

101550

101597

Limit


Thank you.

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