taccor comb

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ertiosero w av e g e nMoletrogyo p ti c a l frequIn addition to the repetition rate RF signal at fR, the taccor comb
provides a long-term stable RF signal at the carrier-envelope
offset (CEO) frequency fCEO (Fig. 1) with more than 35 dB signalto-noise ratio (Fig. 2). Feedback electronics to stabilise fR and fCEO
are provided in the form of Laser Quantum’s TL-1000 unit andthe XPS800-E from our partner, Menlo Systems. The taccor comb
provides the ideal solution for customers who seek to have a comb
source with easy access to the visible and NIR spectral range ata high mode power level in a sealed, plug and play architecture.
The high repetition rate of 1 GHz leads to a large mode spacing
and high power per mode on the order of typically 1 μW after
broadening (Fig. 3). The repetition rate of the taccor comb also
HQDEOHVJHQHUDWLRQRIVLJQL¿FDQWO\PRUHVXSHUFRQWLQXXPDYHUDJH
power in a PCF compared to systems at 100 MHz (100 x more) or0+] [PRUH EHIRUHVLJQL¿FDQWFRKHUHQFHORVVYLDQRQOLQHDUQRLVHDPSOL¿FDWLRQLVVXIIHUHG )LJ 7KLVOHDGVWRDVLJQL¿FDQWO\enhanced signal to noise ratio for heterodyne beat measurements
or direct frequency comb spectroscopy applications.

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To support applications of the taccor as a frequency comb, Laser
Quantum has added the comb extension module to its successful
range of 1 GHz lasers, now making the taccor comb available
to the market. It consists of a matched dispersion compensation
module, supercontinuum generation, and a nonlinear f-to-2f
interferometer, all sealed in a compact housing which is attachedto the turn-key femtosecond taccor laser system. The extension
module consumes around 800 mW of the taccor’s output powerso that up to 1 W can be made available for experiments via a
dedicated exit port or can be further broadened to a supercontinuum
spectrum using an optional second extension module.

enOverview

ca

U n iq u• Turn-key GHz femtosecond taccor laser• Extension module for CEO frequency detection and stabilisation• Repetition rate stabilisation via TL-1000• Large mode spacing of 1 GHz• High-power per mode (typ. 1 μW)• Stable and robust

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1 GHz mode spacinger
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-20-20-30-30-40-40-50-60

fCEO

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fR

Intensity (dB)Intensity (dB)

Click here to request a quotation-50-60-70-80

-80
200

400
600
800
Frequency f (MHz)

1000

103

20Input

102-50Output at 500 mW input

101
10010-110-210-310-4600

800

1000-51200

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Wavelength (nm)Fig. 3 Red: Typical taccor output spectrum used for CEO
detection and comb applications. Blue: Output spectrum after
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0f - fCEO (MHz)510Fig. 2 Close-up of the unlocked fCEO VLJQDO DIWHU DPSOL¿FDWLRQ
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resolution bandwidth of 100 kHz.

Average RF Noise

Power Per 1 GHz Mode (μW)

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Power (dBm in 30 kHz)

0Average Power at 100 MHz
3040506070300700-60-70-80-90200400500600

Average Power at 1 GHz
Fig. 4 Typical average RF noise in the CEO detection as functionof power coupled through a PCF for supercontinuum generation
for a 100 MHz laser (top scale) and a 1 GHz laser (bottom scale).
Above a threshold pulse energy of around 30 pJ, nonlinear noiseDPSOL¿FDWLRQ TXLFNO\ UHQGHUV WKH 3&) RXWSXW LQFRKHUHQW WKXV
heavily favoring a 1 GHz system. Data taken from reference [1].

Turn-key design for stable performance

fCEO - 60 MHz (mHz)fR - 1.00008 GHz (mHz)

The extension module in the taccor comb preserves the long-term stability of the turnkey taccor laser. The system delivers a stable RF output at fCEO over many days without
realignment or signal loss. On a day-to-day basis the taccor comb is operated with
PLQLPDOXVHULQWHUDFWLRQDQGDVWDUWXSWLPHRIPLQVXQWLOORFNHGLQIR and fCEO. Thelong term stability of fR and CEO beat lock are shown in Fig. 5a and 5b.

Time (h)Time (h)Fig. 5a Long term deviations of the stabilised taccor repetition
rate over 100 h showing exceptional stability (limited by RFreference input).

Fig. 5b Long term deviations from the lock point of a CEO beatstabilised at 60 MHz over 100 h showing exceptional stability(limited by RF reference input). No realignment is required forcontinuous operation of the taccor comb over several days.

Carrier envelope phase stabilisation
The ¿QHVVHSXUH&(3 pump laser built within the taccor features our patented CEPLoQTM
technology and allows direct modulation of the 532 nm pump light leading to a fasterand more stable response than traditional methods, e.g. using an AOM. Thus, a very
high feedback bandwidth can be applied to phase-lock the CEO frequency to an externalreference (see Fig. 6).
Phase detection between the measured fCEO and a given reference signal is performed
DQGFRQYHUWHGLQWRDIHHGEDFNVLJQDOWRWKH¿QHVVHSXUH&(3LQSXWXVLQJWKH;36(stabilisation unit (Menlo Systems). Tight locking of fCEO with a large feedback bandwidthenables the taccor comb to show residual integrated phase error of 300 mrad or less(see Fig. 7).
PSD (rad2 / Hz) phase noise (mrad)-20

Intensity (dB)

-30
-40
-50
-60
-70
-80

-400-200

0200400f - fCEO (kHz)Frequency (Hz)Fig. 6 Close-up of the phase-locked fCEO. The data is acquired
using a resolution bandwidth of 200 Hz. The servo bandwidthis about 250 kHz as indicated by the symmetrical peaks aroundthe carrier.

Fig. 7 Frequency resolved and integrated residual phase noise of
the stabilised fCEO beat featuring 230 mrad (1 MHz – 1 Hz).

Repetition rate stabilisation
Laser Quantum offers the timing stabilisation unit, TL-1000, as an accessory to thetaccor series of high-speed femtosecond oscillators. The TL-1000 allows the tightphase-lock of an oscillator’s repetition rate to an external reference such as a synthesiser
or another modelocked laser, with a residual timing jitter below 100 fs. A low timing jitter
option is available that suppresses the timing jitter to typically below 10 fs (Fig. 8, 9 & 10).
A suitable 10 GHz reference synthesiser must be provided by the customer. Stabilisationis performed at a higher repetition rate harmonic.
104

100

Standard
Low jitter option

103

Standard
Low jitter option

10Timing jitter (fs)

PSD [fs2/Hz]

2

101
100
10-1
10-2
10-3

10

1

10-4
10-5
10-6

100

101

102
103
Frequency (Hz)

104

105

100

101

102
103
Frequency (Hz)

104

105

Fig. 8 Phase noise measurements of the taccor repetition rate fR Fig. 9 Timing jitter as acquired by integrating the phase noise
stabilised using the TL-1000. Black and red graphs correspond from Fig. 8. Stabilisation at the 10th harmonic of fR leads to aWRVWDELOLVDWLRQXVLQJWKHVWDQGDUGDQGORZMLWWHUFRQ¿JXUDWLRQVRI sub-10 fs timing jitter.
the TL-1000 unit.

UpgradesThe taccor comb can be upgraded by an additional extension module that can include
RQHRUWZRDGGLWLRQDOSKRWRQLFFU\VWDO¿EHUVIRUIXUWKHUEURDGHQLQJRIWKHtaccor laser
RXWSXWHJLIDVSHFL¿FVXSHUFRQWLQXXPVSHFWUXPLVUHTXLUHGIRUH[SHULPHQWVtaccor comb

High-power frequency comb with
1 GHz mode spacing

Dimensions (mm)86.5

Other information
Cooling system included
f-to-2f interferometer included
fCEO lock electronics included
Weight: 50 kg

06051

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20829 035

170049138Drawings are for illustrative purposes only. Please contact
Laser Quantum for complete engineer’s drawings.

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Useable 800 nm power after fCEO stabilisation

power 8power 10600 mW

1000 mWfCEO beat signal-to-noise (in 100 kHz bandwidth)>35 dB

Repetition rate/comb spacing

1 GHz

Tuneability of the comb mode position (@375 THz)

Up to 20 GHz

Residual phase noise [1 Hz - 1 MHz]Typ. 300 mrad

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100 nW to 1 μW

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520 nm to 1200 nm

Stability

5x10

Accuracy

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LQVKDVEHHQGHPRQVWUDWHG>@:LWKRSWLRQDOVXSHUFRQWLQXXPPRGXOH7KLVRSWLRQFRQVXPHVWKHXVHDEOHQPSRZHURXWSXWQRWUHTXLUHGIRUICEO stabilisation.
:KHQIR is locked to a RF reference. A suitable RF synthesiser must be provided by the customer.
:KHQIR is locked to an optical reference. A suitable optical reference must be supplied by the customer.

References[1] L. Hollberg et al., “Optical frequency standards and measurements”, IEEE J. Quantum
Electron. 37, 1502 (2001)[2] L.-S. Ma et al., “Optical frequency synthesis and comparison with uncertainty at the 10-19level”, Science. 303, 1843 (2004)
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