FR-103XL AUTOCORRELATOR
Specifications:
- Resolution: ~ 1fs
- Minimum Pulsewidth: < 5fs
- Maximum Pulsewidth: ~ 100ps '
- Scan Range: > 195ps '
- Sensitivity: [PavPpk]min=10-7W2 "
- Wavelength Range: 410-5000nm- Interferometric/Background-free
- Crosscorrelation Option
- Fiber Coupled/ Free Space
- Low Rep Rate Option (> 4Hz)
- Computer Data Acqusition Option
" 10-8W2 w/HS version. w/ PMT [550-1700nm]
The FR-103XL is a dispersion-free, 'real-time' NL crystal autocorrelator for the measurement of temporal width of ultrashort laser pulses. Offering unsurpassed sensitivity, resolution and dynamic range, it is easy to operate. The FR-103XL is perfectly suited for the monitoring of low power lasers as common in optical communications, as well as ultrashort (fs/ps) pulses from any mode-locked laser over a wide spectral range.
DISPERSION-FREE, HIGH RESOLUTION
Dispersion is negligible in the FR-103XL for pulsewidths down to ~5fs. Using high reflective metalliccoated optics [the only transmissive element is an ultrathin (<1um) pellicle beamsplitter], an unprecedented resolution approaching 1fs [limited only by the NL crystal thickness] is attained.
ROTATING PARALLEL (//) MIRROR ASSEMBLY
Rapid scan, periodic optical delay is introduced by means of a parallel (//) mirror assembly.* This unique mechanism results in uniform and error-free delay generation. Large delays are easily generated, with dispersion-free interferometric resolution.
WIDE SCAN RANGE/LINEARITY
The delay generated by the // mirror assembly is an exact sinusoidal function of time. The entire scan range occurring within small angles, linear approximation is excellent. [The error in the measured FWHM autocorrelation is <0.5%, even for a pulwidth as long as 100ps]. Optical delay generation is uniform, devoid of errors (position uncertainty) that can be encountered in other delay methods. Furthermore, the autocorrelation delay axis becomes precisely linear by numerical application of the exact sine transformation.
The theoretical calibration factor (CF) of the FR-103XL is not prone to a change since the uniform rotation rate of the // mirrors is crystal locked. Additionally, a micrometer featured on the fixed arm of the Michelson Interferometer set-up allows the user to experimentally check and verify the CF.
With its high resolution and wide scan range, the FR-103XL is ideally suited for simultaneously monitoring fsec pulses and satellite pulses that may occur separated from the main pulse by many psecs. The wide scan range is also useful to observe crosscorrelations with adjacent pulses in >10GHz optical telecommunications signals. Extinction ratios in the pulse wings are readily measured.
* Z.A.Yasa and N.M.Amer, Optics Commun., V36, 406 (1981)
HIGH SENSITIVITY & DYNAMIC RANGE The unmatched sensitivity of the FR-103XL is demonstrated by its noise equivalent signal level of [PavPpk]min = 10-7W2 *. This is further augmented by a dynamic range of ~104.
Autocorrelation of a ~ 1mW cw input at 1552nm (PavPpk=10-6W2) as observed with the FR-103XL. Signal Avg. = 4
* Over the wavelength range of 550-1700nm, and PMT operation w/ 1ps integration time and a NL crystal thickness of 1mm. Sensitivity is 10-8W2 w/HS version
These remarkable figures render the FR-103XL unique for the measurement of weak satellite pulses which is commonly encountered with modelocked lasers.
Commercial fiber laser (1552nm) pulse [500fs/ 1mW avg. power], measured by the FR-103XL.
A weak satellite pulse, separated from the main pulse by ~ 7 ps appears when the same trace is expanded vertically. No signal averaging
WAVELENGTH RANGES (/BBO/KDP/IR/xxxx)
Three optimal NL crystals provide operation to ~ 5000nm. The standard unit comes with one NL crystal, customer specified:
/BBO 410-600nm
/KDP 510-1100nm
/IR 850-5000nm.
These NL crystals accept vertically polarized input beams, they are BBAR coated and fundamental blocking filters are provided for their operational range. For long term reliability, a desiccators is provided to protect the crystal when not in use. The standard NL crystal thickness is customer specified (0.1mm/0.3mm/1mm), with attention to the trade-off between resolution (thinner NL crystal) and sensitivity (thicker NL crystal).
Typically, a 0.3mm crystal thickness can be considered sufficient for pulsewidths down to ~30fs. With shorter pulses, a thinner crystal is necessary. For sub 10fs pulsewidths, a custom (<25µm) NL crystal thickness will need to be specified.
Two types of ultrathin pellicle beamsplitters are used with the FR-103XL, one (VS) which covers the entire wavelength range, and the second (IR) optimized for >700nm operation. When working with wavelengths < 700nm, the (VS) beamsplitter needs to be used. For wavelengths > 700nm, (IR) beamsplitter is preferable.
/xxxx PD modules for extended IR wavelengths
The photomultiplier (PMT) in the standard FR-103XL covers the 410-1800nm operation. This range can be extended in the IR, by plug-in photodiode (PD) modules (/xxxx) which mount in front of the PMT enclosure. The PD module selections are:
/1100 1100-2200nm
/2200 2200-3400nm
/3000 3000-5000nm
Sensitivity is greatly reduced when operating with these PD modules since they lack the gain as provided by a PMT. Typically, a minimum of ~ 5mW avg. power is needed for a subpicosecond modelocked pulse, over the wavelengths covered by these modules.
OPTIONS:
CROSSCORRELATION (/CC)
The FR-103XL has a built-in auxiliary port for crosscorrelation of two spatially separate synchronized beams. A fiber adapter can be installed also at the CC port [/FA(CC)].
INTERFEROMETRIC OPERATION (/IO)
Standard (Michelson Interferometer) configuration of FR-103XL utilizes non-collinear (background-free) SHGmethod.* Optionally, it can be converted to provide collinear (interferometric) SHG. Using the highest resolution setting (<1fs) of its integration-time switch, fringe resolved autocorrelation is obtained. [This setting is of lowest gain, for which higher input power levels may be necessary].
FIBER ADAPTER OPTION (/FA)
An optional gimbal mount with a collimator is installed over the variable input aperture of the FR- 103XL, for easy connection of fiber-coupled beams. Factory aligned, repeated connections with no need for realignment is facilitated. The /FA is easily removable for a free-space input beam. Its standard adapter is FC [FC/PC or FC/APC]. For operation at 1550nm, a PM-DSF patchcord can be attached to the /FA. The collimator of the /FA is focus adjustable to obtain good collimation if necessary to be used over a significantly wide wavelength range. A ƛ/2 plate holder is also provided within the /FA assembly, for the user to install one for their wavelength of operation, if needed for polarization control.
The /FA option can also be applied to the CC port [/FA(CC)].
* E.P.Ippen, C.V.Shank and A.Dienes, APL, V.21, p.348(1972)
LOW REP RATE OPTION (/LRR)
The rotation rate of the // mirrors is phase-locked to the repetition rate (submultiple) of the input beam. With a linear phase modulation superimposed on the rotation rate, autocorrelation traces are readily accumulated (~ 15secs) and continuously monitored for any rep rate (> 4Hz) laser. This mode is particularly useful for < 100Hz rep. rate lasers.
HIGH SENSITIVITY VERSION (/HS)
The standard uniform rotation of the // mirrors is modified in this version of the FR-103XL, by means of a control mechanism. When this version (/HS) is selected, two modes of operation are available: 1. Uniform rotation (as in the standard FR-103XL, but with a lower refresh rate (typically 2Hz)) 2. Controlled movement such that the // mirrors slow down greatly (4 selectable speeds ) over a period when the pulses on the two arms of the Michelson Interferometer set up are overlapping. The // mirrors speed up outside this range, to return quickly for a repetition of the cycle. Whereas the standard FR-103XL ( w/o LRR) provides 'real-time' autocorrelation for typically > 100kHz lasers, this version (FR-103XL/HS) renders the unit suitable for 'real-time' autocorrelation of lasers with any rep rate > 100Hz. This is particularly useful for kHz amplified lasers. Higher sensitivity is also attained in this version, with longer integration times available.
COMPUTER DATA ACQUISITION OPTION (CDA)
A data acquisition board is installed in the FR-103XL/CDA, providing an interface (USB) with any PC w/ Windows OS. With its associated software, traces are displayed, analyzed [averaged and/or fit with typical pulseshapes] or saved.
As shown below in a typical screen capture of the /CDA display, the signal trace (blue) can be fitted with Sech2 (yellow) or Gaussian (red) pulseshapes with corresponding pulsewidths read out.
A cursor can be set at one half-max (HM) of the trace (green vertical line).
The zoom button (blue) at the bottom of the screen is used to expand (compress) the display range.
商品属性 [最小精度] 1fs [波长范围] 410-5000nm [扫描范围] > 195ps [Input pulse duration range] < 5fs ~ 100ps