====== Current Controller and Offset Phase Lock Servo Board ======
Model No. ICE-CP1
Document Revision: 1.0
Document Last Updated on ~~LASTMOD~~
Please read [[:limited_warranty|Limited Warranty]] and [[:warnings_cautions|General Warnings and Cautions]] prior to operating the ICE-CP1.
The guide to programming the ICE-CP1 through serial commands can be [[ice:commands:opls|found here]]. The ICE-CP1 web page can be [[https://vescent.com/us/d2-135-offset-phase-lock-servo.html|found here]].
===== Description =====
The Current Controller & Offset Phase Lock Servo Board has either a 200 mA (ICE-CP1-200) or 500 mA (ICE-CP1-500) precision current source based on the Libbrecht-Hall(( Libbrecht and Hall, A Low-Noise, High-Speed Current Controller, Rev. Sci. Inst. 64, pp. 2133-2135 (1993).)) circuit and an integrated offset phase-lock laser servo. The ICE-CP1 contains a tunable PID loop filter for a robust phase-lock.
===== Absolute Maximum Ratings =====
Note: All modules designed to be operated in laboratory environment
^ Parameter ^ Rating ^
|Environmental Temperature | >15°C and <30°C|
|Environmental Humidity | <60% |
|Environmental Dew Points | <15°C |
===== Specifications =====
^ ^ ICE-CP1-200 ^ ICE-CP1-500 ^ Units ^
^ Current Source ^ ^ ^ ^
| Current range | 0-200 | 0-500 | mA |
| Current setpoint resolution | 200 | 500 | μA |
| Current noise density | <100 | <200 | pA /√Hz |
| RMS Noise (10Hz - 100kHz) | <50 | <100 | nA |
| RMS Noise (10Hz - 1MHz) | <100 | <150 | nA |
| RMS Noise (10Hz - 10MHz) | <300 | <500 | nA |
| Absolute accuracy | 2 || % |
^ Offset Phase Lock Servo Input Signal ^ |^ ^
| Min Offset Frequency | 250 || MHz |
| Max Offset Frequency | Min: 9.5, Typical: 10(( Maximum Offset Frequency depends on power of input beat-note signal.)) || GHz |
| Max Electronic Beat-Note Input \\ (ICE-CP1-SMA) | 10 || dBm |
| Min Electronic Beat-Note Input \\ (ICE-CP1-SMA) | -10 || dBm |
| Min Electronic Beat-Note S/N \\ (ICE-CP1-SMA) | >50 || dB |
| Max Optical Beat-Note Input \\ (ICE-CP1-FC) | 1 || mW |
| Min Optical Beat-Note Input \\ (ICE-CP1-FC)((Approximate value as exact value depends on wavelength of the light and spatial overlap between the lasers.)) | 50 || μW |
| Front-panel Input Connection\\ (ICE-CP1-FC)((ICE-CP1-FC is shipped with an FC to SC multimode patch cord)) | SC || |
| Front-panel Input Connection\\ (ICE-CP1-SMA) | SMA || |
^ Offset Phase Lock Servo Performance ^ |^ ^
| Bandwidth((May be limited by the bandwidth of the laser being servoed)) | 1.5 || MHz |
| Interval reference frequency drift | +/-20 || ppm |
| PFD Noise(( See [[#calculating_phase_noise|Calculating Phase Noise section]] for a full description)) | -213 || dBc/Hz |
^ Loop Filter Parameters ^ |^ ^
| Proportional Gain | -72 -- 0 || dB |
| Proportional Gain Resolution | 2 || dB |
| Integrator | 3, 10, 30, 100, 300 || kHz |
| Differential | Off, 10, 30, 100, 300 || kHz |
| Differential Gain | 18 || dB |
^Electrical Specifications^^^^^
^ ^ Min ^ Typical ^ Max ^ Units ^
|5V_A Current Draw | | N/A | | A |
|5V_D Current Draw | | 600 | | mA |
|+15V Current Draw (ICE-CP1-200)((Current draw depends on output current to laser diode.)) | 80 | | 280 | mA |
|+15V Current Draw (ICE-CP1-500)((Current draw depends on output current to laser diode.)) | 80 | | 580 | mA |
|-15V Current Draw | | 40 | | mA |
===== Setting the Offset Frequency =====
Two numbers control the offset frequency of the ICE-CP1: The divider setting N and the reference frequency. The divider setting N can be set to N=8,16,32 or 64. The reference frequency can be generated internally with a range from 50 - 240 MHz. Or an external frequency reference can be provided (external frequency must be from 32 MHz - 240 MHz). The offset frequency of the laser is given by the following formula:
**Offset = N * Reference Frequency**
The table below shows the offset range for different values of N and using the internal or external frequency reference.
^ ^^ Divide-by-N settings ^^^^
^ ^^ N=8 ^ N=16 ^ N=32 ^ N=64 ^
^ Reference \\ Frequency \\ Setting ^External |250 - 1,920|480 - 3,840|960 - 7,680|1,920 - 10,000|
^:::^Internal |320 - 1,920|640 - 3,840|1,280 - 7,680|2,560 - 10,000|
=====Understanding Gain in the OPLS=====
The charge pump (CP) output is proportional to phase-error when phase-locked, but the slope is proportional to the value of N. This means that when N is increased, the same voltage on the CP monitor reflects twice as much phase-error. The result is that the input to the loop filter has half as much gain with N=16 than with N=8. To compensate, the OPLS internally increases the gain of the Loop Filter by a factor of N so the user does not see a change in the closed-loop gain when changing the value of N.
=====Understanding the Transfer Function=====
{{ :ice:opls-loopfilter-xfer-function.jpg?nolink&700 |}}
The charge pump in the OPLS outputs a signal proportional to the phase-error and the transfer function is as shown in . However, the OPLS will typically be used to control a //frequency//-tunable device (such as a laser). In this configuration, the effective loop filter is not the one shown in , but includes a extra integration corresponding to converting the phase-error input to a frequency error. Thus, ωI sets the frequency transition from single-integration to double-integration and ωI from single-integration to proportional feedback. It is important to understand this 'hidden' integrator when configuring the loop filter parameters.
=====Calculating Phase Noise =====
The phase-noise specified in Section 1.3 is referenced to the phase frequency detector (PFD) at 1 Hz. To convert that to the noise measured on the actual beat-note, it must be rescaled with the following formula:
**D2-135 Phase-Noise Floor = -213 + 20Log(N) + 10Log(ƒREF)**
where N is the value of the divider and ƒREF is the reference frequency as measured in Hz. For more details, please see this [[http://www.vescent.com/2012/calculating-phase-noise-from-the-d2-135/|application note]].
===== I/O (ICE-BOX) =====
Only when purchased with the [[ice:enclosure|ICE-Box]].
**Beat Note Monitor **
The Front Panel for the ICE-CP1 has four SMA or FC connectors. The top-most connector is an SMA which is the digitized (i.e. square-wave) version of the input beat-note after a divide-by-2. For example, if the input beat note is 6 GHz, the monitor will have a 3 GHz output. The signal is ~0 dBm in power regardless of the strength of the input beat-note signal.
**External Reference Frequency Input **
The Front Panel for the ICE-CP1 has four SMA or FC connectors. The second top-most connector is an SMA input for the external frequency reference. The input is AC coupled and 50 Ω terminated. Max power is 10 dBm.
**Beat Note Input **
The Front Panel for the ICE-CP1 has four SMA or FC connectors. The SMA connector 2nd from the bottom is the beat note signal input. When FC, this input should be a <1 mW signal containing overlapped light from both lasers. When an SMA, this input should be an electrical signal, typically the output of the D2-160 or D2-260 Beat Note Detector.
**Laser Current **
The Front Panel for the ICE-CP1 has four SMA or FC connectors. The bottom SMA goes to the laser and drives positive current to the laser. The center conductor of the SMA goes to the laser anode.
===== I/O (OEM Only) =====
Only for OEM versions of the ICE-CP1 purchased without the [[ice:enclosure|ICE-Box]].
{{ :ice:vpn00320_dimensions.jpg |}}
**Beat Note Input **
The ICE-CP1 has one SMA connector which is the beat note signal input. This signal should be an electrical beat -note between -10dBm and 10dBm of electrical power. Input is 50 Ω terminiated.
**External Reference Frequency Input **
The ICE-CP1 has three UMCC ([[http://www.digikey.com/product-detail/en/0734120110/WM5587CT-ND/1894612|Molex PN: 0734120110]]) connectors. The one labelled "Ext Ref" is an UMCC input for the external frequency reference. The input is AC coupled and 50 Ω terminated. Max power is 10 dBm.
**Beat Note Monitor **
The ICE-CP1 has three UMCC connectors. The one labelled "BN Mon" is an UMCC containing is the digitized (i.e. square-wave) version of the input beat-note after a divide-by-2. For example, if the input beat note is 6 GHz, the monitor will have a 3 GHz output. The signal is ~0 dBm in power regardless of the strength of the input beat-note signal.
**Laser Current **
The ICE-CP1 has three UMCC connectors. The one labelled “Laser” goes the laser and drives positive current to the laser. The center conductor of the UMCC goes to the laser anode.
===== Quick Start Commands Guide (Laser Current) =====
Please see the [[ice:servo-peaklock&#quick_start_commands_guide_laser_current|Quick Start Commands Guide (Laser Current)]] in the ICE-CS1 manual.
===== Quick Start Commands Guide (Offset Phase Lock Servo) =====
Please see [[ice:commands:overview|Overview of Commands and Basic Usage]], [[ice:commands:common|Common Commands to all Slave Boards]] and [[ice:commands:opls|Current Controller & Offset Phase Lock Servo Commands]] for a complete command list. Set the ICE-MC1 to communicate with the slot that this ICE-CS1 is in (see [[ice:master#quick_start_commands_guide|Master and Control Board Overview]] for details).
This content is not yet available, sorry.