Both sides previous revisionPrevious revisionNext revision | Previous revisionNext revisionBoth sides next revision |
ice:servo-opls [2016/07/22 17:57] – [Understanding the Transfer Function] Michael Radunsky | ice:servo-opls [2019/11/18 23:34] – [Specifications] Michael Radunsky |
---|
| |
===== Specifications ===== | ===== Specifications ===== |
^ ^ ICE-CP1-200 ^ ICE-CP1-500 ^ Units ^ | ^ ^ ICE-CP1-200 ^ ICE-CP1-500 ^ Units ^ |
^ Current Source ^ ^ ^ ^ | ^ Current Source ^ ^ ^ ^ |
|<html> </html>Current range| 0-200 | 0-500 | mA | | | Current range | 0-200 | 0-500 | mA | |
|<html> </html>Current setpoint resolution | 200 | 500 | μA | | | Current setpoint resolution | 200 | 500 | μA | |
|<html> </html>Current noise density((All measurements guaranteed on design and verified experimentally on D2-105 which uses same circuit.))| <100 | <200 | pA / <HTML> √<span style="text-decoration: overline;">Hz</span> </HTML> | | | Current noise density | <100 | <200 | pA /√Hz | |
|<html> </html>RMS Noise (10Hz - 100kHz)((All measurements guaranteed on design and verified experimentally on D2-105 which uses same circuit.))| <50 | <100 | nA | | | RMS Noise (10Hz - 100kHz) | <50 | <100 | nA | |
|<html> </html>RMS Noise (10Hz - 1MHz)((All measurements guaranteed on design and verified experimentally on D2-105 which uses same circuit.))| <100 | <150 | nA | | | RMS Noise (10Hz - 1MHz) | <100 | <150 | nA | |
|<html> </html>RMS Noise (10Hz - 10MHz)((All measurements guaranteed on design and verified experimentally on D2-105 which uses same circuit.))| <300 | <500 | nA | | | RMS Noise (10Hz - 10MHz) | <300 | <500 | nA | |
|<html> </html>Absolute accuracy| 2 || % | | | Absolute accuracy | 2 || % | |
^ Offset Phase Lock Servo Input Signal^ ^^ ^ | ^ Offset Phase Lock Servo Input Signal ^ |^ ^ |
|<html> </html>Min Offset Frequency | 250 || MHz | | | Min Offset Frequency | 250 || MHz | |
|<html> </html>Max Offset Frequency | Min: 9, Typical: 10(( Maximum Offset Frequency depends on power of input beat-note signal.)) || GHz | | | Max Offset Frequency | Min: 9.5, Typical: 10(( Maximum Offset Frequency depends on power of input beat-note signal.)) || GHz | |
|<html> </html> Max Electronic Beat-Note Input \\ <html> </html><html> </html>(ICE-CP1-SMA)| 10 || dBm | | | Max Electronic Beat-Note Input \\ (ICE-CP1-SMA) | 10 || dBm | |
|<html> </html> Min Electronic Beat-Note Input \\ <html> </html><html> </html>(ICE-CP1-SMA)| -10 || dBm | | | Min Electronic Beat-Note Input \\ (ICE-CP1-SMA) | -10 || dBm | |
|<html> </html> Min Electronic Beat-Note S/N \\ <html> </html><html> </html>(ICE-CP1-SMA)| >50 || dB | | | Min Electronic Beat-Note S/N \\ (ICE-CP1-SMA) | >50 || dB | |
|<html> </html> Max Optical Beat-Note Input \\ <html> </html><html> </html>(ICE-CP1-FC)| 1 || mW | | | Max Optical Beat-Note Input \\ (ICE-CP1-FC) | 1 || mW | |
|<html> </html> Min Optical Beat-Note Input \\ <html> </html><html> </html>(ICE-CP1-FC)((Approximate value as exact value depends on wavelength of the light and spatial overlap between the lasers.))| 50 || μW | | | 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 | |
|<html> </html> Front-panel Input Connection\\ <html> </html><html> </html>(ICE-CP1-FC)((ICE-CP1-FC is shipped with an FC to SC multimode patch cord))| SC || | | | Front-panel Input Connection\\ (ICE-CP1-FC)((ICE-CP1-FC is shipped with an FC to SC multimode patch cord)) | SC || | |
|<html> </html> Front-panel Input Connection\\ <html> </html><html> </html>(ICE-CP1-SMA)| SMA || | | | Front-panel Input Connection\\ (ICE-CP1-SMA) | SMA || | |
^ Offset Phase Lock Servo Performance^ ^^ ^ | ^ Offset Phase Lock Servo Performance ^ |^ ^ |
|<html> </html>Bandwidth((May be limited by the bandwidth of the laser being servoed))| 1.5 || MHz | | | Bandwidth((May be limited by the bandwidth of the laser being servoed)) | 1.5 || MHz | |
|<html> </html> Interval reference frequency drift | +/-20 || ppm | | | Interval reference frequency drift | +/-20 || ppm | |
|<html> </html> PFD Noise(( See [[#calculating_phase_noise|Calculating Phase Noise section]] for a full description))| -213 || dBc/Hz | | | PFD Noise(( See [[#calculating_phase_noise|Calculating Phase Noise section]] for a full description)) | -213 || dBc/Hz | |
^ Loop Filter Parameters ^ ^^ ^ | ^ Loop Filter Parameters ^ |^ ^ |
|<html> </html>Proportional Gain | -72 -- 0 || dB | | | Proportional Gain | -72 -- 0 || dB | |
|<html> </html>Proportional Gain Resolution | 2 || dB | | | Proportional Gain Resolution | 2 || dB | |
|<html> </html>Integrator| 3, 10, 30, 100, 300 || kHz | | | Integrator | 3, 10, 30, 100, 300 || kHz | |
|<html> </html>Differential | Off, 10, 30, 100, 300 || kHz | | | Differential | Off, 10, 30, 100, 300 || kHz | |
|<html> </html>Differential Gain | 18 || dB | | | Differential Gain | 18 || dB | |
| |
^Electrical Specifications^^^^^ | ^Electrical Specifications^^^^^ |
=====Understanding the Transfer Function===== | =====Understanding the Transfer Function===== |
| |
<imgcaption xfer_func center|Schematic of the OPLS right-side panel, showing the configurable transfer function and its user-controls.>{{ :ice:opls-loopfilter-xfer-function.jpg?nolink&700 |}}</imgcaption> | <imgcaption xferfunc|Schematic of the OPLS right-side panel, showing the configurable transfer function and its user-controls.>{{ :ice:opls-loopfilter-xfer-function.jpg?nolink&700 |}}</imgcaption> |
| |
| |
The charge pump in the OPLS outputs a signal proportional to the phase-error and the transfer function is as shown in <imgref xfer_func >. 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 <imgref opls_side_panel>, but includes a extra integration corresponding to converting the phase-error input to a frequency error. Thus, ω<sub>I </sub>sets the frequency transition from single-integration to double-integration and ω<sub>I </sub> from single-integration to proportional feedback. It is important to understand this 'hidden' integrator when configuring the loop filter parameters. | The charge pump in the OPLS outputs a signal proportional to the phase-error and the transfer function is as shown in <imgref xferfunc>. 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 <imgref xferfunc>, but includes a extra integration corresponding to converting the phase-error input to a frequency error. Thus, ω<sub>I </sub>sets the frequency transition from single-integration to double-integration and ω<sub>I </sub> from single-integration to proportional feedback. It is important to understand this 'hidden' integrator when configuring the loop filter parameters. |
| |
=====Calculating Phase Noise ===== | =====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: | 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: |
| |
<WRAP center round box 450px><html><center></html> **D2-135 Phase-Noise Floor = -213 + 20Log(N) + 10Log(F<sub>REF</sub>)**<html></center></html></WRAP> | <WRAP center round box 450px> **D2-135 Phase-Noise Floor = -213 + 20Log(N) + 10Log(ƒ<sub>REF</sub>)**</WRAP> |
| |
where N is the value of the divider and F<sub>REF</sub> is the reference frequency as measured in Hz. For more details, please see [[http://www.vescent.com/2012/calculating-phase-noise-from-the-d2-135/|http://www.vescent.com/2012/calculating-phase-noise-from-the-d2-135/]] . | where N is the value of the divider and ƒ<sub>REF</sub> 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]]. |
| |
| |