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--- waveguide:manual [2016/01/19 01:37] – [Connections and Controls] Michael Radunsky
+++ waveguide:manual [2021/08/26 15:26] (current) – external edit 127.0.0.1
@@ Line 47: / Line 47: @@
 This warranty is in lieu of all other warranties including any implied warranty concerning the suitability or fitness of the product for a particular use. Vescent Photonics shall only be liable for the cost of repairs or replacement of the defective product within the warranty period. Vescent Photonics shall not be liable for any damages to persons or property resulting from the use of the product or caused by the defect or failure of this product. Vescent Photonics' liability is expressly limited to the warranty set out above. By accepting delivery of this product, the purchaser expressly agrees to the terms of this limited warranty.
-<WRAP center round box 400px>[{{ :waveguide:manuals:4_pedestal.png?350|Figure 4. SEEOR 2D beam steerer.}}]
+<WRAP center round box 400px><imgcaption 2DSeeor|SEEOR 2D beam steerer.>{{ :waveguide:manuals:4_pedestal.png?350  }}</imgcaption>
 </WRAP>
 =====Operating Parameters=====
 Absolute Maximum Ratings
@@ Line 60: / Line 61: @@
 =====Terminology=====
-The LS-105 is a miniature electronics module designed to control an LC-waveguide electro-optic laser scanner.  The electro-optic laser scanner is referred to as a Steerable-Electro-Evanescent-Optical-Refractor or SEEOR for short. The LS-105 provides a high voltage square wave of controllable amplitude to the three SEEOR electrodes (Steer Left, Steer Right, and Steer Down) for controllably steering the laser beam. The “horizontal” and “vertical” directions are as defined as shown in Figure 1.  The LS-105 also provides temperature control to keep the SEEOR at a uniform temperature.
+The LS-105 is a miniature electronics module designed to control an LC-waveguide electro-optic laser scanner.  The electro-optic laser scanner is referred to as a Steerable-Electro-Evanescent-Optical-Refractor or SEEOR for short. The LS-105 provides a high voltage square wave of controllable amplitude to the three SEEOR electrodes (Steer Left, Steer Right, and Steer Down) for controllably steering the laser beam. The “horizontal” and “vertical” directions are as defined as shown in <imgref insidecartoon>.  The LS-105 also provides temperature control to keep the SEEOR at a uniform temperature.
-<WRAP right round box 550px>[{{:waveguide:manuals:1_inside_cartoon.png?500|Figure 1. A cartoon depiction of a SEEOR.  The “horizontal” direction is defined as in the plane of the LC-waveguide.  The “vertical” direction is defined as out of the plane of the waveguide. There are two horizontal steering electrodes and one vertical steering electrode.}}]</WRAP>
+<WRAP right round box 550px><imgcaption insidecartoon| A cartoon depiction of a SEEOR.  The “horizontal” direction is defined as in the plane of the LC-waveguide.  The “vertical” direction is defined as out of the plane of the waveguide. There are two horizontal steering electrodes and one vertical steering electrode.>  {{:waveguide:manuals:1_inside_cartoon.png?500}}</imgcaption></WRAP>
 With the LS-105 the amplitude of the square wave for each electrode is controllably adjustable from a minimum value, herein referred to as the Freedericksz voltage, to a maximum value of approximately 100Vrms. This is controlled via two analog input voltages via front panel BNC connectors, one for horizontal and one for vertical.  The LS-105 provides an internal 5 kHz square wave, which may be monitored via a back panel SMA connection.  An external square wave signal may also be applied via a back panel SMA connection.  If an external square wave signal is applied, the LS-105 will detect this signal and override the internal square wave.
@@ Line 88: / Line 89: @@
 =====Operation=====
-The LS-105 is shipped with a 5 V power supply and a cable for connection to the SEEOR, as shown in Figure 2.  If you purchased a chip level SEEOR the cable will have a connector on one end and clip-connectors on the other end.  If you purchased a fiber-coupled SEEOR the cable will be connectorized at both ends.
+The LS-105 is shipped with a 5 V power supply and a cable for connection to the SEEOR, as shown in <imgref shipkit>.  If you purchased a chip level SEEOR the cable will have a connector on one end and clip-connectors on the other end.  If you purchased a fiber-coupled SEEOR the cable will be connectorized at both ends.
-<WRAP right round box 300px>[{{:waveguide:manuals:2_ship_kit.png?250|Figure 2: The LS-105, power supply, and connection cable.  The figure above shows a cable for connecting to a chip-level SEEOR.  For a fiber packaged device, the cable will have connectors on both ends.}}]</WRAP>
+<WRAP left round box 300px><imgcaption shipkit| The LS-105, power supply, and connection cable.  The figure above shows a cable for connecting to a chip-level SEEOR.  For a fiber packaged device, the cable will have connectors on both ends.>{{:waveguide:manuals:2_ship_kit.png?250x}}</imgcaption></WRAP>
-<WRAP right round box 550px>[{{ :waveguide:manuals:3_pin_out.png?500|Figure 3: Pin-Out for the LC-105 connection to the optical head.}}]</WRAP>
+<WRAP right round box 550px><imgcaption pinout| Pin-Out for the LC-105 connection to the optical head.>{{ :waveguide:manuals:3_pin_out.png?500}}</imgcaption></WRAP>
-The cable plugs into the LS-105 with a push connector.  To remove the cable simply pull from the metal housing on the end of the connector.  The connector pin-out is shown in Figure 3.  The clip leads are labeled appropriately.
+The cable plugs into the LS-105 with a push connector (female bulkhead connector: [[http://www.digikey.com/product-detail/en/hirose-electric-co-ltd/HR10A-10R-10SB/HR359-ND/279920|Hirose HR10A-10R-10SB]]; male cable end: [[http://www.digikey.com/product-detail/en/hirose-electric-co-ltd/HR10A-10P-10P/HR116-ND/40909|Hirose HR10A-10P-10P]]).  To remove the cable simply pull from the metal housing on the end of the connector.  The connector pin-out is shown in <imgref pinout>.  The clip leads are labeled appropriately.
 ===Prototype EO Scanner Optical Head===
-The 1.5 µm LS-15-43005-FC/PC is a prototype 2D electro-optical beam steerer.  It requires the prototype EO scanner driver for proper operation, which was also included in the shipment.
+The 1.5 µm LS-15-3005-FC/PC is a prototype 2D electro-optical beam steerer.  It requires the prototype EO scanner driver for proper operation, which was also included in the shipment.  The scanner is packaged with a PM fiber pigtail (see <imgref 2DSeeor>) with an FC/PC connector. This is an engineering package and not intended for field use.  Its input must be linearly polarized light with the polarization axis parallel to the FC key.
-The scanner is packaged with a PM fiber pigtail (see Figure 4) with an FC/PC connector. This is an engineering package and not intended for field use.  Its input must be linearly polarized light with the polarization axis parallel to the FC key.
 =====Connections and Controls=====
 <color red>WARNING</color>
 The user should NEVER disconnect the  control cable from the scanner or driver while power is applied ("hot swapping"). Since the devices does not have internal pull-downs to ground, any voltage left on the device could permanently damage it, causing reduced throughput, highly degraded beam quality, and large in-plane scattering.
-With the power switch in the OFF or down position (see Figure 5) connect the power supply to the wall plug and to the LS-105 back panel (see Figure 6).  Use the provided cable to connect the LS-105 driver to the SEEOR unit.  The unit is now ready to be powered on.  The driver provides up to 110 V to the beam steerer.  Please operate safely.
+With the power switch in the OFF or down position (see <imgref front>) connect the power supply to the wall plug and to the LS-105 back panel (see <imgref rear>).  Use the provided cable to connect the LS-105 driver to the SEEOR unit.  The unit is now ready to be powered on.  The driver provides up to 110 V to the beam steerer.  Please operate safely.
 Please allow 1 to 2 minutes for the SEEOR to temperature stabilize.
 Now the beam steerer is ready for steering.  Connect your voltage source to the front panel BNC marked Horizontal and Vertical. A positive voltage at the “Horizontal” input will steer one way and a negative voltage will steer the other way.  DO NOT EXCEED ± 10 V.  Input impedance is 1 MΩ.  For the “Vertical Scanning” input, use a positive voltage only.
-<WRAP left round box 100%>[{{ :waveguide:manuals:4_front_panel.png?400|Figure 5. LS-105 front panel}}]
+<WRAP left round box 100%><imgcaption front| LS-105 front panel>{{ :waveguide:manuals:4_front_panel.png?400}}</imgcaption>
 Front Panel Controls (from left to right)
 |Power Switch|This turns the unit on.  Up is on and down is off.|
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 </WRAP>
-<WRAP left round box 100%>[{{:waveguide:manuals:5_rear_panel.png?400|Figure 6. LS-105 rear panel}}]
+<WRAP left round box 100%><imgcaption rear| LS-105 rear panel>{{:waveguide:manuals:5_rear_panel.png?400}}</imgcaption>
 Back panel Controls (from left to right)
 |Polarity Clock Out|This outputs the clock frequency.  The driver outputs an AM square wave to drive the beam steerer.  As the square wave transitions polarity, there may be a minute change in the scan angle.  If the user’s application is sensitive to this change the clock out provides a means to synchronize to this.|
@@ Line 122: / Line 122: @@
 |Power In|Power the driver with the AC adapter that is included with the package.|
 </WRAP>
+A typical angle tuning curve for a SEEOR is shown in the figure.  And typical output beam quality is shown next to it.
+<WRAP left round box 400><imgcaption tuning| Angle vs. voltage for horizontal (blue) and vertical (red) tuning.>{{  :waveguide:manuals:seeor_tuning_curve.png?350  }}</imgcaption></WRAP><WRAP left round box 350><imgcaption beamqual| Typical output beam quality of SEEOR.>{{  :waveguide:manuals:seeor_output_beam_quality.png?300  }}</imgcaption></WRAP>
 =====Advanced Settings=====
 ====Background on Driving LC Devices====
 When designing LC-drive electronics there are two important inherent properties. First, for a typical nematic LC, the EO response is via an induced dipole interaction. This means that the LC-molecules respond to the magnitude of the applied electric field but not the sign. Second, it is necessary that the time-averaged voltage across an LC optic is “DC-balanced” to have zero or minimal offset. This can be critical for both the operation and lifetime of the device. Prolonged time-averaged DC offsets will drive ion-migration inside the LC material, which can be deleterious for both the short-term performance and ultimately the lifetime of the device. On short timescales ion-migration will create a shielding field to cancel the applied voltage, which will cause the LC molecules to “relax” or “sag.” Precision applications can be sensitive to this sag even during short timescales. On long timescales ion-migration can result in the build up of permanent charge layers within the LC, thereby causing a “burn-in” which may forever degrade the operation of the device. The LC-drive electronics must account for both the “induced dipole” response and the “DC-balance” constraint.\\
 An optimum voltage waveform that satisfies both of these LC requirements is a high quality square wave with no DC offset. Since the LC material only responds to the magnitude of the electric field and not the sign, by rapidly switching the voltage polarity the LC material will see the same E-field magnitude and simultaneously the need for DC balance will be satisfied. While in principle the square wave provides the ideal waveform, for anyone who has ever worked with square waves they will know that a high quality square wave is easier said than done. This is especially true when driving capacitive loads such as LC cells. Furthermore, high-quality square waves are extremely difficult if one requires higher voltage, such as required for high-speed LC-device driving such as LC waveguides. \\
-<WRAP center round box 90%>[{{:waveguide:manuals:6a_waveform.png?350px|7a.}}][{{:waveguide:manuals:6b_waveform.png?350px|7b.}}]Figure 7: Left) Drawing of a typical square wave as provided by common amplifiers. Slew rate, DC offset, overshoot, and ripple all result in a non-constant E-field magnitude. Since it is the E-field magnitude that the LC responds to this can be problematic. Right) Drawing of an ideal square wave and its related constant E-field magnitude. The goal of a proper LC-driver is to get as close to this ideal as possible.
+<WRAP center round box 90%><imgcaption waveform| Left) Drawing of a typical square wave as provided by common amplifiers. Slew rate, DC offset, overshoot, and ripple all result in a non-constant E-field magnitude. Since it is the E-field magnitude that the LC responds to this can be problematic. Right) Drawing of an ideal square wave and its related constant E-field magnitude. The goal of a proper LC-driver is to get as close to this ideal as possible.>{{:waveguide:manuals:6a_waveform.png?300px}}{{:waveguide:manuals:6b_waveform.png?300px}}</imgcaption>
 </WRAP>
-Common problems with square waves are illustrated on the left of Figure 7. Typically, the square wave is generated via amplification of a low voltage clock from a function generator or other clock source. Frequently, amplifiers are susceptible to several common problems: offsets (often frequency dependent which hampers trimming), limited slew rates, limited settling times (can cause overshoot and ringing), and limited current output. As shown on the left of Figure 7, all of these problems can have dramatic impacts on the magnitude of the electric field, i.e. what the LC responds to. For high-speed LC devices, the slew rate required to minimize any transient LC response during the polarity switch can be >100 Volts/ms, which is beyond the capabilities of most amplifiers when driving a capacitive load. The right hand side of Figure 7 shows an ideal square wave and its associated constant E-field magnitude. Figure 8 plots an example waveform from an LS-105.  The LC-105 is designed to have an optimized waveform for driving the SEEOR capacitive load.\\
+Common problems with square waves are illustrated on the left of <imgref waveform>. Typically, the square wave is generated via amplification of a low voltage clock from a function generator or other clock source. Frequently, amplifiers are susceptible to several common problems: offsets (often frequency dependent which hampers trimming), limited slew rates, limited settling times (can cause overshoot and ringing), and limited current output. As shown on the left of <imgref waveform>, all of these problems can have dramatic impacts on the magnitude of the electric field, i.e. what the LC responds to. For high-speed LC devices, the slew rate required to minimize any transient LC response during the polarity switch can be >100 Volts/ms, which is beyond the capabilities of most amplifiers when driving a capacitive load. The right hand side of <imgref waveform> shows an ideal square wave and its associated constant E-field magnitude. <imgref scope> plots an example waveform from an LS-105.  The LC-105 is designed to have an optimized waveform for driving the SEEOR capacitive load.\\
-<WRAP center round box 450px>[{{ :waveguide:manuals:7_scope_trace.png?400 |Figure 8: Plot of a typical high voltage output from the LS-105.}}]
+<WRAP center round box 450px><imgcaption scope| Plot of a typical high voltage output from the LS-105.> {{ :waveguide:manuals:7_scope_trace.png?400 }}</imgcaption>
 </WRAP>