WSM-160 Manual Optical Tunable Filter Quick Reference Guide

Transcription

1 Insertion Loss (db) WSM-160 Manual Optical Tunable Filter Quick Reference Guide The WSM-160 Manual Optical tunable filter is a reliable tunable filter that features wavelength and bandwidth tuning. The large wavelength range (1510 nm to 1635 nm), the large FWHM tuning range (from 0/25 nm to 60 nm) and the flat-top shape will adapt to many experimental setup. The WSM-160 Manual Optical tunable filter is available in two different models: WSM-160-BP (Band Pass Filter) and WSM-160-NF (Notch Filter): Wavelength (nm) Figure 1: WSM-160-BP Optical Shape for various FWHM 0.25 nm 0.5 nm 1 nm 5 nm 10 nm 20 nm Figure 2: WSM-160-NF Optical Shape for various FWHM WSM-160 Quick Reference Guide Page 1/11

2 Contents WSM-160 Optical Connections... 3 WSM-160 Settings... 5 WSM-160-BP typical settings... 6 How to measure Filter Shape... 7 WSM-160 Specifications & Principle... 9 Technical Support, Services, and Repairs About Yenista Optics WSM-160 Quick Reference Guide Page 2/11

3 WSM-160 Optical Connections Depending to the optical connectors located on the XTM-50 front panel, make sure to respect the connector types: FC/APC for FC/APC connectors (Angled) or FC/PC for FC/UPC connectors (flat). Make sure to use the filter in the right direction. Maximum input power is 0,5W (+27dBm). Figure 3: FC/APC Optical Connections Figure 4: FC/PC Optical Connections CAUTION Do not under any circumstances look directly into the fiber end of an optical cable attached to the optical output while the device is in use for this may cause permanent eye damage and possible loss of eyesight. Note that the laser radiation is not visible to the human eye, therefore, protective cap must always be replaced on the laser output connector after use to avoid involuntary exposure to laser radiation Cleaning and Caring for Optical Connectors and Fibers A drawer located on the WSM-160 front panel allows you to have access to optical connectors for cleaning operation. Figure 5: Access to Optical Connectors WSM-160 Quick Reference Guide Page 3/11

4 1. Unscrew and pull the drawer from XTM-50 front panel. 2. Handle optical fiber with appropriate care and remove the optical fiber connector from the drawer. Keep optical connectors free of outside contaminant to preserve opticalsignal integrity. 3. Use the following items to clean the optical connectors: clean compressed air fiber-optic cleaning swabs isopropyl alcohol Follow these steps to clean the optical connectors: 1. Hold the can of compressed air upright and spray the can into the air to purge any propellant. 2. Spray the clean compressed air on the connectors to remove any loose particles or moisture. 3. Moisten a clean optical swab with isopropyl alcohol, then lightly swab the surfaces of the connectors. 4. Spray the clean compressed air on the connectors again to remove any loose particles or isopropyl alcohol. CAUTION To optimize the performance of the system and to prevent loss of optical power or damage to the optical connectors, keep the connectors clean at all times. When cleaning the connectors with a swab, use gentle circular motions. Use only high quality cleaning supplies that are non-abrasive and leave no residue. To reduce the need for cleaning, immediately replace protective caps on the optical connectors when not in use. Do not over stress or sharply bend optical fiber beyond tolerances specified by the manufacturer. WSM-160 Quick Reference Guide Page 4/11

5 WSM-160 Settings Wavelength & Bandwidth Tuning are done using two high resolution micrometer actuators. The values given in this section are typical value and might differ from one unit to another, please look at the Acceptance Test Report for nominal values of your WSM-160 filter. To adjust the WSM-160 to the required settings: 1. Adjust the Central Wavelength by turning left or right the Wavelength actuator. Moving the Wavelength actuator from position ~11 to ~1 (ie turning right) will increase the central wavelength from ~1490 to ~1650nm (thus increasing the value is decreasing the central wavelength). Figure 6: Central Wavelength Tuning 2. Adjust the FWHM (Full Width Half Maximum) by turning left or right the FWHM actuator. Moving the FWHM rotary knob from position ~9 to ~1 (turning right) will create an increase of FWHM from ~0.3nm to 60nm. Figure 7: FWHM Tuning In case settings are out of the nominal range, the filter could be completely shut. In this case we recommend starting again from nominal position before adjustment (see ATR values). WSM-160 Quick Reference Guide Page 5/11

6 FWHM Measurement WSM-160-BP typical settings The values given in this section are typical value and might differ from one unit to another; nevertheless it gives a good indication to user. Yenista always recommends to check bandwidth and central wavelength of the filter; either using a white light source and an Optical Spectrum Analyser or using a tunable laser and a powermeter (see How to measure Filter shape ) Tuning the bandwidth for a fixed wavelength position is shifting slowly the central wavelength. When bandwidth is tuned from 0,3nm to 60nm; the central wavelength fluctuation is around 2nm (see figure 7). Tuning the central wavelength for a fixed FWHM position is also detuning a bit this position When central wavelength is tuned from 1515 to 1635 the FWHM is fluctuating as much as 10% Wavelength Position=5 (~1602nm) Wavelength Position=8 (~1555nm) Wavelength Position=10 (~1522nm) FWHM cursor Position Figure 8: FWHM versus cursor position WSM-160 Quick Reference Guide Page 6/11

7 Central Wavelkength Measurement (nm) Wavelength Position Figure 9: Central wavelength versus cursor position How to measure Filter Shape There are various ways to characterise your WSM-160 filter optical properties: 1) with a broadband light source and an optical spectrum analyser 2) with a tunable laser source and a power meter 3) with an optical component tester. We recommend use of CT400 from Yenista. Case 1: Broadband Light source and Optical Spectrum Analyser Follow the below process: Reference measurement: broadband light source connected to Optical Spectrum Analyser. Insert the filter and start a measurement Then subtract both curves. See figure 7 for result: black curve: broadband light source blue curve: measurement through filter green curve: difference (filter shape). The FWHM is the width of the curve at -3dB from top (see red lines in figure 7). WSM-160 Quick Reference Guide Page 7/11

8 Figure 10: FWHM Measurement with OSA CAUTION Make sure the optical resolution of the OSA is much smaller than the bandwidth of the filter you want to characterize (we recommend 50pm resolution). Make sure you have around 45d/50B between the noise floor of your OSA and the broadband light source level; otherwise you will artificially reduce the measurement of the WSM-160 crosstalk. Case 2: Tunable Lasers and power meter Follow the below process: P M Reference measurement: tunable laser connected to power meter. Make measurement over the wavelength range with small steps. Power Meter Insert the filter and start a measurement If the laser is good enough in power accuracy, you can skip the reference measurement. In order to simplify this measurement we recommend the use of CT400 and Tunics products. CAUTION Make sure the wavelength step is small enough compare to the bandwidth of the filter you want to measure (we recommend less than 10pm step). Make sure your laser has a large SSE (Signal to Spontaneous Emission) ratio; otherwise you will artificially reduce the measurement of the WSM-160 crosstalk. We recommend SSE ratio > 65dB. You can improve the measurement accuracy by checking the wavelength of the laser at each step using a wavemeter. WSM-160 Quick Reference Guide Page 8/11

9 WSM-160 Specifications & Principle The WSM-160 is based on the use of a reflection diffraction grating mounted in a Littrow configuration (see schema above, note that collimating and/or focusing optics are not shown on this diagram). Fiber In Diffraction grating Optical Circulator Central Wavelength Tuning Mirror (Slit) Bandwidth Selection WSM-160-BP (Band Pass) Specifications: Filter Shape Specifications Interface General Specifications Optimized Wavelength range * 1 Optimized Central Wavelength Tuning Range * 1 Insertion loss * 2 Insertion Loss Uniformity * 2 Polarization dependent loss * 2 Return Loss Maximum Input Power (CW) FWHM (-3dB bandwidth) -20dB bandwidth Flatness * 2, 3 Out-band suppresion (Crosstalk) * 2, 4 Optical connector Manual actuators for Wavelength and FWHM tuning Dimensions (W x H x D) Weight nm >120 nm < 6 db ( <5 db typ.) 0,25dB typ. <0.5 db (0,25 db typ.) 45 db 0.5 W (+27 dbm) From 0.25 to 60 nm (80nm typ.) 0.7 nm for FWHM=0, nm for FWHM=10nm 60.6 nm for FWHM=60nm 0.3 db typ. > 40 db ( 45 db typ.) FC-UPC or FC-APC on SMF fiber High resolution micrometer 224 x 133 x 185 mm³ 2.2 kg *1: the optical cavity has been optimized to be used in 1515 to 1635nm wavelength range. Out of this nominal range, flatness and insertion loss might be degraded. *2: For FWHM >0,5 nm ; in C band. *3: On a centered bandwidth BW = FWHM-400 pm, and for 0.5 nm<fwhm<10 nm *4: Measured 1 nm away from the 3 db points. WSM-160 Quick Reference Guide Page 9/11

10 WSM-160-NF (Notch Filter) specifications Optical specifications Optimized Wavelength range Optimized Central Wavelength Tuning Range Insertion loss (on pass-band edges) Polarization dependent loss (on passband edges) Return Loss nm >125 nm < 6 db ( <5 db typ.) <0.5 db 45 db >125 nm Optical filter Shape ~100 db/nm roll-off P o w ~40 db - 6 db loss Interface General Specifications Minimum channel Spacing *2 Optical connector Manual actuators for Wavelength and FWHM tuning Dimensions (W x H x D) Weight *1: At 20 C, in C band. *2: 100 GHz and above ideal, 50GHz possible. 50 GHz FC-UPC or FC-APC on SMF fiber High resolution micrometer 29 x 16 x 28 cm³ 2.5 kg WSM-160 Quick Reference Guide Page 10/11

11 Technical Support, Services, and Repairs Our Technical Support Center is at your service to answer technical questions and provide return authorization for service, repairs, or other returns. See contact information on About Yenista Optics Yenista Optics, founded by fiber optic experts in June 2003, designs, manufactures and markets fiber optic assemblies, components, modules & instruments used in a broad range of applications. The company has 1000m² facilities located in Lannion, the heart of the French fiber optic's industry and owns over 20 patents protecting its proprietary technologies on measurement techniques, optical filtering and external cavity lasers. With the acquisition in January 2009 of Laboratory Optical Products from Anritsu, Yenista has now the widest tunable filter portfolio for telecom applications. Tunics and Osics products, the well-known external cavity lasers from Photonetics (later acquired by NetTest, then Anritsu), the leading DWDM company of the 90's, were part of this acquisition. Yenista is now working on developing next-generation fiber optics T&M by combining its expertise and intellectual property on cavity laser, optical filtering, interferometers, measurement techniques and fiber optics coupling. WSM-160 Quick Reference Guide Page 11/11