We fusion-spliced with single-mode fiber FC/UPC connectors at both ends. Wavelength can be tuned by turning the knob (potentiometer).

We have tested it with EDFA broadband source and 0.1nm-RBW OSA. Actual wavelength tuning range: 1514.5nm - 1562.8nm (tested value)

See our test data below:

3dB-BW:  1.14nm at 1562.3, 1.32nm at 1531.28nm
Insertion loss is about 1.84dB at 1552nm.
Extinction ratio looks good.

Set wavelength at LCD display (nm);  Tested wavelength at our lab (nm)
1514.9           1514.5
1520               1521.24
1525               1527.48
1530               1533.4
1535               1538.73
1540               1543.6
1545               1548.03
1550               1552.1
1555               1555.6
1560               1559.13
1563.4            1562.8
So the offset between LCD display data and actual tested wavelength is < 4nm over 1514.5-1562.8nm.

You can recalibrate LCD display wavelength by adjusting the 3 screws behind the LCD driver module, (adjusting by screw drivers, after open the enclosure top cover.). One screw is for LCD display range. 2nd screw is for wavelength coarse tuning of LCD, 3rd screw is for wavelength fine tuning LCD. The wavelength in LCD display will drift very slowly, especially after long time, but actual wavelength is very stable.  

The instrument is quite heavy, about 13kg net weight.

Features
•Manual Wavelength Tuning
•Wavelength Range: 1514.5-1562.8 nm
•External Wavelength Input Connection
•Wavelength Monitor Connection
•Optical Input and Output Connections
•Status LEDs